Post by: jravacio on Jun 28, 2015 at 10:11 PM
What's up with Ravacio Amplification?
My son asked me about that last year (he was 9 years old then) and I joke at him saying "that's the seal of awesomeness" hahha Seriously, it would be a good idea for children to see Daddy's handmade equipments at home. Who knows it will inspire them to become Artisans when they grow up.
I'm not selling my amps or my services. I may have advertised the parts I have used one way or the other. Just ask pricing directly from my sources. ;)
How did I start my DIY endeavors?
As early as 2nd year high school, I built my first amplifier using AN214. Although I didn't understand circuits fully at that age I was a persistent little dude who wants to build things from ground up. Somehow, this interest has faded and I then took Computer Science when I went to college. Thus, the last related subjects I took about circuits were General Physics and Logic Circuits and switching.
Fast forward 21 years later from my last build, I started building guitar effects pedal and finally bumped into a starved plate designed overdrive pedal "Matsumin's Valvecaster". From there, I hangout at Philmusic's DIY thread and Elab and started to ask questions. If you look at my posts, I never knew or remember what a voltage divider was way back 2013.
Thanks to the legendary Tony who has been very active and helpful to the DIY community.
What's expected on this thread?
Well previous, current and upcoming build pics and a small write up.Circuit Analysis, and Design Reviews will still be at Elab. The write up may contain what was good and what needs improvement for each build. That way, new DIYers may learn from it.
Post by: jravacio on Jun 28, 2015 at 10:12 PM
.... drum roll...... tada!!! This is my latest build. It uses a 1930's transmitting triode 808. A switch is also provided to toggle from 808 to 811A.
(https://c1.staticflickr.com/1/358/18609789574_379b6b2b86_c.jpg)
Brief Overview
I wanted to gain knowledge and experience on Class A2 amplifiers as well as zero-bias type of tube. In the absence of an inter-stage transformer, I initially thought of using 6EM7 to achieve a positive grid for 808 or 811A tubes.
After going through discussions with Tony at elab(see link below) and readings from the internet, I finally came-up with using 717A as an Input tube, a triode connected 6V6 to provide a positive grid voltage and current to 808/811A tubes.
Full Discussion at: http://www.elab.ph/forum/index.php?topic=34991.1740
Output Transformers
Who doesn't know Edrel's Irons(AT&S) and the quality it has? This build uses an SE 15 Watt OPT which has an M6/Z11 core of 1 1/4 X 1 1/2(inches). Primary Impedance of 3,500 Ohms with Ultra-Linear(which I didn't use in this circuit) and a Secondary Tap of 4, 8 and 16.
Power Transformers and Choke
I tried to bring down the cost at a reasonable level because I have 5 other builds to fund but I'm not selling a single one of them. I'll wound my own power transformers and choke for the upcoming projects. ( :P committing something publicly will most of the time gets a job done). These Irons are M50 which runs hot if not properly compensated via specifications.
Power Transformer specifications:
Secondary:
320-CT-320V @ 200mA - I'm using it about 120mA only.
7.5V @ 6A - Just about what I need to supply the Heaters of 808 which is 7.5 @ 4A FW Bridge.
6.3 @ 2A - I'm using it at about 675mA for 6V6 and 717A heaters
Choke is 1H 200mA (Appproximate since this was measured at about 2H without a load)
These Transformers came bare so I had to put some flux band and paint the end bells. I used a 100W Soldering Iron so the solder was cold and messy. (It needs at least a 150Watt Soldering Gun to install a flux band).
(https://c1.staticflickr.com/9/8758/16941896908_23219ffce6_c.jpg)
The Power and Choke is wound by Mang JV. His shop, is located at inner part of Main street of Paco Manila. He's been supplying transformers to guitar amp DIYers at Philmusic.
Layout and enclosure work
(https://c1.staticflickr.com/9/8722/16942138940_6d2e67799b_c.jpg)
(https://c1.staticflickr.com/9/8740/17090101870_6d3164484e_c.jpg)
(https://c1.staticflickr.com/9/8796/17275821542_4fbbe826c8_c.jpg)
Front and Rear View
(https://c4.staticflickr.com/4/3935/18611614103_c1447d9a41_c.jpg)
(https://c1.staticflickr.com/1/502/19226346212_73bdbe3369_c.jpg)
Gut Shots
(https://c1.staticflickr.com/1/516/19044609970_b736ac8e9e_c.jpg)
Below the sockets of of 717A Tube
(https://c1.staticflickr.com/1/266/18609817014_6d1a46bb0c_c.jpg)
Below the sockets of 6V6
(https://c1.staticflickr.com/1/514/18611764293_a411d55599_c.jpg)
717A Input Tube
(https://c1.staticflickr.com/1/452/18609776874_08539e641d_c.jpg)
What's up with those transformer wires? Why not cut them short?
Re-usability. The tubes I'm using are very rare. Ones they go or you run out of tubes, you can easily re-use your transformers into another amp.
In action
(https://c1.staticflickr.com/1/384/18611627173_475a3c6eb0_c.jpg)
Testing and Final Configuration?
I only have 2pcs of 808 tubes(the rest are 811A) that's why I was aiming for longer tube life. At initial startup, 808 tubes have plate voltage of 375, plate current of 60mA, grid voltage at around +20. Both tubes are dissipating at only about 22.5 watts. From Tony's advice, I could still push it to about 100mA or around 40Watt dissipation and still get a reasonable tube life.
On the 2nd day of testing. I tried to increase the Amps overall B+ by adding a parallel resistor to the existing B+ dropping resistor. Now I'm getting a B+ of 400VDC. I've tested back both 808 tubes at 1ohm cathode resistance. One 808 can dissipate at a maximum of 35 Watts (plate voltage at 390 and plate current of around 90mA, while the other tube is only at about 29watts. Not. sure if it's gassy or just have low plate dissipation. I've swap them too and got the same results.
Now, I have them both dissipating at about 29Watts per tube and just have to live with it for the meantime. When they retire, I'll replace them with 811A.
How does it sound?
Wifey said: "I like that I'm hearing percussion in just the right amount. Cymbals are sprinkled across but doesn't dominate. There is so much clarity in the vocals section it feels like the singer is in front of you. Lastly, the bass feels so smooth that I would like to assume the recordings had fret-less bass on them."
I say, this amp is a very sweet sounding amp. The likes of 300B. This is very good when you're listening to bossa nova, smooth jazz and ballad music. Since I listen mostly to Rock music, I tend to like the dynamics that Tetrodes and the Pentodes have. I played Reggae music on this amp and the bass sounded like a fret-less bass with long sustain. It's supposed to be tight and for Rock a bit punchy. But the Mids and Highs are sparkling.
Well, at the end of the day, the Wifey is very happy with the sound. I wouldn't have to argue with that wouldn't I? :P
Thanks also to Paul Chin for this wonderful Anthony Audio Gold Titus BS. It really brings out the beauty of the amp :)
Schematic
(https://c4.staticflickr.com/8/7769/17329693751_40034e51f9_c.jpg)
* All 22uf Capacitors were replaced with 47uF
* B+ dropping resistors have an effective resistance to 250ohm. In my build, I've installed 2 parallel 1K plus a 500ohm resistor. Installed the 500ohm resistor at the final tweaking.
* Bridge Rectifier right after the 7.5 secondary tap. Note that 4A is wrong and you need 6A.
Acknowledgements
This amp could not be made without all the advises from Tony Tecson. Thanks for always being there.
Edrel and his irons. The amps sound would not be as good as now without AT&S OPTs.
Gerry Sta. Maria. Our regular tube pimp in the DIY community.
To my best ever sound critic, my wifey :P
Reference Circuits
http://www.single-ended.com/direct811.htm
http://park21.wakwak.com/~eyp/jk1eyp/amp/811A/811AS.htm
What's next?
A lot of builds :) but we can't get to the bottom of this journey until we know how to wound our own transformers. So I'll stop building for a month or two and would my own transformer.
Post by: tony on Jun 29, 2015 at 06:52 AM
because these are tubes that are historically known to produce good music....;)
and circuits have been known and debugged many times over,
that making these amps are no brainer... ;)
i really have to tip my hat to you for having the guts to come up with this amp.... 8)
as you know, not many are dong zero bias tubes because of difficulties in driving them....
let us also not forget Gerry Sta Maria, and Rey Luis too....
without these diabolical dynamic duo, where will our local diy'ers be?
Gerry has given me a lot of tubes that nobody else will take,
at least now there is you, Tukkar, and me to partake of those goodies
and play around with them......
our journey has just begun....
more amps to come.... >:D
let us continue to pray for the wifet's continued support and fund releases... ;D
regarding chokes, i do measure them without dc bias and then i take
50% as reasonable assumption when biased, with today's available big caps
there should not be any difficulty at all...
Post by: tony on Jun 29, 2015 at 08:52 AM
btw, Gerry Morales has a #12 gage royal cords that you can use as speaker cables, Edrel knows him, ask mo na lang sa kanya...
Post by: camoteque on Jun 29, 2015 at 10:48 AM
(http://i.imgur.com/TRfz2j7.jpg)
Post by: tony on Jun 29, 2015 at 11:01 AM
another cool looking tube i asked Gerry to find for me...the 316a tube
(http://www.radiomuseum.org/images/tubephoto_klein/316ab.jpg)
(http://www.radiomuseum.org/images/tubesockel_klein/316a.png)
Post by: deist on Jun 29, 2015 at 11:41 AM
BTW, if I'm not mistaken ikaw yung nakita kong nag-post before ng Eminence speakers?
Post by: jravacio on Jun 29, 2015 at 01:22 PM
John, what can i say? the average diy'ers will do a 45, 3A3, 300b, why?
because these are tubes that are historically known to produce good music....;)
and circuits have been known and debugged many times over,
that making these amps are no brainer... ;)
i really have to tip my hat to you for having the guts to come up with this amp.... 8)
as you know, not many are dong zero bias tubes because of difficulties in driving them....
let us also not forget Gerry Sta Maria, and Rey Luis too....
without these diabolical dynamic duo, where will our local diy'ers be?
Gerry has given me a lot of tubes that nobody else will take,
at least now there is you, Tukkar, and me to partake of those goodies
and play around with them......
our journey has just begun....
more amps to come.... >:D
let us continue to pray for the wifet's continued support and fund releases... ;D
regarding chokes, i do measure them without dc bias and then i take
50% as reasonable assumption when biased, with today's available big caps
there should not be any difficulty at all...
Thanks a lot Tony! Yes, I'd like to Thank Gerry Sta. Maria too our all time tube source. I have not meet Rey luis yet, hopefully in the near future.
We're lucky our wifeys are supportive with these endeavors :)
Okay I'll post some pics with the speakers. I don't have speaker stand yet so speakers are sitting on the floor. I'll get some stand hopefully within the week.
Thanks for the tip, i'll PM Gerry Morales for the wires.
Love the 717A tubes. It is what is also used in Yamamoto amps. Cute tubes.
(http://i.imgur.com/TRfz2j7.jpg)
Nice :)
Gerry has those tubes.....we can use them to drive 4P1L's....... >:D
another cool looking tube i asked Gerry to find for me...the 316a tube
(http://www.radiomuseum.org/images/tubephoto_klein/316ab.jpg)
(http://www.radiomuseum.org/images/tubesockel_klein/316a.png)
Yes, Gerry offered me these tubes too but I have not bought one yet because sockets are hard to find
Nice builds John! congrats!
BTW, if I'm not mistaken ikaw yung nakita kong nag-post before ng Eminence speakers?
Thanks, yes my guitar amp head uses an Eminence Speaker.
Post by: rochie on Jun 29, 2015 at 02:34 PM
@John, can you post a picture of your amps connected to the Titus speakers?
btw, Gerry Morales has a #12 gage royal cords that you can use as speaker cables, Edrel knows him, ask mo na lang sa kanya...
I still have 5 meters of gerry's #12 awg speaker wire,I think madami pang stock kay Serafin aka Jojo, last time I heard isang roll yun.
Post by: deist on Jun 29, 2015 at 03:59 PM
Thanks, yes my guitar amp head uses an Eminence Speaker.
Post by: reznor on Jun 29, 2015 at 04:33 PM
Post by: tony on Jun 29, 2015 at 04:40 PM
I still have 5 meters of gerry's #12 awg speaker wire,I think madami pang stock kay Serafin aka Jojo, last time I heard isang roll yun.
thanks for the heads up....;)
Post by: remington on Jun 29, 2015 at 06:43 PM
Post by: jravacio on Jun 29, 2015 at 10:48 PM
I still have 5 meters of gerry's #12 awg speaker wire,I think madami pang stock kay Serafin aka Jojo, last time I heard isang roll yun.
Thanks Rochie.
Posts some sample video/audio link :) Ganda siguro niyan tumunog John!
hahah Mag-Tube Amp ka na rin :P you're very near at Tony's. Visit him sometime and listen to his works. I'm sure you want to take home those amps the moment you listen. >:D
very nice build inside and out sir john! congrats.
Thanks Jhun ;) Appreciate it.
Post by: Superman on Jun 29, 2015 at 11:26 PM
Post by: dana on Jun 30, 2015 at 09:42 AM
Dolphy would surely like it :D
congrats, happy listening!
Post by: tony on Jun 30, 2015 at 09:47 AM
kaya mo yan... ;)
Post by: jravacio on Jun 30, 2015 at 12:53 PM
Thanks you both. Gawa din kayo :)
Post by: edrel sison on Jun 30, 2015 at 06:08 PM
Post by: jravacio on Jul 01, 2015 at 06:16 PM
Splendid work John! Mark of an excellent builder! Glad to have you using my transformers. As I have said you are welcome to drop by the office for a tutorial on how to make those PTXs!
Thanks a lot Edrel. I'll visit you hopefully sometime next month. :)
Post by: @lvins on Jul 02, 2015 at 01:11 PM
Post by: jravacio on Jul 02, 2015 at 07:08 PM
Nice work sir ganda..sana magkaroon din ako lakas ng loob mag DIY.. :)
Thanks Alvin, kaya mo yan :). My first build was an Aikido 5670-12AU7 and B+ at 150VDC. It's quite enough voltage for me to start with at that time. The picture below is my 2nd Aikido Build which uses 6CG7-6n1p and B+ at 250.
I'll do some write-up regarding my first build sometime. ;)
@John, can you post a picture of your amps connected to the Titus speakers?
Here you go Tony, with the Anthony Audio Gold Titus BS. I have to keep all my tube amps during weekdays because a gang of kiddos hangout here. :)
(https://c1.staticflickr.com/1/384/19161458140_08fd3f7951_c.jpg)
Thanks to Pasig day I've got time to further test and monitor the amps temperature. These Power Transformers are running like the temperatures of Hammond Transformers as read from diyaudio.com.
Temperatures are taken after 1 hour the amp is playing at 2 o'clock volume. Power Transformers at 53 celsius degrees. I might be able to cook some eggs in two hour period hehehe.
(https://c1.staticflickr.com/1/404/19349089345_7e77c10359_c.jpg)
The Power Tubes are looking pretty good. It has been like that since it was playing.
(https://c2.staticflickr.com/4/3888/19343002292_1b66665e0b_c.jpg)
Post by: tony on Jul 02, 2015 at 07:26 PM
Post by: Abad Santos 7 on Jul 05, 2015 at 10:12 PM
Post by: jravacio on Jul 26, 2015 at 10:53 PM
Thanks you guys :)
Post by: jravacio on Jul 26, 2015 at 10:54 PM
(https://farm1.staticflickr.com/506/20029347131_be672f8489_c.jpg)
I follow a personal rule, "Thou shall not haggle over a handmade product. Paying the asking price of an Artisan, is a form of respect.".
Now, let's see what we are paying for:
Direct Cost
* Cost of materials used to build the product.
* Direct Labor Cost
* ... and the list goes on
Yet, it is so very comforting to be fearful or lazy and just simply pay for someone else to do the job. But what am I missing? Well unfortunately, almost everything that's not the obvious. Like the following Indirect Cost:
* Time and effort to acquire knowledge and skills to build a product.
* Cost of failures, frustrations and successes along the way or the Artisans experience.
* Time and effort in planning and designing
* ... and the list goes on
More importantly, where's the Kaizen(Continuous Improvent) in there? I've been building tube amps for the last few years but never built a transformer.
Although I have expressed intents to wound my own transformers more than a year ago, I never had the courage to build one. From a DIYers perspective, the experience that we get from these activities are the things money can't buy. But going through all those activities is the ultimate way to go.
Actual Construction
For this build, I've only used M50 or also known as Deeco Cores. That is because my expectation is that it will have a 50% chance of failure. I'll just use a better core the next time around.
"You have to let it all go... fear, doubt and disbelief" :)
(https://farm1.staticflickr.com/344/19997961206_450e38820f_c.jpg)
Winding Setup
I don't have a pulley so I have to use Dumbells as pulley. At this point it's 100 turns Primary Winding at 100 Turns... 485 turns nalang for the primary :)
(https://farm1.staticflickr.com/266/19997956896_6feefae95f_c.jpg)
Primary Winding at 300 Turns... Pwede naman mag-order kay Edrel, sa kanya mo nlng ipagawa >:D . Sarili mo lang kalaban dito.
(https://farm1.staticflickr.com/544/19401583504_c661189a2b_c.jpg)
Primary Winding Done! Primary and Secondary Insulation
(https://farm1.staticflickr.com/304/19837553279_f2a13fda0f_c.jpg)
In terms of safety, this is the highest priority. I had to stop at the primary winding because it's painful to the hands.
HV Tap
This was done few days after I wound the primary winding. Enough days interval for my hand to build muscles. When I wound the secondary, it's no longer painful to the hand.
(https://farm1.staticflickr.com/289/20029449231_6ed1e5b28b_c.jpg)
There where imperfections on the winding because the layers were not fully flat
(https://farm1.staticflickr.com/437/19836077988_64ebe5de6a_c.jpg])
Here at 500 turns still struggling to make it perfect without spaces between the wires
HV Tap Done
(https://farm1.staticflickr.com/313/19836160370_e1d0d986d4_c.jpg)
All windings done!
(https://farm1.staticflickr.com/539/19837504879_dfe93c3971_c.jpg)
(https://farm1.staticflickr.com/276/20016347602_6fa49710a0_c.jpg)
Placing of Iron Sheets - After I dipped the coil into a varnish and dried it for few days
The coil was dipped into a varnish. I only have 500ml of varnish at the moment so alternatively I have to paint the EI Core with Oil-Based paint (Enamel) to prevent EI Core vibration or mechanical hum. The best practice is to dip the whole transformer not just the coil.
(https://farm1.staticflickr.com/542/19837485589_2bd0b07661_c.jpg)
Painted the EI Core with Enamel
(https://farm1.staticflickr.com/531/19837482379_2265deff5d_c.jpg)
The transformer is complete, let's test it.
(https://farm4.staticflickr.com/3819/19837436729_c19d4839af_c.jpg)
Measurements
HV Tap measured at 302VAC - Target is 290VAC @ 414mA
(https://farm1.staticflickr.com/440/20024102025_9c9e8df4d1_c.jpg)
Tube Rectifier Tap measured at 5.7VAC - Target is 5VAC @ 3A
(https://farm1.staticflickr.com/300/19403131323_041c60bb5b_c.jpg)
Heater Tap measured at 6.9 - Target is 6.3 @ 6A
(https://farm1.staticflickr.com/384/20016312772_49ccc77753_c.jpg)
What's brewing?
The finished transformer will be used for an SRPP-LTP driven 829b Push-Pull Amplifier.
(https://farm1.staticflickr.com/519/19403105483_33f9c439c2_c.jpg)
Thanks to Tony for having this very informative thread at elab: http://www.elab.ph/forum/index.php?topic=17495.0
Post by: jravacio on Jul 26, 2015 at 10:56 PM
Safety Note: Tranformers for Tube amplifiers contain lethal voltages, often several hundred volts, which will leave burnt entrance and exit wounds in skin. In addition to burnt skin, these voltages can also cause permanent physical damage and death.
Tube Amp Power Requirements
Primary: 230VAC @60 Hz
Hybrid Rectification on HV using Fullwave Bridge Rectifier then 5u4G Rectifiers
* B+ - 400VDC @ 230mA
* Heater tap - 6.3VAC @ 6A
* 5U4G Heater tap - 5VAC @ 3A
Power Transformer Requirements
Primary: 230VAC @60 Hz
Secondary:
290 VAC @ 414mA (non-center tapped)
6.3VAC @ 6A (We will use 6.8VAC @ 6A for computation)
5VAC @ 5V (We will use 5.4VAC @ 3A for computation)
1. Compute the Output Power
290 * 0.414 = 120.06
6.8 * 6 = 40.8
5.4 * 3 = 16.2
-------------------
Pout = 177.06 VA
2. Compute the required Input Power
Reference: http://www.elab.ph/forum/index.php?topic=17495
177.06/0.6 = 295.1
Where: 0.6 (Tony's recommendation when using M50 or Deeco Irons).
3. Compute the Core Area
Reference: http://www.elab.ph/forum/index.php?topic=17495
CA in SQ. INCH = SQRT(295.1) / 5.58
3.078 SQ. INCH
Commercially available bobbin: 1.5" X 2" = 3
4. Compute the Number of Turns in the Primary (Np)
Reference: http://www.elab.ph/forum/index.php?topic=17495
Np = 1750/3
= 583.33 or 583 Turns
Where: 1750 is Tony's Derived Constant
5. Compute Current in Primary (Ip)
Reference: http://www.elab.ph/forum/index.php?topic=17495
VA=(5.58 * Core Area)^2
=(5.58*3)^2
= 280.2276
Ip = 280.2276/ 230VAC
= 1.218 Amperes
Best wire gauge based on wire power handling: AWG #21 but in order to fit into the bobbin, I used AWG #22 instead.
6. Compute Turns per Volt
Reference: http://www.elab.ph/forum/index.php?topic=17495
Turns per Volt=(1750/3) / 230VAC
= 2.5391 or 2.54
7. Compute Turns per Volt in the Secondary
Ns1 = 290VAC x 2.54
= 736.6 or 737 turns
Best wire gauge based on wire power handling: AWG #25 but in order to fit into the bobbin, I used AWG #26 instead.
Ns2 = 6.8VAC x 2.54
= 17.272 or 17 turns
Best wire gauge based on wire power handling: AWG #14 but in order to fit into the bobbin, I used AWG #16 instead.
Ns3 = 5.4VAC x 2.54
= 13.7 or 14 turns
Best wire gauge based on wire power handling: AWG #17 but in order to fit into the bobbin, I used AWG #18 instead.
8. Determine Bobbin Width
Reference: http://www.elab.ph/forum/index.php?topic=17495 -> Page 77
= 2.25" (2 1/4")
9. Determine Bobbin Height
Reference: http://www.elab.ph/forum/index.php?topic=17495 -> Page 77
= 0.75" (3/4")
10. Determine Winding Width(Ww) and Winding Height(Wh)
Reference: Alexan Electronic Enthusiast - Volume 4 - Transformer Design
Ww = Bobbin Width - 2(margin) - 2(bobbin allowance)
= 2.25 - 0.25 - 0.064
= 1.936"
Wh = 0.75 * 0.80
= 0.6"
11. Compute Primary Turns per Layer
I've used Enamelled Inch diameter for AWG.
If AWG #22 then 1.936"/0.0266" = 72.55 turns per layer
No. of Layers (Primary) = 583/72 = 7 layers
12. Compute Secondary Turns per Layer
I've used Enamelled Inch diameter for AWG.
S1 Turns per layer
If AWG #26 then 1.936"/0.0169" = 114 turns per layer
No. of Layers (S1) = 737/114 = 7.28 or 7 layers
S2 Turns per layer
If AWG #16 then 1.936"/0.0524" = 36 turns per layer
No. of Layers (S2) = 17/36 = 1 layer
S3 Turns per layer
If AWG #18 then 1.936"/0.0418" = 46 turns per layer
No. of Layers (S2) = 14/46 = 1 layer
13. Compute Winding Buildup Total for primary and secondary windings
Inter winding insulation = 0.002"
WB Primary = 8 layers * (0.0266 + 0.002)
= 0.2288"
WB Secondary 1 = 7 layers * (0.0169 + 0.002)
= 0.1323"
WB Secondary 2 = 1 layer * (0.0524 + 0.002)
= 0.0544"
WB Secondary 3 = 1 layer * (0.0418 + 0.002)
= 0.0438"
WB Total = 1.1 * [0.095 + 2*(0.002) + 0.22288 + 0.1323 + 0.0544 + 0.0438]
=0.5623" still within Winding Height(Wh) which is about 80% of the Bobbin
You can compute the MLT for each wire to get how many Kilograms of copper wire you need. In my case, I bought 1/2 kgs for each wire gauge I need.
Post by: tony on Jul 27, 2015 at 07:49 AM
your voltages are spot on....you will find that when loaded those voltages will fall,
so it is better to start them a bit higher, than worry later because your voltages are low...
"gawang Cavite" is true.....
while working at Telefunken Semiconductors in the mid 70's
i had a co-worker from Bacoor who went to a trade school PCAT....
seeing how German production machines were made,
he made his amps look like they were german made......
he later went on to become testing manager after several years...
Quote
What's brewing?
The finished transformer will be used for an SRPP-LTP driven 829b Push-Pull Amplifier.
had i known i would have recommended that you use a voltage doubler as ht winding instead....
reason is so that you can use the half voltage available rather than deriving it from the main B+...
829b G2 needs 200 volts, i run them a bit lower at around 180 volts....you can tweak this voltage also...
Post by: Abad Santos 7 on Jul 27, 2015 at 12:43 PM
Im learning so much for these kind of details... Keep it coming... :) :) :)
Post by: tony on Jul 27, 2015 at 12:48 PM
Very detailed DIY.
Im learning so much for these kind of details... Keep it coming... :) :) :)
you are very much welcome, we hope that we are of service to the community...
please join us here for more detailed technical discussions....http://www.elab.ph/forum/index.php?topic=34991.msg882922#new
Post by: jravacio on Jul 27, 2015 at 01:06 PM
good job as usual John.......
your voltages are spot on....you will find that when loaded those voltages will fall,
so it is better to start them a bit higher, than worry later because your voltages are low...
"gawang Cavite" is true.....
while working at Telefunken Semiconductors in the mid 70's
i had a co-worker from Bacoor who went to a trade school PCAT....
seeing how German production machines were made,
he made his amps look like they were german made......
he later went on to become testing manager after several years...
had i known i would have recommended that you use a voltage doubler as ht winding instead....
reason is so that you can use the half voltage available rather than deriving it from the main B+...
829b G2 needs 200 volts, i run them a bit lower at around 180 volts....you can tweak this voltage also...
Thanks Tony :) oh great you've worked at Telefunken Semiconductors back then and there were many electronics enthusiast and hobbyists. Unfortunately, there are very few electronics enthusiast and hobbyists now a days (well as far as I know).
I've worked for a company of over 700 employees. I only know 3 of us are doing electronics as a hobby. 2 of them are focused on firmware and hardware development so I guess I was left alone on the analog side of things.
Thanks for the suggestion, I'm considering it. I was actually contemplating on winding another transformer for this build using RM18 Cores and shelve this power transformer for some other builds.
My initial plan was to run the 829b in triode mode similar to the japanese designed schematic below. But I have my hesitations, because the G2 is way above the limit of 225VDC Max per datasheet. He ran the G2 at 316VDC. I don't have a datasheet of 829b with a triode connection in it.
I'm thinking of a Mosfet Regulated G2 Power Supply similar to what you've suggested for my 6V6 Push-Pull.
Any thoughts? I saw your upcomming 829b having 0A2 regulator tubes in it. Was that for the G2?
(http://www.asahi-net.or.jp/~zh7y-tkyn/images/829B_V2.gif)
Reference:http://www.asahi-net.or.jp/~zh7y-tkyn/829B.htm
Very detailed DIY.
Im learning so much for these kind of details... Keep it coming... :) :) :)
Thanks :) Join us at elab on the link provided by Tony.
Post by: tony on Jul 27, 2015 at 01:45 PM
My initial plan was to run the 829b in triode mode similar to the japanese designed schematic below. But I have my hesitations, because the G2 is way above the limit of 225VDC Max per datasheet. He ran the G2 at 316VDC. I don't have a datasheet of 829b with a triode connection in it.
I'm thinking of a Mosfet Regulated G2 Power Supply similar to what you've suggested for my 6V6 Push-Pull.
Any thoughts? I saw your upcomming 829b having 0A2 regulator tubes in it. Was that for the G2?
(http://www.asahi-net.or.jp/~zh7y-tkyn/images/829B_V2.gif)
Reference:http://www.asahi-net.or.jp/~zh7y-tkyn/829B.htm
my attempts at a parallel triode mode for the 829b was a complete disaster...
but the 5894 was a complete success, the 5894 had a single cathode
making both halves equally matched as far as transconductance was concerned,
(there is only one cathode structure....;))
G2 at 316 volts? :o i don't know.....
the 832 pp amp i built ran at 180 volts G2 with lots of filtering...
the Audoromy FU29 that i repaired had 200 volts on G2 and
is now well behaved according to the owner....
anyway running G2 at 316 volts only meant running higher G1 negative bias...
i see that he used combination of fixed and cathode bias in there,
i might do it also in my upcoming 829b pp amp build..
but overall if you want the best reliability, then cathode bias is it...
the 2 0B2 gas reg tubes are used as voltage reference for the input stage and
yes, for the G2 supply as well.....a bit complicated perhaps...
btw, in the build article, he did mentioned that he dropped the G2 voltage later on,
probably realized that running the G2 as such high voltage only shortened tube life....
Post by: jravacio on Jul 27, 2015 at 05:12 PM
my attempts at a parallel triode mode for the 829b was a complete disaster...
but the 5894 was a complete success, the 5894 had a single cathode
making both halves equally matched as far as transconductance was concerned,
(there is only one cathode structure....;))
G2 at 316 volts? :o i don't know.....
the 832 pp amp i built ran at 180 volts G2 with lots of filtering...
the Audoromy FU29 that i repaired had 200 volts on G2 and
is now well behaved according to the owner....
anyway running G2 at 316 volts only meant running higher G1 negative bias...
i see that he used combination of fixed and cathode bias in there,
i might do it also in my upcoming 829b pp amp build..
but overall if you want the best reliability, then cathode bias is it...
the 2 0B2 gas reg tubes are used as voltage reference for the input stage and
yes, for the G2 supply as well.....a bit complicated perhaps...
btw, in the build article, he did mentioned that he dropped the G2 voltage later on,
probably realized that running the G2 as such high voltage only shortened tube life....
Okay thanks for those information. It really helps mitigating possible issues.
The article was hard to understand and yes when google translate there was a mention of "drop the voltage of the SG". That would be the G2, but he never mentioned how many volts.
Regarding "running G2 at 316 volts only meant running higher G1 negative bias", that might explain why he had a separate 50VX2,0.1A Noguchi transformer inside the chasis for the fixed bias. The combination of fixed bias and cathode bias is also good to consider.
One last question, if I'll go regulating the G2 say 200VDC or below say 180VDC, I would like to have a safety feature in the case that the G2 voltage regulator goes on failure. The G2 would go floating and the potential will be the same as the Plate Voltage. This is the same as triode connection right? if my plate voltage is around 350V-400VDC then my tubes goes BOOM!
How do you handle such failure scenario? Thanks again.
Post by: tony on Jul 27, 2015 at 07:11 PM
Quote
One last question, if I'll go regulating the G2 say 200VDC or below say 180VDC, I would like to have a safety feature in the case that the G2 voltage regulator goes on failure. The G2 would go floating and the potential will be the same as the Plate Voltage. This is the same as triode connection right? if my plate voltage is around 350V-400VDC then my tubes goes BOOM!
How do you handle such failure scenario? Thanks again.
remember that with tetrodes and pentodes the voltage at G2 controls
plate current unlike with triodes, where plate voltage on triodes
determine plate current, assuming grid1 voltage is held constant...
the thing you have to watch out for is the plate dissipation, make sure you do not
exceed 30 watts on either plate, i run them cooler at no more than 20 watts per plate..
adjust your tube bias accordingly...
Post by: jravacio on Jul 27, 2015 at 09:33 PM
remember that with tetrodes and pentodes the voltage at G2 controls
plate current unlike with triodes, where plate voltage on triodes
determine plate current, assuming grid1 voltage is held constant...
the thing you have to watch out for is the plate dissipation, make sure you do not
exceed 30 watts on either plate, i run them cooler at no more than 20 watts per plate..
adjust your tube bias accordingly...
Sorry but I have not explained well the failure scenario.
Here's the scenario:
My 829b amp is running in Class AB, in pentode connection. The G2 is voltage regulated at 180 VDC and Plate Voltage is 350VDC. 829B are dissipating 20 watts per plate.
While the amp is running, G2 voltage is suddenly lost due to regulator failure or due to G2 wire loose connection. This will result into G2 floating and voltage goes up(probably equal to the plate voltage?). If I won't notice this, it will result into 829bs over-dissipating then dies.
(I've experienced this scenario on my tube tester with a 6L6 on it and I forget to set the G2 on the right settings(hence its floating) and the plate current goes up way above what I've expected. But since 6L6's G2 and Plate Voltage is close 450 and 500 VDC limits respectively. It was not a problem. For for the likes of 829b that has very low max G2 voltage, it might be.)
Is that scenario, something to be worried about? or I'm speculating some very low likelihood scenario?
For the meantime, I'm googling some answers :)
Post by: jravacio on Jul 27, 2015 at 10:49 PM
http://www.photonisusa.com/wp-includes/pdf/TP122.pdf
Post by: tony on Jul 28, 2015 at 07:14 AM
Post by: jravacio on Jul 28, 2015 at 10:31 AM
John, no voltage on G2 cuts off the tube....but leaving elements floating on any tube is no good...
Okay, I'll prepare a full schematic and post it at elab for review.
Thanks a lot for the tips. Really appreciate it.
Post by: tony on Jul 28, 2015 at 02:41 PM
it becomes a diode and acts like a diode,
only the circuit impedance will limit plate current,
it may even red plate, but tubes are so forgiving of this kinds
of mistakes, just power down, fix the problem,
and the tube will work like nothing happened....:D
Post by: jravacio on Aug 03, 2015 at 10:54 PM
just like a triode that had an open grid leak,
it becomes a diode and acts like a diode,
only the circuit impedance will limit plate current,
it may even red plate, but tubes are so forgiving of this kinds
of mistakes, just power down, fix the problem,
and the tube will work like nothing happened....:D
Thanks Tony, it's very informative. Due to the intrinsic robustness of these tubes, it got me thinking that the fail safe I discussed above was actually a "Nice to have" rather than a necessity.
Post by: jravacio on Aug 03, 2015 at 11:12 PM
(https://farm4.staticflickr.com/3768/19638234113_d4c4c7d818_c.jpg)
I'm a fan of AT&S transformers(as seen on the picture above, :) I have a few pairs of OPTs). Over the weekend I had the privilege of visiting Edrel's manufacturing center at EPZA Cavite.
Let us see what and how AT&S transformers are made and why they're world class.
1) Transformers are conservatively designed, that means they're not squeezing in more watts per kilogram. Effectively for power transformer they run cooler and for OPTs have greater frequency response
2) High-end magnetic wires are carefully chosen and used based on current density, thermal ratings, and other quality factors.
3) These are SET OPTs for 845 in the making. Yes, that's 24 interleaved layers of perfectly wound wires of AWESOMENESS.
(https://farm1.staticflickr.com/547/20250864402_abd563cce3_c.jpg)
4) Computer controlled winding machine for accurate number of turns. A wire tension tool is pulling the wires from the bobbin and the spool so that every turn has accurate tightness. Bifilar winding is done by hand instead of the tension tool.
(https://farm1.staticflickr.com/356/20265001071_5b35f38a1a_c.jpg)
5) Japanese Z11 EI Core. Yes, simply Japanese greatness.
6) High-end Insulating materials. Nomex, Teflon. etc. The works! These materials are quite pricey.
(https://farm1.staticflickr.com/277/20250843912_10e60a368a_c.jpg)
What's the other side of the tour?
Here are some M18 EI Core for some serious Power Transformer Winding.
All these quality parts came from Edrel, get yours now :P
(https://farm1.staticflickr.com/477/20259153645_f226dbfc80_c.jpg)
(https://farm1.staticflickr.com/319/20259136685_2bdda49829_c.jpg)
Post by: dana on Aug 04, 2015 at 09:21 AM
sayang, I could have dropped by to meet you too, neighbor ko lan yang si Great Edrel dto sa EPZA.
for sure, I treat tayo ni Great Edrel sa Shakeys nearby! Sideline na lan nya ngayon yan cguro...malakas raket nyan sa LED lighting ngayon ;D
am sure, na meet mo rin assistant nya, si Benji...pag may pyesa ka need na di makita ni Edrel, si Benji for sure may alam kung san nkatago ;D
Post by: jravacio on Aug 04, 2015 at 12:51 PM
cool reporting on your AT&S tour...
sayang, I could have dropped by to meet you too, neighbor ko lan yang si Great Edrel dto sa EPZA.
for sure, I treat tayo ni Great Edrel sa Shakeys nearby! Sideline na lan nya ngayon yan cguro...malakas raket nyan sa LED lighting ngayon ;D
am sure, na meet mo rin assistant nya, si Benji...pag may pyesa ka need na di makita ni Edrel, si Benji for sure may alam kung san nkatago ;D
Oi dana, malapit ka lng pala. Nasa Imus lang din ako. I'll hopefully meet you sometime. Edrel treat me as well.:)
hahha yes, Edrel's place was a wonderland of parts and stuff. Too many to buy them at once. hahaha:) I met Benji the first time last 2014 Hifi show too. He was there over the weekend explaining how things were done.
Post by: tony on Aug 04, 2015 at 12:56 PM
Post by: Courage on Aug 04, 2015 at 01:50 PM
Post by: dana on Aug 04, 2015 at 02:47 PM
John, those 845 OPT's are for a special audiophile......;)
probably a big shot celebrity audiophile?
Post by: Tsnad on Aug 04, 2015 at 03:45 PM
Post by: jravacio on Aug 04, 2015 at 05:19 PM
John, those 845 OPT's are for a special audiophile......;)
Yes like dana said looks like a big shot audiophile. I was hoping to see at least some pics once they're built :) or hear it if its for exhibit during the hifi show.
Awesome.... Nomex and Teflon being used here are products of Company i work..
Good to know :)
Wow... everything is awesome... ganda ng mga trapo at yung mga project ni Sir John >:D
thanks heheheh
Post by: tony on Aug 04, 2015 at 06:55 PM
probably a big shot celebrity audiophile?
yes, Edrel and I have been discussing since more than a year ago...;)
Post by: jravacio on Apr 10, 2016 at 10:19 PM
(https://farm2.staticflickr.com/1642/25717345004_080b009773_c.jpg)
Overview
The thing about DIY is that you can do it in your spare time. Yes, it took me about 7 months to finish this amplifier. But it was all worth it. I had doubts on my design, thinking it will not work the way I want it but it turned out to be awesome.
On top of the laws (Ohms, thermodynamics, etc.) that we have to follow, designing an amplifier has subjectivity as well. And the designer has to balance things or be biased on some aspects of it. I guess an analogy to this is a man looking for a woman. At some point he has to determine if he wants to have a high performance woman at a high cost or a woman with moderate performance at a moderate cost. Performance and cost are most likely to go together but in worst cases it could be a low performance at a high cost. John, what are you talking about? Amplifiers are our mistresses... Well that's what I was suspecting hahahha :)
But anyway, this amp was loosely based on Seiichiro Suzuki 829b Push-Pull amplifier. However, instead of using a cathodyne phase inverter, I took the route of using LTP. Many amps like Audioromy FU29 have already used Cathodyne Phase Inverter. The main advantage of LTP over Cathodyne is that LTP is very linear. The 829b needs to be driven by low impedance output and this LTP using 12AU7 is a good candidate.
Playing safe with the input driver design, I have used a 12AT7 SRPP like you usually see on HIFI amps. Amplifiers using SRPP were called "distortion less audio amplifier" way back in the 50's.
The Output Stage uses the exquisite 829b a double tetrode tubes used in VHF radios in its hay day. I have been collecting a few of these tubes since about two years ago. And prices including the Russian GU-29 soared up on ebay after Cayin and Finale Audio made their amps using these tubes.
...And here's how I did it.
Power Transformer Winding
(https://farm1.staticflickr.com/645/20409511414_2b711c68e4_c.jpg)
(https://farm1.staticflickr.com/677/20843944690_f8b8f1f848_c.jpg)
(https://farm6.staticflickr.com/5764/21005792806_dd10806016_c.jpg)
(https://farm1.staticflickr.com/671/21031711595_db644694c9_c.jpg)
Enclosure layout, Drilling and Paint Job
(https://farm1.staticflickr.com/577/21032119725_17d0639a62_c.jpg)
(https://farm6.staticflickr.com/5634/21039714821_29c6aabaa5_c.jpg)
(https://farm1.staticflickr.com/729/20844211208_8fb75681f1_c.jpg)
(https://farm1.staticflickr.com/669/20844193868_54f3cf65b6_c.jpg)
Point-to-Point - Look mom, no PCB
(https://farm6.staticflickr.com/5751/21195946478_efacf26223_c.jpg)
Gut Shot
(https://farm2.staticflickr.com/1614/26296264176_e7414d6ef8_c.jpg)
Cathode Bypass Capacitors
(https://farm2.staticflickr.com/1554/26296259596_2613a7f8c0_c.jpg)
HV, Bias and Heater Supply
(https://farm2.staticflickr.com/1461/25717352414_ef1be7819c_c.jpg)
Back Panel
(https://farm2.staticflickr.com/1564/25717341234_33b3f4255a_c.jpg)
Side-by-side with my 6V6 Push-Pull amplifier
(https://farm2.staticflickr.com/1631/25717389274_d70e1df038_c.jpg)
In Action
(https://farm2.staticflickr.com/1513/26322227745_5f4a75554a_c.jpg)
12AU7 Glowing
(https://farm2.staticflickr.com/1478/25717372494_2716b7d0f2_c.jpg)
829B Glowing
(https://farm2.staticflickr.com/1678/25717366634_bb380ae011_c.jpg)
Sound Review
(https://farm2.staticflickr.com/1581/26272751291_9cedd6340b_c.jpg)
Wifey's Review
Listened to mostly Crossover Jazz
This design is one of those that allows one to listen to all instruments/frequencies in a song. In fact, it was the first time I noticed a husky voice from a song I've been hearing forever from radio stations (okay, it would be a little too unfair to compare far too distant sound qualities, but...) But even if you are hearing these instruments and voices all at the same time, they do not compete with each other for your attention. What each does is do their part, and complement each other, like how a good sound engineer should arrange a song.
My Review
This amplifier sounds like a MOSFET in a tube. Clear, Punchy and Lively. I have listened mostly to 90's music to test this amp and turned out awesome. I could say this is not a Luscious kind of amplifier.
(https://farm2.staticflickr.com/1594/26322219975_9c4d26b2a9_c.jpg)
Acknowledgements
As always, this amp could not be made without all the advises from Tony Tecson. I am and the rest of the DIY community is thankful of having you around.
Edrel Sison for bringing the best goddies we could have for our builds.
Gerry Sta. Maria for the driver tubes.
Enrico Resurreccion for the wood works.
People at Elab and fb group "POWER AMPLIFIER & ELECTRONICS CIRCUIT TECHNICIAN FORUM" for continuous technical discussions :)
Post by: tony on Apr 11, 2016 at 07:28 AM
now you have a lot of tricks in your toolbag, ready for use in any and all your tubes endeavor....
keep the fire in the bottle burning....
Post by: jravacio on Apr 11, 2016 at 12:01 PM
Thanks again Tony...
I'm still contemplating what would be my next build. I have all the parts to build a KT88 push-pull and parts to complete an 832A push-pull amplifier. However, I could not get to the bottom of this hobby until I get to learn how to wound my own Output Transformers. My Z11 and RM18 cores are hiding in the boxes for months, waiting to get used. :-\
Post by: kayee on Apr 11, 2016 at 12:11 PM
congrats John, it is my lifelong passion to get you and the other younger people into tubes.....Wow...nice build sir.
now you have a lot of tricks in your toolbag, ready for use in any and all your tubes endeavor....
keep the fire in the bottle burning....
Post by: tony on Apr 11, 2016 at 12:29 PM
Post by: kayee on Apr 11, 2016 at 04:51 PM
kayee, musta na? mag pp amp ka na, kaya mo yan....sir tony :)nag start pa lang ako sa enclosure ng gu50 ko na single ended sir paunti-unti muna....after nito mag push pull ako sir gisto ko rin subukan yung sq ng push pull.....
Post by: jravacio on Apr 11, 2016 at 10:21 PM
Wow...nice build sir.Thanks Kayee..Gawa ka din...join our technical discussions at elab http://www.elab.ph/forum/index.php?topic=34991.new;topicseen#new
Post by: edrel sison on Apr 12, 2016 at 02:08 PM
Post by: jravacio on Apr 12, 2016 at 10:29 PM
Congratulations John! 7 months is such a short time for busy people like you and me!
Thanks Edrel! time for a new project ulit heheheh :)
Post by: tony on Apr 13, 2016 at 07:18 AM
Thanks Edrel! time for a new project ulit heheheh :)
John, yang si Edrel tatahi-tahimik pero high ender yan....nakita ko yung tube amp nya sa facebook...:D
Edrel makes world class OPT's for 845 SET amps for a bigtime audiophile....
Post by: jravacio on Apr 13, 2016 at 11:16 AM
John, yang si Edrel tatahi-tahimik pero high ender yan....nakita ko yung tube amp nya sa facebook...:D
Edrel makes world class OPT's for 845 SET amps for a bigtime audiophile....
oo nga eh hehhe 300B at 10Y na preamp. :)
Sana mag e-exhibit yung nagpagawa ng 845 OPTs sometime sa Hifi show.
Post by: tony on Apr 13, 2016 at 02:12 PM
oo nga eh hehhe 300B at 10Y na preamp. :)
Sana mag e-exhibit yung nagpagawa ng 845 OPTs sometime sa Hifi show.
balita ko masikreto yung audiophile na yon...;)
Post by: jravacio on Nov 01, 2016 at 10:33 PM
(https://c5.staticflickr.com/6/5674/30405588260_4808d9787e_z.jpg)
Overview
After 3 years on my DIY Audio journey, I finally made my own Output Transformers. Looking back wasn't that easy. I'm not intrinsically a patient man to take-on the complexities of winding an Output Transformer. I have to grow my hair literally and extend my patience a little bit. Girls called the process "Tiis Ganda" hahahah ;)
The design was pretty much similar to the OddWatt but instead of using 6l6gc, I have used 1625 which is very similar to 6L6 but uses 12.6V on the heater.
(https://c7.staticflickr.com/6/5755/30668734846_2f930d2d19_z.jpg)
Winding the Output Transformers
(https://c5.staticflickr.com/6/5680/30405573460_b8b0e4a39e_z.jpg)
These OPTs were design to run at 40W @ 20Hz with an Impedance of 8K. But this amp is only running approximately at 25 watts per channel. This OPT uses an interleaved design of 5 primary winding sections and 3 secondary winding sections. Sounds complicated? Yes, for first timers like me it is but maybe I'll get used to it as time goes by and more practice.
Draft paper for inter-layer insulation. Without those, wires will fall in between the previous layer.
(https://c5.staticflickr.com/6/5717/30588699332_04d587bf97_z.jpg)
At this point, 1st primary winding sections were done. Side-by-side comparison for each section to ensure consistency between both OPTS.
(https://c6.staticflickr.com/6/5554/30617271661_aff08a3b4d_z.jpg)
Double NOMEX insulation plus Kapton tapes at the side.
(https://c7.staticflickr.com/6/5346/30588690382_1dfcfb6249_z.jpg)
1st secondary winding section were done. This is the 16 ohm tap.
(https://c6.staticflickr.com/6/5328/30071445613_933333e816_z.jpg)
2nd primary winding section continuous.
(https://c2.staticflickr.com/6/5536/30705541705_f07c5a2c7d_z.jpg)
(https://c5.staticflickr.com/6/5824/30073608244_e4faa686c7_z.jpg)
Done.. One layer of Draft Paper and then Nomex tape
(https://c2.staticflickr.com/6/5630/30617246001_12d80b2d88_z.jpg)
(https://c7.staticflickr.com/6/5546/30073605174_6e0ba47bb7_z.jpg)
Bifilar winding on the 4Ohm secondary winding section.
(https://c2.staticflickr.com/6/5659/30071418473_b3993da082_z.jpg)
(https://c4.staticflickr.com/6/5740/30617238411_567e0fa16e_z.jpg)
Done with the 4Ohm secondary section
(https://c5.staticflickr.com/8/7407/28112916956_cea76e6f4b_z.jpg)
Another primary winding section
(https://c4.staticflickr.com/6/5821/30705531155_7bb519056b_z.jpg)
Done with the primary section
(https://c5.staticflickr.com/6/5677/30073593604_21f75a42a3_z.jpg)
After 12 days of OPT winding or 6 weekends windings are finally done
and time to put those eyelets.
(https://c8.staticflickr.com/6/5825/30705525295_a6003a6484_z.jpg)
(https://c3.staticflickr.com/6/5556/30588652082_ddd8d3d22e_z.jpg)
(https://c2.staticflickr.com/6/5535/30617224841_ecd86b1d11_z.jpg)
Impedance testing with a Variac
(https://c8.staticflickr.com/6/5561/30705513095_706280c941_z.jpg)
Varnish Dipping and Sun baking
(https://c4.staticflickr.com/6/5752/30071401083_69fbdd0c5f_z.jpg)
(https://c1.staticflickr.com/6/5636/30073583184_5be82596b2_z.jpg)
Winding the Power Transformers
After winding those OPT, it makes Power Transformer a walk in the park :)
Starting off with the primary winding
(https://c5.staticflickr.com/6/5728/30588644532_97452833bc_z.jpg)
Secondary Windings
(https://c3.staticflickr.com/6/5496/30405505970_055744ecfd_z.jpg)
(https://c7.staticflickr.com/6/5678/30588638542_a7833faed8_z.jpg)
HV tap done
(https://c3.staticflickr.com/6/5681/30588635882_fbacc7eaab_z.jpg)
Meanwhile, Transformer covers are painted with Hammer tone paint
(https://c1.staticflickr.com/6/5577/30588633432_71f65c211a_z.jpg)
Heater windings done
(https://c8.staticflickr.com/6/5629/30705484015_bf5feb9053_z.jpg)
Ready for Testing
(https://c3.staticflickr.com/6/5814/30405489170_6134c097bb_z.jpg)
(https://c5.staticflickr.com/6/5755/30405485860_7e14004fe1_z.jpg)
Enclosure works
(https://c8.staticflickr.com/6/5578/30071367463_6aa679ae1b_z.jpg)
(https://c7.staticflickr.com/6/5334/30588615862_8ea732c6af_z.jpg)
(https://c2.staticflickr.com/6/5796/30705474065_7ff41d609b_z.jpg)
(https://c1.staticflickr.com/6/5633/30668592976_f2ccecf69a_z.jpg)
Enclosure done and painted.. Installed the faceplate
(https://c6.staticflickr.com/6/5620/30617182061_40da1d8eca_z.jpg)
Wirewound pots for balancing the cathode current
(https://c3.staticflickr.com/6/5760/30405467850_d620f73a8f_z.jpg)
70% done
(https://c5.staticflickr.com/6/5323/30073541524_1d956884f9_z.jpg)
All done... I have to wait another weekend before doing the actual test.
(https://c6.staticflickr.com/6/5813/30705573685_4b4d26b84f_z.jpg)
Actual Testing
After I turned ON this amp, I didn't have much problems and most voltage measurements are as Expected. After one hour of playing at full volume, my Power Transformer temperature rises from 30 degrees to 47 degrees Celsius. Although a temperature rise of 17 degrees Celsius is okay I have tried removing the CCS using TL783 and changed it to Cathode Resistor with a bypass capacitor (blue one on the picture above). After listening to it, I have decided to keep the Cathode Resistor.
(https://c7.staticflickr.com/6/5602/30405563270_6c74a8b9de_z.jpg)
(https://c4.staticflickr.com/6/5459/30705578315_c8ae2b0350_z.jpg)
(https://c1.staticflickr.com/6/5702/30405565840_ffd8771a08_z.jpg)
Sound Review
It's been a long write-up so I'll make this short. The sound sits between being punchy and luscious. Just exactly the right tightness but not punchy. It has the clarity and warmness of 6L6 tubes. Tested several records on this amp from Louis Armstrong, Earth Wind and Fire to the heavy metal ACDC, Megadeth and Pantera.
Acknowledgements
Big Thanks to Tony Tecson for our never ending design reviews and discussions at elab.
Many Thanks to Edrel Sison for bringing-in the best quality materials for our builds.
Gerry Sta. Maria for these lovely 1625 bottles.
And to my lovely Wife for her never ending support for my DIY endeavors.
Post by: tony on Nov 02, 2016 at 04:14 AM
Post by: remington on Nov 02, 2016 at 10:58 AM
Post by: Gino on Nov 02, 2016 at 12:49 PM
Post by: shoktongxxx on Nov 02, 2016 at 01:02 PM
Post by: rochie on Nov 02, 2016 at 01:21 PM
Superb craftmanship you got there.
Post by: jravacio on Nov 02, 2016 at 03:44 PM
John, you are a fast learner, i am super glad to see you going well in your own journey......more amps to come....
Thanks for inspiring us Tony! Without you in the DIY community, we would have been lost on where we should start and what we should read.
Ang ganda naman sir john!!! kaka inggit hehehe!!! Congrats...Salamat! Are building a passive preamp? I meet Gerry while he was bringing a Rotary Switch for You. How's that project going?
Now that is what I call hardcore. Interesting build. DIY transformers.Thanks Gino :)
ang galing! :)Thanks Shoktong! :)
Good job John. My SET is still inside its box hahahaha,the preamp that I started is still a chassis with sockets,rca jack,pots, power switch and power transformer hahahaha,but i manage to repair my kt88 during the holidays.
Superb craftmanship you got there.
Thanks Rochie! ayos lang at least one down na yung KT88 from your bucket list. Dahan2x lang, pwede mong gawin yung SET amp mo over Christmas Vacation :)
I'm building a Bench Power Supply for Tube experimentation next. Similar to Heath Kit IP-17.
(http://wd4eui.com/Pictures/Heath_IP_17.jpg)
Post by: tony on Nov 02, 2016 at 05:20 PM
check out the shops along the street at republic supermarket in binondo...
planning to get a pair as well...
Post by: jravacio on Nov 02, 2016 at 11:05 PM
John, there are small variacs that are about 500 pesos each to make an adjustable psu.....
check out the chops along the street at republic supermarket in binondo...
planning to get a pair as well...
Thanks for pointing it out where we could get one. I could use one to make the Heater Voltage variable.
For the HV supply however, since I'll be using a ready made Power Transformer with an HV Tap (375-0-375 @ 200mA), 50V Bias, and another 6.3 it looks like my options are limited to either use a High Voltage Transistor (ex. BU508A) or a Power Tube to make it variable.
Post by: Nelson de Leon on Nov 03, 2016 at 03:16 AM
John, there are small variacs that are about 500 pesos each to make an adjustable psu.....Naalala ko, may gumamit ng variac sa audio system niya to make the voltage stable daw. Dba linear yun so in effect, kapag tumaas ang input voltage, tataas din ang output voltage? Or will it also help in the "isolation".
check out the chops along the street at republic supermarket in binondo...
planning to get a pair as well...
Sent from my ASUS_Z012D using Tapatalk
Post by: tony on Nov 03, 2016 at 05:17 AM
Naalala ko, may gumamit ng variac sa audio system niya to make the voltage stable daw. Dba linear yun so in effect, kapag tumaas ang input voltage, tataas din ang output voltage? Or will it also help in the "isolation".
Sent from my ASUS_Z012D using Tapatalk
the variac discussed here will be used for another purpose....but yes, you still have to monitor voltage and adjust manually...
this is my diy power monitor...variacs are adjustable auto transformers....if gives no galvanic isolation from meralco......
(https://scontent.fmnl3-1.fna.fbcdn.net/v/t1.0-9/14915182_1256303374391294_7707163325132367004_n.jpg?oh=b4b2036c7e93330071c35a06fb31377a&oe=58925D50)
this is the isolation traffo i made, a 1500 watt unit with line filters, my diy line conditioner....
(https://scontent.fmnl3-1.fna.fbcdn.net/v/t1.0-9/14705654_1248029951885303_2757832300535665866_n.jpg?oh=45a1e1e10fc6f1c97b58178bda54c1c6&oe=589C9F16)
Post by: jravacio on Nov 03, 2016 at 11:28 PM
Naalala ko, may gumamit ng variac sa audio system niya to make the voltage stable daw. Dba linear yun so in effect, kapag tumaas ang input voltage, tataas din ang output voltage? Or will it also help in the "isolation".
Sent from my ASUS_Z012D using Tapatalk
I think Tony answered your question ;)
this is the isolation traffo i made, a 1500 watt unit with line filters, my diy line conditioner....
(https://scontent.fmnl3-1.fna.fbcdn.net/v/t1.0-9/14705654_1248029951885303_2757832300535665866_n.jpg?oh=45a1e1e10fc6f1c97b58178bda54c1c6&oe=589C9F16)
After being puzzled to your Isolation Transformer, I did some readings about it and realized it was primarily for Safety Purpose instead of working directly from Mains. hmmmm that would be a good DIY project for me someday :)
Post by: tony on Nov 04, 2016 at 07:19 AM
Post by: tony on Nov 04, 2016 at 08:41 AM
Quote
Actual Testing
After I turned ON this amp, I didn't have much problems and most voltage measurements are as Expected. After one hour of playing at full volume, my Power Transformer temperature rises from 30 degrees to 47 degrees Celsius. Although a temperature rise of 17 degrees Celsius is okay I have tried removing the CCS using TL783 and changed it to Cathode Resistor with a bypass capacitor (blue one on the picture above). After listening to it, I have decided to keep the Cathode Resistor.
the thing with TL783 used as CCS is they are somewhat band limited, so passive work better in most cases....
glad that you came to same findings.....the tl783's are good for such things as a maida regulator which was the main reason why they exist..
depletion type mosfets like the dn2540 when used in cacode present wide bandwith the voltage regulators...
Post by: jravacio on Nov 04, 2016 at 06:27 PM
the thing with TL783 used as CCS is they are somewhat band limited, so passive work better in most cases....
glad that you came to same findings.....the tl783's are good for such things as a maida regulator which was the main reason why they exist..
depletion type mosfets like the dn2540 when used in cacode present wide bandwith the voltage regulators...
Thanks for pointing it out that it was due to band limited TL783. I could not explain the reason behind but when I listened to it at first, parang vocalist na nagpipigil kumanta. I was almost into the conclusion that Screen/G2 CCS would be better than CCS at the cathode hehehe. Choice of parts pa rin pala :)
Here's the before and after pictures :)
(https://c3.staticflickr.com/6/5462/30134606554_1c31b696c2_z.jpg)
Post by: remington on Nov 05, 2016 at 11:11 AM
Salamat! Are building a passive preamp? I meet Gerry while he was bringing a Rotary Switch for You. How's that project going?
Ok na ok yung passive pre amp/transformer volume controll sir john very tranparent ang effect and dead silent. Bumagay sya sa system ko.
Post by: tony on Nov 05, 2016 at 11:48 AM
last time i checked, costs about 500 each....kung hind bagay then we can still use it for another project.........;)
Post by: tony on Nov 05, 2016 at 12:22 PM
Thanks for pointing it out that it was due to band limited TL783. I could not explain the reason behind but when I listened to it at first, parang vocalist na nagpipigil kumanta. I was almost into the conclusion that Screen/G2 CCS would be better than CCS at the cathode hehehe. Choice of parts pa rin pala :)
horses for courses nga.....i have resisted the irge to use them in my circuits, but i am willing to give
Garry Pim a try using mosfet cascodes ccs in my upcoming 1624 Tabor pp amp....
Bud Purvine who coaches me in making OPT's gave a lot of hints in making the OPT.....
(http://www.diyaudio.com/forums/attachments/tubes-valves/433954d1408472202-max-g2-voltage-1624-tube-tabor-tabor_rev3.gif)
Post by: jravacio on Nov 07, 2016 at 05:54 PM
Salamat! Are building a passive preamp? I meet Gerry while he was bringing a Rotary Switch for You. How's that project going?
Ok na ok yung passive pre amp/transformer volume controll sir john very tranparent ang effect and dead silent. Bumagay sya sa system ko.
That's good to hear! :)
horses for courses nga.....i have resisted the irge to use them in my circuits, but i am willing to give
Garry Pim a try using mosfet cascodes ccs in my upcoming 1624 Tabor pp amp....
Bud Purvine who coaches me in making OPT's gave a lot of hints in making the OPT.....
(http://www.diyaudio.com/forums/attachments/tubes-valves/433954d1408472202-max-g2-voltage-1624-tube-tabor-tabor_rev3.gif)
Yes, me too but maybe later next year. I'm still trying to digest(at least in theory) what you and Bud talked about specially the distributed gap. I got several 1624 from Gerry so Tabor is one on my bucket list :)
Regarding the Variac, the Republic Supermarket you were talking about is the one along Soler St. right?
Post by: tony on Nov 07, 2016 at 06:57 PM
but i can discuss some clues when we meet at the Dusit Hotel this coming saturday....
btw, i am Dau bound tommorow am.....bibile ng chicharon....after meeting with JunM...
yes, along the republic supermart, there are shops there selling electrical items....
Post by: jravacio on Nov 08, 2016 at 10:37 AM
Bud gave me training materials but made me promise him not to divulge as long as he is alive....
but i can discuss some clues when we meet at the Dusit Hotel this coming saturday....
btw, i am Dau bound tommorow am.....bibile ng chicharon....after meeting with JunM...
yes, along the republic supermart, there are shops there selling electrical items....
Thanks, my ears are open for those clues. Let's hope for a good weather over the weekend and a successful exhibit of your amps. ;)
Enjoy your meet-up with JunM.
Post by: tony on Nov 08, 2016 at 07:39 PM
see at you 417 on saturday...
Post by: jravacio on Nov 09, 2016 at 04:40 PM
ang sarap ng bulalo sa DAU..i met Jun this am......i will go back there again....
see at you 417 on saturday...
Alright see you there. Punta ako on Saturday after lunch cguro.
I'll try those DAU bulalo sometime and sooner. Only been to Pampanga once :)
Post by: tony on Nov 09, 2016 at 04:43 PM
besides bulalo, meron ding surplusan sa paligid ng Sau terminal....sayang at kulang ang oras para maglibot....
Post by: jravacio on Nov 09, 2016 at 07:27 PM
John, sumakit ang tuhod ko sa 15kg na isolation traffo na inuwi ko galing DAU.....
besides bulalo, meron ding surplusan sa paligid ng Sau terminal....sayang at kulang ang oras para maglibot....
Wow that sure is heavy. 3000W ba na isolation traffo would be that heavy?
Gerry told me that those 4-125A sockets came from some dealer from Pampanga. So it looks like maraming military surplus dyan.
Post by: tony on Nov 09, 2016 at 08:15 PM
Wow that sure is heavy. 3000W ba na isolation traffo would be that heavy?
Gerry told me that those 4-125A sockets came from some dealer from Pampanga. So it looks like maraming military surplus dyan.
a 1kvs 100volt japanese unit.....
DAU is known for military surpluss when the american bases were still in Clark and Subic...
Post by: jravacio on Feb 06, 2017 at 07:29 PM
(https://c1.staticflickr.com/1/348/31896891844_fa838a18d2_c.jpg)
For DIYers like me Isolation Transformers are a MUST for safety reasons. Also, I was inspired to create my own after seeing Tony's isolation transformer during the HiFI show.
Isolation transformer generally has a winding ratio 1:1 with a Faraday Shield to block capacitive coupling between the primary and secondary windings. However, for this project it is not exactly a 1:1 ratio because the input voltage is computed at 240 and the output voltage is 220V. Mains at our home normally run 237V during daytime and 244v during night time. That drives the reason why I decided to make it 240->220. Another advantage of doing it is when the main voltage surges about 10 volts my output will only go up to 230 Max.
External design
My day job mostly deals with Operator Interface software applications for industrial plant. Interface designs are geared at displaying software representation of Analog panel meters which displays measurements (e.g. flow, pressure, etc) which is awesome. But this inspires me to use the real and tangible panel meters for this project.
In almost all of my builds I liked to use only 3 colors.. In this case Silver, blue and black. This keeps the appearance clean and neat. Color combination is also critical.
Transformer winding
Primary Winding
(https://c1.staticflickr.com/1/271/32616470981_b92f460bd2_c.jpg)
Faraday's shield
(https://c1.staticflickr.com/1/735/31896905614_172b5d0421_c.jpg)
(https://c1.staticflickr.com/1/696/32616468431_47aa5ca500_c.jpg)
(https://c1.staticflickr.com/1/769/31896904344_c0254efcfc_c.jpg)
Secondary Winding
(https://c1.staticflickr.com/1/597/32616466641_8a640427f9_c.jpg)
(https://c1.staticflickr.com/1/531/32360191200_bccfdb026b_c.jpg)
(https://c1.staticflickr.com/1/291/31925991513_427a76560b_c.jpg)
Transformer work done
(https://c1.staticflickr.com/1/260/32699478686_59860f9ac6_c.jpg)
Enclosure Work
Got this custom made from Unity Metalworks at Sta. Cruz Manila (2mm)
(https://c1.staticflickr.com/1/542/32699477936_5d8ddc1b12_c.jpg)
(https://c1.staticflickr.com/1/734/31896899534_5994123098_c.jpg)
Here's a snapshot of my newly acquired drill press.
(https://c1.staticflickr.com/1/781/32699464916_424ac4e44e_c.jpg)
Drill bits and Personal Protective equipment
(https://c1.staticflickr.com/1/300/32699475436_9d676fe413_c.jpg)
52mm hole saw
(https://c1.staticflickr.com/1/778/31896897924_ecc60d6676_c.jpg)
Drilling done
(https://c1.staticflickr.com/1/277/32699474076_89faaed04f_c.jpg)
Paint Job
(https://c1.staticflickr.com/1/399/31896896434_bbc5f7a7e0_c.jpg)
Final build
(https://c1.staticflickr.com/1/354/32699471636_30fca9a125_c.jpg)
Testing
This shows that when the line voltage is 242 the output is 222volts. There's always a 20volt difference between the input and output. At almost full load voltage drops around 6 volts.
(https://c1.staticflickr.com/1/621/32616455901_cd7e1470e6_c.jpg)
What can be improved?
I had a chat with Edrel and got his advice to make a multi-tap primary the next time around. It's always a good idea to change the ratio when more power is needed.
Acknowledgements
Well I'd like to thank the usual suspects when in comes to DIY. That is Tony Tecson and Edrel Sison. And mostly to my wife who checks the visuals in all my builds.
(https://c1.staticflickr.com/1/370/32699464366_7fe5aa8e2e_c.jpg)
(https://c1.staticflickr.com/1/532/32740009745_67b87c470f_c.jpg)
Post by: parasound on Feb 06, 2017 at 10:44 PM
Sent from my iPhone using Tapatalk
Post by: tony on Feb 07, 2017 at 07:34 AM
Post by: jravacio on Feb 07, 2017 at 01:57 PM
Well done, very nice looking case
Sent from my iPhone using Tapatalk
Thanks Parasound!
no stopping John now......more tubes to come.....
Thanks Tony...yes more builds to come.