Jolida JD9 op amps and gain experiments

[scorpio333]

Thanks for the info Rgpit. I am guilty for buying op amps from China. With so many options of different chips that “work” I was guessing which ones to get. With state side sellers wanting $30 or more per chip it leaves “rolling” for those with deep pockets. My other mistake was believing what I was reading. I’ve reread a 105 page thread over again and the second read exposes opinion over fact. Too often I think people buy things and try to justify it to the masses on the web. Audiophiles never do that, right??

This article also made me more skeptical of the Chinese parts

  https://zeptobars.com/en/read/OPA627-AD744-real-vs-fake-china-ebay

[rgpit]

The gray market guys will stoop so low it's unbelievable. I had a customer that is large local manufacture of precision instrumentation. They desperately needed parts that unfortunately had a long lead time. Anyhow, they found a 2500pc reel on the gray market. They pulled a few parts off of the reel to validate that they were genuine. The parts were confirmed to be okay and were put on their PC boards with a high speed pick and place machine. Well, the first 100 parts were indeed real after that they were all fake. It cost them a fortune to rework and retest all the assembled boards.

Frequently the Chinese suppliers will take cheap op-amps or other components, sand off the part number and re-mark them with a different and much more expensive part number.

Moral of the story is "buyer beware".

[OldiesButGoodies]

The gray market guys will stoop so low it's unbelievable. I had a customer that is large local manufacture of precision instrumentation. They desperately needed parts that unfortunately had a long lead time. Anyhow, they found a 2500pc reel on the gray market. They pulled a few parts off of the reel to validate that they were genuine. The parts were confirmed to be okay and were put on their PC boards with a high speed pick and place machine. Well, the first 100 parts were indeed real after that they were all fake. It cost them a fortune to rework and retest all the assembled boards.

Frequently the Chinese suppliers will take cheap op-amps or other components, sand off the part number and re-mark them with a different and much more expensive part number.


Yea,  I have 4 fake OPA627s that I got off Ebay some time back from a Chinese seller.  Done with that.  Ditto for fancy capacitors from China.  If it looks too good to be true,  it prob is.
Moral of the story is "buyer beware".