Hello,
I’ve got a question!
I was about to buy a small interface box for two of my effects. but when I saw the price I thought that there was probably not much in it and that I could have everything I needed to tinker with one.
Someone has already opened one of these boxes?
I suspect they have just put an optocoupler and distribute the logic level on the Jack outputs?
And Empress call their one, midibox
Thank you
Bruno
Somebody knows? Before I open one of the effects and maybe do something stupid?
Hi Bruno,
Hm, as the four “control” output ports only have 2 pins and as it is called “midibox”, they will most likely carry the unmodified MIDI signal, only two pins are needed for that (ground/signal).
I agree, that they probably have an optocoupler and maybe some buffering/inversion (e.g. with a hex inverter like for a standard midi thru box) in there.
But as long, as you do not know the exact protocol between the control box and the pedals, there could be also some other kind of stuff going on… if you assume plain midi (as do i), you could try to control one of your empress pedals with an experimental midi breakout cable, one end a 1/4 inch plug, the other end connected to MIDI GND and MIDI data and see if that works.
The more “safe” variant would be to open up a pedal and see, if it looks like a MIDI-IN circuit wired to the “guitar cable” port, i.e. if there is an optocoupler and a resistor connected, if so, you should be able to try sending MIDI without a danger to the fx box.
If that works, you can just build a basic MIDI thru box instead of buying this so-called “midibox” 
Good luck!
Many greets and have a nice weekend!
Peter
Thank you Peter,
You’re right, I didn’t mention it, first is an empress reverb, second is a meris polymoon. their ‘midibox’ supports both brand.
i tried to connect directly to the MIDI pin of the Core, nothing. Tomorrow I will put an inverter between the two. But I will not search deeper, it would be stupid to burn a pedal like this for that price… If it doesn’t work I will buy this interface next month from disaster area 59€. 
But! Once I’ve got it I will open it and share what there’s exactly inside.
Best regards
Bruno
Okay!
We were right, it works fine. Yesterday, I think I needed to sleep, I forget resistors…
Then 2 resistors are enough to replace this boxes.
This is it:
Solved and I saved 60€
Thank you Peter, have a good WE!
Bruno
Awesome!
On 26.1.2018 at 2:06 PM, Antichambre said:
Okay!
We were right, it works fine. Yesterday, I think I needed to sleep, I forget resistors…
Then 2 resistors are enough to replace this boxes.
This is it:Solved and I saved 60€
Thank you Peter, have a good WE!
Bruno
Hi Bruno,
I am having the same “problem”, but I’m not so deep into the whole soldering stuff yet (basically I don’t quite get your blueprint:), could you explain a little in depth or show a picture? This would be great! I want to send MIDI PC to the Polymoon via my Switcher, going into a MIDI quadra through and then to different pedals, but since the polymoon is the only pedal I have that needs MIDI via jack input, I don’t want to spend 65 bucks for a midibox that has four outputs…
Would be awesome if you could help!!
Hello,
this diagram is to connect an fx in jack directly to the uart tx/rx of a Core, i did not test it from and to Midi connectors. There’s optocoupling between rx and midi connector. I have to make some test, unfortunately i left home this morning, i can answer to your question but you will have to wait 2 weeks before that.
is it fine for you?
best
bruno
Hi AntiChambre, I’m also interested in this subject as I’m am looking to buy a Meris Mercury7 pedal but don’t want to buy the whole control box for just one pedal. What is the “Core” you connect to in the diagram you put together?
Also, new to the forum :-). I have been tinkering with midi stuff for a while, using Arduino to add midi to old rockband-drumkits and so on… just found this, and it seems great!
EDIT - I just had a read-through of midibox, and I realize now what “Core” is.
Another question: is the serial data transmitted on the tip and ring on the TRS connector actual MIDI-data?
Best regards,
Gustaf
21 hours ago, GustafRG said:
I just had a read-through of midibox, and I realize now what “Core” is.
Great! Forget your Arduino, come to our Core! This is made for that… MIDI Application!
21 hours ago, GustafRG said:
Another question: is the serial data transmitted on the tip and ring on the TRS connector actual MIDI-data?
Yes, it is… It’s regular MIDI data, rate…
I think there’s just no optocoupler, then it works with an UART directly connected to 
Best
Bruno
Newbie here on all things MIDI - but keen to learn ..
I have a specific question to a new Strymon MIDI feature recently made available on their Sunset / Riverside pedals - and which uses a MIDI to TRS jack connection on their custom cable - unavailable in UK til late October and I’d like to use facility asap - googled and hence I’m here and looking for feedback based on your work above please - realise of course big ask from non contributor to date but any advice greatly received ..
Strymon bespoke cable - is it possible to replicate based on information provided below ?
info ex their site - On our pedals equipped with a 1/4? TRS MIDI connection (Riverside and Sunset), the MIDI data is received by the pedals from the TIP of this connection. When MIDI OUT or THROUGH is enabled on these pedals, the MIDI data is sent out of the pedal from the RING of the TRS connection.
also - recommended interface units - which I dont want to buy as its more pedalboard real estate
nb - this is a question on a youtube posting
Hey guys, could I hook up one of your drive pedals to the Meris MIDI I/O instead? Asking because I already have one of those.
Yes, Riverside and Sunset will communicate via MIDI with any TRS MIDI box that sends signals to the pedal on the TIP and receives signals from the pedal on the RING of the TRS connection.?
best regards and thanks in advance for any advice
I don’t like the idea of combining MIDI in and out on one 1/4" jack. It’s just another variation on the standard that will confuse. TRS 3.5mm jack with individual signals is bad enough :).
What feature do you wish to use? I.e using the MIDI in of the Strymon? Or sending the MIDI out from the Strymon?
8 hours ago, latigid on said:
I don’t like the idea of combining MIDI in and out on one 1/4" jack. It’s just another variation on the standard that will confuse.
I totally agree for me it’s stupid.
But no choice, they did it, we have to deal with it.
To get it properly from a MIDI signal(not from UART directly) we must put something in the middle, I didn’t work on this subject for the moment, but it’s a part of a bigger project then I will do it for sure, just a question of time ;) …
Best
Bruno
13 hours ago, latigid on said:
I don’t like the idea of combining MIDI in and out on one 1/4" jack. It’s just another variation on the standard that will confuse. TRS 3.5mm jack with individual signals is bad enough :).
What feature do you wish to use? I.e using the MIDI in of the Strymon? Or sending the MIDI out from the Strymon?
I just want to use midi into Sunset pedal to access new patch feature - from what I can see ( novice opinion of course ) the cable is unlikely to carry active components ? would this be a simple wiring orientation ie if my reading is correct then pin 2 to trs jack sleeve ; pin 4 to tip? pin 5 to ring ? is there a need for resistors ?
I’m not confident I can work it out from the vague description; it’s not your fault. MIDI is a current loop and the cables are passive. Normally resistors would be a good idea if you don’t know what’s what, but in this case they might hinder the operation by limiting the current. If you don’t mind taking a risk or two, try the orientation you describe and swap it around if there’s no joy. For a MIDI in, normally the 0v (ground) pin is not connected at the port. So you may wish to leave the sleeve of the TRS plug disconnected. Leave the pin two of the DIN connector connected to shield the cable.
You’re free to use a male DIN or even cut an old MIDI cable apart to avoid using a female adapter plug.
Best of luck, YMMV etc.
Ok,
Try to simply do this, the point is to connect the 5V of the MIDI out to the 5V of the MIDI In to get the input optocoupler acting.
Works fine for me on a Polymoon, receive and send. And cabling example:
Normally the 220ohm already present in your MIDI output acts as current limiter, no need for more resistor.
Best
Bruno
many thanks for your replies - one final question as there are two potential solutions for me to try - is there likely to be any risk to either my timeline of the sunset pedals if i get the wiring incorrect ?
I’d say as these are built for guitarists rather than MIDI nerds, it’s more than likely that there’s sufficient protection built in. If the signals are around the wrong way it will not work but probably will not harm the unit.
8 hours ago, jmp220478 said:
is there likely to be any risk to either my timeline of the sunset pedals if i get the wiring incorrect ?
Do it slowly, properly and take care. If it’s like Meris and Empress the same TRS 6,25 is used for expression pedal(analog), for Tap(switch) and for MIDI then this must be highly protected. More than that, as I said before the regular 220Ohm MIDI resistors will act as current limiter.
Don’t put 220V in it that’s all
Notes: With my diagram, MIDI In will work only if the MIDI Out is connected, The 5V for MIDI in is provided by the Output. The trick is there. This must be the function of the disaster box and others, they are actives boxes(powered) they provide this 5V and they distribute and merge to and from their multiples TRS connectors.
14 hours ago, Antichambre said:
Do it slowly, properly and take care. If it’s like Meris and Empress the same TRS 6,25 is used for expression pedal(analog), for Tap(switch) and for MIDI then this must be highly protected. More than that, as I said before the regular 220Ohm MIDI resistors will act as current limiter.
Don’t put 220V in it that’s allNotes: With my diagram, MIDI In will work only if the MIDI Out is connected, The 5V for MIDI in is provided by the Output. The trick is there. This must be the function of the disaster box and others, they are actives boxes(powered) they provide this 5V and they distribute and merge to and from their multiples TRS connectors.
Many thanks for feedback - the exp jack socket on the sunset ( overdrive / distortion unit ) controls volume / other parameters with an expression pedal and midi with their bespoke cable .
With your solution - you are using the out and in of another pedal ie my timeline ? their cable is a single MIDI to 6.35mm TRS lead - enabling me to send midi info ex a programmable pedal board to the timeline => Sunset, otherwise all changes will have be from delay alone ( see below ) .. is there a way to do this without connecting midi out and in on the send device => Sunset ?
currently I have
Programmable Joyo pedal looper - single midi out => Strymon Timeline delay ( used for patch changes )
my ambitiion
as above but Midi out Timeline => TRS EXP jack in Strymon Sunset ( patch changes to align with delay )
many thanks
