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Noise in Bassdrum decay
Posted: Nov 12th, '22, 17:34
by flomo
My Nava has a noise floor in the decay phase of the bassdrum. I've recorded a .wav file here:
https://florianmoser.ch/909-noise-decay.wav
It is recorded right out of the BD-output, but the noise is also there on the mix-output.
Does anyone else have this issue?
Re: Noise in Bassdrum decay
Posted: Nov 19th, '22, 13:37
by gihaume
Re: Noise in Bassdrum decay
Posted: Nov 19th, '22, 15:24
by flomo
gihaume wrote:Could it be
this ?
Thanks, Gihaume. I'm currently unable to check my power supply (it is installed somewhere deep behind a rack). But I recall reading this thread, when I was building the Nava. So I'm pretty sure I took a power supply with >= 1A. But I indeed have a little bit of distortion on the mix out (only visible on the sine wave, almost impossible to hear). And I have installed the Extra9 Kit. However, the noise I recorded is on the individual BD out.
So you don't have this noise in the decay phase of your unit? When recording the linked .wav file, the BD-decay was set pretty high (pot around 3 o'clock).
Re: Noise in Bassdrum decay
Posted: Nov 19th, '22, 16:48
by gihaume
Finally I recall I had this. I probed the + and - 15v and found they had the small oscillation we hear on the bass drum. I could also hear it on the steiner parker filter.
Re: Noise in Bassdrum decay
Posted: Nov 20th, '22, 12:36
by flomo
gihaume wrote:Finally I recall I had this. I probed the + and - 15v and found they had the small oscillation we hear on the bass drum. I could also hear it on the steiner parker filter.
Thanks Gihaume. I guess I'll have to play with another power supply. Maybe simply use a toroidal transformer instead of a wall plug.
Re: Noise in Bassdrum decay
Posted: Nov 27th, '22, 10:53
by flomo
I just tried out a toroidal transformer, 15VAC 2.667A. On load (Nava on and playing a pattern) I measure 18VAC @ 970mA.
But still the same hissing on the BD decay. Gonna have to find something else.
Re: Noise in Bassdrum decay
Posted: Nov 27th, '22, 18:11
by flomo
I finally found the issue. This
post helped me.
In the Bassdrum section, cable 1 and 2 (noise decay in/out) leading from the Nava to the Extra 9 board, must not be bundled with the other cables. There's indeed a crosstalk from noise to audio.
Simply separating these two cables and keeping them 2cm apart from the rest of the cables solves the problem!