Could you make the Maestro FSH filter and sample & hold at the same time.

[skiraly017]

I have not looked into this yet but was thinking about it on my way to work. The layouts I've seen for the FSH have a toggle that allows you to either filter or sample and hold. Could you wire it to -

1) Filter
2) Sample and Hold
3) Both

Just curious. Thanks.

[Processaurus]

Nice idea!  But why settle for a static mix between the two in the "both" switch position?  Pan between the two, keeping the mix/sum of the two in the zone.  Dual linear pot, set up like counter acting volume controls, when one (say the envelope CV) gets turned up, the other ( the Sample + Hold CV) gets turned down, in the middle its 50% of each.  All the options of the three way switch are still there, but you also get everything in between.

I used this (Paul Perry gave me the idea) for mixing two LFOs together for a tremolo, very good for keeping a constant depth over the pot's travel.

[soggybag]

I think you could create a mix between the output of the control voltages that feed the resonance of the filter. They both feed though the envelope/S&H switch.

[~arph]

Great, just had this idea last night.. seems someone beat me to it by almost five years.. Yes, I'd say sum the filter and S/H control voltages and blend between them (ala panning for fun @geo)

[slacker]

An interesting alternative would be to sample and hold the envelope voltage. That would give you a stepped envelope.

[Marcvv]

I tried to use the sample and hold voltage to control the speed (to get a random speed). From the point where the noise transistor is fed I created an extra noise circuit (copy of the existing) to control a led. It did drive the led but then stopped the filter. Never got it working. I might have to look into this again.

[~arph]

An interesting alternative would be to sample and hold the envelope voltage. That would give you a stepped envelope.

Will only work/sound ok at a fast lfo rate then.. as the envelope of the attack usually is pretty quick. On the decay side it might sound interesting. I thought of using the actual guitar signal as the s/h voltage, that would be a rather random signal too.

[Processaurus]

Yes, I'd say sum the filter and S/H control voltages and blend between them (ala panning for fun @geo)

Panning for fun doesn't work very well for blending CV's together, because there is a lump in the middle.  I'm guessing (from the experience of trying to mix two LFO's with that panning circuit) you would find yourself having to turn the depth down when the pan pot was in the middle of its rotation vs the two extremes.  Paul's suggestion of the dual linear pot set up as opposed volume controls worked much better as far as the sum of the two voltages remaining constant across the knobs travel.  This is because in the middle, both CV signals will be at half voltage, whereas with the geo panning circuit they will be each .707 (half power) times the original amplitude, hence the lumpy response.

One could also try buffering the two CV's with a dual opamp and using a dumb panning circuit, with just a pot with the outside lugs tied to the opamps' outputs and the wiper being the average of the two.  That should be half voltage in the middle as well.

I thought of using the actual guitar signal as the s/h voltage, that would be a rather random signal too.

Very cool!  It is a random signal but the window of randomness gets narrower as the note gets quieter...

[~arph]

You're absolutely right.. the dual pot solution sounds like the right choice.

[~arph]

Very cool!  It is a random signal but the window of randomness gets narrower as the note gets quieter...

Plus, think what happens when the LFO frequency is close to a sub harmonic of the note being played