JTM 45 clone making clicking noise

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screamindemon

screamindemon

Well-known member
I got this JTM 45 I’m working on and when I take it off standby it is making this clicking noise. Sounds like the PT or maybe the filter cap over the PT.
I rewired the whole amp as it was a mess with bad solder joints everywhere. It was blowing fuses and burned one of the 350 volt wires come out of the PT to the rectifier tube (purple wire). I repaired the wire. It is not blowing fuses now and has 500 volts DC at the standby in the off position with only the rectifier tube installed. .
Also heater have 3.4 volts and -45v DC at pin 5 of v4 and V5 with the bias pot turned all the way clockwise no power tubes installed.

I tried to take a video but my phone is not working for some reason.
Can someone tell what the may be. Thinking maybe the PT is compromised.
Thanks
 
Here is a picture of the amp.
 

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Can you describe the clicking better? Without a video we don’t have much to go on. It could be a bad bias cap but that is literally a shot in the dark.
 
Does it make the sound with no guitar plugged in? Tried a different speaker cable?
 


Here is a video of the popping noise. I have not installed the power tubes, I am powering it up for the first time and I was afraid to proceed after hereing this.
 
screamindemon said:


Here is a video of the popping noise. I have not installed the power tubes, I am powering it up for the first time and I was afraid to proceed after hereing this.
Click to expand...

So this is just coming from the amp itself and not a speaker. That’s weird af. I really don’t know what that could be. Is there any physical vibration with the clicks? Did you try turning the lights off to see if there is some arcing you can’t see?
 
Yes just the amp not thru the speaker. There are no power tubes installed. I did not try turning out the lights, I will do that and see what happens.
 
OK, so I just figured it out. I turned the lights out as suggested and it is arking from the filter cap above the PT on the ground lug. That is like literaly the only connection i did not resolder.
I will try and resolder it and see what happens. I may just replace both can capacitors because They probubly took some abuse before it got to me.

Thanks for the help !
 
Actually it was acking from the positive terminal of the cap to the ground terminal.
Bad cap ?
Replace?
 
Just occurred to me...didn't I sell you a prototype 2-channel 100W Bogner XTC abortion many years ago? No panels, written in Sharpie, total 'garage build', but good iron, etc.

I would try another cap and just replace it if you think its necessary. But that still sounds strange that it would do that.
 
SpiderWars said:
Just occurred to me...didn't I sell you a prototype 2-channel 100W Bogner XTC abortion many years ago? No panels, written in Sharpie, total 'garage build', but good iron, etc.

I would try another cap and just replace it if you think its necessary. But that still sounds strange that it would do that.
Click to expand...
Are you in Orlando ? Is that what that was ? :p I still have it with aother mod in it.
 
I think i am going to just change Both cans and bias caps as well. This thing was abused !
 
Yep as soon as I heard it in your video I was going to say something high tension is arcing to ground/chassis. Glad you found it.

Odd it’s arcing across the cap terminals. That’s not normal. Replace the cap and make sure you rotate it so that the positive terminal isn’t near one of the attachment lugs to the chassis.
 
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