Chinese DIY amp kits...
Oct 31, 2008 at 7:06 AM Thread Starter Post #1 of 11

kingbuzzo

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EDIT: was able to find what I believe to be the Chinese shop they come from... http://www.maosheng285.cn/athena/off...389812260.html


Here in Vancouver we have an electronics store that sells diy amp kits.

Lee's Electronic Components

I put together one of their kits and am so far impressed (despite being an audio noob
tongue.gif
).

Comes as an assembled pcb that besides a case, pots, and jacks; it needs a transformer for power.

Wondering if anyone has seen these boards before and has opinions. Or maybe others would like to put together a an amp without having to populate pcbs.

My pcb was around $40 CAD says AD-2090 on the board...

here's a picture of the documentation sheet... it's mostly in chinese..

http://i3.photobucket.com/albums/y85...p/HPIM1212.jpg

here are some pics...

http://i3.photobucket.com/albums/y85...p/HPIM1210.jpg
http://i3.photobucket.com/albums/y85...p/HPIM1207.jpg
http://i3.photobucket.com/albums/y85...o/IMG_0016.jpg
http://i3.photobucket.com/albums/y85...o/IMG_0050.jpg

any thoughts?
 
Oct 31, 2008 at 10:00 AM Post #3 of 11

00940

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I don't see how they expect 200W stereo from this thing (undersized diode bridge, heatsinks, caps, etc). At first sight, I've also some issues with the layout.

It could probably be modified for headphones use only, by not using the big transistors. The drivers could probably be enough. The big heatsink could then be used for voltage regulators.

Still, at 40$cad, it could make a very decent little amp for desktop speakers or something like that. Especially considering there seems to be a protection system.
 
Oct 31, 2008 at 5:11 PM Post #4 of 11

kingbuzzo

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Maybe they gave me the wrong documentation. I agree that there's no way it's 200 watts. Looking at the site, it seems like it's the 50 watt one.

Unplugging the audio in on the pcb shuts off the power as I've noticed. However I just put a switch on the transformer.

I just wired the audio out straight to a headphone jack and have been using that. Should I have gone a different route?

I'd like to review if I had nice full size cans and another amp to compare it with. Right now I'm just using px100s, and Qjays in comparison with the amp in my D2. I noticed the soundstage and bass response jumped up a few notches right away. Makes the D2 sounds kind of digital.

FLAC -> M-Audio Transit -> AD-2090 -> Qjays/px100

I'll be getting some senn 595s soon, and I'll test with that.


thanks guys.
 
Dec 18, 2008 at 9:10 AM Post #5 of 11

kingbuzzo

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got a hold of the schematic to post. All the documentation is in chinese though =/

This schematic is actually for the 400w model, while mine is the 200w one. However the layout of everything should be the same.

 
Dec 19, 2008 at 12:33 AM Post #6 of 11

Hz_joe

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Quote:

Originally Posted by kingbuzzo /img/forum/go_quote.gif
got a hold of the schematic to post. All the documentation is in chinese though =/

This schematic is actually for the 400w model, while mine is the 200w one. However the layout of everything should be the same.





Chiness Documnet same - only 24~26V AC x 2 and output power 400W x 2. It seem to be impossible to get 400W at 26V AC x 2.
 
Jun 22, 2009 at 8:42 AM Post #8 of 11

kingbuzzo

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thanks for the help. I've put off the project for a while but have come back to it.

I'm wondering how I might modify this for headphone use, or whether it's worth doing for such a board.

thanks,

King
 
Jun 23, 2009 at 5:19 PM Post #11 of 11

kingbuzzo

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been reading this guide and I think I'll go with this instead so I can use the phones I already have. I'm guessing I'll go with the 40watt option or maybe lower?
 

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