VC-LFO1 drift?

isak · Posted: Mon Sep 01, 2014 11:37 pm Post subject: VC-LFO1 drift?

Hi guys.

No matter if on x1 or x0.1 , in any waveshape it drift.
When turn to x1 it drift up and not stop, when turn to x0.1 drift up and not stop.
Another issue, The rate is high frequancy.
When on x1 on max rate it gets to about 1000Hz after drifting up.
When on x0.1 max rate gets to about 100Hz after drifting up.
I checked BC557B, is correct.
C1a and C1b are tantalum.

I must say that I did ver1 but I wanted the sync of ver2 so I added the components related to that, BS170, 10nF cap and 2 resistors, 10k and 100k.
I removed them for testing and it was the same drifting issue.

Any help will be appreciated.
Cheers,
Isak E.

isak · Posted: Tue Sep 02, 2014 4:05 am Post subject:

By the way I put 220pF for C5 like Yves suggested in the other post for reducing the spikes from the Tri and sine.
Works great, it didn't remove the spike totally, but depress it by much!
Thank for this tip Yves.

CDX · Joined: May 06, 2014 Posts: 4 Location: China

I put a 1uF cap between sine output and ground, the result seems good too.The sine looks purer now.