From yahoo Sent Fri, Aug 21st 2015, 08:51
From yahoo Sent Fri, Aug 21st 2015, 08:51
I'm sorry about your problems with the A-110. Please contact our A-110 specialist directly: Matthias Marass (xxxxxxxxx@xxxxxxx.xx). He has tested more than 10000 A-110 over the last 20 years and is responsible for the service of the A-110. Maybe the internal transistor heaters are defective and the CA3046 have to be replaced. But that's only a guess. Best wishes Dieter Doepfer > -----Ursprüngliche Nachricht----- > Von: xxxxxxx_xxxx@xxxxxxxxxxx.xxx [mailto:xxxxxxx_xxxx@xxxxxxxxxxx.xxx] > Gesendet: Freitag, 21. August 2015 10:39 > An: xxxxxxx_xxxx@xxxxxxxxxxx.xxx > Betreff: [Doepfer_a100] The untunable A-110s > > > > > > > Hi all, hi Dieter (if you're listening :^), > > I'm new to modular synthesis and got my hands on a used Doepfer A-100 base system which worked fine until this year's > scorching summer, or at least I didn't notice any issues before; not sure if there's a connection with the high > temperatures we've been experiencing. > > I know the A-110 VCO's tuning/tracking is often discussed to death on forums, but I appear to be stuck with a pair of > untunable A-110's. > > The two A-110 VCOs in my kit (rev.3, > 15 years old?) have both drifted WAY out of tune. I followed the calibration > procedure on Doepfer's website, but after 4 attempts, I've given up: both VCOs barely track over 1 octave, and the > scaling pots on both (P7) are at their limits. But get this: they are at opposite ends of their respective limits, i.e. > the tracking of these VCOs is actually divergent. I find that pretty weird. > > Just to make sure, I've calibrated the A-190 MIDI-CV interface accurate to 1mV, and checked that the supply voltages are > within spec too. I even checked the relative values of the critical resistors R1, R1', R2, R3, R3'; they are all within > 0.1% as required. > > I'm at the end of my rope. Is it time to replace the aged opamps, or should I just replace both modules outright? > > Many thanks, > ------------------------------------ ------------------------------------ ------------------------------------ Yahoo Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Doepfer_a100/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/Doepfer_a100/join (Yahoo! ID required) <*> To change settings via email: xxxxxxx_xxxx-xxxxxx@xxxxxxxxxxx.xxx xxxxxxx_xxxx-xxxxxxxxxxxx@xxxxxxxxxxx.xxx <*> To unsubscribe from this group, send an email to: xxxxxxx_xxxx-xxxxxxxxxxx@xxxxxxxxxxx.xxx <*> Your use of Yahoo Groups is subject to: https://info.yahoo.com/legal/us/yahoo/utos/terms/