Schmalle

Yes, multiple solutions are possible. Could you be a bit more specific: When you play rhythm do you want to hear the signal through L/R or Send?

Maybe start with listening to some pedal nerds? I've looked up 2 of a gazillion videos that somewhat answer your questions:

Use it with Global Settings -> Ins/Outs -> Send/Return set to Line. That switches the Return input impedance to 10kOhm. A dynamic mic has an output impedance of about 0.3kOhm while a standard pickup has 6 to 12kOhm. A good damping factor (rule of thumb) is 10 to 100. Dynamic mic: 10kOhm / 0.3kOhm = 33 Electric guitar: 1MOhm / 10kOhm = 100 I get some weird 'touching noise' when I use a mic with 1MOhm and touch the HX.

I was just connecting the dots: there have been generations of guitar players who made the same experience you did, just with different technology. You are in the lucky position of being offered the whole palette of tones at your fingertips.

Use 136kOhm to emulate plugging into input 2 (or low input) of a Fender style input stage.

A simple XLR Female to straight mono jack 6.3 mm will do. Put it in input L or R, lower the IN-Z to 10K-Ohm in the Input Main L/R block and use a Studio Tube Pre preamp block with pretty high Gain and Level.

Since you use the HX Stomp: Try a parametric eq block in the end of the signal chain to find the frequencies you're not liking and adjust. This resource on equalization might help - especially 'Approach 1 – Remove Nasty Elements'.

Don't expect answers to questions you have not asked... Be specific, be precise, be concise - that increases your chances for good answers.

Yes, you can do that. Just rename "left channel" to "mic-channel" and "right channel" to "acoustic channel" in your head. You can apply FX blocks to just one or both channels or any mix in between. There are ultimately two ways of usage of the Felix output DIs and you'll have to chose one: Guitar and mic (double mono) OR left and right (stereo). That decision affects the way you use the HX, but both ways are possible.

From the Felix2 website: Use the dual mono fx mode, connect the Felix fx send to HX input L and R with a stereo to L/R TRS cable. In the HX split L/R and use one path for guitar FX and one for vocal. Connect HX Out L and R with Felix's fx return via (another) L/R to stereo TRS cable.

Well, the difference between headphones and main outs it the output impedance. Hx's headphone outs have about 10 Ohm to be able to drive current / move headphone speakers. The main outs have about 300 Ohms and are designed to maximize signal transmission quality for standard audio input stages. They work best with 10kOhm-ish inputs. You described a connection with a high damping factor (Df = Z_load / Z_souce = audio input /headphones out =10k / 10 = 1000) results in a slight enhancement of high frequencies. It gets more audible when plugged into amp (Df = Z_load / Z_souce = guitar input /headphones out =1M / 10 = 100.000). Look up impedance bridging for a technical explanation.

Parameters that influence input gain: Global Settings -> Ins/Outs -> Input Level Input block -> In-Z Global Settings -> Preferences -> Auto In-Z if Input block -> In-Z is set to Auto

No, the opposite: a low impedance of the Helix is driving a high impedance input of the amp.

According to ADAM audio these speakers deliver a max SPL >110dB @1m per pair - that's fairly loud. My ADAM A5x pair is pretty loud, too.

The Helix is able to deliver about +19dBu in line level mode before distorting the DA converters. If you have a preset that puts out -15dBFS and you crank the volume knob you get +16dBu at the output. I'd guesstimate that the patch is +10dBu with the volume knob at 2 o'clock which is twice the level of +4dBu and might well be the max headroom of the Adams input stage.

This. Audio signal transmission is not about maximizing the transmitted power - which would be impedance matching. It's about maximizing level (high voltage) at the input with high fidelity (low current). This is called high impedance bridging / voltage bridging.

Plug your headphones in the headphones jack.

You are right in that an amplifier that needs to tame the signal it carefully amplified to provide a low signal for FX gear isn't that great of a design. A modern amp like a 5150 III i.e. has a tube preamp, an intermediate OP amp based FX loop/preamp send/headphone buffer stage and a tube power amp to do that. Is there a way to use a multimeter to find out the signal voltage and impedance of different points in the signal chain of an amplifier? - Yes, you need a multimeter, a potentiometer or a collection of resistors and a test signal generator for sine waves (a synth/PC/phone will do the job). Then do this.

Something like this?: 60 Hz hum That's most likely coming from a not lifted ground to P.A. which was powered by another outlet. Push the ground lift switch on your Helix when you send a signal to P.A. or ask the sound guy to lift ground on the mixing console.

The USB cable completes a ground loop that acts as an antenna. The loop: socket 1 - power cable - Helix - USB cable - computer - power cable - socket 2 - socket 1. This has 2 effects: 1) Electromagnetic fields inside this loop will be picked up. So if you minimize the area the loop spans you minimize the noise it can pick up. Laying power cables in parallel next to each other helps, also using the USB ports in the back of the computer are usually better, because the loop now doesn't contain the inside of it where the cpu and other stuff produce electromagnetic noise. 2)The loop can also inject mains hum. That can be minimized by plugging PC and Helix into the same wall outlet using a multi socket. Of course not closing the loop is best which can be done by using an USB isolator, but those aren't cheap. If you use a laptop you can unplug it's power supply and prevent a ground loop that way.

HX Edit 3.01, HX Stomp 3.01 Exported patches miss command center settings.

My personal settings for an ambience reverb that I tend to forget it's until I turn it off: Plate - default values with those changes: Decay 2.6 HiCut 6.5 Mix 20% I listen through studio monitors in moderate levels.

Should work if both amps share the same ground. Plug them into the same power strip / multi plug adapter to make sure.

That's normal since the tip of the cable now touches both button paths. If you pull the cable on the HX Stomp a little until it rests (which is exactly the length of the tip) you can test FS5 function as well.

Mine works fine. You can test the button 2 by pulling out the plug on the Mosky a little until it rests naturally. Now it should do whatever button 1 did before.