Schmalle

There is no need for maintenance or inside cleaning in a Stomp. If something breaks either send it to Service Center. If you open it on your own risk loosing warranty. If that doesn't bother you (like me) you can't really repair stuff in it without special equipment because it's tiny SMD parts for the most part. If manage to find a part that is broken you can ask Line6's Support for the parts name and order it from an electronics seller. And you can order a circuit boards via a Service Center and replace them. Line6 doesn't answer in this forum. If you want to address them directly contact their support.

You may get the frequency response right. BUT: listen to the attack. There is a difference in attitude to a bright cap "crushing glass" distortion.

No. Trading latency for a stable sound is working on operating systems like Windows, Mac OS or Linux because other processes can delay the CPU access of the audio process long enough so that audio gaps occur. This is not the case on a real time DSP system like the Helix.

A JCM kicks azz "Sure, we have that amp" they said Wanna kick their azz

IMHO the aggressive bright cap Marshall sound (roaring with crushing glass highs) is more ore less a blind spot in the Helix. Personally I really like the JVM OD1 orange mode and would like to see something like that in the Helix. Also there are rumors that the next update is soon to be released and is likely including a stock 2203 JCM 800. Tip 1: I got pretty close to the JVM OD2 orange model (neutral EQ, Drive 3) with the Badonk with Drive 4.5, B 2.5, M 2.5, T 6.8, P 7.5, Master 4, Depth 5, Sag 7.6. Tip 2:The shelving eq in front of amps works to a degree. Boost high freq at 1.5kHz as a starting point.

Why do you use Helix's Send instead of the Output? That would be the simpler thing to do.

The Send output jack has three pins: Tip, ring, sleeve. SendL sends a mono mixed signal via the Send output's tip, no signal on the ring. SendL/R sends a stereo signal via the Send output using tip for L and ring for R. If you connect to your monitor with a TS cable you get the reverb mixed to mono with SendL and the left reverb channel with SendL/R. If you use mono reverb there should be no difference btw. If you use a TRS cable into a balanced input of the monitor it'll sound weird with the SendL/R unless you use Type Mono and Pan L100.

If you have a healthy guitar the Placater Dirty can get you the amp sound without pedals. Keep the master down to keep things crisp and open. I personally found bias at 5.3 to sound best to my ears. The important thing is the right cab / mic combination to match the recording. I have some favs but I don't wanna spoil your fun. Put a looper first in the chain, play and record a riff and then try to match to the album sound. Don't forget to match the room/ambience for the right feel, too.

I forgot about audio isolators as a practical solution. I can recommend the Behringer HD400 for this.

I'd put thin adhesive tape (i.e. TESA tape) around the flat USB cable plug's metal housing so that it is isolated and not contacting the USB socket. Also some small thin stripe of tape on the left pin (GND). Alternatively you can physically cut shield and GND. Why would that help? - You only need USB's D-, D+, 5V connected. The GND and Shield don't need to be connected because GND is already connected via the power plug. The second GND connection (aka ground loop) via USB causes the problems.

See answer above. It's a lollipop USB hardware design in the PC - some switching noise at the rate of 8kHz propagates via USB. Test it: plug the Helix only in USB but not in mains power. The second you connect mains to the Helix the noise is there.

It's a ground loop. If you have a spare USB cable you can try if cutting the shield helps. If not a USB Isolator helps. Or something like a Morley Humno Noise Eliminatorar.

Yes.

May it was working and something got loose during transport. Asking whether the screen worked after their repair doesn't cost you something.

And toggle between snapshots by setting up i.e snapshot 1 to point to snapshot 2 and snapshot 2 to point to snapshot 1.

No, there is a specific MIDI CC toggle option in Command Center - no snapshots required. But there is no equivalent for MIDI PC toggle - hence the snapshot 'walk around'. You can program a footswitch to switch between snapshots in Stomp Mode - no Snapshot Mode required.

Since the firmware seems to work normally I'm 99% sure for it to be a hardware problem.

If you're just toggling between two CC values (i.e. CC#14 0/127 for bypass on/off) or want to control a parameter with an expression pedal from the Stomp Command Center is your friend. That's easy. To toggle between Mercury7 presets within a HX Stomp preset you need snapshots: As per V3.15 Command Center works per snapshot. This means you can set up a footswitch to switch between snapshots in Stomp Mode. In those snapshots you can send up to 6 Instant Commands which you can program to be MIDI PC or CC messages. You can also deactivate blocks from reacting to snapshot changes which is what you might want to do so that only PC messages are sent and nothing else happens. Or you use snapshots as "presets in a preset": i.e. engage a tube screamer, a chorus and change the Mercury7 program at the same time. On a side note let's hope for a MIDI PC toggle option in Command Center as an update to make this stuff easier.

Sounds like a high Sounds like it's just a low and high cut that is missing in the second clip. Edit: With Reaper's RBJ Highpass/Lowpass set at 80Hz and 4800Hz applied to the second clip they sound identical. There is overall boost btw. Global EQ?

On my Ubuntu system Audacity changes the system's audio settings - I sometimes need to unplug / reset my audio interface after using Audacity. Try record something with Audacity. Then save as .wav and close. Open the file with a player and listen. If it sounds wrong open a normal music file and listen if that sounds wrong, too.

My point is: if your signal level in the Helix is too high it can digitally distort the USB output. The visual waveform representation of recorded tracks in your DAW will hint at that when it hits the upper and/or lower borders.

Do you record via USB? If so check: Global Settings -> Ins/outs -> USB In1/2 Trim - default is 0.0 dB

That's not normal. Get it replaced within warranty.

I got close with combination of EH Deluxe Electric Mistress and Boss CE-1 aka Courtesan Flange and 70s Chorus. Try to match the rhythm tone first - then engage the Flanger and tackle the intro. The Retro Reel can give you the 70s honk if needed. Have fun!

Is it Is it just the USB that isn't working?