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Re: 4xEL34 cathode bias ZNFB - done before?

9/16/2000 11:28 AM
EDGAR
Re: 4xEL34 cathode bias ZNFB - done before?
Hello Lion.  
 
There was an English amp brand, called IMPACT, that obviously had a short life somewhere around 1970-71.  
They had two 60W amp heads, one stright two channels, one with tremolo and reverb. They also had a 100W head and a mixer-amp and some speakers.  
 
I recently got hold on a 60W stright head, and have tried to get some information about theese amps, but with poor result. Not many have ever heard of Impact!  
One guy in England who has one after his father, had heard that they were built from excessed parts from Sound City. Anyone knows for sure out there?  
 
Never the less, a tube lover friend of mine, have a 100W head, and that one is built exactly like what You are asking for! Four EL34's with cathode bias and zero feedback!  
 
I don't think he have tested it very much, but I've got a simple shematic on it, which I can send to You, or put out on the web, if others are interested. I have also drawn up the shematic for my 60W amp.  
I'm just working with it, but it doesn't sound good, and I can't find out really why! Something strange happens in the p.i. stage. But the work continous!  
 
I would be happy to here from anyone who knows anything about Impact amps!  
 
I will put out what I have about these amps on this adress: http://www.edgaraudio.se/tubes/impact.htm.  
(Nothing there yet!)  
 
Regards  
"Edgar"

 
Replies:
EDGAR "I will put out what I have about t... -- 9/16/2000 2:32 PM