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Chinese Mini Amp Invasion


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I thought I'd investigate some of the recent ebay amps people have been using.

 

Well as usual, Buyer be warned.

These 12volt DC amps claiming 20/25 Watts RMS are far from the truth.

 

You are more likely to get 2~5 watts RMS and some pretty heavy clipping when driven even moderately.

 

Bench Tests

Chinese Mini Amp Invasion

 

LP-V3

 

LP-2020A

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I have a few and they work great for me. They've been around for many, many years.

 

I think it depends on usage, application and expectations.

 

I'd never use one to power a jukebox or high end speakers, but for arcade speakers they're more than adequate.

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My 90's Denon bookshelf/desktop amp died a week ago, and I changed it out for a Lepai 2020A+ i'd been playing around with last year - installed with new caps, coils and op amp to bring the total spend to about $30, though I already had a 12V 3.3A power supply lying around. It works really well for the money. Driving the same 6ohm speakers it doesn't sound quite as rich, but it goes louder than i need without clipping or distorting - interesting to hear that's only about 6W RMS though! But I was only using about 10% of the Denon's power output anyway.

 

I was thinking i'd use the Lepai as a stop-gap until i could look into a real amp, but there's really nothing wrong with it and i've already forgotten i'm using it. I'm hardly an audiophile, but when i was looking into cheap amps these seemed to be far and away the best bang for buck, or smoothest bang if you like, being based on the Tripath 2020 discrete chip. Sadly they've changed the design for the newer models, though you can probably find the older models if you hunt around.

 

In other news my Dad, who is an audio freak, has been getting into the Class A/D hybrid stuff by Devialet. He's going deaf though, and my mother doesn't let him turn stuff on in the house (he has headphones for that) so i haven't actually head what the loudspeaker sounds like. Damn heavy, weird-looking thing, though :)

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I bought a box of 5 of these type. Can't remember model. Cost me about $30.00 shipped about 5 years ago. Only ever used them in arcade machines and apart from one install that suffered badly from line noise (from the power supply) I've had no issues. I'd never use one for music output though. RMS is shite.

 

Brad

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Just from a technical point of view.

They have 2 amp power rating on the back. Your only ever going to get about 2 watts RMS from that sort of power supply.

Doesn't matter what the amp is.

 

For 20 watts RMS per channel you NEED about 6~7 amps @ 12 volts (Possibly even more, Can't remember specifics).

For 10 watts RMS per channel I use nothing LESS than 5 amp @ 12 Volts.

 

I really can't agree less on the importance of sound in Arcade, It's half the experience.

My original PCB's (especially Mortal combat and Gyruss) powered out the sound.

And the only amp I have found that can match that output is this:

K5136: 12V 20 Watt Amplifier Module Kit

 

And yes, You'd be mad to use those cheap amps in a jukebox.

 

Funny how Display (CRT) gets so much attention to accuracy but sound is somehow not important.

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Just from a technical point of view.

They have 2 amp power rating on the back. Your only ever going to get about 2 watts RMS from that sort of power supply.

Doesn't matter what the amp is.

 

For 20 watts RMS per channel you NEED about 6~7 amps @ 12 volts (Possibly even more, Can't remember specifics).

For 10 watts RMS per channel I use nothing LESS than 5 amp @ 12 Volts..

 

I really can't agree less on the importance of sound in Arcade, It's half the experience...

 

...Funny how Display (CRT) gets so much attention to accuracy but sound is somehow not important.

 

I'm using more powerful 2.1 systems in my cabs, oddly enough. But the cabs don't need that kind of bass capability, IMO. The 2.1 systems were just convenient when i needed something to drive a PC source that had remote control. And the original setup something like a lowboy came with was never particularly flash, was it?

 

Interesting about the power requirements though, i hadn't really thought about it. It still seems like 3.3A should be enough to get 7W-8W RMS, though it'd be interesting to test a higher amp supply and see how it clips at higher volume vs a smaller supply. Where are these amps marked at 2A, btw? A lot of them come with a 2A supply, but if you look them up on any audio mod forum the suggestion to go higher is easy to find.

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