Aragon 4004 mk2 vs Adcom 555 mk2

Gmood1 - Ok, here is another argument for you - LOL! ;)

I read a McIntosh white paper on the power guards and the distortion sensing circuit has a super high input impedance (order of 1 Gohm) which effectively takes it out of the circuit. Very clever use of JFETs.

The smooth, thick sound that McIntoshes have is probably due to fairly high negative feedback IMO. The Mc guys are all true electrical engineers so NFB is a requirement in their book (and mine too to some extent). The newer designs use less NFB than the older ones like our amps due to BJT improvements but nonetheless, it is a type of sound you have to like to appreciate, I realize. The upshot is that they are indestructible (especially with autoformers but I digress...) and have lower distortion than most amps out there.

Anyway, good system matching is most critical for hi-fi sound regardless of the equipement used. The best sound I have ever heard was a McIntosh MC602 (and C42) with Martin Logan Prodigys. Wow - I will never forget it. One day I will have Mcs and electrostats as the synergy was obvious in the first 3 seconds of music - it sounded like 600W of crystal clear tube amps.

Cheers and enjoy the music! Arthur

I got a question for all of you on feedback. Some people say they can hear feedback in amps, others say they cant. What does negative feedback soundlike? Background noise? I know my cd player is a 0 feedback design, and I run all balanced xlr connections, plus my amps are true balanced designs too(but Im not sure if they are 0 feedback designs, probably not)but I cant hear any extraneous noise when music is playing or between passages or tracks. What am I listening for(if its even possible to detect it in my system)?

Good question Ritteri....well it's not an audible noise.I didn't notice it until I switched the the Mac out with the Monarchy.The Monarchy is supposed to be no feedback.And take also into account the wattage (monarchy)25 wpc verses (mac)300 wpc.Instantly I could hear more background noise..especailly in live recordings.Not hissing noises but people talking and laughing.There was just more ambience of the recording venue getting to my ears.Since then I have been ruined and only listen for amplifiers that can do the same thing.Not even my now removed Music Reference RM9 MKII which is a terrific tube amplifer had that kind of depth.I don't know the specs on feedback with my Adcom 585 but it must be very low because I can also hear these same attributes in it. Instead of just hearing people shouting in the audience you can hear their voices echoe off the walls of the venue.It's just easier for me to hear, when the singer turns his or her head away from the mic and what direction they turn.

Hope this gives you an idea!

Hmmm, Im gonna have to start a new thread on feedback. 0 feedback designs, and if 0 feedback is necessary onlly in the source if using xlr's or the opposite etc.

Gmood1...Negative feedback just means that the amp output is compared with the input, with appropriate gain and phase compensation, and the resulting "error signal" is applied to the input (or at some intermediate stage) so as to reduce the error signal to zero (nearly). There is no fundamental reason why negative feedback is bad, but if an amp requires too much this probably means that the circuit is not too hot to begin with.

Tube amplifiers that use transformers must have negative feedback to get flat frequency response, quite apart from the issue of distortion. The widely used "ultralinear" configuration has taps on the output transformer specifically for the purpose of negative feedback.