Ok i understand 
, but i donāt know if this VCA work like a āstandardā VCA ? I think it is above all a filter
Thereās a thread on it
Hmm right ok cheers for that, will peruse the thread and move from there 
1 Like
Do you have a plain VCA/VCO to test with?
The 1114 has a VCA thatās independent from the filter, so one half of the 13700 and an OpAmp donāt go wastedā¦
It looks pretty standard to me, but the output is AC coupled, so it is audio onlyā¦
3 Likes
Yes have Samās VCO, how would I go about testing it?
Yes thought it was, not sure what could be causing my issue. Will start with the basic troubleshooting I think.
If you were testing with a VCAā¦ output from the VCO to the input to the VCA.
Trigger from your beatstep to the ADSR, and the output from the ADSR to the CV of the VCA.
You should hear the tone from the VCO only when you send the trigger, and with the volume depending on how youāve adjusted the ADSR.
Hope that helps!
Yes was trying that but wasnāt getting a enveloped filtered trigger, it was like a square wave opening and closing the vca, the output led was lighting according to how the pots were moved, but the output gate was just fully open instantly
Had a look through with a meter and all is working fine, even with an oscilloscope, think it may be the filteres vca, might be an internal issue, or i just dont know how to use it 
just to check the filter with the vca level on zero and nothing plugged in is the signal still bleeding?
plug the - (minus) output of the ADSR into it and see if that brings its volume down instead. if it does that means its probably something up in the filter/vca.
1 Like
If the LED is responding to the pots then the output signal should be too, unless somethingās very messed up with the TL072. So if thatās going into the VCA CV input and the VCAās behaving like itās a square gate, the problem must be in the VCA.
Yes i agree, been through the ADSR with the multimeter and oscilloscope to check the output and all is well, currently going through the filter vca circuit to look for anything a-miss
Thanks for the suggestions, No signal bleeding with the vca level on zero, just checking through the vca circuit to see if there are any issues there, the ADSR seems to be completely fuctional
they are both on the same power supply right??
what happens if you plug in the ADSR into the vca but turn down the VCA attenuator??
With the vca level and attenuator both down you get a super shot blip out of it, still sounds like a square wave is opening the gate.
With the attenuator down all the way and the vca open slightly im getting the tone coming out of the vco with no effect coming from triggering the Envelope.
Think theres something odd happening in the filter, went throught it with a multimeter and all seemed fine so not sure where to go from here
Cheers for the help
That seems odd. Your envelope is going into the VCAās attenuated CV input? I donāt have the module and Iām confused by the front panel labeling, but there are two CV inputs for the VCA, one with an attenuator and one not. Try both.
That seems like correct behavior, if youāre going into the attenuated CV input. Normally then if you turn the VCA level down itāll stop the tone, and then if you turn up the CV attenuator the envelope will turn the tone on and off.
Both inputs dont perform as they should, both opening instantly,
this is the same for the vca level pot when you turn it opens up instantly and does change from there, is this normal or should it be gradual?
it should be gradual. so yes sadly something is up! usually the envelope generator and filter work well together. so definitely a problem like you say in the vca build. where im not sure.
solder and resistor values to check R45, R47 and make sure Q5 is definitely a 2n3906 not a 2n3904 (on the 1114 filter)
1 Like
Maybe R44 as well. 
Thanks to you both for the suggestions, unfortunately no change in the VCA, still very much On or Off
not sure what to do next with it, will have a think and go from there