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SOLD: Custom high-end portable

post #1 of 8
4/19/10 at 8:20pm
Thread Starter 
SOLD

My transportable amp, just slightly larger than the Hifiman HM-801 so the player sits well on top of the amp.

It has an Alps RK27 pot, runs of 2x 9V, ground channel design similar to Larocco PRII with LT1210 (1A current sink), left/right channels run off 2x OPA627 with a discrete Class-AB output stage. Battery life should be around 12 hours. I'll include a 24V adapter to charge batteries. Those silver caps are actually 220uF/25V BlackGate FK going from rails to ground. Another 220uF/35V Elna Silmic II sits across the rails beside the ground channel (hiding the trickle charger for the batteries under it). Sounds pretty damn good too.

Input: 3.5mm Mini
Output: 1/4" TRS

Photos:


Price is $200 shipped and I'll include a short Mini-Mini I've been using.

Thanks
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post #2 of 8
4/20/10 at 4:07am
How well would this fare compared to a desktop amp?
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post #3 of 8
4/20/10 at 5:04am
Thread Starter 
Is that really a complete question? "Fare compared to a desktop amp" - in which regard?

The amp has enough voltage swing and the Class-AB output stage can deliver tons of current. The PSU design and ground channel is fairly simple and very good and using batteries makes for a very dark background.
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post #4 of 8
4/20/10 at 11:01am
compared with SR-71A?
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post #5 of 8
4/20/10 at 11:42am
Well mainly SQ wise . My D2000 does not need that much juice so this might be an option. Just need to figure out if I want to deal with batteries at home...
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post #6 of 8
4/20/10 at 1:53pm
the design looks very promising, I wish I have some electronic skill, so I can squeeze it a little smaller.
But I'm sure this sound great.
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post #7 of 8
4/20/10 at 10:21pm
Thread Starter 
I'll just number responses to above 3 posts:
1) Don't remember hearing SR-71A
2) It's a killer portable amp easily besting a lot of "budget" home amps (mostly any stationary amp at this price is "budget"). Mostly portables simply can't delivery the voltage and current output that home amps can. This was fixed using a Class-AB discrete output stage running off 2x 9V batteries. Enough voltage swing, enough current headroom. As size wasn't my biggest concern, performance was, it is a trade-off I accepted.
3) Yes, the design is, for lack of a better way describe - freaking awesome and I like the amp personally, both with uber sensitive IEMs like JH13 and even threw a pair of 600 Ohm AKG K240 at it and they still sound damn good.
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post #8 of 8
4/22/10 at 6:41am
MINE
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