Faderbank Run: See top post for status

[courdek]

Registering my interest in a pre-built or kit for sure. Recently learned it does simultaneous i2c, cv and midi outs per fader

[facetimecontinuum]

I am also interested in a pre-built unit

[Smoth]

I’d get down with a prebuilt unit!

[_taphead]

I am very interested in a pre-built unit, these look amazingly useful!

[MATA]

Súper project! I’m very interested.

[dudadius]

I am jonesing for one of these…

[shellfritsch]

still trying to lock down quotes on panels… once i have that i can share more details about timeline & price

[fever606]

Colour me hyped… the Instagram videos I have seen from the involved parties have sent my head spinning with possibilities…

[karst]

still interested in a built model, assuming that the DIY version proves too complicated as a first project

seems like this could be a killer norns controller too

[spacetime]

very interested. built or DIY, whichever is available first

[bobbcorr]

Now I’m wondering if you could plug one of these into Norns …

[shellfritsch]

20 characters of yup!

[Leverkusen]

After learning that the Grid can actually damage Teletype with its power draw I wonder if it is safe to plug the faderbank into norns.

Would it be okay regarding USB power/current if all 16 faders output 5 V to the modular while it takes the power from norns?

[infovore]

@Leverkusen

After learning that the Grid can actually damage Teletype with its power draw I wonder if it is safe to plug the faderbank into norns.

Where did you see that, out of interest? Understanding why that would happen will help me answer you correctly.

@Leverkusen

Would it be okay regarding USB power/current if all 16 faders output 5 V to the modular while it takes the power from norns?

So, thinking aloud:

• the 5V that powers the CV outs comes straight from the raw usb 5V input, before any filtering, ie, straight from the source (in your example, Norns)
• it’s buffered by an MCP6004 opamp, on +5V/0V rails
• if there’s an issue, it’s going to come down to what you plug the faderbank CV out into - I believe. That’s where the draw upon the faderbank will come from, which will in turn draw on the 5V output elsewhere. I’d imagine this isn’t an issue, owing to input impedance resistors and so forth, but cannot guarantee anything in the magic land of analog
• I should add: there are 1k impedance resistors on the CV outs at 16n end.

[infovore]

quick update: there will be a quick update at some point.

What I mean is: I am on vacation, and @shellfritsch has also been travelling - we even managed to cross paths in the UK. we have, however, still been moving a few things forward - got some new prototype boards into the world and into Europe and America - and making progress on BOM and panels. Proper update when I’m back home.

[scanner_darkly]

@infovore

Where did you see that, out of interest?

Grid ops / integration

My teletype just instantly died (stopped powering up, no leds light up screen all black) after i attempted to plug the grid to it (not powered externally) to test a scene i was working on. I’m aware that i should power the grid externally (had already ordered the cables to do so) but i had no idea i could fry the teletype by trying this Is there anything i can do? Thanks.

[xeric]

Coming into this thread pretty late, and I know these aren’t quite ready yet, but is the plan right now to have individual CV outs per slider? If so that sounds amazing, and I would definitely buy a prebuilt one!

[michael_matos]

Yes. The current build has individual cv outs. It’s magical.

[Leverkusen]

@infovore

the 5V that powers the CV outs comes straight from the raw usb 5V input, before any filtering, ie, straight from the source (in your example, Norns)
it’s buffered by an MCP6004 opamp, on +5V/0V rails
if there’s an issue, it’s going to come down to what you plug the faderbank CV out into - I believe. That’s where the draw upon the faderbank will come from, which will in turn draw on the 5V output elsewhere. I’d imagine this isn’t an issue, owing to input impedance resistors and so forth, but cannot guarantee anything in the magic land of analog
I should add: there are 1k impedance resistors on the CV outs at 16n end.

Thanks to @scanner_darkly for pointing to the source thread for the teletype/grid information - I should have thought about quoting it here. Also it might be a question to be asked in the norns thread regarding the available USB power. I just have no idea how much current a eurorack module might be drawing into its CV inputs and how it sums up at the USB.

Also what comes to my mind is that there was an issue with Mangroves damaging an intellijel module because the run input was directly connected to the raw 12V power rail, I think.

To be honest I have no idea what the opamp buffering or an output capacitor do or if they already address these questions.

[infovore]

@Leverkusen

Thanks to @scanner_darkly for pointing to the source thread for the teletype/grid information - I should have thought about quoting it here. Also it might be a question to be asked in the norns thread regarding the available USB power. I just have no idea how much current a eurorack module might be drawing into its CV inputs and how it sums up at the USB.

OK - so the issue in the TT thread could be described unexpected consequences: a regulator that is perhaps underpowered for delivering 5V to a grid, suddenly experiencing excess current draw, and failing. And given the TT design, no 5V = not much of a Teletype system.

A grid at full brightness draws much more current than any Eurorack module I can think of through their CV inputs (which isn’t the same as the current draw on a PSU).

However: I have no idea what the Norns power situation is, and am not the person to ask (and this perhaps isn’t the thread for that).

@Leverkusen

Also what comes to my mind is that there was an issue with Mangroves damaging an intellijel module because the run input was directly connected to the raw 12V power rail, I think.

So: the issue there was with Just Friends, and it was with an input being normalized to the -12V rail without an impedance resistor (so as to detect when a jack wasn’t plugged in - picking a voltage likely to be unavailable outside the circuit, I’d guess). As a jack scraped past, it might briefly make a connection to said normalized jack, and without an impedance resistor, -12V at a lot of current shot through. If you’re not expecting that at the other end, that could be problematic.

There are loose opinions around input/output impedance resistors in Eurorack, but there are also reasons to implement alternative opinions, mainly down to context.

But regarding this:

Would it be okay regarding USB power/current if all 16 faders output 5 V to the modular while it takes the power from norns?

the answer is still, technically, “it depends what’s at the other end”. Current, not voltage, is the issue.

I mean, personally, I’m reasonably confident there won’t be any other issues, but if you want an 100% correct answer, what it comes down to is what’s powering the faderbank and if the inputs at the other end have some kind of impedance resistor. Most of the time, both of those aspects will be absolutely fine. But I cannot actually confirm how every single Eurorack module in the world works, and if they’ve been designed correctly.

@Leverkusen

To be honest I have no idea what the opamp buffering or an output capacitor do or if they already address these questions.

Sure, but you care enough to ask if it is “safe to plug the faderbank into norns.”, which manages to immediately cast the quality of either object into doubt, and which puts people like me on the defensive immediately. And it feels from the questions that answers involving the phrase “it depends” won’t come over as satisfying.