Hi all,
I would post this in the digitech forums but they are rather empty with not many posts happening per day. Thought Id try here.

I have had my GNX4 for about 3 years now. I have the supermodels CD as well, and overall it has been a terrific sounding unit and I have been very happy with it. Until today. I played this morning, I am running it through the effects loop of my Peavey Valveking 112. Everything was normal, all of my presets sounded great. I unplugged, and about 2 hours later started playing again. Powered everything up, everything is working BUT, I noticed immediately my favorite preset sounded a little fizzy and not quite right. I went into investigation mode. I tweaked the speaker compensation button back and forth and it sounded fizzy both ways (but fizzier with it off which is normal). I A/B'd with my different guitars to make sure the guitar wasnt the problem. Both my Les Paul and strat didnt sound right so I dont think its the guitar. I plugged straight into my amp to also check the guitar, and everything sounded normal, so I know the issue is with the unit. Even more of interest, it only appears to be happening with gain type presets. Anything with high gain. My JCMClassic setting still sounds clean and nice, but when I switch to any of my higher gain presets I get the off fizzy sound. Its hard to describe, its subtle, but its definitely not quite right. Its almost as if I have an electronic tube failing within the unit! This sounds the same both through my headphones as well as outputting to the Peavey.

I am at a loss, and it quickly brings to the front how much I rely on the GNX4 for my sound. I dont want to buy a Mark V until I have my Les Paul paid off, but if I have nothing but my Peavey to rely on for sounds its going to drive me nuts. Have any other GNX4 owners experienced this? WHat could be the problem?
Last edited by GuitarDTO at Jun 27, 2009,
I haven't experienced that. But hopefully you've saved your presets to the computer with XEdit and can try restoring them. It may be something with the cab settings.
I am suspecting something may be wrong with the power supply, but why it would fizz up some presets is beyond me. I tried again about an hour later, and I noticed that my power cord wasnt fully plugged in. It was obviously in far enough to power the unit, but it was still sticking out a little bit. The unit sounded back to normal when I powered it up, but then after I switched back and forth from headphones to amp, it went back to being fizzy. I know bad power supplies are considered one of the widespread failures on the GNX4, but I dont know if this is the result of that or not. I am going to keep playing with it and hopefully the problem just doesnt happen again, but we'll see.
Quote by fly135
I doubt it's the power supply.

Any speculation on what it would be then? It was the only variable I played with that seemed to make a difference....otherwise its internal circuitry to the unit in which I have no idea how to fix. Played twice today and it was fine the first time, fizzy the 2nd time. I have a friend with a GNX4 who is letting me borrow his this afternoon and I am going to play around with the power supplies and do some A/Bing with units.