Parasound HCA-3500, Am I Crazy?


Hello to all,
I recently borrowed a friends Parasound HCA-3500 power amp just for the heck of it. [I was always curious how this amp sounded].
I unhooked my Parasound Halo JC-1's and hooked up the Parasound HCA-3500 in its place.
Much to my shock, there were some things that the 3500 seemed to do better than the JC-1's in my system:
The HCA-3500 actually sounded more transparent, open, and more extended on top than the JC-1's! This was especially true at lower volume levels.
The HCA-3500 also seemed to have a deeper soundstage, and a blacker background.
The JC-1's seemed superior in most other regards, however.
The JC-1's sounded smoother, cleaner, had slightly more body, more detail, and better bass control than the 3500.
The 3500 did sound a touch etched and slightly grainy, but it sure sounded damn clear, open, and transparent!
How could this be?
Anyone else out there experienced this?
Break-in is not an issue. My JC-1's have close to 1,800 hours on them.
I am just puzzled folks, thats all.
audio_girl
audio_girl

Showing 3 responses by rcrump

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........
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.........
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.......