Schmalle

MIDI is used to change stuff on outboard gear by sending messages. Those messages can be of several types. Most used are PC (Program Change) messages to trigger program (preset) changes and CC (Continous Control) to control parameters on other devices. Your picture shows a CC Toggle set up but for changing presets you need a PC command.

That cable should be fine. Cable from Helix MIDI Out to Boss MIDI In. Global Settings > MIDI/Tempo > MIDI Base Channel = OMNI (or the channel that the Boss is set to) Global Settings > MIDI/Tempo > MIDI PC Tx = ON Now changing presets on the Helix should trigger the same preset number on the Boss. Once that works you can set Global Settings > MIDI/Tempo > MIDI PC Tx to OFF and program each patch or snapshot or footswitch to perform a MIDI PC (program change) via Command Center.

Yes. The Paint Audio MIDI Captain DUO is compatible with the HX Stomp (XL) and you can program it to change presets using MIDI PC (program change) messages. Other stuff like controling effects or changing snapshots works, too.

The only way I can think of is using a Send block in front of each amp model. You'll then have to mix the two signals externally. Some amps have multiple inputs.

Are you using the fx in front of the amp (amp used as a pedal platform) or in the fx loop?

Make sure you haven't accidently set up a footswitch to change the preset in Command Center.

If by "CM patcher" you mean 4CM patches: These patches are made for the 4-cable method (read the manual's Quick Start section). You need a guitar amp for that. Without the amp's preamp in the loop you'll hear nothing. But you can bypass the fx loop block if you want to hear the effects on their own.

Name the mic for a meaningful answer.

Press MODE and TAP to bypass all effects. Manual p.11:

It depends. I'd like to eq my in-ears (Phones Out) exclusively with the Global EQ. But that's not possible right now. It makes sense to eq your amp to your needs - to add or cut some imperfect frequencies from the amp or to adjust to the room / space your playing in. It makes less sense to eq the PA sound with the Global EQ. That is what a mixer should do. Low and high cuts are in the cab and IR blocks. Adjust these in a rehearsal at volume in band context.

Global EQ is never heard from the Send or USB outputs.

Split the signal late in the signal chain and put the cab block on Path B which you route to Stereo Send L/R ( manual p.19 "Setting path B's output"). Use Global Settings -> Ins/Outs -> Phones Monitor to listen to it via headphones.

Gary is quoted with this statement:

It's four snapshots on the HX Effects so you can do: FS1: activates my amp's channel one via MIDI with a compressor and reverb on; FS2: activates my amp's channel two via MIDI with a noise gate and and OD; FS3: same as FS2, but with channel three of the amp; FS4: same as FS3, but adds a delay, and an EQ; FS5: adds a single chorus effect; FS6: adds a single select effect (e.g. a poly pitch). Use Stomp Mode for this. Configure FS 1...4 via Command Center's Snapshot Commands and FS 5+6 via Bypass Assign. Configure the four snapshots to switch MIDI via Instant Commands and noise gate, comp, reverb and OD via stock snapshot bypass.

It's four snapshots on the HX Effects.

Sounds like the decay of the noise gate in the input block is set so that it 'slowly' closes. Experiment with it's Decay and Threshold parameters. Use less gain, a well-shielded guitar and remove or keep distance to noise sources (e.g. electronic devices).

Think of the path lines connecting the blocks as stereo cables. A stereo cable can carry a dual mono or a stereo signal.

Those two EV preamps are suspiciously low level even for Helix preamps which is a shame because they sound very good. Played into the power amp of my PV Bandit they sound great. In general the HX preamps are 24dB tamed compared to the original circuit which is a controversial design decision and should be revisited by Line 6. Here is my one block +24dB linear boost that you can put after the preamp: Parametric EQ, LoGain +12 dB, LoFreq 1.6 kHz, HiGain +12 dB, HiFreq 400 Hz, Level +12 dB. Save as Favourite and call it "+24dB". I still need to crank the EV preamps' channel volume with that but it works.

The only parameter to adjust the input gain globally is Global Settings -> Ins/Outs -> Guitar In Pad. You can use it padded for the active and non-padded for the passive pickups. Or put a gain block first in the signal path,and use it as a boost for you "weak" passive guitar. Or use a footswitch to dial in two different gain settings in the amp model using Controller Assign.

Yes, that is exactly what I was talking about. Alternatively you can open up the pedal and isolate the ring pin of the expression socket (Out 1) with some electrical tape. That's all it takes to mod the EP1-KP to be a SP1-L6H.

Sounds like the guitar is picking up electromagnetic noise from other devices. Sometimes this occurs when the guitar's bridge (and by extension the strings and the player) is not connected to ground (faulty wiring). Is it a single coil guitar? Is the noise level depending on your position in the room?

The Kemper EP1-KP works if you use this cabling: a (stereo) Y-adapter (TRS male -> 2x TS female) in the HX's footswitch socket. Then a TRS cable for the expression part and a TS or TRS for the switching part. Mission Engineering offers an expression pedal for Line 6 (SP1-L6H) which also works. With that you can use a simple Y-adapter (TRS male -> 2x TS male). The Boss FV-50H is a volume pedal that will not work as expression pedal for the HX. I have a Donner Viper which is cheap and ok for home use. I modded it by adding a toe down foot switch. I would not recommend it if you want something sturdy for live use.

Most certainly ground loop issues. When you connect only to USB how do you listen to the Stomp?

It's a ground loop issue. A ground loop is a wiring issue that occurs when multiple devices share multiple paths to ground which can cause unwanted noises, such as buzzing or humming. By plugging into the amp you introduce another path to ground.

It's already possible via Bypass Assign and/or Controller Assign.