[sdiy] AD9833 Signal Generator Module price.. fake or not ? Questioning..

[Ben Bradley]

On Mon, 19 May 2025 at 17:09, brianw <brianw at audiobanshee.com> wrote:

> Basically, there is a wide range of pricing and quality, so it really helps to learn the marketplace for a given chip.

It used to be you could trust the manufacturer's datasheet - even with
a competitor's part, the numbers (like delay time) would be close, and
things like power supply voltage range would be the same. Nowadays
there's parts like the XR2206, no longer made by the original
manufacturer, and you can't find an "official" datasheet from the
Chinese manufacturer of the knockoff, whoever that is. The Exar
datasheet says supply voltage is 10V to 26V, but 26V will apparently
destroy a currently-made knockoff part. You really do have to "learn
the marketplace" and hope to find threads discussing the part of
interest, like this:
https://www.eevblog.com/forum/dodgy-technology/dont-buy-any-kit-with-xr2206-wfg/

I've seen Adafruit (a "respected US maker" but apparently they sell
some of the same stuff as on Amazon, ebay and Aliexpress) selling a
similar DDS breakout board at a price less than even a quantity price
for the AD chip it uses, and I've wondered how.

Something that may or may not be related, I see "new Shure" SM-57
microphones on ebay for under $40, and I don't believe those are
authentic.