Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: jerrydyer on April 09, 2012, 02:35:17 pm

Title: Dougs loop
Post by: jerrydyer on April 09, 2012, 02:35:17 pm

I see on Dougs library of info, a loop he used on his 50 watters. between the treble and MV with a tube driven receive buffer before the singal goes off to the PI.....I dont know why, but this is the only loop I haven tried yet. I love the simplicity of it. Have any of you tried it yet? Hoping to get some people to chime in before I dive in tonight.. Thanks to you in advance.

Title: Re: Dougs loop
Post by: Tone Junkie on April 11, 2012, 01:59:20 am

Jerry Ive looked everywhere and i cant seem to find what your talking about.
Thanks Bill

Title: Re: Dougs loop
Post by: topbrent on April 11, 2012, 09:21:56 am

This is the one in question.
(http://www.el34world.com/Hoffman/images/H50pre.gif)

Title: Re: Dougs loop
Post by: jerrydyer on April 11, 2012, 10:38:12 am

sorry, yes I should have posted that pic. I figure most of the guys here have tried it at some point..  I like the way it looks. Tube recovery but just a simple voltage divider bringing the signal down. Its a minmalist approach and I want to use it. I started wiring it up last night. if anyone has tried it let me know what you decided about it. thanks

Its funny looking at all these cool marshall hotrod tricks Doug has had up forever and on some of the other forums I go to, they think all these variations are something new. Ive given up on most forums. Mostly kids being stupid. I still always come back here for good solid factual help.  RigTalk is a cool one and metro is still good more the most part but the old pros are here.  :worthy1: :worthy1: :worthy1: :worthy1: :worthy1: :worthy1:

Title: Re: Dougs loop
Post by: jerrydyer on April 13, 2012, 12:50:06 pm

Loop is in..sounds awesome. I cant hear any tonal changes but I dont have a bypass switch so just trying to go by ear. Its my circuit so I know it well. Sounds great. One prob, the tail of the reverb gets louder when switching to my clean channel ...I use a vactrol system to switch channels.

Title: Re: Dougs loop
Post by: tubenit on April 13, 2012, 01:35:24 pm

As I understand the layout, this would be Doug's loop with the exception of the send jack which would not be shortening & the additional .02 coupling cap going into the LTPI.

With respect, Tubenit

Title: Re: Dougs loop
Post by: jerrydyer on April 13, 2012, 02:57:24 pm

pretty much dead on.. I have two channels meeting in the same spot. one is crunchy one is clean. my rv3 reverb tailing off comes up in volume as i switch from crunch o clean but not in reverse. any remedies?

Title: Re: Dougs loop
Post by: EL34 on April 28, 2012, 03:00:22 pm

Late to the party, I don't check here every day

Anywho, that loop works great, hope you like it.
Add the Meat control for some gut churning bottom end.