Parasound HCA-3500, Am I Crazy?

Audio_girl,

Excuse me, but since I don't know you or your experience level, I have to ask:

Did you use all the same power cords, interconnects, and speaker cables when you performed your evaluation? Or, did you try different things to try to optimize the performance of each amp? Were they plugged into the same AC line? Through an AC conditioner or not? Did they use the same mechanical-coupling methods or vibration control? Heck, I've heard some gear sound appreciably different just by setting the component on a different surface or by using different footers.

On the surface, one would think that performing the evaluation keeping everything exactly the same would be the fairest possible methodology. In my experience I have found that this is not always to be taken for granted.

These days, when I make such comparisons, I try to optimize the installation for each amp (or other component) so that each piece will sound as good as I can possibly tweak it to sound. What works best for Amp A may put amp B at a disadvantage (and vice-versa). So what, on the surface, would appear to be an impartial evaluation or observation, may be (unintentionally) slanted due to factors that simply may not have been considered. Your comments about the 3500 sounding "grainy" or "etched" might be right on the money -- but they could also be telling you that the 3500 does not like the same cabling or footers (or whatever) that work well for the JC-1's.

If you haven't had the amp to play with and tweak over a period of time then you probably have not heard it at its best. Brief shootouts can be misleading. Extended evaluations over time are more reliable indicators.

I don't own either amp you're speaking of, so I have no stake in the outcome one way or the other. But I do like to see things done fairly and competently. For sure, there are a lot of variables to consider.

It's just food for thought...

Plato,
I have extensive experience setting up gear for comparisons.
I am still borrowing and using my friends Parasound 3500 as we speak. He did say that he had removed the stock Vishay 47K feed-back resistors and replaced them with Holco 47K ones. He said this was the only deviation from the stock units.
I have tried various cables and vibration control devices on both amps, and the results are basically the same. I use dual dedicated lines for the amps. I use a Shunyata Research Hydra 8 power distribution device as well.
I also tried out an Adcom GFP-750 preamp with the HCA-3500, and it matches up really well with it! Actually the 3500 sounds better with the Adcom than it does with my Ayre preamp! Low volume detail, transparency, and openness is remarkable with this combo. It is great at higher levels as well, but really shines at lower volume levels.
While I overall prefer the OVERALL sound of the JC-1's, the 3500 is remarkably clear, transparent, and has extremely extended highs. It also have remarkable image depth. Again, the main drawbacks are a slight etch and some slight grain on certain cd's. LP's sound marvelous on the 3500.

Audio girl, the HCA 3500 has a ton of 2nd harmonic distortion compared to the JC-1 and that is probably what you like and dislike about the 3500........I changed out a couple of mosfets and the 2nd harmonic dropped dramatically and the two amps sounded quite a bit more like each other with the JC-1 being a significantly better amplifier for long term listening.......faster, cleaner and things that a better layout will allow in the JC-1...........The etched sound of the HCA3500 sure can be addictive as several folks have reported liking the old war horse better than the JC-1s, but once the 2nd harmonic is reduced it can become a much better amplifier........

Audio_girl,

It appears you've conducted your evaluation very well. Thank you for sharing the details; it's always helpful to be aware of such things. I don't take anything for granted these days.

Rcrump, what, in your book, equates to "a ton" of 2nd harmonic distortion? I thought it was mainly tube amplifiers that were guilty of that. Shucks, now I have to wonder whether I like my solid-state amps because they are accurate or because they also mimic tube distortions.

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.........