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Old 26th April 2009, 04:43 PM   #11
Minion is offline Minion  Canada
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I recently bought a 2 x TDA7293 kit on e-bay for $23 , I haven"t but it together yet but the PCB quality is pretty good , the TDA7293 chips look a bit schetchy , don"t have the same type of printing on them but I"ll see how it turns out...

The PSU PCB looks good and was only $5 with most of the parts...


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Old 3rd May 2009, 05:46 PM   #12
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So, if all the other components (and PCB) appear to be O.K., buy the amp and replace the supplied chip with your own chip and see if it improved the sound. I don't think it would take much to de-solder the old chip then solder a new chip in. $12.00 for a board and components doesn't seem to be a bad deal.
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Old 4th May 2009, 02:36 AM   #13
nrg2009 is offline nrg2009  United States
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Did you say that kit came assembled as well? Sounds too good to be true. They even made an attempt to put some nicer components on the kit.
It's hard to beat a kit like Peter Daniel's though.
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Old 4th May 2009, 05:30 PM   #14
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Well the input caps have had their values sanded right off and they have been relabeled. The electrolytics look fishy too, phyiscally small and the wrapping is a bit bubbly in places. I don't trust any of the components on that board.
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Old 10th August 2009, 10:16 PM   #15
kgc-jr is offline kgc-jr  United States
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I recently purchased a YuanJing LM1875/NE5532 amplifier kit/board (fully assembled) for $15 (included shipping) on Ebay, and the board construction and components look to me to be of good quality.

The kit does not come with a heatsink for the two LM1875's, but it does have the DC power supply built into the board (FW bridge & 4x4700uF elec.). It also came with the mica insulators and nylon spacers for the LM1875's. All I need is a suitable 18VCT transformer, heatsink, volume control, connectors/jacks, and chassis to build a complete ~25W/ch stereo power amp. Once I have assembled the amp project, I'll post pics and my listening results.

The specs & pics from the auction listing are as follows:

.. uses fiberglass PCB, excellent electrolytic and film capacitors, and precision metal film resistors.

Description:

30W+30W
AC voltage 18V-0-18V
Size 10.4CM X 7.3CM

Package contents:

2 X LM1875+NE5532 Audio Amplifier Board (does not include the aluminum heastsink)

Click the image to open in full size.
Click the image to open in full size.
Click the image to open in full size.


The only problem I have with this kit is that there aren't any schematics or documentation (just the board and the auction information). I'm guessing that a 18VCT @ 6A - 7A (100-120VA) Hammond toroid power xfrmer ought to do the trick. If anyone out there has a recommendation for a less expensive transformer source, or can wind one of these for me, I'd like to know.

Additionally, can anyone direct me to the best place to find the heatsink. I'm also not quite sure what size heatsink I should get.


Kgc-Jr
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Old 10th August 2009, 10:28 PM   #16
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Quote:
Originally posted by kgc-jr
I'm guessing that a 18VCT @ 6A - 7A (100-120VA) Hammond toroid power xfrmer ought to do the trick. If anyone out there has a recommendation for a less expensive transformer source, or can wind one of these for me, I'd like to know.
No, 18 - 0 - 18 is not 18VCT, it is referred to as 36VCT.

There must be thousands of posts on cheap sources for gainclone transformers on this forum; please search.
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Old 10th August 2009, 11:13 PM   #17
Minion is offline Minion  Canada
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Well I assembled my 2 x TDA7293 kit from this guy and it totally fried , Kept blowing fuses so upped the fuse size untill it finally went up in smoke , Both chips fried in the same spot on the plastic and all the elctro"s exploded ..... after words I checked the continuity on the PCB with my DMM and there were a bunch of problems with the through holes not makeing contact with the traces and some shorting on others , I also believe the caps were relabled .... I complained to the seller but he refused to get back to me .....

total crap !!!


The PSU PCB worked fine though ....
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Old 10th August 2009, 11:25 PM   #18
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But for 15 watt, wouldn't these T-AMP be better?

http://cgi.ebay.com.au/ClassT-T-AMP-...d=p3286.c0.m14

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I reckon it's harder to clone these things as compared to LM chips?
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Old 21st September 2009, 11:04 AM   #19
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I agree that the wimas all are fake.the price of the four MKP caps is higher than 12 dollars,so dont buy it if just for its low price.
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Old 22nd September 2009, 05:55 AM   #20
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Hi guys, the kits from china always cheap, because they use caps, trans even ICs used from junk yard. That make kits cheap. Sometimes they change original mark on caps, trans or ICs with other mark. When you push voltage to standard, they blowup, because its fake.
Be careful to buy kits from china, they resend junk to your home.
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