Moog Music Forum

I'm curious- Would it be a possible to swap out OSC 1 and 2's variable waveform pots with "set" ones, ala the vintage varieties? I can dial in the classic waveforms I want on the fly, BUT I have to isolate the OSCs to do it- I use OSC 3's variable one for modulation fun, so would leave that pot as is- I'm just envisioning a 4-5 "set" position dial on 1 and 2 vs the continuously variable ones existing... anyone tried this?
thanks

It could technically be done by positioning the potentiometer exactly on a desired waveform, and then measuring its value precisely. Repeating the procedure with other waveforms. Then replacing the potentiometer with a multiple contacts rotary switch that would connect different fixed resistors to produce the fixed waveforms.

But that would require quite a lot of work, especially just to remove the pots and then replacing them with rotary switch since there is a printed circuit board that would be in the way. Although I guess still feasible IMHO.

This area now has a great tech with all the experience/equipment/know-now, but yeah, if it's quite a bit more than just a pot swap, I'd probably be Moogless for too many gigs... just a thought- worked out how to dirty it up; this is my last minor gripe-

moogslob wrote:This area now has a great tech with all the experience/equipment/know-now, but yeah, if it's quite a bit more than just a pot swap, I'd probably be Moogless for too many gigs... just a thought- worked out how to dirty it up; this is my last minor gripe-

Thanks for the kind words.
Maybe you could swap your Old School for a regular Voyager instead. Since it's programmable, you could simply recall a patch with its waveforms already selected in it.
I've always thought the Voyager was ideal for live performance with the ability to recall patches on the fly, and the Old School much more suited for experimenting and tweaking as a hobby, or still professionally, at a slightly lower cost.

I had an Old School a while back, but sold it precisely because I didn't like the continually variable waveforms as it made it rather difficult to obtain exact waveforms (like sawtooth) without seeing it on an oscilloscope. And having the choice of getting a Voyager or a Minimmog D, guess which one I went for...

Oh, and if you're not considering a Voyager because of its digital capabilities and want to remain "analog all the way", let me remind you that its digital side provides 16384 possible values (14 bit resolution) for each knob on the front panel (even if the display only shows a rounded out number, it still works internally with full resolution), and the sound producing board is receiving those converted numbers in the form of analog control voltages, and each value of those 16384 represents a 0.0006 volts variation. No stepping here folks!

And the analog board in a regular Voyager is the same as in the Old School, minus slightly different hardwired section for modulation purposes.

I actually meant this area, meaning Southeast NC has a tech that does it all, but I DO appreciate your educated and timely response!

The programmable interface on the LP always threw me off, hence the Old School- (I've spent too many years on non-programmable synths, old dog syndrome)- I actually relish on-the-fly changes, and swinging the waveforms around has sometimes gotten me even better than anticipated results, BUT when I want the perfect square and I miss it by a millimeter... doh! The audience never knows, but I end up waveform fixing in the middle of a solo anyway- Really, with a switchable waveform knob, this'd be my end-all synth (I'm a big sucker for Osc sync and sample/hold)

moogslob wrote:I actually meant this area, meaning Southeast NC has a tech that does it all, but I DO appreciate your educated and timely response!

The programmable interface on the LP always threw me off, hence the Old School- (I've spent too many years on non-programmable synths, old dog syndrome)- I actually relish on-the-fly changes, and swinging the waveforms around has sometimes gotten me even better than anticipated results, BUT when I want the perfect square and I miss it by a millimeter... doh! The audience never knows, but I end up waveform fixing in the middle of a solo anyway- Really, with a switchable waveform knob, this'd be my end-all synth (I'm a big sucker for Osc sync and sample/hold)

Hahaha, I suspected you weren't necessarily talking about me !
And just to be clear, I'm not a tech. I'm just a self-taught electronics hobbyist who enjoys analog synths.

And as for having the old dog syndrome, I hear ya. I've got it too. All of my gear has as many knobs as possible for real-time tweaking fun.

BTW, you maybe surprised to know that even on a Minimoog D (at least on mine), the square wave isn't a perfect 50% duty cycle waveform. I measured it at between 49 and 51% depending on different oscillators.
That's due to electronic component tolerances. But on the Mini, it's not possible to adjust it. So you see, in that regard you're better off with an Old School after all...

well, I'd like to think so, but I DO know that before I die, a bona fide Mini WILL be sitting in my music room, if I have to sell a kid to make it happen, so be it! (thank the maker my wife doesn't follow these forums)

Waveshaping is just a CV

All you need is a rotary switch with a voltage divider network on each tap, with common terminal routed to waveshape CV input on the analog board

Fitting the rotary switch would be the hardest part - it has to be low profile to clear the PC board on the front panel

Digi-key sells a rotary switch with x # of steps. I picked up an 8 position rotary for an Analog Sequencer that I built. It's part number:
CKN10204-ND description ROTARY SP 8POS SLD.

And if I recall correctly, they use the same part (with a key inserted and broken off contacts) for configurations up to 12 steps.

Mouser likely sells something similar.

MC wrote:Waveshaping is just a CV

All you need is a rotary switch with a voltage divider network on each tap, with common terminal routed to waveshape CV input on the analog board

Fitting the rotary switch would be the hardest part - it has to be low profile to clear the PC board on the front panel

Yeah, not to mention getting the exact resistor values in order to get exact waveforms.

thealien666 wrote:Yeah, not to mention getting the exact resistor values in order to get exact waveforms.

Trimpots!

latigid on wrote:

thealien666 wrote:Yeah, not to mention getting the exact resistor values in order to get exact waveforms.

Trimpots!

Naturally, but soldered on the legs of rotary switches ?
A small printed circuit board would be more appropriate, which would add some work to the mod...

What about an alteration to the existing pot? Just some tangible "bump" on the exact waveforms for saw and square would suffice...

moogslob wrote:What about an alteration to the existing pot? Just some tangible "bump" on the exact waveforms for saw and square would suffice...

Let's not get carried away here...

I think some sort of simple removable markings (as to not damage the faceplate) at precise locations around the waveforms knobs would work equally well, and would be much less intrusive and complicated...

haha, yeah no need to franken-synth my new Moog- just theorizing