Hey, I just won an MF-102 and acquired an MF-103. I have a technical question. Reading from the MF-103 manual:
“When connecting one or more pedal control input jacks to a source of external control voltage such as an analog synth or a MIDI-to-CV converter, you should use patch cords with tip-ring-sleeve (TRS) phone plugs. The ring terminal on the plug should not be connected to anything, so that the MF-103’s source of +5.7 volts is not shorted out.”
What does this mean in plain English? To me it says if I plan to connect say, my Voyager (an analog synth), to one of the pedal control input jacks on the MF-103, with a TRS… the ring terminal on the plug should not be connected to anything so that the MF-103’s source of +5.7 volts is not shorted out??? If I’m connecting something (an analog synth) to the pedal control inputs with a TRS how can the green text then make any sense? It reads like this to me : to connect an analog synth to the pedal control inputs… use a TRS, BUT if the ring terminal on the TRS is connected to anything the MF-103 will short out. This makes no sense.
I did understand that if I wasn’t planning on using an expression pedal on the pedal control jacks that using regular old mono TS cable for any of this would be kosher - but as long as I was using ANY TS cable, it would be impossible to plug in an expression pedal using TS. So that brings me around to thinking “why don’t I just use TRS all the time…” but then we roll back right into my initial question - it says hook up the analog synth to the moogerfoogers with TRS, but if the ring terminal on the TRS is connected to anything ??? the MF-103 will short out…??? AGGGHHHHHH! It makes no sense to me!!!
By the way, I tried something strange. I routed the LFO out on the MF-103 to the Audio IN. It was strange. I used a TRS to do it. Did I do something wrong that could screw up my 103? It sounded cool.. see, I’m so new to patching modular style that I’m just afraid I’m going to fry my gear. I would so much appreciate a response to help me get started in style…
As of now, I don’t have an expresssion pedal - just a Voyager OS with all those outputs. And I’m going to PLAY the moogerfoogers themselves also, which should be fun. Your guidance is so appreciated.
Please help - I’m new to hooking up stuff in this manner!
Moses Goldman
If you want to use expression pedals, use TRS cables. It doesn’t matter whether the ring terminal has a connection or not. Technically, the only reason you would use a wired TRS cable would be to extend the reach of an expression pedal.
The CV outs and audio don’t need TRS, but it doesn’t hurt either.
TRS Y-cable on the MuRFs to separate out the tap/step input.
So basically, go ahead and use TRS for everything - it won’t hurt anything and I’m somehow misreading the manual? What exactly is being said when the manual says “the ring terminal on the plug should not be connected to anything, so that the MF-103’s source of +5.7 volts is not shorted out.” I really want to understand that! It reads like I’m should use TRS but I’m going to screw something up if I do…in the same paragraph! Technical manuals are beyond me sometimes! TRYING to understand.
But thanks. I guess I’ll just go for broke and buy a bleep-ton of TRS patch cable so I can use expression pedals in the future… but I still want to get what the manual is trying to tell me. Just to know.
The pedal inputs use 3 contacts: Tip is the CV return after it has be routed through a potentiometer of an expression pedal. Ring is ~+5V, to supply said pedal. Sleeve is ground.
When you plug a TS cable in, there is no ring. But the piece of metal is still there, connected from where the ring would be to the sleeve. So inside the 'fooger, the +5V supply connected to ground. The supply is shared for all exp inputs (exception: Mf-107) and so when you try and use a pedal, there is no voltage to power it.
One way around might be to take regular TS plugs and Dremel/etch out a “ring”. There is an insulating jacket; that’s how the tip is isolated from the sleeve in the first place. If you carefully cut a phantom “ring” terminal, you would be sweet (sorry, NZ vernacular). Probably easier just to solder new T[R]S plugs (even on one end only, I’ve done this) or to order new cables.
so, to throw this back at you my friend the ring on the TSR supplies the expression pedal with voltage which is routed back through the tip to supply the variations in CV that control a given parameter via expression… and the sleeve is the ground. so, if you use a TS - the +5V supply is connected to no ring, but a sleeve, and therefore… a ground… so if you were to try attaching an expression pedal at that point in another pedal control jack, there would be no voltage to power it. that’s why we use tsr cable. to supply voltage to power the pedal so it can supply changes in CV.
now, if it doesn’t matter whether the ring has a connection or not… why does the manual for the mf-103 read “the ring terminal on the plug SHOULD NOT be connected to anything, so that the MF-103’s source of +5.7 volts is not shorted out” - I really don’t get that phrasing just yet. What exactly in layman’s terms is being said? one has to admit, using a double negative (should not, is not) in the same sentence just muddles things. technicians make poor writers! and when I hear “shorted out” I think BAD BAD BAD… I’m not thinking like an engineer here, I can hardly speculate how to translate that sentence. it’s driving me nuts. arggggghhhhh.
EDIT - MY BRAIN HAS DAWNED WIDE OPEN WITH SUN SHINY RAYS OF MOOG’S OWN INEFFABLE LIGHT… 'tis sweet. What the manual is trying to say (poorly) is that if I connect devices other than an expression pedal (pedals which would be connecting to the ring terminal of a TRS cable to get power so they can send CV changes through the tip) to said pedal input jacks, there will be nothing zapping energy from the moogerfooger, THUS the +5.7V doesn’t get shorted out. THUS, having used TRS instead of TS to connect, say, my Voyager to any given pedal input jack- the voltage isn’t connecting to ground and getting “shorted out” and I am leaving myself open to use an expression pedal freely in another pedal input jack if I so desire.
Sounds freakin’ convoluted - but I totally get it now. THANKS for bearing with me! If Bob wrote that technical information he was counting on a careful studied reader and not a moron like me!!!
You don’t need to use fully-wired TRS cables, unless you have an expression pedal attached. TS will suffice BUT
You shouldn’t short the Ring to Sleeve, that will disable expression pedals if you try and use them SO
Use a two conductor cable and a three conductor connector (TRS). Leave the ring “unconnected”, i.e. connect neither Tip and Ring nor Sleeve and Ring in the SAME connector. Connecting Ring to Ring (on the other end of the cable) is okay. This is how I’ve wired mine anyway, so I know it works
ACK! OOP! Now I’m absolutely lost. How do I find just that without making it myself? I’m afraid it’s time to speak with my friend who is in audio/visual and makes cables everyday…
Simple solution: Buy TRS 3 conductor cables. Having the ring connected will make no difference!
Cheap solution I: Make TRS 2 conductor cables
Cheap solution II: Make cables TS on one end, TRS on the other by cutting a regular cable in half and soldering on a TRS jack, no connection to the ring. Two for one!
Experimental “solution”: etch out a phantom ring on a TS cable or whack some tape on it, or borrow your sister’s nail polish and paint a ring on with varnish.
Basically, from my experiences, if you plug an lfo with a TS cable into say the ringmods freq input, the frequency will rise up and down with the external lfo you just applied. Now plug another lfo or moog ep-2 expression pedal into the mix cv input on the ringmod, It will cancel out the two lfos (or maybe just the first TS lfo I don’t recall) and no modulation will take place. Hope this helps
That sounds like youre doing something wrong – CV input works consistently but a TS plug will short out the necessary current for the EP-2 or similar pedals
ACK! OOP! Now I’m absolutely lost.