

Moderators: Kent, luketeaford, Joe., lisa
And that you don't make the common mistake of thinking the tab/back of 79xx is GND. It is on the the 78xx, so these cannot touch each other -typically through shared H/S- or wierd things can happen. Keep your 78xx isolated from any 79xx.
I didn't say anything about reversal. I said if there is contact between the tabs of 78xx and 79xx, weird results can and do show up. And this does not necessarily blow the Vregs. It's as much a reminder warning for anyone reading this thread asfor you personally. It's happened enough times to others besides you to beworth mentioning when 78xx and 79xx share a PCB. /fix typos
Thanks a lotAlfrede wrote: ↑Wed Apr 15, 2020 10:37 amHey Croodey, look at this perhaps it helpes: http://www.emusic-diy.org/Schematics/Effects
Might be useful for builders who may have similar problems, hereby some instruction how to ‘follow’ the signal though all filter cards.
All commercial sold vocoder kits are upgraded with the patch for offset compensation (R200, R201 & R202). This is necessary using HA-4741 OpAmps. Only 2 prototype sets without the patch were distributed to testers and they are aware of this.zephyrin wrote: ↑Fri Sep 25, 2020 4:20 amFetchie could you please give us the informations about your modification around the 741 , I have several trouble with filter that I don't have with original board that I have made.
I wanted to return to original schematic without resistor R200 201 AND R202 , because I see that it's work better without that !
All commercial sold vocoder kits are upgraded with the patch for offset compensation (R200, R201 & R202). Only 2 prototype sets without the patch were distributed to testers and they are aware of this.