ampage
Tube Amps / Music Electronics
For current discussions, please visit Music Electronics Forum. New: view Recent Searches.
New: visit Schematic Hell!
The sunn still shines online!

 
Listen to great tunes streaming live right now!

ampage archive

Vintage threads from the first ten years

Search for:  Mode:  
  View Thread

Signal after treble pot - impedance?

3/15/2000 7:51 PM
lion
email
Signal after treble pot - impedance?
I’m planning to make a effect loop in one of my DIY amps.  
 
I want to make it a parallel loop only – keeping the dry signal in the tube domaine – and mixing in the wet (digital delayed) signal.  
 
The preamp is pretty much standard, with a CF driven tone stack – into the PI.  
 
I intend to tap the send signal off the treble pot wiper - and pad it down a little through something like a 100k send-level pot.  
 
For the return signal I’m planning on an extra tube stage, to bring the level back up, and from that into the unused lower part of the PI (using the PI inputs as a mixer like some Matchless - and others, I think!)  
 
But I need some advise regarding the send signal. What would be the impedance after the treble control followed by a 100k send level pot?  
 
(There was some debate here regarding this a long time ago, but I didn’t save the thread – and I can’t remember the conclusion)  
 
I’m going for the best S/N ratio, so I’m considering whether it would be better to add a CF stage for the send signal, or I could do without it? - and use it in the recovery stage instead – running 2 triodes in parallel for a little less noise?  
 
The phase of the dry/wet signal should be allright (with or without the CF driver) – with the added recovery stage and mixing the wet signal into the other half of the PI – right?  
 
The usual expert advise, comments and help otherwise from this board will be highly appreciated.  
 
Take care  
Lion  

 
Replies:
Gil Ayan q{The preamp is pretty much standar... -- 3/15/2000 8:53 PM
Dietmar Engl has done a well fitted paralle... -- 3/16/2000 10:58 AM
dpcoyle You could have a noisy time trying ... -- 3/17/2000 9:38 PM