Model 10+15 Oscillator Tracking

[PaulLawler]

I have both the model 10 and model 15. The 901 tracks different to the 901bs and the 921 tacks different to the 921bs.

Is there some technical reason that happens ? It can be quite a challenge to use all 3 oscillators because of it.
Thanks

[till]

I have both the model 10 and model 15. The 901 tracks different to the 901bs and the 921 tacks different to the 921bs.

Is there some technical reason that happens ? It can be quite a challenge to use all 3 oscillators because of it.
Thanks

Same here on my Synth-Werk. And getting a 901ABBB combination in tune within itself over 3 octaves and a single 921 is a live time challenge.

But the 901Bs sound so wonderful. The triangle waveshape alone is unique in its character. And superb for low bass sequences.

I do admire the skills of the 901 Moog Modular users even more since I own a cloned 901 VCO bank.

[PaulLawler]

I have both the model 10 and model 15. The 901 tracks different to the 901bs and the 921 tacks different to the 921bs.

Is there some technical reason that happens ? It can be quite a challenge to use all 3 oscillators because of it.
Thanks

Same here on my Synth-Werk. And getting a 901ABBB combination in tune within itself over 3 octaves and a single 921 is a live time challenge.

But the 901Bs sound so wonderful. The triangle waveshape alone is unique in its character. And superb for low bass sequences.

I do admire the skills of the 901 Moog Modular users even more since I own a cloned 901 VCO bank.

Not quite what I meant, I wasn't trying to get the same tracking with the 901s and the 921s together, its the 901s with the big 901 and the 921s with the big 921. You'd think being in the same system they might kind of work together.

I also have the Synth-Werk 901ABBB - I think I prefer the 921s to all of them

[till]

In theory, you get these tuned well over several octaves. But not in real live with not perfect calibration and temperature changes.

[analogmonster]

I run two oscillator banks in my Moog System 55 Clone I built over the years. One is my 901ABBB bank, and the other is a Minimoog oscillator bank I constructed the same way as bank, meaning a separate TMINIA oscillator driver and three TMINIBs. This topology does not exist in the Moog world, AFAIK, but I liked the bank conceopt that much that I invented a "Minimoog Bank" somehow.
Anyway, the Mini Bank runs stable, the 901 Bank not. The reason is the temp compensation which does *NOT* work with a heated transistor array in the expo section. For the bored: I posted several times about that topic before. Neither the 901 nor the 921 expos do that. The 901 in its original form uses a diode array (that's what I cloned), and the 921 uses a temp resistor, which is sub optimal as well. Moog just is resistant for any advice concerning this.

Normally I don't speak about uncompleted and untested projects of mine, but all this tracking stability discussions made me setting up an autotune project for Moog Modulars. I plan it as a module which you can add to your modular. It is in development state currently. If I will be successful, I will present my results here. If I fail, I won't, as this would be too embarrassing for me
If it works, it might be a help for those with oscillators which have a poor or rough tracking and stability.
Whish me luck...

[analogmonster]

Done Yesterday I completed my T908 AUTOTUNE module. See my post Autotune for everyone
It is able to auto correct a 901(B) which is totally out of tune and out of scale. It can be added to any modular system as stand alone module and take over the control over detuned VCOs, so you don't have to take care about it yourself and you can get rid of tuning and scaling adjustment processes. This is useful especially for the 901(b) users who hate the repetitive and iterative annoying process of tracking, tuning and scaling
That is what happened to me, and as I want to keep my 901(abbb) bank, I developed the T908 AUTOTUNE as a feasibility study, and here we are.
I can provide the module to anybody who is interested. Please contact me offlist via email
([email protected]) or via private message.

[goranjean]

I face a similar situation with my Synth-Werk. Achieving a well-tuned 901ABBB combination across three octaves and a single 921 is a lifelong challenge.

Yet, the 901Bs produce such delightful sounds. The distinct character of the triangle waveshape alone is remarkable, particularly for crafting superb low bass sequences.

I hold even greater admiration for the expertise of 901 Moog Modular users, considering I own a cloned 901 VCO bank.