I Built a 2in/2out TRRS interface for OP Z (works with guitar and line in)

Hey OP forum world. I’m new, and i love my OP Z. But i hated having 20 dongles to get things to work right. So i went on a great quest, to understand TRRS and TRS and TS inputs and line/mic/instrument signals and all that jazz.

It’s still a work in progress, but i have finished my first rapid prototype today! :grinning::upside_down_face:

Basically it’s an all in one interface for OP Z. It plugs into the trrs port on the opz. It has one 1/4" stereo headphone out and one 1/8" stereo headphone out. Both can be used at the same time.
It also has a 1/4" mono instrument input and a 1/4" mono line in (since opz only has mono thru mic anyway). Both signals are attenuated and work through the opz mic in. Only one can be used at a time and either is picked with a toggle switch. it’s activated normally by holding screen button and selecting input 2 on the opz.

So far in all my tests everything worked great. This is just a prototype.

i want everyone’s opinions. Would this be something you would appreciate? Could you see yourself using this? What other features do you want?

If there’s enough interest i might build a handful of 2.0 models with a few more features like: dedicated volume on outputs, dedicated volume on inputs, and maybe a trrs or trs jack for a mic. And i might sell them or even give some away in some kind of giveaway.

let me know what you think sorry for the rant!!!

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I’d really be interested to use one!!!

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Awesome, I’d really love to have something like this but with 3.5 mm inputs only.

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Another angle.

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Neat!

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so like two 1/8" headphone outs, and one 1/8" line in. But would you want the instrument in to be 1/8" as well? What would be the advantage to that?
Thanks for checking out the thread.

Actually I’m not sure, I don’t have a guitar, I only have synths. For a guitar a full-sized jack makes much more sense obviously.

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Looks great! And i love that you cared about proper attenuation for the line in!

Should be reason enough to buy it…

If you ask for futures
Maybe some more inputs connected to the headphone out so that you can jam along with other gear… maybe with proper opamp mixing.
One step further make the inputs switchable to op-z or or to headphones😀

Anyway nice work. If you sell it some day, announce it here…

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if You manage to add a usb hub and midi porta out you have the all-in-one OP-Z connection box…that would be ubercool

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Okay! cool, glad there’s at least some interest. now i can justify spending 100$ on some new components :upside_down_face::+1:

alexwasashrimp Actually I’m not sure, I don’t have a guitar, I only have synths. For a guitar a full-sized jack makes much more sense obviously.

What kind of output do they normally have? Is it a headphone out or line out? 1/8" i assume… but the two are not the same despite what many device manufacturers make it seem.

nbtbl
Looks great! And i love that you cared about proper attenuation for the line in!
Should be reason enough to buy it…

Thanks!

Maybe some more inputs connected to the headphone out so that you can jam along with other gear… maybe with proper opamp mixing.
One step further make the inputs switchable to op-z or or to headphones😀

Can you please elaborate?

The way it is setup currently is as follows: You can have a guitar or a line in source selected. Now hold screen and select input 2 on the opz. Now the mic light should be lit. You can then play with the opz sequencer thru headphone out and live jam via guitar and it will pass thru the guitar audio to headphone out. So you can jam over a drum beat for example. Even still. You can plug in a midi keyboard and jam via both a keys synth and with a friend on guitar while playing a drum sequence. VERY FUN!!! You can also go to a blank sample slot and record the guitar or line in with the opz and chop it/fx it whatever.

The way i use it is a smidge different, but waaaaay fun.
To make it usable for one person!
I have the output of my H1n recorder going into the line in. A guitar or bass plugged into 1/4" input. And one output going to the line in on the same H1n. This makes a “one person sampler”
Basically i can record a whole length of guitar or bass riffing into the H1n, then flip the input switch from guitar to H1n, and play the recorded guitar back into the opz, NOW i can sample the perfect section of riffing into the 12 sec of drum slot to chop up later. It wasn’t possible to play anything with 2 hands before.
Same goes with a mic, i can have a beat going in my headphones and record a flute part into the mic/H1n and play it back thru the opz to resample the perfect sections. :+1:
god this post was long i’m done

Radio
if You manage to add a usb hub and midi porta out you have the all-in-one OP-Z connection box…that would be ubercool

Omg i can’t even process what that would take right now :face_vomiting:

version 2.0 will have even more features and switches and even a couple dials!! :heart_eyes: i am trying to develop a way to live jam over an opz track but send ONLY the guitar into the H1n
any way any support or words of wisdom are appreciated. I am doing this for us :hugs:

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would you mind to share your wiring of the TRRS connection? with a picture or something. :+1:

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I see it‘s very good the way it is with the play through of the op-z.
I have a bunch of small synth and i always think i need a small mixer that‘s fit my synth. Like a bastl dude or behringer mx400…
As i saw your box i thought that it would be a nice addon.
I‘d like to connect a monotron, a volca fm, a guitar and the op-z to this box and mix them out to headphones…
Then i find a good riff on the guitar or a cool sound on the monotron and want to sample it into the op-z. So in my imagination i switch that particular input from the headphone mix to the opz mic line without the need of rewiring anything…
Just an idea that could fit in…
By the way the bastl dude schematics are available for inspiration :wink:

This one is much simpler…
http://www.interfacebus.com/opamp-audio-mixer-circuit-design-schematic.html

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JohnnyEgo
would you mind to share your wiring of the TRRS connection? with a picture or something.

Not at this point. The circuitry is still suspect. Right now there is a very simple attenuating circuit that isn’t quite optimized. It uses basic components (resistors, capacitors, etc) but the exact values are not dialed in. The guitar in is a little cold and the line in is a little hot. When everything is fine tuned and i know for sure it won’t blow out anyone’s op z i’ll upload the diagram. Anyone with moderate soldering skills should be able to make it.

nbtbl
I see it‘s very good the way it is with the play through of the op-z.
I‘d like to connect a monotron, a volca fm, a guitar and the op-z to this box and mix them out to headphones…
Then i find a good riff on the guitar or a cool sound on the monotron and want to sample it into the op-z. So in my imagination i switch that particular input from the headphone mix to the opz mic line without the need of rewiring anything…
Just an idea that could fit in…

yes, that is basically the idea. Everything can plug directly into this box, no extra adapters, cables or dongles, and no switching back and forth plugging and unplugging :+1: The main challenge is how and where to mix the signals. My goal is 3 inputs, 1 instrument level, 1 mic level, 1 line level (or variations like 2 line, 1 guitar etc…). Mixing can happen before they go into opz but each signal has to be attenuated separately, FIRST, before they can be mixed and sent to the opz (for pass thru playback/live jamming). There’s basically a large number of ways i could design the circuit and each way affects its functionality, the sound quality, and how complicated it is to build.

By the way the bastl dude schematics are available for inspiration

thanks! I checked the link out. This is a circuit and IC i am very familiar with :slightly_smiling_face:. A very basic active mixer. The issue with the zBuddy (trying to give it a name, open to suggestions) is that each signal is of vastly different strength and all has to come to a mic level into the opz. The mixer you linked to is very simple because its taking 4 signals of the same level, mixing them, and amplifying the end mix. Compared to the zBuddy this is very simple. But please keep sending me stuff like that i have a big library of schematics i reference.

If things get too complicated and large then just using a real mixer is the better solution. zBuddy is supposed to be an entirely passive, small solution to op z audio I/O.

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This looks awesome - instabuy for!
I’m not a tech savvy, but does the device in any form drain the battery of the op-z faster then a set of regular headphones?

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it shouldn’t drain the battery any more, not like using a midi keyboard would. If you used two large pairs of headphones connected at the same time, it would theoretically drain slightly more than if you only used 1. Because each pair of headphones uses a certain amount of current to drive the coils. But this is very little compared to how much a midi keyboard would. If you plug in 2 line out speakers, each speaker is amplifying the line signal so it wouldn’t drain any faster.
At least that would be my understanding

Would this work on OP1? I like my OP1 for it’s creative workflow, but always struggle getting the line-in at the quality I want.

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Honestly i don’t know anything about the OP1. Does it have a TRRS jack? The trrs is the one with 4 contacts, verses a normal headphones or line trs jack that has 3.
IF it has TRRS, then yes, this would work just the same. I have no idea what exactly the op1 has though. I’ll take a quick glance at their specs page when i get a moment.

this looks amazing! wow wow wow, I use the rc505 looper with my opz and would like my headset mic audio technica but I think maybe an irig 2 would work, that being said this looks mint I could possibly use one

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bro this is epic, I have a friend who made me a midi controller for the rc505 maybe you guys could talk he doesn’t use libraries whatever they are but uses arduinos, but I am still developing my set up and I have a guitar opz and the looper and sing as well and want to do it all busking thanks

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