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OPA1656: High-Performance CMOS Audio Op Amp

ADA4625-X has excellent specs indeed, better than ADA4627-X, so very tempting. And then comparing both just listening to music during a shootout in a very simple test rig (adding them in the loop merely in a non demanding application to see their potential sonic signature) a couple of years ago, I found ADA4627-X better sounding on nearly all aspects.

That one was very very good, but then again beaten slightly overall by OPA1656... to my ears. Of course depending on application that could be different, some OP amps not even running or suited! Plus you may want to alter slightly your sonic signature and use Ad's tremendous speed (I was always an AD fan).

For more details on this shootout please use advanced search function, I posted quite in length back then and there was also my long time favourite AD825 biased in Class A with 2SK170 (overkill bit 20y ago it was cheap LOL).

As long as OPA1656 is used within its application field, and musical flow and neutrality are key (eg one is not trying to colour the music, suggering or drying it), OPA1656 does indeed an excellent job that is difficult to beat (provided proper PS as ever). Of course I would be delighted to find a new king, so open to suggestions!

All IMHO / I hope it helps

Have fun

Claude
 
Hi everybody! Anyone know is it original opa1655 or fake?

IMG_20230927_094307_106.jpg

May be it is new marking style )
 
I can not see why anyone would go through the bother of putting a fake part in a sealed tape format. Look at the TI spec, they show info on the part marking scheme. Looks genuine, if not doing a damn good job at making fakes. There are a few simple tests to verify it’s real.
I do wonder how these parts get into Russia however, I thought the country is sanctioned. Oh, now that I think about it some more, Russia is in tight with China and China don’t care about sanctions, so ask your China source if they are real or they are stealing your $.
 
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I´m afraid the specs make it a bit difficult to compare.

When both amps at Vout=3.5Vrms, Gain=1 and Load=2k

The INA851 specifies THD+N at -110dB @ 10Khz and at a BW of 500Khz.
The OPA1656 specifies THD+N at -130dB @ 10Khz and a BW of 80Khz, why is that, how does the spectrum look beyond 80Khz ?

Also take into account that when using three opamps, distortion will increase accordingly.
I would be surprised when the INA851 can't match it.

Hans
 

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