I had one of these, I took it to Marshall for an intermittent fault, they did a repair service on a Friday, so I booked a factory tour as well! They couldn't trace the fault ( it cut out randomly) and they had it on the bench for a week, so what they did was order a complete board with my name on it! And run it through the factory (they work the lean system) so I got a brand new preamp apart from the case ! And as they couldn't locate the fault on the day they only charged...... wait for it.....£40 labour!!! What incredible service, had a brilliant time , got my amp fixed and a factory tour!! I finally got peed off lugging a rack system about and got one of the little jcm 2000 tsl 601 combos, good little amp nice with a 4x12 up graded to a tsl 100h now that was a good amp
You are indeed a master of the art. In 35 years of working on electronic and mechanical devices I have never once picked the correct size tool by eye the first time ;)
I have a JMP-1 and one of the main reasons you lose the locknut on the 1/4 inch jacks is precisely because the thread pitch is so coarse. The shallow pitch facilitates the nut working loose. Use locktite blue to stop it from occurring.
The bad valve had very mismatched triodes I noticed when you retested it a 2 and a 9 I think . The Orange tester fails valves with more than a 5 digit mismatch I believe because it is a severely unbalanced tube .
I have 2 JMP-1 preamps, the first one, if I put my Midiverb IV in the FX loop, every so often the delay effects will just cut out. I have to restart the JMP-1 to get the delays back. both of mine are in dire need of a service, as I use them on a daily basis. Great to connect with a JMP-1 repair video,
I had the same problem. I bought one on Reverb, and it was missing the nut and bezels for the input and headphone in. I got black replacements from Plasma music in England. Took a couple weeks to arrive here in the US, but fit perfectly.
Once again, a very intresting video! You have a self made tester voor power amps? Maybe a good item for another intresting video? Continue the good work!
You don't need to remove the gold front panel to remove the lid. Just remove three screws at the back, one on top, then the six holding the rack ear reinforcers on and the lid will come off.
I have a pedal with a tube preamp, and I wouldn't be surprised if the tube were completely dead and the user didn't notice. Switching channels, you never really know if you are on tube preamp or solid state. You might get one used and have some channels that just scream or show show some other issue and simply never use it. And the heart of the problem might be a microphonic or bad tube and you just never address it. Tubes can show their ugly faces in alot of ways, be fine in one position, but move it to pushing your reverb or phase invertor and be a complete failure. This guy might get back his rig and find it has alot more to offer that he was ever aware of.
Use a dremel tool to make a slit into the screw and use a flat screwdriver to get it out... So easy instead of drilling and you are not gonna damage something as fast as with a drill.
The reason it rejected the valve was the very poor balance between the sides.. Man of no faith ...One side 2 the other side 9 ... The tester is quite good . I ave checked it against my At1000 and it was actually better !!
I had one of these, I took it to Marshall for an intermittent fault, they did a repair service on a Friday, so I booked a factory tour as well! They couldn't trace the fault ( it cut out randomly) and they had it on the bench for a week, so what they did was order a complete board with my name on it! And run it through the factory (they work the lean system) so I got a brand new preamp apart from the case ! And as they couldn't locate the fault on the day they only charged...... wait for it.....£40 labour!!! What incredible service, had a brilliant time , got my amp fixed and a factory tour!! I finally got peed off lugging a rack system about and got one of the little jcm 2000 tsl 601 combos, good little amp nice with a 4x12 up graded to a tsl 100h now that was a good amp
Glad to see you're keeping it real. Thanks for the video on the jmp1
You are indeed a master of the art. In 35 years of working on electronic and mechanical devices I have never once picked the correct size tool by eye the first time ;)
I have a JMP-1 and one of the main reasons you lose the locknut on the 1/4 inch jacks is precisely because the thread pitch is so coarse. The shallow pitch facilitates the nut working loose. Use locktite blue to stop it from occurring.
Good job! I love your videos.
Great videos. Just found you, i can see there is allot i need to see, ✊🏻👍🏻
The bad valve had very mismatched triodes I noticed when you retested it a 2 and a 9 I think . The Orange tester fails valves with more than a 5 digit mismatch I believe because it is a severely unbalanced tube .
Another trick with those stripped screws is to use a dremel and cut a small slot across the top, then use a flat head screw driver to remove it.
I have 2 JMP-1 preamps, the first one, if I put my Midiverb IV in the FX loop, every so often the delay effects will just cut out. I have to restart the JMP-1 to get the delays back. both of mine are in dire need of a service, as I use them on a daily basis. Great to connect with a JMP-1 repair video,
I had the same problem. I bought one on Reverb, and it was missing the nut and bezels for the input and headphone in. I got black replacements from Plasma music in England. Took a couple weeks to arrive here in the US, but fit perfectly.
Splendid . On kung fu .. Bruce Lee was the catalyst for the craze .. I queued an hr to see Enter the dragon 🐉 .Happy days 😃
Once again, a very intresting video! You have a self made tester voor power amps? Maybe a good item for another intresting video? Continue the good work!
You don't need to remove the gold front panel to remove the lid. Just remove three screws at the back, one on top, then the six holding the rack ear reinforcers on and the lid will come off.
I have a pedal with a tube preamp, and I wouldn't be surprised if the tube were completely dead and the user didn't notice. Switching channels, you never really know if you are on tube preamp or solid state. You might get one used and have some channels that just scream or show show some other issue and simply never use it. And the heart of the problem might be a microphonic or bad tube and you just never address it. Tubes can show their ugly faces in alot of ways, be fine in one position, but move it to pushing your reverb or phase invertor and be a complete failure. This guy might get back his rig and find it has alot more to offer that he was ever aware of.
I'm afraid I have to totally disagree with you on this one Stuart...
Why isnt that unit reparable ? The ADA MP-1 (JMP-1 "brother") had several guys reparing it.
Use a dremel tool to make a slit into the screw and use a flat screwdriver to get it out... So easy instead of drilling and you are not gonna damage something as fast as with a drill.
The reason it rejected the valve was the very poor balance between the sides.. Man of no faith ...One side 2 the other side 9 ... The tester is quite good . I ave checked it against my At1000 and it was actually better !!
I had the single valve version. I cheated on me and went home with someone else after a gig. Sadness.
We call mole grips vice grips in america...lol