Is there another option for the 10 Volt control voltages and line level audio, into the 1V signal ranges for LZX modules? I was curious since the Cadet V Scaler, Voltage Bridge, Expedition Series Bridge were built for 5V to 1V scaling. But what about those audio eurorack modules going beyond 5V? The original “LZX Voltage Interface I” satisfying this requirement is discontinued. Any other suggestions?
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Passive attenuator or flip your own version of the unipolar 5V to unipolar 1V Cadet Scaler.
Source is here: lzxcadet/C5 at main · lzxindustries/lzxcadet · GitHub
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Also, what specific audio eurorack modules were you interested in interfacing? Most audible signals or LFOs in audio eurorack are +/-5V (10Vpp). Most logic signals are +5V and envelopes can often go up to +8V.
Scaling a +/-5V signal with a 5V to 1V scaler is going to get you +/-1V. You’d just need to bias that up by 1V with something like Cadet Processor, TVP, Passage, Proc, Fox Access, etc. and then you’ll have 0-2V swing. That shouldn’t present that much of an issue if you’re plugging that signal into the majority of video modules that have attenuators or attenuverters on their inputs.
Depending on how you adjust/patch the above modules, you could also easily get 0-1V from a +/-1V signal using both the attenuverters/bias controls.
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I have been having good results with a PROC. Actually just ordered a 2nd as I am starting to see its value in mixing within my patches. To me (a total greenhorn) It is feeling much the same as mixing CV in audio patching. It just adds so much more range to patches. My thoughts for a 2nd PROC is based on how quickly I can use this one up and how well it deals with bringing in 1 or 2 “euro audio” signals. I did get a Curtail 5-1v level shifter but sometimes still end up running into PROC for more control. Some of my Euro is 0-10v. I have a Mordax Data and wondered if it would be helpful but so long as you are getting the looks you want and are watching what the inbound “hot signals” are doing and not just blowing things out, Does the “data” mater all that much? I guess for now as I am learning it could be nice.
Interested to see how others are doing it.
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Fox Burroughs @Fox has helpfully posted the necessary mods to the Cadet Scaler for 10V operation.
He covered
1V → 10V
10V → 1V
+/-10V → 1V
and promised to give us the magic numbers for 1V → +/-10V
I have not tried any of this yet but it sounds legit. Fox knows his stuff whereas I am a total n00b
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Helpful info everyone and I appreciate the responses!!! Yes and I was thinking of some euro modules operating higher than 5V. i.e. certain envelope modules, random generator modules, sequencers etc. Looking for items offered “pre-built/assembled”. DIY kits welcome if available as package!
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This is the trick about CV vs. audio vs. video in patchable formats. Those are the exact same things: voltage. They’re just operating across different frequency ranges. A lot of literature out there separates control voltages and audio rate signals into different abstracts of parameter control vs. audible tones but they’re really the same thing just at different rates and can be readily cross-patched. In a wide bandwidth system, we can appreciate this principle even more when we can generate/process from DC - many MHz and have an extra tangible dimension with a synced raster.
Adjusting bias/DC offset is quite a bit more important in video patching compared to how it affects timbral changes in audio. Using something like Passage/Proc/Access, essentially voltage processors (bias + attenuverter), to sum a modulating signal with a bias can often be critical for getting the precise look/animation range you want.
Using voltage processors in series can increase the effective resolution of bias and overall parameter controls, making for very fine control pots. You could try this out just by self-patching one PROC. I don’t have one but you may find that it clips at +/-5V, e.g a 0 to +10V signal will clip at +5V and you’d be better off passively attenuating or less conveniently using a wide bandwidth attenuverter that operates +/-12V rail to rail before patching into PROC.
I’m not quite sure what you mean in your post but Mordax Data is going to be most useful in monitoring signals more in the LFO to low audio range.
I really doubt it would be able to accurately track anything as high frequency as an H range signal or external video signal at any format timing. You can probably sync a V ramp just fine, I’d have to try one out to see if it would sync to a H ramp.
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As a Serge user I am well aware of the “voltage is voltage” lesson. Byond that I think it also helps in freeing the mind a bit for creative patching and looking at things and asking yourself “what if I try this” Your note on bias is something I think I am seeing more and more. I am glad you pointed that out.
Mordax was indeed not all that impressive. My thought was less about the scope and more about the utilities it offers. It did have one interesting feature of a “wave generator” that will let you scale the frequency but for what it is, I did not see it as a nice module for using in video.
i have a voltage interface 1, that i just got back from a friend on tour…
willing to sell
I would be surprised if PROC clips at +/-5V. If it does, I would consider that a design limitation. @creatorlars can you clarify?
Anyway, the main problem with using PROC (or any LZX format attenuator / attenuverter) as a 10x divider is the physical range of the knobs. It’s not easy to set the knob to exactly 0.1. For a high voltage input signal, tiny movements of that knob will have massive effects on the resulting output voltage. And if one needs to attenuate multiple signals, it’s damn near impossible to get them all the same.
At the end of the day, 10x multipliers and dividers are the only practical solution for the voltage differential problem.
You’ll find that pretty much the majority of LZX production modules since the start of the Expedition series will inherently clip +/-5V because of the ADA4851-4 op amps that are used throughout their designs. Their maximum voltage range they’ll accept before blowing up is +/-5V and they have protection circuitry on their inputs to shunt any voltages above or below that. All of the Gen3 modules I’ve torn down to look at use ADA4851-4 or ADA4851-2 for wide bandwidth op amps, I just don’t have a PROC to directly reference.
You don’t really need 10Vpp processing in video synthesis if the intention is to put your signals into an encoder. An encoder will clip your signals off at 0-1V to make a valid video signal, anyway.
If you’re trying to interface with a scope that is expecting signals with a wider range than +/-5V, just use a fixed voltage scaler designed to the conversion you need.
The Cadet V Scaler schematics are here and here’s an op amp gain calculator. You could just have the default Scaler boards printed and populate them with the correct components for the conversion you want.
It’d be nice to have the flexibility to have modules that can go rail to rail on +/-12V but LM6172s that fit that description are more expensive and less desirable for board layout space since they’re only dual op amps.
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All LZX modules (all Gen3 and most of Expedition) run off +/-5V power. Headroom is linear to at least +/-3V in most cases, and clipping should occur at something like -3.5V and 4V (exact numbers in the ADA4851-4 datasheet.) It is safe to patch in voltages up to +/-12V due to input schottky diode protection, but that does not mean the voltage processing headroom is that high. According to our 1V spec, all modules should tolerate EuroRack levels, but are only obliged to process / pass the portion from 0V to 1V.
So use passive attenuators or fixed attenuation before the input if you don’t want to clip the source. Some of our designs used passive attenuators on the inputs (Visionary, Cadet, etc) but with Gen3 we’ve moved to an entirely CV controlled path (attenuverter pots are controlling video VCAs.) This has definitely improved the edge response of the system as a whole, and is maybe the biggest performance improvement over previous generations, but it does remove the ability to attenuate a source that’s outside the clipping range of the input buffer.
Remember, slew rate is our limiting factor for video bandwidth in the system – the smaller the voltage, the faster the signal. So keeping things around 1V levels throughout the processing path lets video live in its natural ecosystem.
If I were planning a system with lots of audio eurorack modulation sources? I’d make a control / sequence / modulator system in a separate case, and include passive output attenuators in that case at it’s exit points. Treat it like your rig’s “animation subsystem.”
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Great, thanks for the clarification, Matt and Lars. What this ends up meaning in a practical sense is that there is no off-the-shelf way of dealing with any voltages beyond +/- 5V. The modified Cadet V Scaler seems to be the way to go.
Regarding putting audio modules in a separate case, there are a bunch of reasons why I didn’t do that. I have worked hard to design the system layout optimally for accessibility and efficiency. That ended up meaning that video modules are clustered in the center, with audio modules mostly around the periphery.
Another thing that’s important to me is sending LZX format signals to audio modules. Not necessarily to process video, although in some cases that may be possible. But really what I’m after is the ability to perform complex processing on 1V control signals. I’ve got all of these Bahascillators and Syntonie quadrature and sawtooth oscillators, plus 2x DWO3 on the way. For best results sending these signals to audio modules, voltages need to be bumped up to at least 5V, and in many cases (Maths) ideally should be 10V. Same goes for The Analog Thing.
I do think this is a hole in the ecosystem. I’m prepared to modify these Cadet Scalers I bought from a DIY seller on Reverb. But when LZX has a chance to breathe, I’m hoping some effort will be put into Gen3 modules for scaling. I know that Eurorack is the wild west, and there really are no voltage standards. But it sure would be great to have the ability to convert between the following via patching and panel switches… no need for attenuverters, we already have that with Proc and SMX3.
1v → 10v
1v → +/-10v
1v → 5v
1v → +/-5v
10v → 1v
+/-10v → 1v
5v → 1v
+/-5v → 1v
Thanks again.
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BTW, I am aware of the VH.S 5v transformer in development by @brownshoesonly … this looks great but I ended up going with the Cadet Scalers because A) alternative build can handle bipolar signals, and B) they can be modded for 10v operation.
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Don’t worry, I’m with you entirely… Fixed level voltage translation has been an important part of the ecosystem since the first set of Visionary modules (Voltage Interface I, Voltage Bridge, Cadet V, Bridge, etc). I think the new one is probably a 12HP module, but whether it’s all patchable (like Sum/Dist) or has switchable blocks (like a DSG3 style layout) I’m not sure yet. Another approach is the “universal super function” - or an 8HP module that is multi-modal (with lots of amp/atten modes) but only processes a single signal. It’s a big footprint for a single function. I’m not in a big hurry to release something here, due to XFMR, but this function group should be present in some form in the core Gen3 lineup.
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I wouldn’t be in the market for an 8HP module that only handles a single signal. That’s just way too big of a footprint.
My preference would be for switchable blocks. Any way we can reduce the spaghetti is good. It is often difficult to grok a patch due to noodle clutter. The only problem with the sexy Gen3 switches is the amount of surface area they take up. But clarity and durability / longevity are higher priorities.
A 12HP converter module with a DSG3 style layout would be great. Four inputs / outputs, each with the following switches:
Arithmetic: multiply or divide
Factor: 1, 5 or 10
Input polarity: unipolar or bipolar
Inverter: on or off
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Wait, I just got a better idea. Instead of an Invert switch, a dedicated output for the inverted signal. I can imagine situations in which both the inverted and non-inverted signals would be useful in the same patch.
As a bonus, that would be the same as the DSG3 layout.
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a 10v input signal will be reduced to 2v with existing converters (divide by 5). this is well within the processing range of video modules and their attenuators. A 10v input to video with NO 5:1 converter will definitely clip ahead of the attenuator, which is not desirable
as far as video to audio system patching. yes. depending on the osc. and your goals. You could re-bias a 0-1v signal to be bipolar -0.5 to 0.5v, and then go 5x gain or more. But this bias is just changing how your signal interacts with the possible attenuverter controls on said audio module. modulation will only move positive of your bias compared to swinging on both sides of your bias control with a bipolar input.
Im not sure what you are referencing about Maths needing 10v. Maths has no input requirements, except for a comparator threshold on the Trigger input for channel 1 or 4. Maths has one channel of 10v available bias, and outputs 10v envelopes when using a trigger input. but using the signal input your envelope will have a peak value of your signal inputs peak value (depending on rise/fall settings)
Im also unsure of what complex audio processing you have that can handle processing lzx and video bandwidth signals.
ultimately, i dont see any reason for 10v peak (not p-p) signal processing/attentuation, but willing to hear you out.
0-10v signals are not common in eurorack. I think some serge 4u definitely hits higher but not in my wheelhouse of experience.
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Hi Nick, regarding all of this, I’m trying to A) minimize the number of modules required and B) maximize the bandwidth of everything.
E.g. sending a weak signal to an audio module will give poor signal to noise ratio.
E.g. sending a 2V signal to a video module cuts the usable range of the attenuverter in half. That in turn means it’s more difficult or impossible to dial in the exact level you want.
Not trying to put video signals through audio modules, but am trying to use audio modules to process LZX 1V standard LFOs etc.
Thanks
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Signal to noise is certainly a thing to be considered. But I wouldn’t press my mind on it for LFOs
Seems like chaining two
Converter channels with an attenuator will get what you need. You could get an inline-in cable attenuator to save hp.
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