Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: ammscray on May 19, 2015, 11:00:50 am

Title: Question about adding power amp in jack to Bogen
Post by: ammscray on May 19, 2015, 11:00:50 am

Hi I lurk here all the time but this is my first post thanks for looking!

I have a bogen 35 watt challenger that I use to power a leslie 147, but sometimes its too hot so I wanna be able to bypass the preamp when I dont need jon lord all the time :)

I also wanna rewire the master volume from its usless position and put it in front of the PI so I have the control like it was a leslie amp

so the question is, do I take the signal at pin 6 of V2B, then go into a new coupling cap say .022, then to a shorting jack, then into the master volume, then into the junction of the .01/330 ohm?

Or, do I simply take the output from the .01 cap at pin 6 of V3 into the jack, then the master volume, then directly to the grid of V3?

Any suggestions/corrections are greatly appreciated!

Title: Re: Question about adding power amp in jack to Bogen
Post by: sluckey on May 19, 2015, 12:08:47 pm

You need to think of V2B as part of the power amp. Here's what I'd do...

Title: Re: Question about adding power amp in jack to Bogen
Post by: ammscray on May 19, 2015, 01:37:24 pm

thanks Sluckey!

That raises another question then...b/c I was considering originally to insert the jack right BEFORE where the master is stock, to preserve the tone controls...would be nice to have them

 since I would be using 1/2 of V2 anyway if I do it your way, how much away from a power amp would it be if I did the above and used all of V2 and the tone controls?

a leslie 147 amp just has a 10K volume pot going into a 12AU7 as a PI into the two 6550s

thanks again

Title: Re: Question about adding power amp in jack to Bogen
Post by: sluckey on May 19, 2015, 02:04:03 pm

You already have that capability. Just plug into the aux input.

Title: Re: Question about adding power amp in jack to Bogen
Post by: ammscray on May 28, 2015, 02:44:48 pm

sorry man I had to go into the hospital....will try your suggestions as soon as I'm able
thank you

Title: Re: Question about adding power amp in jack to Bogen
Post by: PRR on May 28, 2015, 10:41:40 pm

> I had to go into the hospital....

Glad you got out.

(I was in and out last year. Got stab-marks but they are not even impressive.)