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Re: Tom & Clap ground loop noise/hum noise

Posted: Jan 22nd, '19, 19:55
by TKYK
KlangGenerator wrote: Maybe try out a different PSU. I had annoying hum with a cheap PSU I bought from China. These work good:

https://www.ebay.de/itm/OEM-AC-ADAPTER- ... :rk:9:pf:0

I bought ac adapter in mouser.
https://www.mouser.com/ProductDetail/Tr ... ALTLvnnT0=

Furthermore, I bought two kinds of ac adapters, but the problem was not solved.
Does ac adapter which you told not have any problem?

Re: Tom & Clap ground loop noise/hum noise

Posted: Jan 22nd, '19, 20:18
by TKYK
gihaume wrote:For the Toms in v1, someone found that grounding the switches case was helping, not sure if they aren't already or not.
I solved a problem of v1 to see this topic
viewtopic.php?f=16&t=720&hilit=switch+ground

ver2 was improved, and the legs of the switch was connected to the ground.
However, a new problem is taking place.

Re: Tom & Clap ground loop noise/hum noise

Posted: Jul 27th, '19, 20:46
by TKYK
Hi
I solved some problems

L/M/H Tom & Clap hum/buzz
Noise was generated because the voltage supplied to the op amp was slightly higher.
power supplied to each part were changed resistor value 0 Ω to 100 Ω in the same way as yocto1 and original 808. noise is gone by this

PC-2 oscilator bleed
I Changed resistor value of R24 47k to 0 ohm.
always leaking oscillator has stopped

I still have the last problem.
Cowbell oscilator is always leaking a little
Vincent told me it's a problem with vca bias.
I changed the resistor value of Q14 and Q15 VCA area
But there was no improvement.

I would like to solve this problem anyway.
Please give me some advice!

thanks

Re: Tom & Clap ground loop noise/hum noise

Posted: Jul 29th, '19, 07:26
by TKYK
uploaded my Cowbell part track
Can you hear the high pitch oscillators that are playing all the time in the background?
https://www.dropbox.com/s/run94daf8mi3t ... r.aif?dl=0

Re: Tom & Clap ground loop noise/hum noise

Posted: Apr 12th, '20, 21:04
by j.colt
I can confirm that replacing R24 with 0 ohm almost completely remove the oscillator leak in the master output. Did you find a solution for the Cowbell oscillator leak?

Re: Tom & Clap ground loop noise/hum noise

Posted: Jun 22nd, '20, 02:46
by j.colt
TKYK wrote: L/M/H Tom & Clap hum/buzz
Noise was generated because the voltage supplied to the op amp was slightly higher.
power supplied to each part were changed resistor value 0 Ω to 100 Ω in the same way as yocto1 and original 808. noise is gone by this
Thank you so so much for this! I spent weeks changing voltage regulators, transistors, checking ground continuity, etc... Changing these PSU resistors did the trick. I guess the sum of dry signal and fake reverb is too hot with 0R in the PSU.