JP2C Trouble Shooting

[9Hour]

So I had some bad tubes in my JP2C and fixed some humming issues I was having but now I'm having some other issue that I'm not sure if normal or not.

First thing I was wondering is it normal for my amp to make some humming even when on standby through my cab and I mean VERY quiet. I can still hear a slight hum through my cab on standby but only if I'm literally 1 foot from the speaker, I'm just wondering if thats normal or if something could still be messed up with the tubes because I was having problems.

Second one thing I'm sort of worried about is my amp started making this crackling sound 2 times every time I swap the standby on or off. It just makes like 2 weird crackles it didn't used to and I'm wondering if i should be worried about it.

And third I just wanted to know if the gain on my amp sounds normal because I feel like hearing other peoples amps, mine is making very weird electronic noises that I don't know if it used to make before either.

Sorry if I seem like an amp noob Its my first time having tube problems and my first mesa.

 

[Darkstar2]

Do you turn the amp on with it pre-set to channel 2 or 3? I always put my amps to clean channel before turning them off, so that when I switch them on, it's the clean channel. I just switched mine on and off a few times (always let it warm up upon first power-up, at least 30 seconds -- i follow this religiously).

So, I know I have dirty power (and my amp outlet is also the same as the power for a fader swich in the basement), and while I don't have the fast, double-pop you do, I do have the noise on channels 2 & 3. It's pretty oppressive with the amount of gain i'm running, and you appear to be running high gain too. I use a noise gate that's always on, and switch to another amp for my clean toans. With the noise gate off, it's quite terrible.

I've read that others don't have this issue with their JP2C's, but mine has always been fairly 'white-noise' on channels 2 &3 since I received it 1.5 years ago. I've changed out preamp tubes and power tubes and it's always like that.

EDIT: I have tried the amp on different outlets/circuits in my house and it's about 50% quieter, so I know that fader circuit its on is wreaking havoc on it; it's just the best location for my setup...

 

[9Hour]

Do you turn the amp on with it pre-set to channel 2 or 3? I always put my amps to clean channel before turning them off, so that when I switch them on, it's the clean channel. I just switched mine on and off a few times (always let it warm up upon first power-up, at least 30 seconds -- i follow this religiously).

So, I know I have dirty power (and my amp outlet is also the same as the power for a fader swich in the basement), and while I don't have the fast, double-pop you do, I do have the noise on channels 2 & 3. It's pretty oppressive with the amount of gain i'm running, and you appear to be running high gain too. I use a noise gate that's always on, and switch to another amp for my clean toans. With the noise gate off, it's quite terrible.

I've read that others don't have this issue with their JP2C's, but mine has always been fairly 'white-noise' on channels 2 &3 since I received it 1.5 years ago. I've changed out preamp tubes and power tubes and it's always like that.

EDIT: I have tried the amp on different outlets/circuits in my house and it's about 50% quieter, so I know that fader circuit its on is wreaking havoc on it; it's just the best location for my setup...

I usually start on channel 2 so if i forget to swap my channels and I get a loud pop its not as loud if i swap to my clean instead of the distorted channel. I know that's a common thing with mesa mine pops really loud if I don't like pre swap around the channels after just turning on the amp while on standby.

IDK what's up with the double pop thing with my standby and i think it started doing it with the new tubes, I also run very high gain and shred on which ads a lot of noise but mainly just wondering if that's a normal amount of sound for those channels. I'm just trying to make sure what seems normal for the amp because I was just some other problems I mostly fixed but want to see if it all seems normal for the amp. I mostly think its all ok

The double pop standby thing is what's most annoying and concerning for me tho.

 

[bandit2013]

The noise you hear when putting it into standby is normal. I get that with every Mark amp I have. Mark VII makes more noise than the JP2C but on occasion I will hear it. Standby is just a disconnection from the high voltage supply. That choke gets a sudden loss of current so it will have a flyback effect (impulse transient). Also, I would hear a really weird surge in sound when killing the power switch. Mostly with the Mark VII or Mark V90. If I wait for a few seconds to allow the voltages in the main supply to settle, before shutting off I do not get that noise.

The "electronic" sound you described is noise floor, almost sounds like fan noise but if it was the fan, the frequency would be much higher than that. Some tubes can be noisy and some are not. Since you can control the level of the noise with the volume control, it is not power tube noise but preamp tube related. If it was power tube, that noise would be there at all times. V2 may be the noise maker. Sure it is the fx driver tube but the channel master volume is driven from the output of V2 just before the GEQ.

I have two rooms in my home I cannot run any amps without excess noise floor from the amps. It is either power in those rooms, or its vicinity to the central air handler unit. Usually when the central fan is running the noise is apparent. The old dishwasher I had would make any guitar time off the table if it was running as you would hear the electrical noise from that thing. It was almost as audible as the noise effects in the opening part of "Welcome to the Machine" from Pink Floyd.

 

[bandit2013]

Yeah, I do not use the shred voice because it increased the noise floor too much.

The pops you hear when powering down or taking it in or out of standby is normal. I get some noises like that with the Mark VII and JP2C when going into standby or out of standby. Standby cuts the main power to the tubes, this includes the preamp tubes as well. Heaters will still be active as well as the other electronics.

I have yet to experience any channel change pops. with either amp.

 

[9Hour]

Yeah, I do not use the shred voice because it increased the noise floor too much.

The pops you hear when powering down or taking it in or out of standby is normal. I get some noises like that with the Mark VII and JP2C when going into standby or out of standby. Standby cuts the main power to the tubes, this includes the preamp tubes as well. Heaters will still be active as well as the other electronics.

I have yet to experience any channel change pops. with either amp.

Interesting my JP2C pops when I swap to any channel after just starting it up and only does it for the first swap. Its been like that since I got it pretty sure. Saw a lot of people saying they get that with some mesas and its static building up.

I'm probably just gunna replace my preamp tubes and maybe get one of those spax7 tubes for the V1 and see if it helps anything. Interestingly some of that electronic sound got quieter the other day so I do think something in the house is causing it.

Good to know about the standby thing I wasn't sure if I should be worried about it. Also do your cabs make any hum while on standby. Mine makes a VERY VERY quiet hum now but just wondering if it is normal to hear any sound through it at all while on standby. I just got the new power tubes because I was getting a different hum on standby that was fixed with the new tubes, but now I'm just noticing the very slight electronic sound from my cab and I mean like I have to put my ear almost to the cab to hear it, I've just gone down a rabbit hole now trying to remove all the sound from my amp lmao. Pretty sure its all normal but just wondering.

 

[Darkstar2]

Regarding instant shutdown from standby, I almost always let my amps sit in stand-by before final shutdown for at least a few seconds, usually up to 30, just like warm-up. On the few occasions I've accidentally shut-down with no standby engaged - whoa, that's bad - it will make a terrible sound! Especially my EVH 50-watt Stealth (switches are a PITA and on the back...).

I do get channel pops with mine, upon first switching. Oh, and I've never felt I've needed to use Shred; I tried it when I first got the amp, and it went off and hasn't gone back on, ever.

FYI, when I first got the amp, after about 20 hours, I did swap in 2 of those SPAX Mesa sells (premium tubes) and noticed no difference from the stock JJ's.

 

[9Hour]

Regarding instant shutdown from standby, I almost always let my amps sit in stand-by before final shutdown for at least a few seconds, usually up to 30, just like warm-up. On the few occasions I've accidentally shut-down with no standby engaged - whoa, that's bad - it will make a terrible sound! Especially my EVH 50-watt Stealth (switches are a PITA and on the back...).

I do get channel pops with mine, upon first switching. Oh, and I've never felt I've needed to use Shred; I tried it when I first got the amp, and it went off and hasn't gone back on, ever.

FYI, when I first got the amp, after about 20 hours, I did swap in 2 of those SPAX Mesa sells (premium tubes) and noticed no difference from the stock JJ's.

interesting i mean I'm prob gunna swap new tubes anyway for my preamps eventually and will still just get one anyway but I'll go in not expecting it to do much with the SPA tube. Also the shred mode is awesome especially for super high gain sounds and drop tune. I've been using Ola Englunds sound from youtube if you know that guy and it sounds killer you should try it out. the main thing is to have max treble with no mids and no bass and also can put shred on.

 

[9Hour]

Regarding instant shutdown from standby, I almost always let my amps sit in stand-by before final shutdown for at least a few seconds, usually up to 30, just like warm-up. On the few occasions I've accidentally shut-down with no standby engaged - whoa, that's bad - it will make a terrible sound! Especially my EVH 50-watt Stealth (switches are a PITA and on the back...).

I do get channel pops with mine, upon first switching. Oh, and I've never felt I've needed to use Shred; I tried it when I first got the amp, and it went off and hasn't gone back on, ever.

FYI, when I first got the amp, after about 20 hours, I did swap in 2 of those SPAX Mesa sells (premium tubes) and noticed no difference from the stock JJ's.

This is what ive been using its shred on, pulled gain, pushed presence. You can bring the gain super far down as well if you want it super tight.

 

[bandit2013]

I see you have the bass and low mids boosted and the treble cut on the GEQ. Never have explored the controls on the JP as much as I should. I found pushing the midrange and backing off on the others provides some nice gain structure. I have seen a few of Ola's videos. I thought the Fart pedal one was one of his best work. It was funny as all hell. He may be part of why I got into the Badlander as he did a good job exploring the amp to some extent. I did not watch any on the JP2C so perhaps I will do that.

 

[bandit2013]

Ah ha. You are both correct on the pops at start up. I do not use the footswitch much as I do not have the space for it. I leave the amp on CH2 most of the time. I am also running the Mark VII and two badlanders with it at the same time. I got hooked on multiple amps vs just one.

 

[9Hour]

Ah ha. You are both correct on the pops at start up. I do not use the footswitch much as I do not have the space for it. I leave the amp on CH2 most of the time. I am also running the Mark VII and two badlanders with it at the same time. I got hooked on multiple amps vs just one.

check out his chug test video on the JP2C it sounded BRUTAL.

 

[9Hour]

I see you have the bass and low mids boosted and the treble cut on the GEQ. Never have explored the controls on the JP as much as I should. I found pushing the midrange and backing off on the others provides some nice gain structure. I have seen a few of Ola's videos. I thought the Fart pedal one was one of his best work. It was funny as all hell. He may be part of why I got into the Badlander as he did a good job exploring the amp to some extent. I did not watch any on the JP2C so perhaps I will do that.

also yeah you kinda gotta bring the treble side down a bit on the GEQ with the shred on and treble that high and you can boost a lot of bass

 

[bandit2013]

Ok, seen it. Not going to post a link to it though, not sure if that is in line with code of ethics in the forums. He is a trip, cameras were crapping out. Thought the fart pedal video was funny, this one is close.

 

[ultra high gain]

interesting i mean I'm prob gunna swap new tubes anyway for my preamps eventually and will still just get one anyway but I'll go in not expecting it to do much with the SPA tube. Also the shred mode is awesome especially for super high gain sounds and drop tune. I've been using Ola Englunds sound from youtube if you know that guy and it sounds killer you should try it out. the main thing is to have max treble with no mids and no bass and also can put shred on.

I have been a huge fan of Ola since 12 years ago! He gets the chug tones well. I usually try to be more conservative with the eq, but I tried the Ola setting (T-10, M-0, B-0), and I'm hooked! No turning back now! Chug chug chug...