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

[engineerjoel]

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? 

[LPF83]

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"

[HockeBocke]

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 !     )


Cheers !

[LPF83]

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 !     )


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.

[h4ndcrafted]

Just checked my P5 , no I don’t 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]

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).