Short observations on fake CS4270 codec

With all of this mess around shortage of Cirrus Logic CS4270 chips I want to share my experience of buying fake one on AliExpress. There is also original one for comparison. The funny part: original one also bought on AliExpress.) I’l try to be as brief as possible.

I’ve bought first IC in July. Price was around 14 USD. Seller with a good feedback. Chip comes in perfectly sealed tape reel package and looks totally new and genuine. After I finished shield I instantly stuck with “Supercollider fail” error. 10 Minutes of tinkering leads me to there is no sound card in system. You can check it easily with cat /proc/asound/pcm or with dmesg

I spend whole next day with looking glass, multimeter and oscilloscope. Everything works perfectly except codec. Soldering was ok: I’ve checked each line from IC to RPi header — no breaks, no shorts. Crystal was fine too.

At this point I realise the chip is fake. I’ve gone mad and bought bottle of acetone to check if IC is remarked or not. Remarking is a popular Chinese tech for selling refurbished ICs. Mine was not remarked. Actually they no need to remark packages like TSSOP-24 — there is plenty of fabs which could sell “blank” package so they only need to engrave any image which will sell.)

Seller do not answer me, so I rise the claim. AliExpress stands to the side of the seller so I’ve got no refund. It was not a surprise: frankly speaking it is a soldered part and my only evidence was a screenshot of dmesg output.

So I placed order for 5 pcs to big and trusted IC reseller company. With 90 days leadtime.) At a same time I bought another IC from AliExpress but told with seller first. He frankly said that IC is refurbished but will work. The price was around 23 USD.

When I’ve got 2nd IC from Ali I immediately noticed the difference with 1st one. It comes into simple zip-lock with remaining of lead on pins. But after soldering (to the same board for sure) it started immediately without any problems. I’ve also tested it with acetone for no reason. It is not remarked.

Here it is the differences:
1. First pin mark on original IC is obviously bigger. I consider this as major difference which is hard to copy.
2. Engraving on both IC is very different (size and placement). You also can compare datecodes. Im pretty sure most of fakes shares their datecodes.
3. At a bottom side original IC has small “CN” mark engraved while fake IC has big ejection pin mark.

If you was scammed with fake or remarked codecs from Ali, Tmall, eBay, please share pics and your observations here. Maybe it helps to form list of features which belongs to fake codecs exclusively so one can avoid them in future.


Thanks, super interesting!

With all this chip shortage and automobile manufacturers taking all the chips i cannot help thinking: each one of those ugly stinking cars could have been a beautiful synth instead. Tragic :performing_arts:


As someone who like to scavenge parts whenever possible, I’m wondering if these chips can be scrounged from commercial electronics. The data sheet says:
“The CS4270’s wide dynamic range, negligible distor- tion, and low noise make it ideal for applications such as DVD recorders, digital televisions, set-top boxes, and effects processors.”
I did a brief search to see if I could find any schematics that mention it in use but couldn’t find any.
EDIT: I did find an Amazon review that mentions that the chip is found in “ XMOS USB Audio 2.0 Reference Design asynchronous DAC.”


You can find CS4270 in PreSonus USB audio cards. Like Audiobox USB 96 or Studio 26.


Hi everyone. I’ve been wanting to build a norns for a while but it’s always been fairly far outside my budget as a student. I recently found out about the full DIY option and was interested. However, I can’t seem to find a Cirrus Logic CS4270-CZZ anywhere reputable. Stock projections on these sites say late 2022/2023. I found some options on ebay but I’m skeptical on if these are legit/useable.

Has anyone had any experience with this? Or with eBay chips?

e: Thread was merged - this is helpful. Any heads up on reputable sellers on eBay or Ali?

i never did say thanks @Atarity for documenting and sharing your experience. tremendously generous of you.

@amosdixonxc we moved your post to this thread, thinking it might best answer your question. (there is also lots of discussion in the main norns: shield (diy) thread, but that one is quite long and dense.)


Currently thinking about going with this listing. Figured I should check here just in case this was one of the sellers any of you have had experience with.

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I bought this on AliExpress months ago, but never started the shield project. It looks different than both ICs posted above. The text is left justified. There is nothing on the back side (no “CN”, no ejection pin mark). It came in a clear plastic bag (no static protection)! A few other buyers claim it is fake. I’m guessing they are right.

The silkscreen alignment looks a tiny bit off? (Closer to right edge?) But hard to tell.

The fact that it’s clearly a salvaged part is maybe a good sign if anything…

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Hey everyone - had an AliExpress come in yesterday. Attaching photos below. Seems to be in line with the legit chip posted above.

Is there an easy way to go about testing the ic pre-soldering? I have access to a multimeter. I recognize this probably isn’t possible with my limited equipment.

Screen Shot 2021-10-23 at 3.24.17 PM

Chip is looking good. I would go for it and install on the board.

Any soldering issues would present themselves the same as a bum codec in the end so make sure you have proper magnification, lighting, small gauge solder, wick, and as tiny of a tip as possible.

If you do run into issues, there is plenty of help to be found over in the DIY Shield thread.

Happy soldering :v:

In my experience with the cirrus chips with the larger pin one circle have been legit, also that font looks right!

thanks for this. have to say there is no customer service at all at Ali which makes me furious. received two broken codes at a price point of around 19€ each - but the seller got right in dispute so no refund.

gonna try an old audiobox …

I bought these from aliexpress and they worked great, were not fakes. this was last year… There is even a review of someone saying they worked in their norns…