Looking for an affordable USB amplifier.
December 16, 2009 7:13 AM   Subscribe

Looking for an affordable ($100) USB amplifier.

I've switched over to digital for all my music; currently I use an external sound card (I think it's a "Xitel hi-fi link") to a phono input on my amp, which drives a pair of reasonable bookshelf speakers. I'm pretty happy with the sound quality, but the amp is on its last legs and I'd like to replace it.

I assumed that by now it would be possible to buy an amplifier with a USB input which could drive my speakers (i.e. doing the job of both the USB soundcard and amp). Just a box with USB input, speaker cable output and a volume knob. Or even without a volume knob!

But all I can find are audiophile products like this. Anyone know of a cheaper (£70/$100) version of this? Or is the market at this price point served by USB speakers?
posted by primer_dimer to Computers & Internet (13 answers total) 6 users marked this as a favorite
2.5 W is about the limit for the power output of a normal USB socket. And while that's enough power to produce something audible, it's not really going to do a very good job of powering a pair of speakers meant to be driven by a typical hi-fi amp.
posted by le morte de bea arthur at 7:23 AM on December 16, 2009

And the amp you linked to runs from a wall-wart (i.e. it's not USB powered)
posted by le morte de bea arthur at 7:24 AM on December 16, 2009

Response by poster: To clarify: I'm not looking for an amp that's powered by USB - I assume that it will need AC power. Just looking for something that will take USB input (i.e. appear as a usb sound card to my computer).
posted by primer_dimer at 7:33 AM on December 16, 2009

I would HIGHLY recommend the Art USB Dual Pre pre-amp/mixer. It's main purpose in life is as a digital audio interface for recording on your PC, but it's also a dandy output amp. Plug it in to your PC via USB, and it's automatically set up as a new sound device. You can output the sound from there via 1/8" or 1/4" stereo, either as a flat monitor signal or pre-amp'd.

The preamp itself can be powered via 12v adapter (included), 9v battery or via the USB bus, so it's very flexible. My experience is that the audio is very clean, especially at this price point, and pre-amp works great.

Mfg. page
User's Manual (Warning: PDF Link)

Costs $99 at most place. It's a great deal, and just handy to have around because it's so flexible.
posted by sprocket87 at 8:37 AM on December 16, 2009 [2 favorites]

Response by poster: Looks nice, I used to use a couple ART preamps for recording. Doesn't look like it's designed to drive hifi speakers, though.
posted by primer_dimer at 8:45 AM on December 16, 2009

Best answer: Ahh I misread the original question - thought your external sound card was on its last leg, not the amp itself.

Why do you want to integrate it with USB? Standard amps with phono inputs are cheap and plentiful (Killer 70s/80s-era amps are always available for a pittance on Craigslist). All the power you need to drive your bookshelf speakers and can take the output of your current ext. sound card just dandy.

But anyway, back to your original query, I don't know of any combination amplifier / USB DAI. They probably exist in the digital recording arena but would be pricey. I would stick with the two-device setup personally.
posted by sprocket87 at 9:10 AM on December 16, 2009

Update: Maybe the Griffin PowerWave? It only provides 20WPC of power but according to this MSNBC Review it does a remarkable job of driving even high-end hifi speakers. I think it's discontinued but was under $100 MSRP...
posted by sprocket87 at 9:23 AM on December 16, 2009

I'd recommend you replace your amp with a class T amplifier, like the T-Amp Type 2. Phenomenal sound from a small package.

Don't let the low wattage fool you - audio quality is not all about watts, and the t-amp should drive most any pair of bookshelf speakers beautifully. There are tons of reviews of these devices on the web, almost universally glowing.
posted by namewithoutwords at 11:32 AM on December 16, 2009

Whoa, awesome tip on that T-Amp! I'm going to have to check that out.

Taking it a step further: Sonic Impact, one of the T-Amp vendors/resellers, sells a PCI card-based amp. 30W RMS and supposedly kickin'. Looks good for $80. The audio board is basically identical to the original T-Amp.

You'll notice the card has 3.5mm minijack outputs for L/R speakers, but it comes with adapter cables for 3.5mm to +/- tinned leads that go to your speakers. Pretty slick.
posted by sprocket87 at 11:44 AM on December 16, 2009

Also of interest re: the T-Amp circuits in general: There's a pretty decent writeup about their SQ that mentions the following:
6. The T-Amp design works best in small rooms driving extremely efficient (>90dB) speakers. THD+N (distortion & noise) is quite respectable until you drive the Tripath chip above 5W output per channel. If you crank it up, THD+N rises to an icky 10% at full-power (15W into 4 Ohms).

7. For best results, use a stabilized AC power adapter that puts out no more than 13.2V DC at 1.2 amperes. The Tripath chip *will* be damaged if you overdrive the voltage. While we're in warning mode -- continuous operation at high volume *will* shorten the life of this amp - the circuit board doesn't have a heat sink and will get quite warm if you pump a lot of power through it.
Though it looks as if the updated T-Amp 2 version selling on ThinkGeek addressed the overheating & overvoltage issue.

So, this would be a great option if you have very efficient speakers and don't need to run at very high gain levels...
posted by sprocket87 at 11:51 AM on December 16, 2009

The issue is that you're looking for two different devices in one package: an amplifier and a USB DAC (digital to analog converter). As suggested by other, a T-Amp can be a great and affordable device to fulfill the amplifier part of your need. You should be able to find one for under or around $45 USD. The cheapest good USB DAC I know of is the Emu 0202, but it's around $100. There is also this Behringer device, but I don't know about its sound quality.
posted by paulg at 12:10 PM on December 16, 2009 [1 favorite]

The amp you want probably doesn't exist. There's no reason to make an amp with a USB audio in when there are perfectly good when SPDIF and audio over HDMI are so widespread. If you're stuck with your computer's current outputs, you'll probably have to continue with the Xitel (or the onboard thing), and tell yourself that you ears aren't that good.
posted by Monday, stony Monday at 9:47 PM on December 16, 2009

Response by poster: Thanks for all the suggestions. Guess I'll stick with the Xitel and pick up a new cheap amp - I was just hoping to take the opportunity to ditch a few cables :-)
posted by primer_dimer at 2:27 AM on December 17, 2009

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