JP-2C issue

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jhilbert
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Posts: 19
Joined: Thu Apr 07, 2016 2:05 pm

JP-2C issue

Post by jhilbert » Thu May 19, 2016 6:51 pm

First time poster, long timer reader and boogie user.

I fired up my JP-2C today after work and switched the amp from standby to "on." All I get is a sound similar to when the volume is nearly off on a guitar. There is no sound from channel 1, but 2 & 3 have a very, very slight tone/volume, I can't emphasize how slight the volume actually is. In addition, I checked the fuse and it's okay, and all of the power tubes look good--they glow and are warm. Not sure what to do next. I left a voicemail with Mesa and also sent an email after not hearing back from them. I've never had an issue with any of my other amps. I've owned a .50 Caliber +, Mark IV, and currently own a Mark V:25 and the JP-2C (which I love). Any suggestions? I've tested guitars, cables, etc.

Thanks!
Own:
JP-2C, '83 MK IIC+, '85 MKIIC+ DRG

Sold:
Early 90's Mark IV, Mark V:25, .50 Caliber+

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dlpasco
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Posts: 689
Joined: Mon Oct 08, 2012 1:12 pm
Location: Seattle
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Re: JP-2C issue

Post by dlpasco » Thu May 19, 2016 10:03 pm

jhilbert wrote:First time poster, long timer reader and boogie user.

I fired up my JP-2C today after work and switched the amp from standby to "on." All I get is a sound similar to when the volume is nearly off on a guitar. There is no sound from channel 1, but 2 & 3 have a very, very slight tone/volume, I can't emphasize how slight the volume actually is. In addition, I checked the fuse and it's okay, and all of the power tubes look good--they glow and are warm. Not sure what to do next. I left a voicemail with Mesa and also sent an email after not hearing back from them. I've never had an issue with any of my other amps. I've owned a .50 Caliber +, Mark IV, and currently own a Mark V:25 and the JP-2C (which I love). Any suggestions? I've tested guitars, cables, etc.

Thanks!
Double check that the speaker is set to "on" in the cab clone controls and that the speaker plug is seated all the way in? I've had similar scares before and sometimes it's just a control issue, thankfully.

I hope it works out okay for you!
Mark IIC+, III, V, Recto Reborn, TC-50
Sold: JP-2C, V25, Road King II, Tremoverb, Electra Dyne, ROV25
Twitter:mammothguitar

Ibanezex718
Bottle Rocket
Posts: 20
Joined: Mon May 09, 2016 2:35 am

Re: JP-2C issue

Post by Ibanezex718 » Fri May 20, 2016 1:28 am

jhilbert wrote:First time poster, long timer reader and boogie user.

I fired up my JP-2C today after work and switched the amp from standby to "on." All I get is a sound similar to when the volume is nearly off on a guitar. There is no sound from channel 1, but 2 & 3 have a very, very slight tone/volume, I can't emphasize how slight the volume actually is. In addition, I checked the fuse and it's okay, and all of the power tubes look good--they glow and are warm. Not sure what to do next. I left a voicemail with Mesa and also sent an email after not hearing back from them. I've never had an issue with any of my other amps. I've owned a .50 Caliber +, Mark IV, and currently own a Mark V:25 and the JP-2C (which I love). Any suggestions? I've tested guitars, cables, etc.

Thanks!
Are you getting any sound at all when you play your guitar? Or is this tone you're hearing coming through when nothing is being played but everything is on and plugged in?

jhilbert
Bottle Rocket
Posts: 19
Joined: Thu Apr 07, 2016 2:05 pm

Re: JP-2C issue

Post by jhilbert » Fri May 20, 2016 4:57 am

I am getting a sound, very low and almost like I have the volume on the guitar turned down to "1."
Mesa called me last evening and said that it sounds like a premature preamp tube failed. I'm going to swap a preamp tube from the mark v:25 this evening and hopefully the issue will be resolved!
Own:
JP-2C, '83 MK IIC+, '85 MKIIC+ DRG

Sold:
Early 90's Mark IV, Mark V:25, .50 Caliber+

jhilbert
Bottle Rocket
Posts: 19
Joined: Thu Apr 07, 2016 2:05 pm

Re: JP-2C issue

Post by jhilbert » Fri May 20, 2016 3:50 pm

Issue resolved. I swapped a preamp tube into the the first socket on the JP2C and... BOOM! amp fired right up as it should! Thanks for the help all!
Own:
JP-2C, '83 MK IIC+, '85 MKIIC+ DRG

Sold:
Early 90's Mark IV, Mark V:25, .50 Caliber+

Ibanezex718
Bottle Rocket
Posts: 20
Joined: Mon May 09, 2016 2:35 am

Re: JP-2C issue

Post by Ibanezex718 » Sun May 22, 2016 5:04 pm

jhilbert wrote:Issue resolved. I swapped a preamp tube into the the first socket on the JP2C and... BOOM! amp fired right up as it should! Thanks for the help all!
Good to hear! Keep jamming!

Markedman
Donating Member
Posts: 1419
Joined: Wed Jun 26, 2013 3:56 pm
Location: Norfolk, CT

Re: JP-2C issue

Post by Markedman » Sat Aug 06, 2016 8:30 am

My issue is that Mesa put the power cord input between the transformer and the shell where it is hard to get at. For those of us who are constantly taking the head in and out of a case it can get to be a pain in the butt to put back in. An 8" extension was made! https://flic.kr/p/KQJ6f9 My other gripe is the sound of the reverb, a short/long switch would be cool as I find the reverb tails off to long. I don't want the hassle of setting up a loop just for reverb so I'll probably switch out the reverb tank. Maybe I'll invent a two stage tank with long and short duration, sounds simple enough.
This amp otherwise is absolutely perfect for my needs and wonder how other players can live without one. Other amps pale, sound mushy and seem like toys in comparison, and I've had this amp for only two weeks.
JP2C, Mark llC++ DG, Mark IV-A/B.

Jjbc
Bottle Rocket
Posts: 8
Joined: Thu Apr 01, 2021 8:50 am

Re: JP-2C issue

Post by Jjbc » Sat Apr 10, 2021 5:09 am

I had exactly this issue once. It happened exactly after testing it with an attenuator and I was going crazy. It turns out that the FX switch was turned on buy my fx pedal was disconnected.. Very scary. I turned the FX switch off and rock on.

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