Author Topic: DIY 6SL7/2a3 SET Project  (Read 6691 times)

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Offline parasound

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DIY 6SL7/2a3 SET Project
« on: Apr 15, 2017 at 10:13 AM »
All check! kumpleto na, waiting na lang for power transformer & choke (niluluto pa ni Edrel S)





Trial lay out, in preparation for cutting hole for transformers, tubes & capacitor mount.













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« Last Edit: Apr 19, 2017 at 12:21 PM by parasound »
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Offline parasound

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DIY 6SL7/2a3 SET Project
« Reply #1 on: Apr 18, 2017 at 07:31 AM »
Received the power transformer & choke last night from Mr. Edrel S,





Start cutting the aluminum chassis for power transformer mount (using Dremel 3000)









Thanks



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« Last Edit: Apr 18, 2017 at 07:43 AM by parasound »
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Offline parasound

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Re: DIY 6SL7/2a3 SET Project
« Reply #2 on: Apr 18, 2017 at 08:49 AM »
Hole Saw trial,
28mm dia & 50mm dia







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Offline parasound

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DIY 6SL7/2a3 SET Project
« Reply #3 on: Apr 18, 2017 at 11:38 PM »









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« Last Edit: Apr 19, 2017 at 10:29 AM by parasound »
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Offline parasound

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DIY 6SL7/2a3 SET Project
« Reply #4 on: Apr 19, 2017 at 04:01 PM »
Update









Wiring na lang


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Offline Abad Santos 7

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Re: DIY 6SL7/2a3 SET Project
« Reply #5 on: Apr 19, 2017 at 05:19 PM »
Ayos.....  8) 8) 8)

Kainggit ung Trapo.... >:D >:D >:D

Offline parasound

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Re: DIY 6SL7/2a3 SET Project
« Reply #6 on: Apr 19, 2017 at 09:38 PM »
Marami pa available yan brod,  pili ka lang Tango U808 or FW20s. Good for your 45

Ayos.....  8) 8) 8)

Kainggit ung Trapo.... >:D >:D >:D



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Offline redstarrising

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Re: DIY 6SL7/2a3 SET Project
« Reply #7 on: Apr 20, 2017 at 10:15 AM »
Galing mo naman Ronald. Asan na yun sa akin  :D :D :D
ST70, DIY Tube Preamp, DIY FR Visaton B200, DIY Lenco L75, Lehman Black Cube, DIY Cinemags SUT

Offline tony

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Re: DIY 6SL7/2a3 SET Project
« Reply #8 on: Apr 20, 2017 at 10:39 AM »
another tubero is born, i remember S2KOV, andy is now in canada...
how do we defend our freedom? by the truth when it is assaulted by Marcos lies....

Offline parasound

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Re: DIY 6SL7/2a3 SET Project
« Reply #9 on: Apr 20, 2017 at 11:17 AM »
Kaya mo din yan sir, basta meron proper tools & parts. Then advise and help from our tube gurus like sir Tony

Galing mo naman Ronald. Asan na yun sa akin  :D :D :D



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Offline tony

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Re: DIY 6SL7/2a3 SET Project
« Reply #10 on: Apr 20, 2017 at 11:19 AM »
it is hard to go wrong with a SET amp as a newbie project,
simplicity makes this a fine way to start with tubes....
as you gain more experience, then you can move on the the bigger tubes...
how do we defend our freedom? by the truth when it is assaulted by Marcos lies....

Offline parasound

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Re: DIY 6SL7/2a3 SET Project
« Reply #11 on: Apr 20, 2017 at 11:22 AM »
Yes Sir Tony, the first time i met Andy (s2kov) was at the wiredstate Nov Hifi show way back 2005, then the last time we exchange message was when he still based in SG.

another tubero is born, i remember S2KOV, andy is now in canada...



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Offline tony

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Re: DIY 6SL7/2a3 SET Project
« Reply #12 on: Apr 20, 2017 at 12:25 PM »
i still get messages from Andy from time to time....

this 2A3 worked best when biased at 250 volts plate and 60mA cathode current, this is the thing to watch out for on power up...

so to complete the operating points, 250volts plate, 60mA current, and -45 volts grid bias....
how do we defend our freedom? by the truth when it is assaulted by Marcos lies....

Offline parasound

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Re: DIY 6SL7/2a3 SET Project
« Reply #13 on: Apr 20, 2017 at 02:03 PM »
Thanks Sir Tony, will set it to 250Vi use Bourns 100 ohms 2 watts VR (hum pot) - https://www.bourns.com/pdfs/3590.pdf

i still get messages from Andy from time to time....

this 2A3 worked best when biased at 250 volts plate and 60mA cathode current, this is the thing to watch out for on power up...

so to complete the operating points, 250volts plate, 60mA current, and -45 volts grid bias....



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Offline tony

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Re: DIY 6SL7/2a3 SET Project
« Reply #14 on: Apr 20, 2017 at 02:46 PM »
ever wondered why the plate load reflected 2.5k primary?
that is because at a plate voltage of 250 volts, plate resistance is 800 ohms approx. so that  three times that or 2400 will give more or less power with reasonable distortion...max power is at twice plate resistance but distortion will be higher...
how do we defend our freedom? by the truth when it is assaulted by Marcos lies....

Offline parasound

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Re: DIY 6SL7/2a3 SET Project
« Reply #15 on: Apr 21, 2017 at 11:30 AM »
Wiring Done



Pero meron Hum


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Offline parasound

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Re: DIY 6SL7/2a3 SET Project
« Reply #16 on: May 01, 2017 at 05:12 PM »
https://youtu.be/EFB0A1lWs2k


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Offline tony

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Re: DIY 6SL7/2a3 SET Project
« Reply #17 on: May 02, 2017 at 07:32 AM »
good job.....congrats...
how do we defend our freedom? by the truth when it is assaulted by Marcos lies....

Offline parasound

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Re: DIY 6SL7/2a3 SET Project
« Reply #18 on: May 07, 2017 at 12:12 AM »
thanks sir tony, to be continued on December. rewiring ulit
good job.....congrats...
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Re: DIY 6SL7/2a3 SET Project
« Reply #19 on: May 07, 2017 at 08:59 AM »
i told your friend when i talked to him about the basic practice that i follow when building amps, you can also use tagboards, that will make
your amp look clean, but the basic principles of running B+ and ground returns will be the same...
how do we defend our freedom? by the truth when it is assaulted by Marcos lies....

Offline parasound

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Re: DIY 6SL7/2a3 SET Project
« Reply #20 on: May 07, 2017 at 11:07 AM »
Yes sir,   Lessons learned, tira lang kasi ng tira, hehehe. But this time drawing ko na para mas madali at malinis ang layout ng parts, then i will use turret board. Time na lang kailangan ko, back to work na ulit.



https://youtu.be/sSTQOZddQik






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Offline tony

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Re: DIY 6SL7/2a3 SET Project
« Reply #21 on: May 07, 2017 at 12:32 PM »
23 weeks ang rotation mo?
how do we defend our freedom? by the truth when it is assaulted by Marcos lies....

Offline parasound

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Re: DIY 6SL7/2a3 SET Project
« Reply #22 on: May 07, 2017 at 01:43 PM »
yes sir.
 
23 weeks ang rotation mo?

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Offline tetablanco

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Re: DIY 6SL7/2a3 SET Project
« Reply #23 on: May 09, 2017 at 09:40 PM »
Wiring Done



Pero meron Hum


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Master TonyT told me that humming is a common feature of direct heated tubes.

Offline parasound

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Re: DIY 6SL7/2a3 SET Project
« Reply #24 on: May 09, 2017 at 10:34 PM »
Malaman natin pag balik ko at na i re layout yung components and tamang grounding..

Edrel S currently building one (same circuit) for him, malaman kung saan nagkamali.

Thanks

Master TonyT told me that humming is a common feature of direct heated tubes.



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Offline tony

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Re: DIY 6SL7/2a3 SET Project
« Reply #25 on: May 10, 2017 at 08:53 AM »
Master TonyT told me that humming is a common feature of direct heated tubes.

more so with 300b because of the 5 volts in the heaters, humdingers are definitely required...
there are those who advocate the use of Rod Coleman regulators,
but as Tim de Paravicini would have it, "i do not mix water with wine"
i tend to agree....:D
how do we defend our freedom? by the truth when it is assaulted by Marcos lies....

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Re: DIY 6SL7/2a3 SET Project
« Reply #26 on: May 10, 2017 at 08:56 AM »
Malaman natin pag balik ko at na i re layout yung components and tamang grounding..

Edrel S currently building one (same circuit) for him, malaman kung saan nagkamali.

Thanks



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grounding is real...
in all my builds, i use a common psu ground point,
where all wires that need to be at 0 volts are joined there...
another principle is that all B+ psu wires need a return to 0 volts ground, if you do this, then hum are avoided...
how do we defend our freedom? by the truth when it is assaulted by Marcos lies....

Offline parasound

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Re: DIY 6SL7/2a3 SET Project
« Reply #27 on: May 10, 2017 at 09:16 AM »
Maraming salamat Sir Tony for your very informative advise.


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Offline Abad Santos 7

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Re: DIY 6SL7/2a3 SET Project
« Reply #28 on: May 18, 2017 at 07:34 PM »
Nald,

Do not connect your safety gnd and your signal gnd directly together.
Your safety gnd should be as short as possible connected directly to your chassis.
Then the center tap of your power transformer connected to the first negative terminal of the filter capacitor.
Do not use this as the start of star gnd since this is the noisest. Tap another wire going to the 2nd filter capacitor. This point can now be considered as the start of star gnd or gnd bus.

From the 1st capacitor terminal, install a gnd loop breaker circuit to connect to chassis for safety.

Your audio circuit already indicated which terminal need to be connected to gnd bus. Just follow it and you will be good.

Cheers.


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Re: DIY 6SL7/2a3 SET Project
« Reply #29 on: May 18, 2017 at 07:56 PM »
yes, safety ground connects to one of the bolts holding the IEC power inlets,
it is bolted to the chassis at that point...this protects the user from shocks in case there is a power leakage to chassis...
how do we defend our freedom? by the truth when it is assaulted by Marcos lies....