A4 CV output, curious issue, cables not working if fully depressed


#1

Hi all. I have bought Hosa splitter cables like this: https://www.rubbermonkey.co.nz/Cables-Connectors/Audio-Cables/Mini-jack-Cables/Hosa-YPM-523-1`4-Male-to-Dual-3-5mm-Female-Stereo-Splitter-Cable-6

They split TRS into tip and ring. I have verified that these work by running audio in and confirm these are splitting to let and right (ie tip and ring).

The curious thing is that these do not work with cv from the A4 unless I pull the Eurorack cv cable slightly out of the tip (or ring) end of the splitter. This is odd to me, since audio seems fine if the cable is snugly connected.

To be clear, cv output works fine from the A4, I just need to pull the Eurorack patch cable out a bit, so that it is unstable.

I suspect I am missing something fundamental here.


#2

The description in the link is misleading, it implies dual stereo, whereas the image clearly indicates tip and ring is split - it sounds like somehow the 3.5mm female connectors are TRS when they should be TS

Try in your headphone jack with some 3.5mm stereo headphones and switch outlets to double check what you wrote above about left only going left etc

This is for the A4 Mk1 right ?! Do you have any other 3.5mm mono cables to try, if you read other forums you can see that some are better than others in various connectors, it may be marginal tolerances both working against you - put a small nylon washer over the jack to offset it in the meantime

Easiest to test all this if you have a voltmeter that can check continuity/resistance but you should be able to methodically work out what you have


#3

Thanks Avantronica

I did this: “Try in your headphone jack with some 3.5mm stereo headphones and switch outlets to double check what you wrote above about left only going left etc”

i confirm that I hear only one side of the signal, but in both earpieces, from the female 3.5mm connector marked Tip, and the other side of the signal, but in both earpieces, from the female 3.5mm connector.

Is this behaviour correct, or does this splitter send out a stereo signal comprised of tip, and vice versa (and so is this not the cable I need?).

I suspect that this is the wrong cable - if so - I can solder - presumably it would be easy enough to cut the cable, but 2 x 3.5mm mono female jacks, and wire this up?


#4

Sounds like the adaptor is not what it needs to be (although the description suggests it is not what you’d assume was shown !) - I can assure you that the official Elektron splitter will only present sound in one ear, the left

So if you plug a headphone in the Tip feed you get the left signal to the left ear and if you plug the 'phones into the ring you get the right signal to the left ear - i.e. the right-ring is dropped as per a TS outlet - so if you are hearing in both the cable has used TRS sockets and these are wired to work better for a listener - the adaptor isn’t ideal for your use case

adapting this short moulded adaptor would be tricky, simpler to make your own, pick up the handy Elektron one or start again hunting for a suitable one


#5

Thanks. Regarding requiring this short cable, surely it won’t be too difficult? If I strip the end. And just wire a new 3.5mm female mono jack in, I’d be in business. There is about 8cm of cable to work with.

Or am I missing something?

As a fallback i am happy to wire my own, is there a diagram of photo showing what is needed on this site?

Thanks!


#6

A bit fiddly, worth doing then if you can’t return. Just be sure to drop the respective cable from either side - so if you are wiring the Tip side, lose the red cable (lose the white on the ring socket) - this assumes the manufacturer uses the correct colours or coloured cable at all

TRS is probably internally White sheath Red sheath Copper or Black Red Copper


#7

I can’t return these, so I will do this :slight_smile:


#9

I now have a theory for what is happening here.

What I know for sure that the Hosa splitter is doing, is splitting the original stereo signal into two stereo signals. One new stereo signal contains only the original Tip signal, but sent to a new tip and ring (to create a stereo image of the original tip only). I am not sure what use a cable like this is, but that is what it does. The other split signal is the same, but for ring.

My theory is that the splitter is creating a new (eg) tip and ring signal made up of only the original tip, but with inverted phase, which when combined into a mono cable produces no signal - hence silence. That’s the only way this makes sense to me. If the L and R signals are identical (and not out of phase), I can’t see why these wouldn’t just combine and be sent along the mono jack cable to my Eurorack.

I am going to cut the female jacks from the cable, and wire up new female jacks, attaching only the original tip, through to only a new tip (but not ring), and vice versa.

I’ll report back.

Curious that Elektron released a device which requires a highly unusual cable!


#10

I don’t think they’d be out of phase. The cable you bought looks like it’s designed to split L and R to two separate stereo-compatible connections. I have a similar cable that converts a single mono connection into a stereo connection, so I can use my EM pickup with my Zoom H1 and not just hear audio in the left channel when monitoring with headphones.

As for why it’s cancelling out, I’ve had similar experiences when plugging stereo cables into mono inputs in a mixer, so I guess it’s something to do with the ring being connected/shorted to ground (ie. sleeve). Pulling the cable out slightly means that the ring and sleeve of the socket connect with the tip and sleeve of the plug, thus acting like a normal connection.

A possible quick and dirty solution to this would be to rig it up in a permanent configuration of having some Eurorack cables plugged into the sockets, but with a bit of electrical tape/nail polish around the 3.5mm plugs where a ring connection would be, thus not making that connection. Like I said, it’s a bit dirty, but if you set it up somewhat permanently, and keep the plugs inserted in the sockets on the adapter with some tape/heatshrink securing them, it should work properly.

It’s just space saving really. QuNexus works in a similar way. 1x TRS to 2x TS is a pretty common adapter.


#11

Thanks Pselodux, good advice.

Can you think of any reason why I wouldn’t cut the jacks, and solder new female jacks, but only connect:

  • the original stereo source tip --> tip of one female jack (as well as sleeve); and
  • the original stereo source ring -> tip of the other female jack (as well as sleeve)?

(I have bought jacks which I assume are TRS - but if I don’t use Ring, then these should work as mono jacks).

EDIT: I have done the above and it works flawlessly. Thanks all :slight_smile:


#12

That should work fine :smiley: