SAE X25 Class A Amplifier Circuit


We have an SAE X25 Class A Stereo Power Amplifier. This Amplifier have been "Butchered" by an inept service technician, sections of it has been modified beyond recognition. We wish to restore this amplifier, which we believe was particularly good, and use it as a reference amplifier against a very high quality valve amplifier we are developing. Does anyone have a circuit diagram of the SAE X 25 to help us to restore the unit to original condition? Please contact [email protected] or post details here.
poulkirk313e

Showing 2 responses by murphy_t

Hi. It has been awhile so I hope this gets to you. Just did this whole response offline and lost it trying to post to this site so I am not going to worry too much about errors. You raise some interesting points: 1) Crossover distortion was identified about 25 years ago by David Hafler who called it "notch" distortion so not to confuse it with problems caused by speaker crossovers. I think it is the main reason so many ss amps sound grainy in the high treble. For some reason (the quest for power?) it has been largly ignored bythe audio world. 2) Amp: N.E.W. has a class a amp, HCMaudio has (had) the 120 volt version on sale for $500. Audiovideotoday has the 12 volt version on closeout ($700?, I am not sure). The 12 volt version works off a large rechargeable battery, instantaneous and pure power. Nelson Pass published some class a designs in Audio Amateur magazine, takes a lot to build though. I have a sumo nine class a amp (60 watts a side) that I got used and did some upgrading and mods to. I wouldn't call it reference quality but it is very revealing of every tweek and change I have made. I have tried to salvage some trashed gear and it never seemed to be worth the time and money it takes. Also most good vintage gear gets a cult following and is talked about. I have never heard the SAE, nor have I heard of it. Could be a great amp, I don"t know. 3) Speaker cable: If you are developing cable for your own use then whatever sounds good to you is it. If you are trying to make cable to sell something than is too revealing may not be good. Audioquest makes many cables that punch up the bass and smooth out the highs. Sounds good in a 15 minute store demo so they sell well. Too revealing may not be marketable because of notch distortion. See RJM audio cable web page for more on this. Plus a lot of hype and BS in the cable's ad copy seems to help. Good luck with you project, Tim