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Post by birthofahero on Sept 23, 2015 15:14:19 GMT -7
Please check out this short video I made. Also notice when I flip the standby how much noise is being made. Then the obvious noise when I turn up the master. I love this amp so much and I'm deathly afraid it is toast.
Edit: is the video link appearing? It won't show for me on mobile.
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Post by DRZ on Sept 23, 2015 15:35:07 GMT -7
Though I'm not sure what is wrong, I can assure you your amp isn't toast. Did it just start doing that with no warning issues? What was the last thing you changed on the amp? Try swapping V5 the Phase inverter any good 12AX7 will do for this test. Z
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Post by birthofahero on Sept 23, 2015 15:42:35 GMT -7
Though I'm not sure what is wrong, I can assure you your amp isn't toast. Did it just start doing that with no warning issues? What was the last thing you changed on the amp? Try swapping V5 the Phase inverter any good 12AX7 will do for this test. Z
Thank you for such a quick reply Doc! Always a comfort to know you care so much about every amp you produce. About a year ago, it just started making the noise. It's been at our rehearsal space ever since and I got way too busy to try and fix it. I'll swap the PI tube out and report back.
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Post by birthofahero on Sept 23, 2015 17:28:54 GMT -7
Switching out the PI tube did nothing. If you tap on the top of the cab, it will make a popping noise like there is a bad connection somewhere. Perhaps a loose tube, but they are all inserted as good as they can be.
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Post by pcns on Sept 23, 2015 17:37:08 GMT -7
You might try pulling all the tubes and reseting them. A small amount on electronic cleaner could help too. If you tap on the top of the cab and it's making noise could a tube on its way to going out. You could do the pencil tap test on each tube to which one it making noise.
The Doc certainly does care about his amps!
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Post by birthofahero on Sept 23, 2015 17:53:35 GMT -7
You might try pulling all the tubes and reseting them. A small amount on electronic cleaner could help too. If you tap on the top of the cab and it's making noise could a tube on its way to going out. You could do the pencil tap test on each tube to which one it making noise. The Doc certainly does care about his amps! If I were to replace the EL84's could I do it on a tube by tube basis, or would I have to get a matched quad?
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Post by heynewguy (Ol’ Bill) on Sept 23, 2015 18:15:49 GMT -7
Matched quad.
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Post by DRZ on Sept 24, 2015 5:23:08 GMT -7
The more I listen the less I think it is a tube, unless it is very sick EL 84. Try that next exchange the quad .
If that doesn't do it I'm thinking a broken lead on the main filter cap, which is mounted on the board. Kind of unusual to have this failure on an amp that does move, and sits in a rehearsal room. A gut shot of the board might help as it will be very obvious.
Beyond that the 13 year old amp will need to be looked at.
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Post by birthofahero on Sept 24, 2015 22:59:47 GMT -7
The more I listen the less I think it is a tube, unless it is very sick EL 84. Try that next exchange the quad .
If that doesn't do it I'm thinking a broken lead on the main filter cap, which is mounted on the board. Kind of unusual to have this failure on an amp that does move, and sits in a rehearsal room. A gut shot of the board might help as it will be very obvious.
Beyond that the 13 year old amp will need to be looked at. This is ultimately what I want to do. Send it in for a tune up, however I just don't have the funds to ship my amp and pay for a repair. Perhaps soon tho. Do you mind telling me what a typical tune up would cost?
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Post by DRZ on Sept 25, 2015 3:35:52 GMT -7
Hard to give an exact cost of repair/tune-up, but I could safely say a couple hundred dollars for tubes, parts , labor, and return shipping. Z
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Post by fishman on Oct 2, 2015 7:52:18 GMT -7
I have had the pleasure of the Z guys working on some of my Z amps...they always come back better than they ever were. They don;t just "fix" it..they go thru it, update parts and dial it in the X ring...Just my opinion but I wouldn;t take one of my Z'z to any one but the Z guys. Until Z comes up with a certification program for his dealers and their techs I just won;t let it go to anyone else. I don;t believe that Z makes a killing on repairs..I am sure he covers costs and makes some profit or else it would not work. Going by what it has cost me in the past compared to what amp guys around here (there are none-have to go to VT. to find a good one) Z is more than reasonable, service is 100%, and its fixed once, and fixed right. If you want your amp to be as good as it can be its a no brainer to send it to the people who built it. You won;t regret it and your amp will be better than it was new.
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Post by jimmysmith on Oct 6, 2015 19:20:07 GMT -7
i second this,,,, fast turn around times,, 200 bucks may seem like a lot, but for a 13 yr old amp, that is LOW. i attest they will do you right... i bought a real harry joyce 100 watt amp, new, (from chassis made by harry joyce and given to an amp maker here in the US who i wont name,, but the main solder joint was bad, went bad, etc,, who knows,, easy fix, but i dint know at the time, had a tech in tulsa who has passed on now, but, it definitely is something minor. i have owned a 38 about that time period.
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Post by birthofahero on Oct 8, 2015 13:15:01 GMT -7
Thanks for the confidence in sending my amp in for repairs. I just got a new job so hopefully I will be able to afford it in the near future. I ordered a matched quad set of EL84's to see if that helped, it didn't. Although, I think I managed to find the problem. The tube I am pointing to in this picture: It is loose or something. Because when I move it, it will stop making the god awful noise, but when I start playing and the amp vibrates, it comes loose I think and starts making that noise again. I don't have another "good" tube to throw in there to test if it's the tube itself but I'm wondering if the connectors have come loose and if it's something I can fix myself. Hopefully this made sense. I'm trying everything I can to troubleshoot this as much as possible before sending it off.
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Post by birthofahero on Oct 8, 2015 13:21:54 GMT -7
CORRECTION: The noise stops when I jiggle the second pre amp tube from the right.
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Post by headshrinker (Marc) on Oct 8, 2015 16:55:04 GMT -7
Swap the tube that you think is the problem with the one closest to the power tubes. Then jiggle the one now in the socket that made a noise before. If it stops, it is likely (not positively) the tube that was in there. The last tube before the power tube is the phase inverter and is less affected by a noisy tube than the others. You could also swap the tube that is in the first socket with the one in the second. If the problem is now with the first socket tube, again likely that tube. I would do both. The basic idea is to see if the problem moves with the tube or stays with the socket. If it's the socket, it is likely you just have to retension the tube guides in the socket. Not a hard job. See if that's the problem. If it is, one of us will jump in and explain how you can retension them.
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