A x0xs0urce with noisy VCA

Discuss x0x construction and related issues

Moderators: altitude, adafruit_support_bill, adafruit, phono, hamburgers

Please be positive and constructive with your questions and comments.
Locked
User avatar
diplowave
 
Posts: 103
Joined: Wed Aug 21, 2013 9:49 am

A x0xs0urce with noisy VCA

Post by diplowave »

Hi, x0xerz
I have repaired a x0xsource that was broken. But now it works,
The VCA produces a little white noise and it's pretty unpleasant when we used other x0xb0x... I'm not used to that...
I tried to replace some of the VCA components without improvements.
That said i noticed it was equipped than 2SC945Q and they are not the same HFE better than 945P's . What would be the repercussions on the synthesizer to have placed these transistors, maybe a x0xerz expert opinion?
Attachments
IMGP3066.JPG
IMGP3066.JPG (168.28 KiB) Viewed 952 times
HFE   2SC945.PNG
HFE 2SC945.PNG (78.27 KiB) Viewed 952 times

User avatar
antto
 
Posts: 1636
Joined: Thu Apr 15, 2010 3:21 pm

Re: A x0xs0urce with noisy VCA

Post by antto »

is that Q30?
Q30 is part of the VCO slide switching circuit.. it's not in the audio path really

User avatar
diplowave
 
Posts: 103
Joined: Wed Aug 21, 2013 9:49 am

Re: A x0xs0urce with noisy VCA

Post by diplowave »

Yes it is, it was an example, they are all 945Q, everywhere ...
It's just that i find it rather strange idea as to have built with these transistors. I'm wondering if the problem does not come from there. What do you think? Personally i have never built a x0xb0x with 945Q, i do not know if it changes anything.

Locked
Please be positive and constructive with your questions and comments.

Return to “Making x0x”