Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Mats on May 04, 2010, 12:50:24 pm

Title: Cap in Stout amp
Post by: Mats on May 04, 2010, 12:50:24 pm

Hi !
I´m newcomer to tubeamps.
I have looked in some books about LTP inverters.
When I looked at the Stout amp, I see the cap to "7" is connected to the top of the 47k,
instead of ground.
Why is that, is it just in this PI or ?
What would it sound like if it is connected to ground ?
What is the purpose ?
/Mats

Title: Re: Cap in Stout amp
Post by: sluckey on May 04, 2010, 12:57:57 pm

The cap should be connected to ground. It's purpose is to hold the unused grid of the differential amp at AC ground reference. I've never heard Doug say why he connected it that way. My theory is that it's a 'happy accident'.

Title: Re: Cap in Stout amp
Post by: Mats on May 04, 2010, 01:08:30 pm

Tanks!
So its not a good thing to connect "the hoffman" way then ?
Or is it one of those things that one could try and see/listen ?
/Mats

Title: Re: Cap in Stout amp
Post by: LooseChange on May 04, 2010, 01:10:04 pm

Hook it up the Hoffman way.  It sounds good and is not "wrong" just different.

Title: Re: Cap in Stout amp
Post by: Mats on May 04, 2010, 01:14:06 pm

Hi !
Ok I will try it.
Thanks.
/Mats from Sweden