parasound hca 1000a

[infiniti52]

I just bought my first hca 1000a and would lik eto upgrade the parts in it. for example it has 12 .33/3w ceramic/sand resisors. Can I use like mills mra's or carbon types for warmer sound. All electgrolytics caps elna cerafine.nichicon mus or black gates and finally the film caps with maybe soniccaps,auric caps etc.

Your opinion would be appreciated. i use 4 tannoys and going to buy another hca 1000a or hca 1500.

[DCPreamp]

The HCA1000a is a fantastic amp already. I own an HCA3500 and love it.

As far as mods to improve the sound, I wouldn't do a thing. It's designed by John Curl, who graces this web-site by the way, and really has no weaknesses to make up for IMHO. It uses excellent quality components, a very clean layout and topology, and is DC coupled (no caps in the signal path). Anything you do will simply reduce the reliability of the amp and in all likelihood worsen the sound (though, without double-blind testing, may be perceived as an improvement). Other's on this site may have suggestions for improvements, but after combing through the schematics of my HCA3500, I can't spot any obvious weaknesses.

I know it sucks with that gut feeling of "what's next?" As far as your amp goes, nothing's next. Just enjoy it as it is. Now speakers, on the other hand, in all reality are the weakest link in the audio chain, but I digress. . .

[john curl]

Well said, DC. The HCA1000a is a small amp, it is compromised in some ways, but it is difficult to rebuild and get much more from it. Think of a Honda Civic. Could you really make one perform much better without adding a lot of money and effort to it? Why, instead, not buy an Acura for the same added expense?
I have an HCA1000, and it WAS upgraded in future products to the HCA 1000a. What I first found wrong with the 1000 was too small filter caps, BUT there was no extra room at the time for any more capacitance. This was partially fixed with the 1000a.
Everything else SHOULD be sort of OK, but IF you find something suspicious, tell me.
I use my 1000 for my video system, when I want more fidelity than the TV sound, itself.

[birdyman]

My hca-1000a had few issues with capacitors. It had leaky four power supply caps and 2 film caps (0.05k 100 FULL PSB), at bias circuit, were shorted. I replaced filter caps from 10000uf 63v to 15000uf 80v and replaced all electrolytic caps and all four 0.05uf (0.05k 100) caps. You might want to check those caps. I am excited to hook up my HCA-1000a tonight.

[john curl]

Leaky caps with vintage cheaper amps can be a problem. They are Chinese, and we found they exaggerated the specs to market better, BUT they sometimes went into thermal runnaway and burned up the amps. This was a BIG problem with Parasound and another similar company (where Dimitri works now) and I had to work with the other engineer to get to the bottom of the problem. I love Japanese caps.