AB763 Style Power Amp Layout ?

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Soulchief
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Joined: Tue Nov 08, 2022 7:31 pm

AB763 Style Power Amp Layout ?

Post by Soulchief »

Hello all,

I would like to build an AB763 2-6L6 style power amp section only with a 1/4” input.

Maybe with a Super Reverb OT.

I know the Power Amp Section begins at the .001uF Coupling Cap entering the PI.


Does anybody know of or have a layout to correctly add Input Jack and Volume Control and anything that needs to be adjusted ?



Thanks for any help and advise
sluckey
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Re: AB763 Style Power Amp Layout ?

Post by sluckey »

Here's mine...
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Soulchief
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Re: AB763 Style Power Amp Layout ?

Post by Soulchief »

Oh wow thank you!

Regarding my initial post, I misinformed about Super Reverb OT (2 ohm), SR was in my brain, just planning 2-6L6 - Multi-Tap OT or just 8 Ohms.

That schematic looks great!

The main value changes I see are the .1 > .047 PI to Power Coupling Caps -- and -- 220 > 1R Grid Leak Resistors

For Power Section only build like this, do you recommend to keep these adjusted values from original?

Planning to go with 2 6L6 if any difference..


Thanks again
sluckey
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Re: AB763 Style Power Amp Layout ?

Post by sluckey »

Soulchief wrote: Sun Jul 21, 2024 6:04 pm The main value changes I see are the .1 > .047 PI to Power Coupling Caps -- and -- 220 > 1R Grid Leak Resistors
It's popular to use .047 rather than .1 coupling caps for a tighter bass sound. You do not need to replace the 220K grid leaks, especially with a 1R resistor!

Fender's smaller 2x6L6 amps used 10K and 10K power supply droppers while the larger 2x6L6 amps used 1K and 4.7K droppers. I would use 1K and 4.7K for a 40 watt (or greater) size amp.
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xtian
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Re: AB763 Style Power Amp Layout ?

Post by xtian »

Soulchief wrote: Sun Jul 21, 2024 6:04 pm1R Grid Leak Resistors
No, the 1R are bias sense resistors.
I build and repair tube amps. http://amps.monkeymatic.com
Soulchief
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Joined: Tue Nov 08, 2022 7:31 pm

Re: AB763 Style Power Amp Layout ?

Post by Soulchief »

xtian wrote: Sun Jul 21, 2024 8:35 pm
Soulchief wrote: Sun Jul 21, 2024 6:04 pm1R Grid Leak Resistors
No, the 1R are bias sense resistors.
Oh yes I see that now. I accidentally skipped a path with my eyes.

Thank you all so much!
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