Help me out with some ideas

Started by stonerbox, January 10, 2017, 11:20:07 AM

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stonerbox

Planning to do a collection of saturators that is chosen through a rotary switch much like (but not as advanced as) Elektron's Analog Heat. One thing needs to be ironed out though. And there will probably be more down the line.
https://www.elektron.se/products/analog-heat/

1. Using only a few set of controls for 4 different saturation/distortion circuits is a... challenge. Is there a circuit that can translate resistance? 0-100kohm > 0-500kohm.
I know that this is probably a nightmare to actually pull off but I like nightmares.

There is nothing more to be said or to be done tonight, so hand me over my violin and let us try to forget for half an hour the miserable weather and the still more miserable ways of our fellowmen. - Holmes

stonerbox

#1
Really quite here. Not that surprising though the request is rather strange and unorthodox. Probably better to build a set of custom ganged potentiometers instead.
There is nothing more to be said or to be done tonight, so hand me over my violin and let us try to forget for half an hour the miserable weather and the still more miserable ways of our fellowmen. - Holmes

vigilante397

It's probably quiet because there isn't a really good answer. Your basic idea is absolutely feasible, but I think the big problem is that you want it to be like something else. If you were to design the circuit from scratch it could absolutely be done, but if you're looking at the analog heat and trying to see what you could do similar to that, it's going to get very tricky, because frankly their signal path may be analog but there's clearly quite a bit of digital circuitry in there, and trying to copy a commercially available digital pedal with analog circuitry just doesn't go well.

Best of luck to you though ;D
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anotherjim

Voltage control would let one pot work several circuits that have different needs. I suppose vactrol would be the easiest approach?
You have the option to drive separate vactrol LED's to help get individual responses in addition to ranging the LDR with parallel & series resistance.
That Elektron thing looks cool, but far more expensive than I'd want to pay for a distorter!

stonerbox

#4
Quote from: vigilante397 on January 11, 2017, 01:28:26 PM
It's probably quiet because there isn't a really good answer. Your basic idea is absolutely feasible, but I think the big problem is that you want it to be like something else. If you were to design the circuit from scratch it could absolutely be done, but if you're looking at the analog heat and trying to see what you could do similar to that, it's going to get very tricky, because frankly their signal path may be analog but there's clearly quite a bit of digital circuitry in there, and trying to copy a commercially available digital pedal with analog circuitry just doesn't go well.

Best of luck to you though ;D

It's not a easy task and in no way would I set out to figure out how they did it. I'm more into the simple idea of a collection of saturators and a big sexy knob to switch sound with.

Quote from: anotherjim on January 11, 2017, 01:55:28 PM
Voltage control would let one pot work several circuits that have different needs. I suppose vactrol would be the easiest approach?
You have the option to drive separate vactrol LED's to help get individual responses in addition to ranging the LDR with parallel & series resistance.
That Elektron thing looks cool, but far more expensive than I'd want to pay for a distorter!

If I could I would give you a hug and 15+ beers. You just made my day Jim. :)
Yeah the Heat has an incredible sound quality and flexibility. I got one of their analog drum machines and it's nothing short of amazing. Elektron stuff is very pricey but for a good reason.
There is nothing more to be said or to be done tonight, so hand me over my violin and let us try to forget for half an hour the miserable weather and the still more miserable ways of our fellowmen. - Holmes

ElectricDruid

I can see several approaches to this:

1) Analog circuits with one set of controls that are switched between one circuit and another.
I think this is what you had in mind originally, and the problem as you've pointed out is that some circuits might need 100K drive pot, whereas others might need 500K. This isn't insurmountable - we can redesign the circuits so the pots are the same. But it's not easy.

2) Voltage control
Take notes from the synth world, and build voltage-controllable saturator circuits like Jim suggested. This is probably the way I'd go. After all, voltage-controlled gain is a simple VCA, and there are a million circuits for that. voltage controlled filters are also common. Voltage-controlled tone controls are rarer, but not impossible by any stretch.

3) Digital control
Use digipots in each saturator circuit controlled from a central uP. Do we know how well the Analog Heat deals with real-time parameter changes? Do you get noise if you tweak knobs while it's playing?
Alternatively, multiplying DACs could be used to control levels in different parts of the saturator circuits. This would offer better resolution than digipots, although it might not completely solve the potential for stepping.

4) Something else I haven't thought of
There's always one of these, so it's best to include it so I don't grow a big head.

HTH,
Tom




stonerbox

#6
Thanks for the input ElectricDruid! I got a lot to study now then off the drawing board.
There is nothing more to be said or to be done tonight, so hand me over my violin and let us try to forget for half an hour the miserable weather and the still more miserable ways of our fellowmen. - Holmes

FiveseveN

I've developed something similar in principle, maybe my approach may give you some ideas.
1st of all, think of what controls are really intrinsic to the saturator. The gain/drive control might be an obvious issue: some vary a resistance in a feedback path, others are interstage volume controls, or maybe you're keen on some more exotic variation.
My solution was to use some fixed gain in the saturator part (two switchable "presets" actually) and control drive by varying the signal level going into it.
Then post-distortion filtering can be treated separately (as with the Analog Heat), maybe also switch between different kinds of filters if you find they are important for a particular sound.
Volume and dry blend or whatever else you want to add would also be independent of the actual saturation circuits.
So something along these lines:



I used electronic switching, a CD4051 (or two) would be suitable.
Quote from: R.G. on July 31, 2018, 10:34:30 PMDoes the circuit sound better when oriented to magnetic north under a pyramid?

Quackzed

yeah, as above ,you could tailor all the circuits to use  the same 100k volume pot and input level pot (gain) etc, and switch in/out different clipping/amplification circuits between 'em. the more building block-ey it is the easier it'll be to accomodate different amp/clip/tone circuits...  maybee a 2p6t rotary switch to switch in different distortion blocks and another for different tone shaping,speaker sim blocks... might be possible to hack a rotary switch into a 3 or 4p6t switch...
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