Mono or stereo synth panels?

My first pannel is completed! The 4710 safety valve. Although upon testing it I only get audio out the left channel of my headphones. Are these pannel mono only or have i soldered my jacks poorly? Being mono isnt a problem, i just want to solve the issue so i can get sound through both sides of my headphones or speakers.


Synth signals are almost always mono. The reason you’re hearing it only in one channel, is because you’re connecting the stereo jack of the headphones to a mono jack on the synth, connecting only one channel. Usually people use some kind of output module, which will condition the signal to protect your headphones and your ears, as well as provide the stereo output. Personally I use the Behringer RX1602 rackmixer for this, but there are many options.


Oh awsome, thanks for getting back so quick. I was panicked that I had built it wrong or broken something. I was slightly under the suspition that it was mono but the jacks that fit in the mounting holes were indeed stereo. I guess that was what confused me but as long as its all good then im happy. In terms of audio equipment does it follow the same “U spec” as server equipment? It would be neat to make a shielded box and have all my stuff in the same rack as I already have one under my desk where im planning on having the modular sit.

The behringer is mighty expensive for me just having this as a small hobby. I have an Alto zmx-52 with an unbalanced single jack that i normally use for a mic. Can I use this in a similar way to how the Behringer unit works or will I run into issues?

Yeah I get the confusion. We often use stereo jacks as they are more stable to mount (as they have 1 or 2 more contacts), but the signals going to them are mono. The ring terminal is simply unused.

Eurorack does, Kosmo doesn’t. It has it’s own specs:

@lookmumnocomputer has written a guide on how to build a cheap case. Also, @Chilltz builds cases to order under the flag of Modular Perfection.

Of course, agreed. This thing only makes sense when you’re building a larger system!

You can absolutely use this! Plug in the synth signal as an unbalanced mono signal. Be careful though, synth levels are very ‘hot’ compared to audio standard (aka line level). So start with the gain all the way down, and carefully bring it up. Don’t wanna damage anything!


Oh fantastic, I can always work up to the Behringer if i ever need the extended inputs but for pannel testing the alto should work fine for now, I have my mic usually close to my face anyway so the gain is set really low to begin with. Im no audio engineer but it sounds ok lol. Good to know the reason for stereo jacks and mono output, makes sence now that im reading about it.

Thanks a million for your help :slight_smile:

1 Like

With the alto i can change what i believe to be the highpass and lowpass filter, I assume for more mic usage. Do i just leave this in the middle for synth stuff or is there a way of properly setting it all up?

Just checked the thing more properly. It doesn’t seem to have separate gain settings for the line channels, only for the mic preamp. In that case, just turn down the levels on those. I would guess the EQ section only applies to the mic preamp, so wouldn’t affect the line signals you plug in. If it does, just leave it in the middle.


So…plug it into the line level and not the mic preamp. Do they make mono to seperate left and right cables?

Yes absolutely don’t plug it into the mic preamp. See how the line jacks say L/mono? A mono signal goes only to the left jack, then gets internally switched to the right channel too. No converter cables required!

1 Like

Ohhh, that makes a heck of alot of sence now, i was under the impression it was mono left and mono right to make a stereo signal, not interally switched and things. Thats cool, Ill try it when i get home from school.