Problem: Mark V35 Switching w/EM Customs MIDI Box

Hi all,

New here, but not new to the Mark V:35. I picked up a MIDI switcher interface from a Polish company called EM Custom (https://emcustom.eu/amp-midi-switcher-interface.html) after seeing videos where channel switching, EQ on/off and solo boost on/off worked seamlessly.

I received the box today and immediately had issues.

My MIDI controller (Morningstar MC-8) and the EM Customs MIDI box work fine together. A MIDI signal gets sent from the MC-8 to the MIDI box, and from the MIDI box to the amp's footswitch jack. That all works. However, the pop between channels and functions makes the amp **** near unusable. (yes, I know the channel pop is a thing. I've had two MV35's, a full-size MKV, a Rectoverb, a Dual Rec, but this is ten times louder).

Troubleshooting steps I've taken: replace V6 phase inverter tubes, switch MIDI cables, move MIDI controller to isolated power supply, etc. - no luck. I've also contacted EM Customs (great guys to deal with) and they're as stumped as I am.

Any thoughts?

So does the pop occur, at the same level with an alternate switching mechanism ie: footswitch?

It does not. It's significantly louder. I've since returned the MIDI box and am looking for an alternate solution.

itsthedon86 said:

It does not. It's significantly louder. I've since returned the MIDI box and am looking for an alternate solution.

Click to expand...

kinda water under the bridge now but the speculative thoughts were the I/O signals it was sending was probably in an unexpected order or with a timing pattern that didn't allow for proper relay settling. Would venture to guess a Mesa Matrix wouldn't have the same type of issues.

Hello.
It is Marek from EM Custom.
I have to confim that early lot of V35 switcher had pop issue.
It applies to V35 version only.
We replace the malfunctioning devices free of any charges.
Just contact us.
[email protected]