Noisy P5/10...Please Listen to MP3 file

Noisy P5/10...Please Listen to MP3 file
« on: May 26, 2022, 01:29:16 PM »

Prophet 5/10 Rev 4

Please listen to the attached .mp3 file.

With all Oscillator waveforms turned off and both Osc volumes (including Noise) turned down, you can still hear background information when I play the keys.   

You can hear me sweeping through both Oscillator's frequency knobs; then, you hear me turn up/down the Cutoff frequency.    It's pretty noticeable even with the Master Volume is about 10:00.

Anyone else hearing this phenomenon? 

P5 Rev 3.3/P5 Rev 4 (w/Expansion board)/OB8/Jupiter 6/Juno 60/MKS80/MKS70/CP80/S80/AN1x/SK30/Motif XS Rack/CS6R/Crumar DS-2/Performer/ARP Axxe.

LPF83

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Re: Noisy P5/10...Please Listen to MP3 file
« Reply #1 on: May 27, 2022, 05:09:49 AM »

Prophet 5/10 Rev 4

Please listen to the attached .mp3 file.

With all Oscillator waveforms turned off and both Osc volumes (including Noise) turned down, you can still hear background information when I play the keys.   

You can hear me sweeping through both Oscillator's frequency knobs; then, you hear me turn up/down the Cutoff frequency.    It's pretty noticeable even with the Master Volume is about 10:00.

Anyone else hearing this phenomenon?

Yes, I hear it on my P10...  Oddly it seems to stop if I switch to Rev 1/2 mode from Rev 3, or if I toggle off "Preset"
Prophet 10, Prophet 6, OB-6, Prophet 12m, Prophet Rev2-16, Toraiz AS-1, Virus TI2, Moog SlimPhatty, Hydrasynth desktop, Korg Minilogue XDm, Roland JP-8080, Roland System-8, Roland SPD-SX SE / Octapad, Maschine, Cubase

Re: Noisy P5/10...Please Listen to MP3 file
« Reply #2 on: May 27, 2022, 06:26:11 AM »
Aaah ...  They try to replicate the leakage noice from old tonewheel Hammond's    ::)

But seriously, why playing the keys with sound off ?  Are you using the P-10
as a MIDI controller and that noice is heard on P-10's track when recording, or .... ?

Just curious about when this noice is an issue IRL ....

( My old DX7 MK1 is another story regarding noice / hiss ....    Cheesus Chrysler !   :o  )


Cheers !
1976 MiniKORG700s // 1978 Prophet-5 rev.2 // 1981 KORG CX-3 // 1984 DX7 // 2020 Prophet-10 rev.4 // MoPho Box // 2 Creamware MiniMax // Creamware Pro-12 // 2 EMU-Proteus 2000 // EMU-Vintage Keys  // Casio VZ-10M // Roland VK-8M // Fatar SL 880 //

LPF83

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Re: Noisy P5/10...Please Listen to MP3 file
« Reply #3 on: May 27, 2022, 07:17:18 AM »
Aaah ...  They try to replicate the leakage noice from old tonewheel Hammond's    ::)

But seriously, why playing the keys with sound off ?  Are you using the P-10
as a MIDI controller and that noice is heard on P-10's track when recording, or .... ?

Just curious about when this noice is an issue IRL ....

( My old DX7 MK1 is another story regarding noice / hiss ....    Cheesus Chrysler !   :o  )


Cheers !

Well if nothing else, even if it is intentional it represents an interesting difference between Rev 1/2 and Rev 3 filter types that doesn't appear to be documented elsewhere, such as the fact one mode produces a saw wave and the other a ramp on init patch.  My first thought was maybe the Rev 3 had a higher noise floor than Rev 1 so they're being true to the original but that wouldn't explain why it disappears when the Preset button is toggled off.

I consider a certain amount of noise "normal" in analog synths (at times maybe even desirable), but I do think when present the cause for it should be identifiable.  Any amount of noise will get added into the individual harmonics and thus impact the overall tone of a synth in some ways.

Prophet 10, Prophet 6, OB-6, Prophet 12m, Prophet Rev2-16, Toraiz AS-1, Virus TI2, Moog SlimPhatty, Hydrasynth desktop, Korg Minilogue XDm, Roland JP-8080, Roland System-8, Roland SPD-SX SE / Octapad, Maschine, Cubase

Re: Noisy P5/10...Please Listen to MP3 file
« Reply #4 on: June 21, 2022, 06:58:52 AM »
Just checked my P5 , no I donít have this at all, even when turning up max , I hear nothing right up to where the noise floor starts on my ssl six. Which is quite high up.

LPF83

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Re: Noisy P5/10...Please Listen to MP3 file
« Reply #5 on: June 21, 2022, 04:14:02 PM »
I tried this again today and was not able to reproduce anything like your MP3, just a slight increase in what I consider "normal" analog noise (around -85db or so).  I did notice some noise when I was in manual mode (preset light off) with oscillators off and I didn't notice that the resonance was set high enough that it was starting to self oscillate but that was easily solved once I realized what was going on. 

@engineerjoel have you eliminated filter self-oscillation as the culprit? (set resonance to zero).
Prophet 10, Prophet 6, OB-6, Prophet 12m, Prophet Rev2-16, Toraiz AS-1, Virus TI2, Moog SlimPhatty, Hydrasynth desktop, Korg Minilogue XDm, Roland JP-8080, Roland System-8, Roland SPD-SX SE / Octapad, Maschine, Cubase