From yahoo Sent Wed, Aug 29th 2018, 08:05
From yahoo Sent Wed, Aug 29th 2018, 08:05
Hello, I'm sorry about the problems with the module. I assume that the bleed is in the range -40dB (i.e. about 1/100 of the signal). The phenomenon is related to the output impedances of the CV sources (S&H, LFO, Random). The A-138e circuit is working 100% perfect only with sources that have zero output impedance. But virtually all A-100 modules have a protection resistor (typ. 1k) in the output which protects the output against short circuits (e.g. if two outputs are patched together by mistake). In case of the A-138e this leads to a small bleed. I see two workarounds to solve the problem: shorten the protection resistors of the modules (but then the outputs are no longer protected against mis-patching) or use buffers with zero output impedance (e.g. A-180-3 or the planned quad buffer A-180-4). Best regards Dieter Doepfer > -----Ursprüngliche Nachricht----- > Von: xxxxxxx_xxxx@xxxxxxxxxxx.xxx [mailto:xxxxxxx_xxxx@xxxxxxxxxxx.xxx] > Gesendet: Mittwoch, 29. August 2018 08:43 > An: xxxxxxx_xxxx@xxxxxxxxxxx.xxx > Betreff: [Doepfer_a100] A138e - patching and leaking > > Hello, > > I'm facing some issue with module A138e, in the three way crossfader mode. > > The patching : > > I have in the A138e an S&H output (input A), an LFO square wave > output (input B) and a QRV A149-1 output (input C). > This is modulating a VCO. > If the potentiometer is fully ccw, I should get only the effect > of the S&H, BUT somehow the S&H is affected by the LFO. > The LFO itself doesn't seem to be affected by the S&H or the QRV. > The QRV is also not affected by the other modulations. > I tried on different inputs of the 138e and same thing occurs. > If I plug only two modulation sources, like the S&H and LFO, it > works fine. > With audio sources, at high volumes, I have some leakage also, > like for example with high resonance values from 106-1 or 101-6 I > can hear it on B when its in the A input. But this I can > understand better and get the volume down. > Where it gets weird (back to the CV sources problem) is that if I > unplug everything and re-patch, slowly, putting first input A, > then input C, then having the module to work as a two-way > crossfader and ONLY THEN add the input B, it works fine ! > > Just curious if there is any explanation to that or if the module > is just not working properly (still under guarantee). > > A > > > Posted by: xxxxxxx@xxxxx.xxx ------------------------------------ ------------------------------------ ------------------------------------ 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/