Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: chocopower on November 04, 2010, 01:25:18 pm

Title: Blackface champ effects loop
Post by: chocopower on November 04, 2010, 01:25:18 pm

hi there..

A friend of mine want a pasive effects loop in his champ clone (don´t ask why...)

where could be a good palce for it?

after the .022 just before the 6V6 grid or after the volumen pot?

thank in advance and sorry for the weird question.... :embarrassed:

Title: Re: Blackface champ effects loop
Post by: tubenit on November 04, 2010, 02:17:40 pm

To be honest with you, I probably would try after the .02 prior to the power tube first .................. & then also try after the volume pot and see which one I like the best with the effect of my choice.

It would just take a little bit of time to experiment with both.

With respect, Tubenit

Title: Re: Blackface champ effects loop
Post by: Fresh_Start on November 04, 2010, 03:15:47 pm

In the AA764 circuit, the NFB loop goes encloses the point where that .02 cap is.  IMHO adding effects at that point would cause problems because the NFB signal wouldn't match the original.

I'd try after the volume pot and/or between tone stack & volume pot.  The problem there is that you have only one of the two gain stages before the effects loop.  In a sense, the second gain stage is part of the power amp in that it's inside the NFB loop.

HTH

Chip

Title: Re: Blackface champ effects loop
Post by: PRR on November 04, 2010, 10:26:47 pm

The signal at the 6V6 grid is WAY too high for most effects.

The best place is probably before the input jack.

If he must cut into the amp, take the volume control wiper.

Title: Re: Blackface champ effects loop
Post by: Boots Deville on November 05, 2010, 07:13:43 am

LooseChange has had good luck with it in his Silver Face right after the volume pot.  I wouldn't think the BF would be much different.

Refer to his post in this thread:
http://www.el34world.com/Forum/index.php?topic=6916.msg60809#msg60809

Title: Re: Blackface champ effects loop
Post by: chocopower on November 05, 2010, 07:42:28 am

Quote from: PRR on November 04, 2010, 10:26:47 pm

The best place is probably before the input jack.

i agree with you, but he wanna try it...

I´m gonna test it after the volumen control.

thanks everybody!