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Pro studio recording equipment and music production/industry.

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RE: Best Amp for Audiophile

Posted by psemeraro@cfl.rr.com on August 28, 2010 at 14:22:02:
I'd like to conditionally suggest QSC as the best amp (and probably annoy Bob Lee at the same time...)

1) purchase CX502 for $250 in perfect condition from that auction site
2) audition and be very surprised overall how good it sounds
3) replace low voltage (housekeeping)power supply caps as standard maintenance with good quality cap of choice (I like Rubycon ZA/ZL)
4) add missing pair of 200v 2200uf power supply caps (available at QSC website)because you can
5) replace 100v 470uf power supply caps with 1000uf 90v caps (available at QSC website)because its cheap and you can
6) replace 33078 input opamp with LM4562, check with scope notice no oscillation and virtually no DC offset
7) jumper DC blocking cap after opamp before volume control
8) replace second DC blocking cap after volume control with 10uf 600v polyproplene of choice bypassed with .2uf teflon of choice (I will NOT engage in cap wars...)
9) perform final check on scope
10) audition and notice it sounds as good as anything you have ever heard
11) check sanity by soldering short wires and switch to first dc blocking cap
12) audition and notice that with real music amp sounds noticably less good with cap engaged, clearer, wider, "faster" etc with cap bypassed, much more "detail"
13) ask your self why people spend $10,000 on amps that do not sound any better or months building their own that sound far worse

My theory is that the "sound quality" difference between properly designed competing amplifiers (QSC, Bryston, Krell for instance)is actually the sound of the coupling capacitors (or lack of and to a MUCH lesser extent the sound of the opamps.