Hybrid OpAmp Test Shootout

rlaury said:

Here's the data along with the test fixture schematic.

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rlaury said:

Thanks Abby for the response.
I was suspicious with SNR of 990C-1 and 990C-3 when I was populating the Excel spread sheet.
I apparently measured SNR at the 0.0 dBu level and not at the .01% distortion point. I have corrected them.

As to what I hope to achieve, I started about 2 years ago developing a DOA for an OEM product that required
an output stage with enough current  to drive a 75 ohm transformer primary.  Yep, I could have bought any one
of the MANY DOA's but that cut deeply in to the profit margin. So I decided to develop my own. I designed and prototyped
several. A BJT and a JFET version. I had some success, but by the time I matched components and the other labor intensive
and expensive stuff, I would be better off buying something already made.

  I was "lucky" enough to be best friends with Dave Baskind. One of the B's in B&B audio. Hey gave me some of the B&B hybrids
that were supposedly developed for API and that API built and used during the 70's. It was simply an op-amp driving a pair of
output transistors. Dave and I talked about continuing development of the original B&B circuit before he passed away in 2001
I have since developed a new version of that circuit. It requires very little matching and is stable, reliable and almost bullet proof.
and I also have a +/-24 V version.

  So that's my mission. "To develop a hybrid that's economical to produce and can compete sonically and reliably with the DOA's"
Sorry for the long reply but I thought others may be interested in my craziness  too.

RonL

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