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Post by kdridnour on Jul 6, 2021 16:26:17 GMT -7
I was playing my Z Plus and turned it off for a minute , turned it back on and no sound! I took off the tube shields to see if one tube wouldn`t light up but they all do! Any suggestions? Thanks in advance!
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Post by Jaguarguy (Mike) on Jul 6, 2021 16:36:04 GMT -7
Do you have a spare rectifier (a 5AR4)? Try replacing the existing rectifier. Also, check to make sure your cables are fully plugged in. It might help to watch Doc's trouble shooting video.
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Post by mrcapers on Jul 6, 2021 16:56:28 GMT -7
Funny, the same thing happened to me with the Jetta. Turned it off at practice, then we decided to do one more song. Turned it on then nothing! Took it home, plugged it in and it worked fine. Been fine ever since. Probably not your issue, but really strange.
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Post by kdridnour on Jul 6, 2021 16:57:11 GMT -7
I watched Dr Z video but my fuse is good! The amp lights up , all the tubes , just no sound! I bought the Plus about a year and a half ago and the guy I bought it from didn`t use it much and neither do I!
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Post by kdridnour on Jul 6, 2021 17:03:58 GMT -7
I use to mess with Fender Blackface Reverb combos! I`d move around 12AX7`s! Can I move around the tubes? I`ll have to check out the preamp tube chart!
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Post by kdridnour on Jul 6, 2021 17:14:19 GMT -7
I see the tube chart! I have the amp set on Half Power and I use the Lo input , I play in the bedroom and the amp can get plenty loud with those settings. There are 5 preamp tubes 1-12ax7 2-12AX7 3-12at7 4-12axy 5-12ax7. Can I AB these 12ax7`s and see if I can get it to work? Switch tube 1 for tube 5? I know if it the 12AT7 I`m out of luck but got I to start somewhere!
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Post by premiumplus (Dave) on Jul 6, 2021 17:23:05 GMT -7
Sure, you can move them around, but unless the issue is because of a tube pin not making contact in the socket you'll still have a bad tube...just in a different position. Assuming your problem is a tube, which 99% of problems are. Don't you have a known good 12AX7 that you could replace the tubes with, one at a time? That would eliminate preamp tube problems. Another thing to try is plugging a guitar cable between the send and return jacks of the loop. Sometimes those switching jacks get oxidized and can cause a loss of signal.
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Post by "Z" Steve on Jul 6, 2021 18:25:55 GMT -7
Sure, you can move them around, but unless the issue is because of a tube pin not making contact in the socket you'll still have a bad tube...just in a different position. Assuming your problem is a tube, which 99% of problems are. Don't you have a known good 12AX7 that you could replace the tubes with, one at a time? That would eliminate preamp tube problems. Another thing to try is plugging a guitar cable between the send and return jacks of the loop. Sometimes those switching jacks get oxidized and can cause a loss of signal. Thus the name "Premiumplus!" Dave is spot on! Keep us updated re what you find out!
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Post by kdridnour on Jul 6, 2021 19:37:36 GMT -7
I moved some 12AX7`s in different spots but no luck! I may have to take it in!
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Post by j4gitr (John) on Jul 6, 2021 21:11:18 GMT -7
Did you check the rectifier as Mike suggested? Many years ago I had a Maz18 do the same thing. Fuses were fine, just no sound. An email to headquarters and Doc suggested replacing the rectifier and voila; all was well. Good luck
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Post by kdridnour on Jul 7, 2021 4:36:27 GMT -7
Thanks Dave! I`ll do that today!
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Post by kdridnour on Jul 7, 2021 5:01:47 GMT -7
Owning blackface amps I’ve never had a problem with a Recifer tube , I’ve always thought they work or they don’t! Mine lights up so I’ve thought the problem is something else! Could it still be The rectifier even though it lights up?
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Post by premiumplus (Dave) on Jul 7, 2021 5:21:45 GMT -7
Owning blackface amps I’ve never had a problem with a Recifer tube , I’ve always thought they work or they don’t! Mine lights up so I’ve thought the problem is something else! Could it still be The rectifier even though it lights up? Just lighting up doesn't mean the tube is good at all. It only means that the filament is heating.
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Post by kdridnour on Jul 7, 2021 5:40:24 GMT -7
Thanks! I’ll have the rectifier tube checked out today!
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Post by DRZ on Jul 7, 2021 7:27:52 GMT -7
OK let me jump in. Most of the time if a rectifier fails or a power tube fails it will blow the fuse. This didn't happen . Turn the amp on turn up the Master Volume and put your ear to the speaker. Do you hear the amp breathing , or is dead quiet like its in Stand-By ? If you hear a little electronic noise then the rectifier is good. And probably the 6V6's are as well , try the Single /Parallel switch to test the 6V6's. My best guess is a pre-amp tube, get one good 12AX7 and try it one at a time in each pre-amp slot. If that doesn't work you have a very unusual problem , turn off a working amp , then turn back on in a few minutes and it doesn't work. Not your typical failure . No one will be able to tell you online , " Oh yeah change resistor R5 " . This will need to be benched if it's not just a failed tube which I believe it is.
This is a used amp so you really do not know its true history.
DR.Z
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Post by kdridnour on Jul 7, 2021 8:40:49 GMT -7
Thanks Dr.Z , always good to hear from you!
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Post by kdridnour on Jul 7, 2021 10:22:46 GMT -7
Dr.Z and everybody , it was the Rectifier tube! I turned up the master volume and listened to hear something but didn`t and then looked at the rectifier and it didn`t look like it was lighting (before I thought it was) up! So I put a JJ GZ34 in and now I`m back in business. The bad rectifier was a Sovtec but all the other tubes preamp and 6v6`s are JJ`s! Thanks everyone for your input!
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Post by purpletele on Jul 7, 2021 17:02:49 GMT -7
Dr.Z and everybody , it was the Rectifier tube! I turned up the master volume and listened to hear something but didn`t and then looked at the rectifier and it didn`t look like it was lighting (before I thought it was) up! So I put a JJ GZ34 in and now I`m back in business. The bad rectifier was a Sovtec but all the other tubes preamp and 6v6`s are JJ`s! Thanks everyone for your input! Kdridnour, The JJ GZ34 with the Z-Plus will cause issues!!! I speak from experience. Please order the Shu Guang 5AR4 or an NOS Rectifier right away. The JJ rectifier doesn't take the start up voltage and it can blow a fuse and cause confusion and issues.
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Post by premiumplus (Dave) on Jul 7, 2021 17:10:22 GMT -7
Does the JJ GZ34 perform differently than another brand of GZ-34? I thought the GZ-34 was the British designation of the 5AR4.
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Post by purpletele on Jul 7, 2021 22:08:03 GMT -7
Does the JJ GZ34 perform differently than another brand of GZ-34? I thought the GZ-34 was the British designation of the 5AR4. Dave, Yes, the JJ GZ34 does perform differently than others. I had to take my amp to Ben Fargen to figure out the issue. Spoke with Z via email and he confirmed that the Z-Plus has a significant jolt at start up and the JJ Tubes don't respond well resulting in an Event. I put a nice GE NOS rectifier in my Z-Plus and haven't had an issue. Also, take a look at the rectifiers that are recommended for each amp. How often do you see the Shu Guang 5AR4 recommended?
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Post by premiumplus (Dave) on Jul 8, 2021 1:07:22 GMT -7
Does the JJ GZ34 perform differently than another brand of GZ-34? I thought the GZ-34 was the British designation of the 5AR4. Dave, Yes, the JJ GZ34 does perform differently than others. I had to take my amp to Ben Fargen to figure out the issue. Spoke with Z via email and he confirmed that the Z-Plus has a significant jolt at start up and the JJ Tubes don't respond well resulting in an Event. I put a nice GE NOS rectifier in my Z-Plus and haven't had an issue. Also, take a look at the rectifiers that are recommended for each amp. How often do you see the Shu Guang 5AR4 recommended? Thanks for the info, Brian. I'm always learning and it's interesting that JJ has tubes with different characteristics than what they were originally spec'd with. Take the JJ 6V6; it's more like a 6L6 than a 6V6 in plate voltage, for instance. It's a lot more tolerant of higher voltages.
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Post by kdridnour on Jul 8, 2021 10:34:06 GMT -7
Dr.Z and everybody , it was the Rectifier tube! I turned up the master volume and listened to hear something but didn`t and then looked at the rectifier and it didn`t look like it was lighting (before I thought it was) up! So I put a JJ GZ34 in and now I`m back in business. The bad rectifier was a Sovtec but all the other tubes preamp and 6v6`s are JJ`s! Thanks everyone for your input! Kdridnour, The JJ GZ34 with the Z-Plus will cause issues!!! I speak from experience. Please order the Shu Guang 5AR4 or an NOS Rectifier right away. The JJ rectifier doesn't take the start up voltage and it can blow a fuse and cause confusion and issues. purpletele , I decided to order a Shu Guang 5AR4! I switched to Dr,Z amps because being a Fender Blackface guy , I just didn`t want to have an amp breaking down on me anymore!
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