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Offline jravacio

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John's Build Pics
« on: Jun 28, 2015 at 10:11 PM »
After more than two years on my tube journey, I think it's about time to give back to the DIY community and share my experience. Hopefully this will inspire individuals who have zero knowledge about tubes to start their own tube journey as well.

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.
Rock n' Roll \,,/

Offline jravacio

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Re: John's Build Pics
« Reply #1 on: Jun 28, 2015 at 10:12 PM »
Single Ended 808/811A Monoblocks

.... 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.



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).



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







Front and Rear View





Gut Shots



Below the sockets of of 717A Tube



Below the sockets of 6V6



717A Input Tube



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



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



* 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.
Rock n' Roll \,,/

Offline tony

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Re: John's Build Pics
« Reply #2 on: Jun 29, 2015 at 06:52 AM »
John, what can i say? the average diy'ers will do a 45, 2A3, 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...

« Last Edit: Jul 01, 2015 at 06:18 PM by tony »
how do we defend our freedom? by the truth when it is assaulted by Marcos lies....

Offline tony

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Re: John's Build Pics
« Reply #3 on: Jun 29, 2015 at 08:52 AM »
@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...
« Last Edit: Jun 29, 2015 at 08:53 AM by tony »
how do we defend our freedom? by the truth when it is assaulted by Marcos lies....

Offline camoteque

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Re: John's Build Pics
« Reply #4 on: Jun 29, 2015 at 10:48 AM »
Love the 717A tubes. It is what is also used in Yamamoto amps. Cute tubes.


Offline tony

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Re: John's Build Pics
« Reply #5 on: Jun 29, 2015 at 11:01 AM »
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


« Last Edit: Jun 29, 2015 at 11:22 AM by tony »
how do we defend our freedom? by the truth when it is assaulted by Marcos lies....

Offline deist

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Re: John's Build Pics
« Reply #6 on: Jun 29, 2015 at 11:41 AM »
Nice builds John! congrats!

BTW, if I'm not mistaken ikaw yung nakita kong nag-post before ng Eminence speakers?

Offline jravacio

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Re: John's Build Pics
« Reply #7 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.



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




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.
« Last Edit: Jun 29, 2015 at 01:23 PM by jravacio »
Rock n' Roll \,,/

Offline rochie

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Re: John's Build Pics
« Reply #8 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.

Offline deist

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Re: John's Build Pics
« Reply #9 on: Jun 29, 2015 at 03:59 PM »
YGPM  :)

Thanks, yes my guitar amp head uses an Eminence Speaker.

Offline reznor

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Re: John's Build Pics
« Reply #10 on: Jun 29, 2015 at 04:33 PM »
Posts some sample video/audio link :) Ganda siguro niyan tumunog John!

Offline tony

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Re: John's Build Pics
« Reply #11 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....;)
how do we defend our freedom? by the truth when it is assaulted by Marcos lies....

Offline remington

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Re: John's Build Pics
« Reply #12 on: Jun 29, 2015 at 06:43 PM »
very nice build inside and out sir john! congrats.
tube + audio nirvana = beyond...

Offline jravacio

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Re: John's Build Pics
« Reply #13 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.



Rock n' Roll \,,/

Online Superman

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Re: John's Build Pics
« Reply #14 on: Jun 29, 2015 at 11:26 PM »
Congratulations! IMPRESSIVE! :D
Fyne|EAR|Hana|Technics|SAEC|Wiim|Western Electric|Audiolab|Acrolink|Oyaide|Oppo|Tellurium

Offline dana

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Re: John's Build Pics
« Reply #15 on: Jun 30, 2015 at 09:42 AM »
super sexy and very curvaceous naman ng amp tube mo sir...
Dolphy would surely like it :D
congrats, happy listening!

Offline tony

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Re: John's Build Pics
« Reply #16 on: Jun 30, 2015 at 09:47 AM »
Don, simulan mo ng gumawa ng tube amps mo, suportahan kita...  8)
kaya mo yan... ;)
how do we defend our freedom? by the truth when it is assaulted by Marcos lies....

Offline jravacio

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Re: John's Build Pics
« Reply #17 on: Jun 30, 2015 at 12:53 PM »
@Superman and Dana

Thanks you both. Gawa din kayo :)
Rock n' Roll \,,/

Offline edrel sison

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Re: John's Build Pics
« Reply #18 on: Jun 30, 2015 at 06:08 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!

Offline jravacio

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Re: John's Build Pics
« Reply #19 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. :)
Rock n' Roll \,,/

Offline @lvins

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Re: John's Build Pics
« Reply #20 on: Jul 02, 2015 at 01:11 PM »
Nice work sir ganda..sana magkaroon din ako lakas ng loob mag DIY.. :)

Offline jravacio

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Re: John's Build Pics
« Reply #21 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. :)




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.



The Power Tubes are looking pretty good. It has been like that since it was playing.

« Last Edit: Jul 02, 2015 at 11:33 PM by jravacio »
Rock n' Roll \,,/

Offline tony

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Re: John's Build Pics
« Reply #22 on: Jul 02, 2015 at 07:26 PM »
good job John......;)
how do we defend our freedom? by the truth when it is assaulted by Marcos lies....

Offline Abad Santos 7

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Re: John's Build Pics
« Reply #23 on: Jul 05, 2015 at 10:12 PM »
Very nice DIY....Congrats....

Offline jravacio

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Re: John's Build Pics
« Reply #24 on: Jul 26, 2015 at 10:53 PM »
@masa6614 and @Abad Santos 7

Thanks you guys :)
Rock n' Roll \,,/

Offline jravacio

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Re: John's Build Pics
« Reply #25 on: Jul 26, 2015 at 10:54 PM »
My first DIY Power Transformer



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" :)




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 :)




Primary Winding at 300 Turns... Pwede naman mag-order kay Edrel, sa kanya mo nlng ipagawa  >:D . Sarili mo lang kalaban dito.




Primary Winding Done! Primary and Secondary Insulation



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.



There where imperfections on the winding because the layers were not fully flat


Here at 500 turns still struggling to make it perfect without spaces between the wires

HV Tap Done


All windings done!




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.




Painted the EI Core with Enamel



The transformer is complete, let's test it.


Measurements


HV Tap measured at 302VAC - Target is 290VAC @ 414mA




Tube Rectifier Tap measured at 5.7VAC - Target is 5VAC @ 3A



Heater Tap measured at 6.9 - Target is 6.3 @ 6A



What's brewing?

The finished transformer will be used for an SRPP-LTP driven 829b Push-Pull Amplifier.



Thanks to Tony for having this very informative thread at elab: http://www.elab.ph/forum/index.php?topic=17495.0
« Last Edit: Jul 26, 2015 at 11:26 PM by jravacio »
Rock n' Roll \,,/

Offline jravacio

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Re: John's Build Pics
« Reply #26 on: Jul 26, 2015 at 10:56 PM »
Design as Built

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.
« Last Edit: Jul 26, 2015 at 11:12 PM by jravacio »
Rock n' Roll \,,/

Offline tony

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Re: John's Build Pics
« Reply #27 on: Jul 27, 2015 at 07:49 AM »
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...

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...


« Last Edit: Jul 27, 2015 at 08:09 AM by tony »
how do we defend our freedom? by the truth when it is assaulted by Marcos lies....

Offline Abad Santos 7

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Re: John's Build Pics
« Reply #28 on: Jul 27, 2015 at 12:43 PM »
Very detailed DIY.

Im learning so much for these kind of details... Keep it coming... :) :) :)


Offline tony

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Re: John's Build Pics
« Reply #29 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
how do we defend our freedom? by the truth when it is assaulted by Marcos lies....