Parasound HCA-3500, Am I Crazy?

Hey Plato, International Rectifier makes some mosfets that are set up as switches and strangely enough Harris makes a replacement part that works well and does not spew a ton of second harmonic......Second harmonic comes across as a bright etched quality in the upper midrange and seems to be what audiogirl likes and dislikes in the two amps.......My partner has a nice test rig for checking out the spectral analysis. Funny, IR changed the parts from the introduction of the HCA3500 to the point in time we had prototypes of the JC-1s and we specified the change after Curl ordered fifty of each, IR and Harris, to test........Nothing is particularly easy, but changing over to Harris parts took care of the problem.......I posted the part no here a couple weeks ago for those with 3500s that wanted to fix the problem.........

Rcrump: Isn't it crazy how an individual component ( semiconductor ) that measures "flat" in terms of the primary amplitude linearity can actually alter the tonal balance of what one hears due to lower level distortions inherit to the part itself?

This is the kind of stuff that fools a lot of people even though the most commonly taken and interpreted specs look to be quite good. This is part of the reason why many components that "measure the same" sound "different" from one another. Without the proper test equipment and knowing how to really interpret the data, it would be easy to make such assumptions.

Kudo's to you for taking the time to both share this info and offer a detailed explanation as to the why's and how's. On top of that, you even made others aware of how they can easily upgrade their own components to a higher level of performance. Not many in the industry would be willing to do something like that, especially when they themselves offer similar services. Ya gotta respect that in an industry professional. Sean
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Hey Sean, thanks for the kudos, but Curl was the one who found the problem when he started testing the JC-1 prototypes and luckily there was a second source for the part originally developed by IR that didn't have the curve tracer drawing circles :-) Thought I would add my 2cents as a couple dollars of parts will make the HCA3500 a much better sounding amplifier.......

Audio girl,
I too own JC-1s and although I've never heard the 3500 seems to me the synergy with the rest of your system might be the deciding factor in what you are hearing.Also I believe true "transparency" should never be accompanied by etch and grain.You state that the bang for the buck Adcom 750 preamp(designed by Pass if i'm not mistaken)sounded even better than your Ayre(recommended by many as a top notch line stage and one I would consider if I were to get the itch to change my Pass X1,unless I should have the good fortune to actually be able to afford a CTC Blowtorch).Does that mean that the Adcom is BETTER than the Ayre?tThough it may be possible,I doubt it.Most likely the 3500 and the 750 combination of strengths and weakness-es better complemented each other.
On a sidetrack i see you are using au24 speaker cable.I'm currently looking to replace my recently sold AZ Hologram II SCs.My ICs are either Analysis Plus Solo Crystal 8 or Cardas Golden Reference and besides these two brands i'm considering the Audiences for SCs, even though i don't have the ICs.Unfortunately there is no local dealer.Before buying the au24s what did you compare them with and what was it that determined your final decision?it's been said that au24 SCs are comparable to anything out there,regerdless of price.my speakers are dynaudio c4s.
Your observations will be most helpful I'm sure.

This is going to look like a "love fest", but kudo's to you again Bob. Giving credit where credit is due is why you get the respect that you do. Honesty and friendliness are some of your best features : ) Sean
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PS... Crump is too big for me to say anything but nice things about him : )