oscillator B tuning is out

olilarkin commented 10 years ago

for some reason oscillator B tuning is very wrong with p600fw. it is fine with the Z80 though. affects all voices. this is with october 26 alpha. pressing TUNE doesn't fix it. I quite like the microtonal sounds i'm getting but would be nice as well to get it in tune!

gligli commented 10 years ago

does it happen with all the voices? ie are they all out of tune the same way?

olilarkin commented 10 years ago

well they are all out of tune, but not out of tune by the same amount. If I play in unison mode with just Osc B i hear a lot of beating indicating that the tuning is off by different amounts in each voice i think.

matrix12x commented 10 years ago

Might you have unison detune turned on? "to tape", button 8, first press.

olilarkin commented 10 years ago

i will try it. but the tuning is way out when not in unison mode too

gligli commented 10 years ago

I have a idea what could cause this problem, do you still get even a faint osc A sound when the mixer knob is fully couterclockwise? It could also happen during tuning and cause osc B tuning to fail...

olilarkin commented 10 years ago

no, when osc A level is down i can't hear osc A at all, even if i turn the volume right up

gligli commented 10 years ago

Just remembered I had a similar problem with alpha oct26, it had to do with how the bender was handled. I made a new alpha today which fixed this and other stuff for me.

olilarkin commented 10 years ago

tried it and it is still a problem with the latest version. If you like i can provide some sound examples

gligli commented 10 years ago

Okay, I made a few changes to the tuner, to see if it changes something for you, here are the files: http://sfx.gligli.free.fr/zik/p600/dev/2013-11-02_2/

olilarkin commented 10 years ago

this made the oscB tuning much worse!

gligli commented 10 years ago

Ha, that's unexpected, that last version seems to improve the tuner for many. I'm starting to think it's not really related to the tuner itself, maybe some problem with polymod,sync, unison detune or something like that... maybe even a scratchy "fine B freq" pot...

gligli commented 10 years ago

Is this still an issue?

olilarkin commented 10 years ago

yes. OSC B is unusable in the current firmware for me, since it is so badly out of tune. The Z80 is fine though.

gligli commented 10 years ago

Well, I see 2 possible reasons for this problem:

The chip U418 (a CD4051, U415,U416,U417 too maybe) is too worn-out to allow for the faster update rate of my firmware.
It's an issue with one or more of the patches parameters (fine B freq, unison detune,...)

I'd like to tell you I can fix it by software, but I can't I think.

Still, maybe a sound example could make me see the problem differently...

olilarkin commented 10 years ago

here's a video - not sure it's any use

http://www.youtube.com/watch?v=uHwZ8bwIYDs

gligli commented 10 years ago

Ok, one last test before I give up: http://sfx.gligli.free.fr/zik/p600/dev/2013-12-11_tune_test/ This version has some tuner tweaks, and tuner will produce tones on audio out, if it still doesn't work, i'd like a record of it.

olilarkin commented 10 years ago

still no joy :-(

http://www.youtube.com/watch?v=3i09_xV4LOk

gligli commented 10 years ago

Arf. The tuner sound pattern seems to be correct tho, it must be something else...

Here's a few thing you could still check:

Does Osc A frequency seems to affect the one on Osc B ? (even by a small amount)
Did you calibrate the bender ? ("from tape" + "3")
Did you do scaling and dac adjustments ? (they are described in the original service manual, you will need the Z80 for this)
Did you try to reflash the teensy with the USB cable ? (this will clear all settings/patches, maybe try it last)

gligli commented 10 years ago

0b808a494843e09cc9b1f9ad5ec0479d49f89ae4 probably fixes it, alphas starting with august 28 should have it!

gligli commented 9 years ago

I think this one is fixed, reopen it otherwise!

gligli / p600fw

oscillator B tuning is out #7