Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Searing on March 03, 2011, 07:14:28 am

Title: AB763 in a box?
Post by: Searing on March 03, 2011, 07:14:28 am

So, I want an AB763 in a box, like the project Doug has on his site.  I will be using a solid state amp with it.  I just need an input, V2, and the tone circuit, Volume, Treble, and Bass.  A master may be helpful also.  I think?!?  I want to put all of this into the box Doug used for his project.  I don't think I need 2 tubes do I?  So I will send this out to a solid state amp.  Will this work?  Any suggestions on doing this?  Thanks!

Chris

Title: Re: AB763 in a box?
Post by: sluckey on March 03, 2011, 07:31:44 am

One tube will work for a single channel AB763 preamp. The output would be meant to feed into a power amp, not the instrument input of another amp (ss or tube). But you could pad the output way down to feed into the instrument inputs.

Title: Re: AB763 in a box?
Post by: Searing on March 03, 2011, 10:23:08 am

So, looking at the Schem for AB763 I would tap it out right before the 2 220k's?

Title: Re: AB763 in a box?
Post by: Searing on March 03, 2011, 11:19:22 am

And, I would only need power for the heaters in the one tube right?  No other power would be needed?

Title: Re: AB763 in a box?
Post by: Willabe on March 03, 2011, 11:44:15 am

Quote from: Searing on March 03, 2011, 11:19:22 am

And, I would only need power for the heaters in the one tube right?  No other power would be needed?

No, you still need the B+ for the plates of that tube, also.


            Brad        :smiley:

Title: Re: AB763 in a box?
Post by: Searing on March 03, 2011, 12:55:44 pm

Ah, and with that B+ I would need a couple of filter caps.  How many?

Title: Re: AB763 in a box?
Post by: thermion on March 03, 2011, 01:11:45 pm

I've used: PT -> 2x 1n4007 -> 2x 20uf for single dual-triode preamps and it works nicely.