Old School US Amps 50HCA vs. USA-50HC

[bigdwiz 10+ year member]

I recently bought a MINT 1992'ish US Amps 50HCA, which was sold to me as a USA-50HC. I think there has been much confusion over this amp style as I've seen 2 others just like mine for sale and they used the USA-50HC specs instead of the 50HCA's. My amp has "50HCA" on the circuit board and I found the model listed in the 1992 CA&E Buyer's Guide. I'm not sure what year the USA-50HC was introduced.

I got a spec sheet directly from US Amps and my model has "50HCA" marked on the circuit board.

So, what's the big deal or difference between the two? Well, my 50HCA uses a 30A fuse for power protection, while the US-50HC requires a 75A fuse! The ratings are very similar

The 50HCA's specs from US Amps are the following:

And here's a pic of my amp; US Amps 50HCA:

2 Questions:

1) Can someone verify my research above is correct

2) Does anyone have a manual (PDF) for the 50HCA? I can't seem to get US Amps support to scan it for me.

update: even Ampguts shows a model VERY similar to mine as a USA-50HC

US Amps USA-50HC - AmpGuts.com

A difference in my amp and the one looking VERY similar on AmpGuts is the end plate where the RCA's connect. The USA-50HC has a silk-screened "USA-50HC" on the end plate where mine has no model number noted on the end plate.

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[akheathen Premium Member]

the quickest way to tell, is to actually take a look at the board, circuitry, and take output voltage readings, really. there was a period where they actually cloned the orion hcca cheaters, before getting sued, and changing them again. the time they changed them, they moved to no lettering, and "x" series. i know someone knows a lot more about them than me, and hope they chime in, but it would like to see the gut shots of yours. btw, the ratings are seriously underrated, and at low voltage

 

[bigdwiz 10+ year member]

Thanks for the info, I should have posted a guts shot initially, but here ya go:

BTW, I'll test actual output power very soon using my setup:

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[Louisiana_CRX 5,000+ posts]

I amost bought that amp...you'll enjoy it They are very clean SQ wise

 

[akheathen Premium Member]

ah yes, same basic guts of the 150x of 99, or close to that year. bit more stable p/s, and lower capcitance bank, though. that means that it can take a little more abuse, but have lower peak output. my ps bench setup took a dump while i was trying to bench one, but i got 306.25w @4ohms bridge; 10v power. 2ohm bridged got 420wrms @9v ps...... you should expect to see similar, and 0ver 650rms somewhere 12.5-14.4 volts. if i get the time soon, i'll set up my 200x and see what that really does.

 

[PPI_GUY 10+ year member]

Glad to see some folks taking the time to bench these old school heros! Had a friend that competed with US Amps back in the very early 90's. All I remember is that they got REALLY loud on a couple of Kicker 15" Competitions in a sealed box in the back of his Blazer.

 

[gunz4me2 10+ year member]

Is it possible that the HCA is biased more towards class A operation? If so, that would explain the fuse rating. I currently own one amplifier that would pull 95 amps to make 400 watts RMS in its stock configuration. That amp was initially built as a high current amplifier and biased more towards the middle, so it is a tad bit more efficient (believe it or not). I used to own an old school amp that would pull the same amount of current to make 500 watts RMS. Of course I could be wrong and this wouldn't be the last time I was wrong.

 

[Heeltoeclutch 10+ year member]

30A fusing sounds low - I have a 50HC and it has 75A of fusing according to the manual... I thought the HCA was higher-performance?

edit: didn't notice you mentioned this //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif sry. still... oddity.

I love these old things //content.invisioncic.com/y282845/emoticons/inlove.gif.6846f78f06b405429ef3a00129788a2a.gif

 

[bigdwiz 10+ year member]

ah yes, same basic guts of the 150x of 99, or close to that year. bit more stable p/s, and lower capcitance bank, though. that means that it can take a little more abuse, but have lower peak output. my ps bench setup took a dump while i was trying to bench one, but i got 306.25w @4ohms bridge; 10v power. 2ohm bridged got 420wrms @9v ps...... you should expect to see similar, and 0ver 650rms somewhere 12.5-14.4 volts. if i get the time soon, i'll set up my 200x and see what that really does.

I'll try and get mine benched today and post the results. Only problem is I can't do 1ohm mono or 0.5 ohm stereo as my resistors can only be configured to 2ohms. I'm going to get another bank of them soon so I can do 1ohm.

Thanks for all of the info thus far, very helpful. I would still like the PDF manual if anyone has one to scan....not that I NEED it, I just like to have the manuals with all of my gear...KWIM?

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[bigdwiz 10+ year member]

I was expecting the 50HCA to be a beast, but not so much. Here are the results (RMS unless otherwise stated):

Test Voltage: 13.8v

4ohms stereo - 33.4w/ch

2ohms stereo - 59.6w/ch

4ohms bridged - 126.3w

2ohms bridged - 198.2w

Max Output at 2ohms mono - 282.5w (hard clipping)

(The 50HCA is rated to handle 1ohm mono and 0.5ohms stereo and I don't have the resistor bank loads to test these configurations yet)

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[mclerico83 5,000+ posts]

http://www.caraudio.com/forums/amplifiers/503660-amp-name-just-picked-up-dont-know-what-lol.html

his guts look similar to mine. i dont know much about these amps, when bridging it does it matter what positive and negative of the other channel i use. I know my orion hcca250 and 225 2nd gen are picky. I was wondering if u need an external bridging modulator like the original orion.

 

[bigdwiz 10+ year member]

amp name it, just picked it up dont know what it is LOL

his guts look similar to mine. i dont know much about these amps, when bridging it does it matter what positive and negative of the other channel i use. I know my orion hcca250 and 225 2nd gen are picky. I was wondering if u need an external bridging modulator like the original orion.

No bridging module needed, but I can't recall the wiring. I'll check later and post back. If anyone knows, please post.

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[mclerico83 5,000+ posts]

No bridging module needed, but I can't recall the wiring. I'll check later and post back. If anyone knows, please post.
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thx would like 2 know. dnt want to stink it up with a single sub

 

[bigdwiz 10+ year member]

Check the 1999 Owner's manual here. Bridging for the HCA50 is the same:

TECH :: US AMPS

Left negative and Right Positive for bridging

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