Pro Audio Design Forum

You might look at Skrill.

I've bailed on PayPal and ebay both. etsy takes PayPal or Credit Cards but it's transparent to me. Not using PayPal and ebay let me cut some prices. etsy has been a wonderful venue though its taken Google awhile to find me there. RF: I recall something on the PayPal forums some time ago about infreq...

I would like to see a citation where someone has actually measured degradation. The one post I did locate could not find, in a MM cartridge, any measurable performance change with bias currents. Not sure I bookmarked it but I recall it being on DIY Audio. I'd like to see some data where it does. Hav...

And please see my contribution as a way to contribute in a positive way.

I do, and appreciate it!

I made the Ios measurement pretty quickly.
At the time my expectation was that it would be high enough to measure directly.
Next time I have it powered on the bench I'll measure it through the output.

I think it's 0.36 nV/√Hz because the decimal was moved. The 80 nA was pure luck as I was expecting to see 10 uA or more and the measurement may be subject to errors. Because I saw 80 nA on one I didn't get convinced they would all be that good. In fact it is still an area of concern... I measured th...

Thank you for joining us Hans! I haven't measured the bias current but Ios - cartridge current - comes in at 80 nA. In the test circuit the Ios was 80 nA. Not all ZTX851/951 may match this well. I expected worse. I see moving coil preamps with input coupling capacitors in the thousands of uF as if t...

"A Single Potentiometer Adjusts Op-Amp's Gain Over Bipolar Range," Jerald Graeme, Electronic Design, July 19, 1975. This is a very handy circuit that is a combination polarity flipper and gain control. I've used the unity gain version - using a THAT1240 - in both the Stereo Width Controll...

"Low Frequency VCO Gives Exponential Response," Thomas Henry, Electronics, January 13, 1983. Some early work of Thomas Henry published as an Electronics "Designer's Casebook" design idea. "Low Frequency VCO Gives Exponential Response," Thomas Henry. Pdf: https://www.pr...

"Op Amp Circuit Collection," National Semiconductor, AN-31, Robert C. Dobkin, February 1970. This is the original National Semiconductor version of "Op Amp Circuit Collection" written by Bob Dobkin. In later editions National and TI scrubbed Mr. Dobkin's name (who later founded ...