Sunday, October 9, 2016

Amplifiers ARE different

Krell FPB 300 has been taken offline.  Amplifier a friend says may be the best I have, the Parasound HCA-1500A, essentially the brilliant Curl amplifier design that has lived on through upgrades in the 3500, JC-1, and beyond.  Curl knows what he is doing, we agree.

It doesn't take long for me to hear the difference.  It is brighter, more forward.  The image comes slightly in front of the plane of the speaker.  And deep images are just as deep, kind of beyond forever in the background.  The Krell has a more subtle depth, what I call "layered," which seems more real.

About the brightness too, one might consider it "more open," or even "more transparent."  But I feel the Krell is equally transparent, just more subtle.  The Parasound, to me now, seems artificially lightened, as if someone turned on the stage lighting.

I'm thinking this comes down to You Can't Fool Mother Nature.  A low bias Class AB amplifier is not going to sound like a Class A amplifier with enormous reserves.  The Class AB no matter how well designed is ultimately going to give away the cheat.  (And it could be that my 20 year old Parasound needs a bit of a tune-up, to reduce the crossover notch.)

And the regulated power helps too.

I need the higher power too.  By my meters and calculations I have already put the Parasound beyond its ratings and probably it's limits, discovering the huge musical crash that starts "Her Majesty" on Abbey Road.  The Parasound clips at a lower input voltage which my DAC can exceed, but it also has more gain so I may have been playing louder than usual too.  So without adding more gain to the Krell, the actual limits are about the same, but I can't push the Krell into clipping or near it, and I can with the Parasound, adding an extra barely noticable strain (you can't tell much in the Her Majesty crash).

But this could be all wrong.  I'm not setting up my ABX test rig to test Parasound among other smaller amps until I get the Krell back from repair.  If I feel safe about this, I may ABX the Krell then also.  Hooking the Krell up has always seemed too dangerous though it has always been in the hoped future.

This is threatening the universe of magic to collapse for sure.  But I know how to understand such things.  My suspicion already is that I won't be able to tell differences.  But that won't mean I'll concede nothing matters.  I'll just know I've found a real subjective/objective anomaly, a doorway to greater discovery.

My long term plan has always been to have ABX available at all times.  Preamps IMO should have ABX capabilities built-in, and that's what mine will when I get around to building it.  For starters all inputs should have adjustable gain using the lowest noise amplification if needed, OPA211's.

I'd been playing the marvelous Saint Saens on Reference Recordings on SACD on my 9000ES.  After a month offline, I hooked up the Denon DVD-9000 and stuck the disc into that machine to see if its CD layer was HDCD.  Indeed it was, and I played that.  Did not sound anywhere near as good as the SACD.  Grainier, lumpier.  I'd never heard that same grainyness on the Krell.

So the Parasound is making SACD sound relatively better, and R2R sound relatively worse.  I'm also suspicious of the CD layer on that SACD.

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