KB Amount Glitch

[magnet]

Hi- It is the "keyboard amount" . All the way to 4095.
Cannot understand why it would ~seem~ to be a software issue, but not so widespread. ( I hope.)

[Bääx]

Hi- It is the "keyboard amount" . All the way to 4095.
Cannot understand why it would ~seem~ to be a software issue, but not so widespread. ( I hope.)

Thanks for your post - up until now I'd counted four LP's with the error and none without. I'd hoped to hear from more LP owners to see if it was a universal problem or a selective problem. Though, if you're running OS 1.04T, it could be something in OS 2.xx systems.

Any OS 2 users care to check their units?

[Sir Nose]

stage 1 SE0851 OS 2.21

Kb amt via pot goes upto 3798
in precision mode with value encoder it goes upto 4095 but has a jumpy behavior (definately could be my encoder)

I have not check what values will or will not save with a patch, yet.

Also, the tribute edition also has more parameters that use the Moog RAC technology. I am not sure if KB AMT is one of them. I think it is a couple more. From stage manual "In the Stage Edition,
RAC provides responsive analog control for the Osc 1 & 2, Filter Cutoff, Filter Resonance,
EG Amount, Overload and Filter EG Sustain parameters."

[audiostatic]

Noprobs here with my Tribute (serial # 29) running OS 2.10S

[Bääx]

So far with the error are three Stage I's and two Stage II's. And the two Tributes mentioned are free and clean.

Also, the tribute edition also has more parameters that use the Moog RAC technology. I am not sure if KB AMT is one of them. I think it is a couple more.

This is an interesting point. I've just taken a look at the Tribute manual and it doesn't mention any specific parameters for the RAC. So, it's quite possible that the Tribute does have RAC control for the KB amount, which could be why they don't have the problem, regardless of their firmware version.

I've made a couple sweet patches now based on the tone coming from the noise source through the resonant filter. And it sucks that this KB Amount blackout is right in the sweet spot where my keyboard would play the filter in tune.

There's still a glimmer of hope in my mind that it could be a firmware fix instead of a re-calibration, because it's so much easier to update the firmware than ship the thing across the border to Moog.

If Rosser understood and researched my question properly, and the Stage II's coming out of the factory are now fine, then it may involve a factory repair. I suppose it's a good excuse to get the CV output mod done.

[Sir Nose]

Yeah, at some point in the future my LP has to go to the factory anyway. I need a new value push encoder as mine is getting more and more jumpy, the CV out mod, and I would like the keybed spiffed up a bit. I am hoping the firmware will fix this problem though.

[Bääx]

Through several e-mail exchanges, Rosser helped me figure it out.

From my own assumptions at this point, it would seem that the KB Amount is factory set to stop at 3700ish because that is an approximation of true keyboard tuning, and it does sound pretty close when the LP's keyboard is octave neutral (without any of the octave transpose buttons lit).

But with the last patch I made using filter resonance, my ear liked the sound of the KB Amount at 3800ish, and it bugged the living daylights out of me that I couldn't save the patch there (also, that the tracking would just skip from 3400ish to 3738).

Through the Hidden Mode, the KB Amount can be set to it's full range of 0-4095, or have it's range restricted to a lower value of choice, which makes sense if one wants to quickly dial in a tuned filter resonance.

So, for those Stage edition owners thinking their KB Amount would benefit from its full range of 0-4095, or would like to re-tune it to a different value, here's the formula:

1) Enter the LP's Hidden Mode by turning the unit on while holding down the buttons Cursor, Enter, and Octave Down.

2) Using the Master Menu, scroll to "FILT KB CALIB" then use the Select button to underline the '52' displayed.

3) Use the Value Encoder to change the number to '76' (only one click away) Beside the '76' is the top-out value of the 'KB Amount,' which on my unit was 3738

4) You can use the keyboard to hear the filter tuning and use the value encoder or the 'KB Amount' (as selected through the filter pot) to change the range of the filter tracking - whether you'd just like it tuned differently or would like the full range of 0-4095.

5) Reset your LP, make a sweet patch with your newly liberated filter tracking, and then do a little dance.

[magnet]

Cool-Glad to hear there was a fix for that, and you got in a little dancing. Don't blame you !

[Sir Nose]

That's weird because I thought the keyboard AMT was 100% tracking at 12 O'clock and 200% tracking at max.

I thought I read that somewhere in the manual. So, that would mean 200% tracking is not possible then?

[Sir Nose]

If the KB AMT is recalibrated does it screw up the patches that have been saved with the old calibration?

[Bääx]

I've just spent some time playing with my new filter settings and here's what I've come up with:

That's weird because I thought the keyboard AMT was 100% tracking at 12 O'clock and 200% tracking at max.
I thought I read that somewhere in the manual. So, that would mean 200% tracking is not possible then?

I looked it up in the Stage II manual, though it's possible there's a difference with the Stage I:
"...when the KB AMOUNT is set to it’s highest level (100%), the filter cutoff will rise by an octave each time you play an octave higher on the keyboard."

This would explain why the Stage editions' KB Amount top out at 3700ish, because that's approximately where this happens. It's possible that my filter did drift out of tune, though there seems to be some variance in the filter tuning depending on where the Filter Cutoff value is.

Just using the filter's resonance for tone, I tried several things. There are a few variables that affect the tuning of the filter resonance, which make this kinda tricky. The resonance will self oscillate starting at about 3150 and will drop about a semitone when turned up to full 4095. It's also interesting to note how the character of the waveform changes in between these values, and also through changing the filter pole. The EGR Amount in combo with the Filter EG Sustain will also affect where the filter sits.

According to my ear (which is somewhat reliable, as I've been tuning violins and guitars by ear for a couple decades), when the filter is tuned to Osc. 1 at the 16' setting, the KB Amount is at 3500ish. And when it's tuned (using the Cutoff) to Osc. 1 at the 2' setting, the KB Amount is the familiar 3738. And for the filter to be tuned to higher octaves, the KB Amount sounds good above 3800. This was done with the Filter Resonance at 4095, and playing scales and octaves back and forth between Osc.1 and the Filter Resonance.

If the KB AMT is recalibrated does it screw up the patches that have been saved with the old calibration?

I did discover that changing the calibration value does affect the saved patch value of the KB Amount. When calibrated at the old 3738, a patch that had a saved KB Amount value of 2929 changed to 3209 when the filter was recalibrated to 4095. It's a minor change, unless you've got patches with very finely tuned filter resonance.

[nikola]

but why the jump from 3400 to 3738? sorry, i don't get it

oh, and Baax, thanks for your research on this
my dearest instrument is now ready for a grand finale !

[Bääx]

but why the jump from 3400 to 3738? sorry, i don't get it

This is also a mystery to me - perhaps a weird digital artifact from the calibration point? I'm just happy that I now have the missing 20% of range with my keyboard tracking.

Glad I could help with your grand finale.

[denoiser]

Bääx,

same was mappening to my SE2 but I didn't care too much.

But now, thanks to your research, is fixed and perfectly tracking!

Thank you!

[Bääx]

Happy to be of service, Denoiser.