midibox CV aout_lc problem: Calibration ok, but midi convertion out of scale...

[Alkex]

Hi,

I am playing with my first aout_lc but am having trouble getting the cv's to sound right:

In calibration mode, all is fine.

I got the min and max voltages perfect on calibration and 1v, 2v, 4v, and 8v sound like perfect octaves thru the oscillator,

but as soon as I exit the calibration mode and start sending the midibox cv midi notes, the intervals are completely out of tune(4th become a semi, octave, a 3rd etc).

I checked that the curve is V/oct and that I have my hardware set up correctly (I switched to resolution mode A)

Any ideas?

oh, and I replaced the trim pots with multiturn for more precision, was this a mistake?

THanks for your help

best regards

Alex

[TK.]

Hi Alex,

so far I remember, I only tested the calibration mode with a AOUT, but never with a AOUT_LC module... it could be a bug, but I'm not sure (because the implementation is straightforward)

When the CV output is assigned to a CC (e.g. modulation wheel), do you see a linear change with increasing CC values?? If not, it's a hardware problem

Best Regards, Thorsten.

[Alkex]

Hi Thorsten,

Thanks for your support,

I have tried cc mode, but cant get any cv from either channels (tried mod wheel and many other cc messages) .

Pitch mode is perfectly consistent to Dr Moog's v/octave law but only for values 64 and above (scales become random below 64).

Velocity mode on the other hand works perfectly normaly: 127 is a perfect octave above 64 that is a perfect octave above 32, etc

I guess I could just use the velocity mode and write a buffer handler that would change incomming midi notes into velocty values before treating them, but it seems strange that nobody else has encountered my problem...

wouldnt be suprised if I got something wrong on the hardware side, but this is the second aout_lc i built and exact problem repeats itself, would be a strange coincidence

thanks again for your help, cant wait to start analoging ;)

Best regards

Alex

[TK.]

Hi Alex,

the usage of another software to convert a note value to velocity just sounds "perverse" ;-)

I think there are two problems: one in the configuration, another on your AOUT_LC board.

Configuration: doublecheck the settings. Use the select button to check the other channels as well. If you are unsure, just upload the application again - you should get the default setup with linear curve. The calibration is only hardware specific (you adjust the pots), there are no related values which would be stored anywhere

Hardware: check the output voltage of the R-2R latter - does it behave linear? If yes, the error might be around the OP, if not, maybe a resistor of the R-2R latter has no contact?

Today I tested the calibration with a MBHP_AOUT_LC module, it works.

Best Regards, Thorsten.

[Alkex]

hi thorsten,

I m very embarrassed  :-[ the synth turned out to be an exponential curve, although the documentation that came with it says linear.

anyway, all is well that ends well,

sorry to have had you test your hardware especially, I did strongly doubt it was a mistake from your behalf,

Now all works fine and I must admit your cv software is excellent, especially the way it handles note stacks!

thanks again for your time and keep it up!