ebay amp kits

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Member
2005-11-18 1:01 pm
crete
EBAY KITS

Certain merchants on ebay are reliable. One i have dealt with is Jim's Audio and found him to be quite reliable and helpful. Unfortunately, many of the circuit designs are used without the designers permission . Also unfortunate is the fact that people buy these stolen designs.

Your best bet is to buy the circuit boards, if available, from these people and select your own part choices from one of the many world wide suppliers.
 

forr

Member
2004-12-01 6:46 pm
Next door
I was given an Ebay kit, it was a stereo amp based on LM3875s and LM318s.I thought it was some kind of gainclone, but reverse engineering showed it was the Mauro Penasa's circuit. The underside of the PCB was a bit dirty. When mounted in a box with power supply, it oscillated, so I rewired it according to the standard application of the LM3875.
This experience with asian Ebay stuff like that was a real loss of time.

"High-end Pure Class LME49830+2SK1530+2SJ201 400W Mono Power Amplifier Board"

Pure Class, what's that ?
 
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Member
2005-11-18 1:01 pm
crete
i have the amp ay the first link.i found a thread about it in this forum and with the advices of some people i it some modification to eliminate an oscillation and make it work with higher rails and it sounds great.

i wanted to know if somebody have tested the other two since they have dc servo input and they look better designed.
 
I have no problem buying ebay kits, assembled amps, chips or other components coming out of China. I see the same kits for sale in the USA for 2-3 times the price and it is the exact same kit, same picture even.
As for blowing up in your face, I had a regulator do that and it came from the USA. I replaced the cap that blew up and the regulator has been working fine since.
 
I bought couple of kits/parts from Chinese ebay sellers they are all worked fine for the price I paid. If the price is too cheap quality was also like that. But if you avoid too cheaper items and buy from reliable sellers there is no reason for panicing. I frequently bought from Along..., Skubli, MiniShow sellers, I've really amazed by the quality/price of those items. Especially some of the PCBs are of very high quality and tolerated lot of abuse of soldering/desoldering. But a blanket statement of bad about all eBay Chinese sellers is not helpful for the person asking a question.
 
I second the idea to just buy the PCBs and get semis (especially) locally....

This is NOT a blanket endorsement but those in the electronics manufacturing business here in China ONLY use imported 'complex' ICs or the latest in technology.

For mundane passive and active parts, Chinese made stuff seems fine. For the more complex, or more advanced, or more esoteric go with well established sources.
 

johnr66

Member
2009-03-05 1:55 pm
Any audio IC I bought shipped in from China was fake. When I tested them, I found they lag in performance and may lack the built in circuit protections. When I cracked open the case, I found the die size to be 1/3 of the authentic part. No way it will last very long.

At the price of those kits, I have strong doubts about the parts.

There are good dealers who deserve your money.
 
Any audio IC I bought shipped in from China was fake. When I tested them, I found they lag in performance ....When I cracked open the case, I found the die size to be 1/3 of the authentic part.

Just to clarify, as I understand the terms:

fake part - a part that is rubbish or so badly off spec it is useless

unlicensed copy - factories produce according to OEM 'blue-print'
however it does not mean it matches the original specs

mis-labeled - a part labeled as better than it is, trivial example would be a TIP31B being labeled as a TIP31C
 
The output transistors in the first kit you've mentioned in your first post seems to be fake as the price of the entire kit is almost as low as the 10 output genuine output transistors. Yes, genuine parts cost more, that is the price you need to pay for quality :)

On the other hand, the rule-of-thumb is that if something cost X amount overseas from the factory, it will retail for 3X
And electronics seem to suffer from a high retail mark-up - I have seen the exact same item made in China selling from 5X to even 10X in the USA.
 
On the other hand, the rule-of-thumb is that if something cost X amount overseas from the factory, it will retail for 3X
And electronics seem to suffer from a high retail mark-up - I have seen the exact same item made in China selling from 5X to even 10X in the USA.

I completely agree with you on exorbitant prices on some of these items in USA. One example is when I replaced digitizer on my Garmin Nuvi GPS, price of that item from US sellers was almost 4 times of that of Chinese sellers. I bought from Chinese seller and its working fine for couple of years now. If not for these Chinese eBay sellers, most of these commodity electronic stuff is not repairable for sane prices and end up in the dump.