Need a boring module - cv shifter

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oldgearguy
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Need a boring module - cv shifter

Post by oldgearguy » Mon Oct 12, 2020 9:54 am

Does anyone make a dedicated quad cv shifter? Ideally it could do shifting and scaling, but I'd be happy with just shifting.

The reason is I have some modules that prefer 0 -> +5v modulation inputs rather than 0 - 10 or +/-10. Right now I end up using an attenuator + a mixer to scale and shift a typical +/- 10 to 0 -> 5 or 0 -> +10.

A scan of modulargrid and a few usual vendor sites didn't yield anything obvious.

thanks

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steffengrondahl
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Re: Need a boring module - cv shifter

Post by steffengrondahl » Mon Oct 12, 2020 10:21 am

Quad CV shifter - you mean 4 units that all can attenuate and shift (add offset), so your bipolar +/- 10V signal to unipolar 0-5 V (or 0-10 V). Not sure it exists.

stg soundlabs active attenuator, http://www.stgsoundlabs.com/products/attenuators_mu.htm, will be able to add 5V and then attenuate. A bipolar +/- 5V signal will then be turned into unipolar 0-10 V if attenuation is 1 (i.e. full clockwise), and you can easily attenuate to 0-5 V. You have 3 cells that can do the trick. But if your input signal is +/- 10 V it will not work (or rather you have to use one cell to attenuate to +/- 5V and another to then add the offset).

Synthesizers.com Q125 Signal Processor, https://synthesizers.com/q125.html, can do the trick even for +/- 10V, but only one channel, not four. So can the Corsynth C112 Assistants, https://corsynth.com/home/modules/assistants, using the attenuator and the +/- 5V to 0-5 V converter.

Please notice, the Q125 first attenuates and then adds offset (AFAIR), whereas the stg soundlabs active attenuator first adds offset (if you do not plug anything into input 1) and the attenuates.

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Re: Need a boring module - cv shifter

Post by LesMoMo » Mon Oct 12, 2020 11:32 am

The Moon 592 it will work as a triple cv shifter if its inputs are "carefully" patched ...
Plus 5 volts will be normalized "downwards" if nothing is patched in INPUT 1.
And the destination switches do allow to add voltages if more than one is assigned to an output,
Gert
Last edited by LesMoMo on Mon Oct 12, 2020 11:38 am, edited 2 times in total.

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Re: Need a boring module - cv shifter

Post by Tofupancho » Mon Oct 12, 2020 11:36 am

NE Lapsus Os?

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Dave Peck
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Re: Need a boring module - cv shifter

Post by Dave Peck » Mon Oct 12, 2020 12:10 pm

Look for names like voltage processor, signal processor, CV processor. There are tons of them. Like this:

https://synthesizers.com/q125.html

Some of them also work as mixers, with +5VDC hard wired to an input so turning up that knob with no external signal patched into it adds a voltage bias (shift) to whatever is patched to another input. Like this:

https://synthesizers.com/q114.html

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Re: Need a boring module - cv shifter

Post by oldgearguy » Mon Oct 12, 2020 1:13 pm

I've been looking at the suggestions. The Q125 looks like a generally good choice, but it's a single processor per 1U.
I typically use the STG Mixer to do this since it has a +5v wired to one of the mixer inputs, so by combining attenuation on an input plus the offset on another, I can get what I want, but it seems a shame to tie up an entire quality mixer like that just for level+offset duties.

I was hoping to run across a dedicated module that could support multiple copies (kind of like the Lapsus Os), but at this point maybe it is worthwhile to give up a couple U of panel spaces to some Q125's.

thanks for the suggestions.

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defutura
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Re: Need a boring module - cv shifter

Post by defutura » Mon Oct 12, 2020 1:46 pm

oldgearguy wrote:
Mon Oct 12, 2020 1:13 pm
I typically use the STG Mixer to do this since it has a +5v wired to one of the mixer inputs, so by combining attenuation on an input plus the offset on another, I can get what I want, but it seems a shame to tie up an entire quality mixer like that just for level+offset duties.
Did you take a look at the STG Soundlabs Active Attenuators? It has +5V normalised to the first input, and then the signal cascades down to the other two units if the normalization isn't broken.

Edit: I see Steffen beat me to it... :doh:

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Re: Need a boring module - cv shifter

Post by Dave Peck » Mon Oct 12, 2020 2:22 pm

oldgearguy wrote:
Mon Oct 12, 2020 1:13 pm
I've been looking at the suggestions. The Q125 looks like a generally good choice, but it's a single processor per 1U.
Nope, it's two independent channels per module, each with separate input & output, with slightly different functions/features for the top & bottom sections.

- Top half does offset, invert, plus signal level adjust (attenuate to zero, or amplify to 200%) in any combination.

- Bottom half does offset and invert.

Two of these Q125 modules would give you four independent offsets, with four independent invert controls, and two of the four channels would also give you the ability to adjust the signal level from zero to 200%.

I have three Q125s and they get a LOT of use for both CV and audio processing.


Also, the new Q114 Mixer++ has a neat 'hidden' feature that might be perfect for your needs - those little switches in each of the four channel sections don't have to do what the front panel label says they do. There are PCB jumpers that can be set to change the function of each switch, independently. So you can set ALL FOUR of them to just add 5VDC when you put the switch in the upper position. And each of the four sections can be used as an independent processor, they don't have to cascade together and mix all of the inputs together, so you would have four processors that add 5VDC (and attenuate the input, using the knob) in a single panel width.

I also have a Q114 and I changed one of the switch jumper settings for CH#4, so I have two channels that can invert the input. Works great.

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Re: Need a boring module - cv shifter

Post by oldgearguy » Mon Oct 12, 2020 2:27 pm

defutura wrote:
Mon Oct 12, 2020 1:46 pm
oldgearguy wrote:
Mon Oct 12, 2020 1:13 pm
I typically use the STG Mixer to do this since it has a +5v wired to one of the mixer inputs, so by combining attenuation on an input plus the offset on another, I can get what I want, but it seems a shame to tie up an entire quality mixer like that just for level+offset duties.
Did you take a look at the STG Soundlabs Active Attenuators? It has +5V normalised to the first input, and then the signal cascades down to the other two units if the normalization isn't broken.

Edit: I see Steffen beat me to it... :doh:
Yep - it becomes a question of what's going to be most useful (and what's available).
If I generally have some LFOs/Mod sources that have built-in attenuators, then the STG module can help three times. If I have +/-10 then as suggested, one input is used for attenuation, then the next for shifting. Still, two of them gets me a max of 6 and a minimum of 3, so that might be the better option if I'm going to use 2U for this process.

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Re: Need a boring module - cv shifter

Post by josaka » Mon Oct 12, 2020 5:42 pm


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Re: Need a boring module - cv shifter

Post by Sugarfree » Mon Oct 12, 2020 10:06 pm

Similar to Moon M525M CP Attenuator/Mixer, the regular M526 Reversible Mixer could probably be modified to provide voltage offset on one of the unsued inputs. @LesMoMo what would be a reliable 10V source on the M526 pcb?
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Re: Need a boring module - cv shifter

Post by oldgearguy » Wed Oct 14, 2020 5:05 am

So, maybe I'm approaching this whole thing wrong.
What do you guys do that have large systems and have been working with modular for years?

In my modest configuration, I have:
a module with cv inputs expecting 0 to 3.3v (~5v with a simple mod),
modules with cv input and out ranges set to -3.5v -> +6.5v,
and modules expecting 0 -> 10v

A lot of them do not have attenuators on all/any of the inputs.

All my LFOs and S&H modules are putting out -10 to +10 and the envelopes are 0 to +10.
A few envs and LFOs have output attenuators, and one LFO has a range control to set 0 -> 5v

Do you all have dedicated banks of attenuators and DC offset modules? Do you modify the modules to match the cv sources?

Both the "C" and the "V" are important, but when I have to patch in the DMM and scope to adjust input modulation amounts to match the destination, it kind of feels like menu-diving when programming a synth.

I appreciate all the effort in porting Buchla/Serge/Euro/etc modules to the 5U format. The additional sounds/features are excellent, but the interfacing can be a challenge sometimes. I'm sure you all don't just patch stuff in direct and ignore the fact that most of the modulation range is unused. That's why I started this thread because I was sure I was missing something obvious.

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Re: Need a boring module - cv shifter

Post by fac » Wed Oct 14, 2020 7:46 am

I have a fairly large system (90 spaces). I have two dotcom Q125 that get a lot of use, since not all my modules have attenuators on them and sometimes I also need offset: for instance, I like the ability to add an offset to a pitch CV before quantizing, or add an offset to S&H noise that will trigger an envelope, so that the offset controls the triggering probability. I haven't felt the need of another Q125, though. Two are enough for me: that's four channels of offset/inversion, with two of them also having attenuation/amplification. Very useful tools.

I also have an Oakley Multimix, which can be used as a regular 4-input mixer, or you can separate some of the channels from the mix and use them as individual attenuator/inverters (e.g., have a 3-input mixer and a single attenuator/inverter). Also, when no input is connected to a channel, the input is wired to +5V, so you can use the corresponding output as a constant voltage generator, connect that output to another input and then you can add an offset to another signal (but it would consume two channels). So, in general it's a very useful and versatile module, but if you don't need the mixing features, the Q125 is probably a better choice for applying gain/offset to a signal The dotcom Q114 Mixer++ has similar functions to the Multimix and is probably cheaper and easier to obtain, particularly in the US.

I also used to think these modules were kind of boring, but they give you an extra degree of control, and therefore, extra fun. They are often the answer to "what if I could...?" questions.

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Re: Need a boring module - cv shifter

Post by steffengrondahl » Wed Oct 14, 2020 7:51 am

I got a 110 U system (plus a 8U table top and a 8U rack) if that is considered large ;) However, I don't have the big need for attenuating and offsetting as most of my modules are well behaved: VCO and LFO from dotcom and Corsynth is -5 to 5 V, so is my noise and sample & hold (dotcom) and envelopes are 0 to 5 V (dotcom). I do not have any modules with strange CV expectations and many modules has attenuators on the inputs.

The problem is probably that your ported modules haven't been modified to provide more reasonable CV input and output ranges, nor expanded with appropriate attenuators. Which is understandable, as this is (I assume) a much bigger job than re-panneling and making the needed power changes. So I believe, than unless you can modify these modules further, you have to accept providing a lot of attenuators and DC offset modules, perhaps even amplifiers.

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Re: Need a boring module - cv shifter

Post by oldgearguy » Wed Oct 14, 2020 8:56 am

steffengrondahl wrote:
Wed Oct 14, 2020 7:51 am
The problem is probably that your ported modules haven't been modified to provide more reasonable CV input and output ranges, nor expanded with appropriate attenuators. Which is understandable, as this is (I assume) a much bigger job than re-panneling and making the needed power changes. So I believe, than unless you can modify these modules further, you have to accept providing a lot of attenuators and DC offset modules, perhaps even amplifiers.
Agreed, and if that's the answer, then that is the answer. However, since some of the modules are very popular/common (like the Ornament and Crime), I thought others may have found a different/better solution.

(I have DotCom, Corsynth, Moon, and Oakley LFOs, envelopes, S&H and they all are slightly different).

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Re: Need a boring module - cv shifter

Post by fac » Wed Oct 14, 2020 9:22 am

oldgearguy wrote:
Wed Oct 14, 2020 8:56 am
(I have DotCom, Corsynth, Moon, and Oakley LFOs, envelopes, S&H and they all are slightly different).
Most of my modules were originally designed for the MU format, but I still sometimes have problems with some weak clock or trigger signal. Adding a small offset and/or 200% gain with a Q125 takes care of the problem.

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Re: Need a boring module - cv shifter

Post by Dave Peck » Wed Oct 14, 2020 2:32 pm

oldgearguy wrote:
Wed Oct 14, 2020 5:05 am
So, maybe I'm approaching this whole thing wrong.
What do you guys do that have large systems and have been working with modular for years?

In my modest configuration, I have:
a module with cv inputs expecting 0 to 3.3v (~5v with a simple mod),
modules with cv input and out ranges set to -3.5v -> +6.5v,
and modules expecting 0 -> 10v

A lot of them do not have attenuators on all/any of the inputs.

Yeah, the modules in my 88-space rig are probably more consistent than what you are dealing with. Pretty much everything has mod inputs that accept at least -5V to +5V except for VCAs that expect 0V to 10V. And the CV sources tend to be well behaved and provide signals in those same ranges (although I think the levels from my SSL Quad LFO are a tad low). I don't have anything with those odd -3.5 to +6.5 ranges, either as outputs or expected inputs. And nearly all of my modules have attenuators on their cv inputs, although sometimes I use those up and then have to patch into an unattenuated (or 1V/oct calibrated) CV input, and that's one of the times I need a signal processor module between the CV source and destination.

If those -3.5 to +6.5V modules seem to be the bulk of the issue, maybe whip up a simple circuit with just an in & out jack that adds a +1.5V offset to any standard +/- 5V CV source that you patch through it, and put a few of these in some spare panel real estate, like in a multiples module? Or put one in each of the 'oddball' modules, as a separate cv IN jack, so you can choose between using the stock cv input and the new input that adds the 1.5V offset?

Other than that, I really think the Dotcom Q114 mixer++ (with the right jumper settings for each channel to optimize it for your rig), and maybe a Dotcom Q125 or two, is what you need.

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Re: Need a boring module - cv shifter

Post by oldgearguy » Wed Oct 14, 2020 3:40 pm

Dave Peck wrote:
Wed Oct 14, 2020 2:32 pm
oldgearguy wrote:
Wed Oct 14, 2020 5:05 am
So, maybe I'm approaching this whole thing wrong.
What do you guys do that have large systems and have been working with modular for years?

In my modest configuration, I have:
a module with cv inputs expecting 0 to 3.3v (~5v with a simple mod),
modules with cv input and out ranges set to -3.5v -> +6.5v,
and modules expecting 0 -> 10v

A lot of them do not have attenuators on all/any of the inputs.

Yeah, the modules in my 88-space rig are probably more consistent than what you are dealing with. Pretty much everything has mod inputs that accept at least -5V to +5V except for VCAs that expect 0V to 10V. And the CV sources tend to be well behaved and provide signals in those same ranges (although I think the levels from my SSL Quad LFO are a tad low). I don't have anything with those odd -3.5 to +6.5 ranges, either as outputs or expected inputs. And nearly all of my modules have attenuators on their cv inputs, although sometimes I use those up and then have to patch into an unattenuated (or 1V/oct calibrated) CV input, and that's one of the times I need a signal processor module between the CV source and destination.

If those -3.5 to +6.5V modules seem to be the bulk of the issue, maybe whip up a simple circuit with just an in & out jack that adds a +1.5V offset to any standard +/- 5V CV source that you patch through it, and put a few of these in some spare panel real estate, like in a multiples module? Or put one in each of the 'oddball' modules, as a separate cv IN jack, so you can choose between using the stock cv input and the new input that adds the 1.5V offset?

Other than that, I really think the Dotcom Q114 mixer++ (with the right jumper settings for each channel to optimize it for your rig), and maybe a Dotcom Q125 or two, is what you need.
Right - it's not like I'm sitting here crying into my patch cords or anything. Based on what I've seen on the net, swapping out some resistors on the input and output stages of the O_C will get me 0 -> 9v (also have to recompile the firmware and reinstall it), but it's surface mount which is slow and tedious for me to work on. But, it can certainly be done; just need to order parts and find time.

I was just more curious how homogeneous other folks systems were and what they were doing to bridge the gaps. For the O_C especially, having 0v be minimum makes things like using the Turing machines much more enjoyable because you can freeze the variance by sending a minimum voltage to a cv input (if you set things up in the menus of course). -3.5v (or lower) is a less obviously available voltage in a typical modular compared to 0v.

I guess it's time to break out the magnifying lens and do some work.

Thanks to all for the various suggestions. Based on what I currently have in my system and what I need, I decided to contact STG and order a pair of his active attenuators.

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Re: Need a boring module - cv shifter

Post by Dave Peck » Wed Oct 14, 2020 5:13 pm

oldgearguy wrote:
Wed Oct 14, 2020 3:40 pm

Thanks to all for the various suggestions. Based on what I currently have in my system and what I need, I decided to contact STG and order a pair of his active attenuators.
BTW I also have one of those STG triple active attenuators, and if you ask him, he'll sell you a version that goes from -200% to +200% instead of just inverted unity to unity, so you can use it to boost signals as well as attenuate & invert. Nice!

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Re: Need a boring module - cv shifter

Post by KSS » Thu Oct 15, 2020 12:42 am

I've said before how useful attenuating and diode patchcords can be. Make a few of those and pair them with some x2 gain capable mixers and a lot of your problems go away. 50% attenuating patch cord is two equal value resistors in one endshell. One to tip, one to GND/ Instant divide by 2! No SMD needed. Put a green HS over the plug for "5" to signify 50%. Multi color bands just like resistors if you go beyond a couple ratios. Roger's new short patchplugs with the o-rings would be perfect.

If you don't like the idea of tieing the attenuation value to specific length patchcords <-- I don't find this a problem, just use two sockets back to back like a garden hose coupler. Same connections and now you can put it where you want it between two cords.
33%, 25% and 10% also useful. The latter duplicate thw modulation switches on the Roland 700.

Patchcords with a diode in series at one end -mark the endshell to show it's the cathode end <-- and wire it that way! and you've got a solution to module that don't want less than zero. Also a divide by two, if you can make use of the way it "divides" by clipping. Put it the other way to clip the other side of the signal. Diode cords also let you selectively mix triggers and gates

'Mult' panels can be re-wired the same way as these patch cords to re-purpose and solve your problems. I've done that too, but the special patchcords are more universally applicable IME. Actually both styles -fixed and traveling- have their good and bad points. But having fixed-ratio attenuators and one-way diode patchcords is pretty useful. However you achieve it.

I try to always have at least one module devoted to bias/offsets. Usually also with attenuation and polarity. Mixing comes along for the ride. This is handled differently if you have multiple CV jacks per function, so you can just add in a bias voltage. Like the old gear guys did. ;)

Don't discount the old moog port-a-pots and move-a-mults. That's another old gear trick that handles some of these kinds of problems well. You can buy the variable attenuating patchcords now from a few places, but I haven't found those to be the right..? something. Might be great for others though.

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Re: Need a boring module - cv shifter

Post by dubonaire » Thu Oct 15, 2020 1:07 am

Have a look at the Doepfer A-183-4 Quad Level Shifter.

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Re: Need a boring module - cv shifter

Post by KSS » Thu Oct 15, 2020 1:26 am

dubonaire wrote:
Thu Oct 15, 2020 1:07 am
Have a look at the Doepfer A-183-4 Quad Level Shifter.
For 5U?

Edit: It's also 1bit digital AKA comparators x 4. OP needs analog.

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Re: Need a boring module - cv shifter

Post by dubonaire » Thu Oct 15, 2020 3:54 am

KSS wrote:
Thu Oct 15, 2020 1:26 am
dubonaire wrote:
Thu Oct 15, 2020 1:07 am
Have a look at the Doepfer A-183-4 Quad Level Shifter.
For 5U?

Edit: It's also 1bit digital AKA comparators x 4. OP needs analog.
I didn't check the forum (obviously).

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