Pro Audio Design Forum

Do go back and have a look here. This will give you a hard knee:

viewtopic.php?f=6&t=268&start=2

PS: Don't forget to vote early and often in mid term election coming up. Well, I guess the year going fast was a good thing. :D Still, I'll miss summer. From August to September I got two houses exteriors painted and only lost maybe three days to rain. I suppose by mid November I'll have to give up...

Wasn't it the UV reacting with CFCs that was going to end life as we know it? :D With UV declining does this mean we can start using real Freon cleaners again? "They [the solar cycles] are contributing nothing to long-term global warming," she said, "and it has no bearing on what we u...

Seems fast to me too. Not ready for Summer/Indian Summer to end.

I think you may want to tie everything to ground. Now that this thing has become an SE version (with both halves of the 1570 doing both L&R) there's no virtual ground summing node for the - leg. That just occured to me. With CM rejection only being realized in the 1240, the source impedance feed...

Yes a direct path to ground. The VCA should go directly to ground and most other nodes as well. I'd use that extra pin and tie a resistor from it to ground. That build-out resistor would feed the - leg of the bus. Have you also looked at connecting pins 3 of the 1240s (U3 and U6 after the 1570) to t...

I don't think you want R18 where you have it. I think that node needs to be ground (R18=0R). You may need another pin on the connector. I really need to look at the dwg on a printed copy. EDIT - What I meant by "quasi-balanced" is that only the + leg was driven. They couldn't field modify ...

FYI drawings don't auto scale here. I can't remember if it's broken or a board mod is required. I try to limit mine to 700 pix or so. I'll save your drawing off-line so I can look at it.

There is a second page I need to post with PSU and metering I had forgotten about.

It was early 1970's era.

Simple Circuit Turns Scope, Function Generator Into JFET Curve Tracer:

https://www.electronicdesign.com/displa ... rve-tracer