Pro Audio Design Forum

My tester for EMI, hum, thermal drift is a hair drier. A cheap tool that does it all. An anecdote about thermal stability: A design of mine about a test equipement to test TV reference monitors. When they put my proto, in thermal testing to check the compliance with requirements about stability of l...

First off, thanks to show all this nice work.

I do want to get some mu-metal....and I'll try lining the metal Hammond box with it.

I am very interested about this.

I see these software are mostly locked to: Output = Ordering PCBs to a specific manufacturer. PCB express has a netlist file, how could it not have it, however I found no way to import or export to LTspice for instance. Gerber files, same thing. Is there a true free software, open to alternate softw...

I am not familiar about the effect of noise on an integrator. May be naive, I see integration, filtering out noise. I see the noise at the input averaged, buried in the integrating capacitor. 1/f noise looks scary because going to infinity for f going to 0 while gain of an integrator goes to infinit...

About low Vos balanced integrators I am afraid we are stuck with OPA2277 or go the route of choppers with adaptation board. I do not see how to use two OP07 with two trimmers. I see no way to trim correctly those two that will interact. OTOH. One trimmer for the two op-amp makes the adjustment possi...

From the data sheet, one can expect 5µV Vos with trimming using OP07E.
It comes in two flavors OP07E ( better ) and OP07C.
There is another flavor OP07D ( not so good, lower cost ).

LM4562/LME49720 and now-discontinued LME49860. I am shocked to see Texas Instrument continue publishing datasheets for these op-amps tooting low noise: 2.7 nV / rt Hz. And they continue to sell an op-amp they have discontinued without any warning like "not for new design". Clearly, they c...

Bad contacts before, good after contact cleaning spray. So, there was some contact contamination: Corrosion, oily film, some residu left from manufacturing, storing, handling. Who knows wether the culprit is the socket or the IC. Well, you are stuck with those, all you can do is to keep the stabilan...

LM4562, LME49720, LME49860 the same chip. Better than NE5532, pin compatible.
2.7 nV/rt Hz THD 0.00003% 55 Mhz 140dB capable to drive 600 ohm ( Iout +/- 26mA ).
Please, double check.

Beautiful.