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Compatibility with RK-006

I just hooked up the Arp and like it so far. My plan is to integrate it with my existing setup that's based around the Retrokits RK-006. I think this is a very flexible partner for the Arp, allowing control over many MIDI devices and the RK is rock solid in my experience. I have it set up in mode 1 (basically a simple MIDI thru setup, where the RK duplicates incoming MIDI to all its out ports).

My plan is to use the MIDI host capability of the RK (I've connected a powered USB hub to it). This works well with other MIDI devices, e.g. I can use my Digitone Keys to play notes via USB and the RK passes them through to other MIDI devices connected to the out ports as expected.

When I connect the Arp to the RK with the same USB-B cable as I used for the Digitone, it powers up and I see the lights of the RK blink when I press play, signifying it's receiving data from the Arp, but I can't get my devices to play anything the Arp is supposedly transmitting. If I hook up the Arp via regular MIDI, either via the RK or directly into the unit, it plays back as expected. I also tried powering the Arp separately and connect to the RK with a the other Arp USB port (type A, both ends) cable but that doesn't work either.

Any thoughts as to what I can do to get it to work? Or is the USB on the Arp only designed to work with a computer, as the manual states "supports MIDI over USB to connect to software sound generators, VSTs and DAWs."

4 comments

Comments (4)

Chris Brown

Aug 17, 2023

I don't know how the RK behaves but ARP should take power and send MIDI data over the Type B port when connected to any class complaint MIDI Host.

Connecting two Type-As together is unlikely to work, this signifies that both ends of the cable are a USB Host. ARP will act as Host if not connected to another Host via it's Type-B port.

Assuming ARP is powered by the RK, it should be emitting MIDI data on all three ports, USB, USB Host and DIN Out. Is it possible there's a configuration option on the RK to receive data? I'm not familiar with it but there seems, from the docs, to be a number of configuration options.

jeroen

Aug 17, 2023

Replying to

Yes it's available to receive data; when I connect my Digitone Keys to the RK via USB (only) and configure it to send MIDI over that USB connection, the RK passes through the MIDI data to connected synths on the MIDI channel set on the Digitone.

When I do the same with the Arp, same channel, the RK blinks but doesn't pass MIDI out; when I connect the Arp via DIN to the RK MIDI in, it does work so MIDI channel etc should be configured.

I have the RK in it's basic mode (mode 1, essentially taking any input and route it thru to all its 10 ouputs). But to be sure I'll reset the RK when I get home tonight and see if that changes anything, will update if I find out more.

Chris Brown

Aug 17, 2023

Replying to

Does the RK blinking denote that it is receiving MIDI from ARP? The only additional thing I can think to try is disabling MIDI Thru on ARP... in case something weird is going on there.

jeroen

Aug 17, 2023

Replying to

Yes, the blinking denotes receiving MIDI, and if I increase on the Arp the number of steps per beat for instance, the blinking on the RK changes along. The blinking happens on for the USB and regular MIDI connection from the Arp.

MIDI Thru on ARP is off.

I've reset the RK so I'm sure it's in its most basic mode (simple MIDI Thru) and the issue remains, the lights blink but the other synth doesn't respond. With the same cable, the Digitone kan send USB to the RK and it will be passed on to the other synth; the Arp only works directly with the regular MIDI out port.

To check if the RK is involved, I removed it from the chain and instead tried a Kenton USB MIDI Host Mk3 as USB host to the Arp,. This powers it and should pass data it receives on USB to its regular MIDI out port. Again, the Digitone can play my other synth, while the Arp doesn't. The A/B test is simply swapping the USB cable between Arp and Digitone. Once I plug the same regular MIDI cable directly into Arp it works again, so I'm sure the Arp is configured correctly to send MIDI to the synth.