It never ceases to amaze me how difficult "budget" amps make it for me to test them. Whether that be unstable voltage, messy, noisy or generally funky AC waveforms, inconsistant QC and/or results... whatever. They make it pretty difficult to get an idea of their performance.
I've also been asked why in the hell I "waste my time" testing amps like this. Well, it's because people are broke. And I know people are going to buy budget amps no matter what I say or no matter how much I advise against them. So, let's at least see what people are getting themselves into. That- and we all know what "good" amps do. AND maybe, just maybe... one day we will strike gold on that magical amp that defies the "you get what you pay for" golden rule.
With that said... I made a pretty scathing post about the Pure Audio 3000 in the Zv.4 vs HD thread. I got a brand new, in box amp to test for the owners and just reported what I got.
The amp made 80v clean
unloaded. But AS SOON as I put a load on it, it went to shit. On that particular occasion, I went right to 1 ohm resistive and saw this from the gain and volume position where I had set it unloaded.
Yeah... that's fugly. That's ~ 2,600w at 1 ohm resistive and 57% efficiency.
Well, upon further inspection... I found that I couldn't make the sum'bish do clean voltage no matter what I did. This is making a whopping 18w @ 2.5 ohms resistive at gain and volume position nothing.
Still fugly. All of this was a bit of a head scratcher because this was the 3rd one of these I'd tested and the other (2) weren't anything like this. AND it made 80v clean unloaded.
It became pretty obvious that the amp I have may be a bad one. So, to verify, I had the guy from this test...
My test: Pure Audio PA-3000.1D (quick and dirty) bring one of his in for me to double check. I just ran a quick test of it at 2.5 ohms resistive and it came out just fine. It did 775w @ 2.5ohms and 12v with 73% efficiency. Not earth shattering, but at least it was clean. Noisy... but not clipped.
This is the kind of shit that happens when you buy new at $0.10/watt. But whatever. I'll pursue more comprehensive testing of it when I get the time. And a new amp.
For the second half of this... A Popcorn 6k made its way into the shop somehow. This isn't going to be a full write-up, just a quick screen shot and initial impression.
When I went to snatch this thing up, I had to get my feet under me. It's much heavier than I thought. And you guys know I like hefty amps. It's a big bish. Like a 6k ought to be. I don't have any pics of it, but there's plenty out there. Dual power and grounds. And I suspect they're 2/0 because 1/0 "CA" wire went in smooth with no frayed stands. Single set of 8awg speaker outputs. Lame, but whatever.
I set about setting it up like I always do. Unloaded with a scope and voltmeter. This is where it gets into the making it difficult for me part. I couldn't find a sweet spot on this thing. It was either millivolts or between 120-170v. And when I say "between"... I mean it. It was jumping all over the damn place. 123, 162, 154, 131, 173, 140... WTF?!?! Ugh. AND the wave looked just like it does in the loaded screen shot. Shit on it. I left it at the minimum gain position where it was making anything over millivolts.
I didn't have a ton of time to test, and since 2.5ohms resistive is my new favorite load...
What you see here is ~ 2,100w at 2.5ohms (resistive) at 11.8v pulling 220A (~ 80% efficient) and whatever THD you want to call that wave. That's as good as I could get it.
I don't know what the amp is rated for- 6k @ 1, 3k @ 2, maybe. So it's right there at rated on fixed resistance and really low voltage. And with good efficiency. Not so clean though.
So, stay tuned for more testing of that one too.
Pure and Popcorn. Exhausting.
Pure and Popcorn
if u peek inside, there's a tracer/resistor/cap that needs a tune up, Murphy knows 
Linear Mode
