Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Soulchief on July 21, 2024, 10:20:10 am

Title: AB763 Style Power Amp Layout ?
Post by: Soulchief on July 21, 2024, 10:20:10 am

Hello all,

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

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

Title: Re: AB763 Style Power Amp Layout ?
Post by: tubenit on July 21, 2024, 11:40:48 am

Can you talk more about your thinking and how you will use the AB763 poweramp?  That might help us give you some more direction?


Do you have some kind of specific preamp you wish to run into the power amp? If so, what is it?


Are you planning to use an electric guitar thru it ........... or some other type of instrument?   


It's relatively easy to look at some of the AB763 layouts and modify them to be just a power amp.


With respect, Tubenit

Title: Re: AB763 Style Power Amp Layout ?
Post by: pdf64 on July 21, 2024, 12:08:29 pm

Why an OT with a 2ohm output?
2ohm cabs seem pretty unusual.

Title: Re: AB763 Style Power Amp Layout ?
Post by: Soulchief on July 21, 2024, 12:41:45 pm

OT — you’re right, my correction, meant 50w (cleanest headroom) multi-tap.

(Super is just always on my mind)

Electric guitar - yes
I have a Super Reverb with an effects loop someone before me installed (for some reason).

Lately I have been running some ‘Kingsley Preamps’ into the Return and thinking to build just that side of the amp (power) but with 50w Multi-tap OT for a cool mini rig to leave my Super at home.

Thinking Input and Volume before the Power section but no experience.


Any ideas will be helpful, thanks again

Title: Re: AB763 Style Power Amp Layout ?
Post by: Latole on July 21, 2024, 02:17:59 pm

Quote from: tubenit on July 21, 2024, 11:40:48 am

It's relatively easy to look at some of the AB763 layouts and modify them to be just a power amp.

With respect, Tubenit

It is like to ad a Line In and a master volume.

Title: Re: AB763 Style Power Amp Layout ?
Post by: tubenit on July 21, 2024, 08:44:27 pm

Based on what you're aiming to do ................. maybe something like this?  The active FX loop would be your master volume.


With respect, Tubenit

Title: Re: AB763 Style Power Amp Layout ?
Post by: DummyLoad on July 22, 2024, 02:47:51 am

https://www.hammfg.com/part/1760L

That part would work well.


--Pete

Title: Re: AB763 Style Power Amp Layout ?
Post by: Soulchief on July 22, 2024, 08:17:15 am

Thanks for all the input and suggestions.

Making a lot more sense now

Title: Re: AB763 Style Power Amp Layout ?
Post by: Dave on July 22, 2024, 08:22:38 am

Ok, I have hesitated to say this, but... Are you happy with the tone that you get from the amp you are using?
If so, why not open up the amp, find the injection point of the the FX return and simply copy everything from that point to the end.
Then add a PPI master volume control and call it a day.
It's a simple idea, gets you where you want to be, and you have an example to follow right in front of your face.


Dave