AC1DF0X

Pretty straightforward. Guitar > Helix > Amp, then Send > Silencer > Helix > Return.

It's mostly just volume drop because the loop isn't true serial- If you select the output block for send 1/2 and give it +1-2dB of boost going back into the amp, it'll take care of it. Your ears will perceive it as tone suck simply because it's quieter. There's also the button on the back next to the loop that affects the send volume, so try it on and off, I can't fully remember which way around it is. If I was you I'd go back to basics using the regular 4CM, then set up a new preset with guitar input going straight to the effect loop output, that you can switch to when you want to use amp models. That way it just entirely skips the pre-amp and should work with no problems.

I usually keep the channel volumes around 11-12 o'clock. It starts adding saturation above that point I've noticed, which is desirable for some sounds (you get a good authentic Plexi crunch that way keeping the gain low), but not desirable for the kind of tight thrashy tones I want on the OD1-2 channels. My gain is usually 10-11 o'clock on those channels too, and never above noon. The JVM is a very modern amp so it is designed for plenty of headroom, it doesn't start sagging on you until you have that master well above halfway, and that's already deafening. The masters are meant to be your main volume level control, or at least, I assume that's why they went to the effort of giving you two which are foot-switchable for boosts. Everything before that is tone shaping. I got the midi figured out pretty quickly all considered, thanks to that guide. Unfortunately it isn't possible to replicate the JVM default footswitch behaviour, which would have been nice, but the next best thing for me is having a preset for each channel, with each mode saved as snapshots within them. The view mode that gives you 4 presets and 4 snapshots on screen works very nicely with that config.

Alright so I tried your method (I think I got it right at least, as a disclaimer I might have done something differently without realising) and it seems to work okay for me. I did notice that running the channel volume that high gives you a lot of background noise, which the noise gates didn't handle very well without cranking it up to a level that really interferes with your playing. Using my EHX Silencer instead worked perfectly however, but the noise gate on the Helix seems to work a different way. I think the channel volume cascades into the next stage after the loop and drives the PI stage a bit hard maybe? I feel like those channels are definitely intended to be played with a higher headroom kind of setting, rather than driving the PI. Also potentially of note is that I'm not running the stock preamp tubes (Marshall uses JJs as stock IIRC, I put a set of Shugangs in mine) so maybe that has some influence. Shouldn't be drastic though. But yeah in general it sounds like the amp you had definitely had a problem with the loop. Your new one should work. My task for today is figuring out MIDI switching... I'm hoping there's a way I can set it up to simply replicate what the JVM's actual footswitch does on a separate patch, but we will see.

Ahh I see what you are going for, bypassing the JVM preamp to run an amp model in place of it. I can't see any reason it shouldn't work that way. I had briefly considered that as an option myself, I can see it being handy, but I haven't got around to experimenting with it yet. If I'm not mistaken there should be a way to do it without having to change the method of connecting the cables though- You could still do it with the "normal" 4CM wiring, and just make a preset with different I/Os, right? I would have to have the Helix in front of me, I can't summon the brain power to map it out in my head haha. Come to think of it, that does mean you'd want to use the line level serial loop, not the serial/parallel one. If I remember correctly, the JVM's circuit puts the serial loop directly between the pre-amp and power-amp, so using that, you would totally take the pre-amp out of the equation. But using the serial/parallel loop, you'd still be pushing that signal through the last valve stage of the pre-amp. Might make a difference, might not. Anyway I'll give your method a try when I get chance and report back. The JVM effect loop does behave strangely compared to other amps I've owned (being tube driven might account for some of the strangeness), but I can't see any reason the issue you're having would happen, as long as the loop is working properly. (And yup, it's brand new, it won't stay that way for long ;) )

What a coincidence. I've just got a Helix, I use a JVM, and I'm using the 4CM without any issue. In fact that's the main reason I upgraded to the Helix from the little Zoom multi-FX unit I had before. Here's how my Helix is set up. I did watch a few videos, but it seems like everyone goes about this in different and sometimes really non-intuitive ways. I basically disregarded everyone else's advice, and figured this set-up out for myself. I'll try to explain as concisely as possible: - Set JVM's FX Loop Level to 100%, and make sure the little button is pulled out. - Set Send/Return 1 on the Helix to "Instrument" in Global Settings > Ins/Outs. - JVM's Send is connected to Helix's Return 1. JVM's Return is connected to Helix's Send 1. - Guitar is connected as normal to 1/4" guitar in, and left/mono out to the amp. - Top row is set as "Input - Guitar", and "Output - Multi". - Bottom row is set as "Input - Return 1" and "Output - Send 1/2". - Highlight the output block on the bottom row and boost the output by +1 or 2dB. (The JVM FX loop does lose a bit of volume.) - Effects that you want to go in front of the amp (wah, drives, modulation) go on the top row. - Effects that you want in the loop (noise gate, delay, reverb, looper) go on the bottom row. - See attached picture, you should have something like that, and you're in business. I'm not sure why everyone gets stuck on the send/return blocks, as far as I can see they're totally unnecessary. If you're not using the second signal chain for some other reason, I can't see why you wouldn't just do it this way. Also- I've tried using both the loops on the JVM, and I had better results with the serial/parallel one for some reason. Not sure exactly why. I believe the serial loop is line level (it goes directly between the preamp and power amp in the circuit), and you have to change settings on your Helix to reflect that, but for some reason it just doesn't work as good. The other benefit of using the serial/parallel loop is it goes before the amp's reverb, in case you still want to use that, and also allows you to footswitch the whole loop on/off if you need to. The setup I have described here is super flexible, you can do things like record a clean loop, and play over it on a different amp channel while retaining perfect sound. Having a gate in the loop as well as a gate at the input stage is essential too, because the JVM has an ungodly amount of background noise, and you can completely clean it up. It does take some trial and error to figure out the threshold for the gates, but I ended up setting the gate in the loop to ~25-30db and it eliminates any noise from the amp. Hope this helps :)