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Post by prsnstrat on Jun 8, 2006 7:50:19 GMT -7
Hi fellow Z owners, I have a problem with my Maz Jr. 1x12 combo. Last night after playing for a couple hours, all of a sudden I got a really loud buzz that kept getting louder and louder, so I had to frantically turn the amp to standby! I turned the amp off, tried again, and same result! I did notice that when I fiddled with the reverb knob quick while the amp was on the noise seemed to change frequency...?? Weird. Does anyone have any ideas or experienced this with their amps?? THanks in advance for any information!!
Sincerely,
Brandon
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redgl
Junior Member
Posts: 62
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Post by redgl on Jun 8, 2006 8:18:48 GMT -7
Check the connections from the reverb tank on the chassis. One may be loose.
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Post by prsnstrat on Jun 8, 2006 8:38:54 GMT -7
Thank you for the suggestion redgl. I will try that asap and report back.
Brandon
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Post by myles on Jun 8, 2006 9:01:44 GMT -7
If it was a hum you may have lost one of your output tubes.
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Post by prsnstrat on Jun 8, 2006 11:22:35 GMT -7
It's more like a really loud buzz. It has some hum as well, but more of a loud buzz. I tried the reverb tank connectors but that didn't seem to make a difference in this case. However I did not do anything to the plugs on the tank side, just where they plug into the amp.
I emailed Z about it and he mentioned that it sounds like an output tube to him as well. Brand new JJ's!! If it is the output tube that is a tough one to swallow.
Thanks again everyone.
Brandon
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Post by kruzty on Jun 8, 2006 11:26:03 GMT -7
I emailed Z about it and he mentioned that it sounds like an output tube to him as well. Brand new JJ's!! If it is the output tube that is a tough one to swallow. Thanks again everyone. Brandon Where did you get them? Many places with replace within a certain number of days.
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Post by billyguitar on Jun 8, 2006 11:29:24 GMT -7
Pull the connections for the reverb off of the chassis, keep track of them so you can put them back on correctly. The output tube is the most likely suspect.
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Post by myles on Jun 8, 2006 11:32:52 GMT -7
It's more like a really loud buzz. It has some hum as well, but more of a loud buzz. I tried the reverb tank connectors but that didn't seem to make a difference in this case. However I did not do anything to the plugs on the tank side, just where they plug into the amp. I emailed Z about it and he mentioned that it sounds like an output tube to him as well. Brand new JJ's!! If it is the output tube that is a tough one to swallow. Thanks again everyone. Brandon Brandon, If it is one of Z's stock GT EL84S tubes that he uses these would be covered and replaced under the GT warranty. If this is the case call Patrick at 1-800-459-5687 and he will replace the tubes if less than three months old or in the case of preamp tubes the warranty is six months.
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Post by prsnstrat on Jul 18, 2006 7:58:32 GMT -7
Well, here I am a few weeks later, and still the buzz is haunting me when it feels like rearing it's ugly head. I'ts very loud and it's going on more often than not these days. Here's what I've tried so far to address the issue:
1. Replaced output tubes to a matched GT set...still buzzing
2. Replaced V3 with a brand new JJ 12AT7....buzzing
3. Unplugged reverb cables from chassis...uhgghh more buzzing.
4. Wiggled rectifier tube...buzzing
The only thing that is noteworthy or giving me any clues are that the buzz (it's loud by the way!) gets a bit quieter and changes frequency when I turn the reverb knob down all the way. Also it changes a bit when the reverb tank is disengaged...so that tells me the tank itself is probably still good...it's in the amp somewhere.
Any thoughts you guys given the information above?? The hardest part about this is that I recently purchased this from a guy on the Gear Page, and I haven't even gotten to gig with it yet! I truly love the amp and the sounds i'm getting...so you can probably feel my pain. Anyway, any insight I'd truly appreciate.
Thank you!
Brandon
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Post by billyguitar on Jul 18, 2006 8:50:30 GMT -7
It shouldn't buzz at all when you unplug the reverb cables from the chassis. If it was me, I'd take the chassis out and see if something is shorting the reverb cables inside the amp. My feeling is someting has come loose inside during shipping. IF YOU HAVE NO EXPERIENCE INSIDE AN AMP DO NOT DO THIS. There are voltages in an amp that can kill you dead even with the amp off and unplugged. I'm sure it's something relatively simple that's wrong but you probably better take it to a tech.
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Deleted
Deleted Member
Posts: 0
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Post by Deleted on Jul 18, 2006 12:14:04 GMT -7
This same thing happened to me when had my Boogie Blue Angel. Out of no where a loud buzz/hum that kept getting louder and louder. It turned out to be one of my preamp tubes. Take it to a tech and go through the other preamp tubes. If it is not that then I am sure the tech will figure out what is the problem.
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Post by billyguitar on Jul 18, 2006 13:14:27 GMT -7
NOW I notice that he didn't change out all of the preamp tubes. Just change them out with any old tube you know works. Then if no luck, off it goes to the shop! The 4th preamp tube is the reverb recovery you definitely have to check that one. If that's the 12AT7 you can still sub a 12AX7 just to see if the hum goes away, it won't hurt anything.
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Post by prsnstrat on Jul 18, 2006 14:29:28 GMT -7
Hi guys, thank you for the great input, i'll try them tonight. I'll post the results in the morning. Thanks again!!
Sincerely,
Brandon
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Post by BW on Jul 18, 2006 22:03:44 GMT -7
One more thing to look at--I had a friend's Senior over here once that was making a lot of racket intermittently, turned out one of the the wire clips that hold the EL84's in place was bent up under one of them and--very intermittently-- shorting 2 pins together. Make sure that none of the clips are bent up under the output tubes. Chances are you'd be blowing fuses if this was the problem, but its worth a look.
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Post by prsnstrat on Jul 19, 2006 7:31:18 GMT -7
Hi all, well, I don't want to speak too soon, but I think the culprit was the V4 preamp tube...reverb return? Ran it for a couple of hours with no buzz...I do have to say that out of this I discovered that I like the JJ output tubes just a wee bit better than the GT's, but they are both very good tubes. Thank you all for your help! I'll be revisiting this thread if this rears it's ugly ugly head again. Sincerely, Brandon
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Post by johnnyl on Jul 19, 2006 9:47:36 GMT -7
I'm pretty sure that GT's are JJ's but maybe someone else will verify. Glad to hear your back up & running!
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Post by Hohn on Jul 31, 2006 14:59:52 GMT -7
It shouldn't buzz at all when you unplug the reverb cables from the chassis. If it was me, I'd take the chassis out and see if something is shorting the reverb cables inside the amp. My feeling is someting has come loose inside during shipping. IF YOU HAVE NO EXPERIENCE INSIDE AN AMP DO NOT DO THIS. There are voltages in an amp that can kill you dead even with the amp off and unplugged. I'm sure it's something relatively simple that's wrong but you probably better take it to a tech. You can make a shorting lead for discharging capacitors from a high power-resistor and some extension wire. grab a big ceramic resistor with high resistance and power ratings, and connect one end to an alligator lead. Then you can discharge the hi-test caps (tube supply voltage) safely, and get a slow discharge at lower current instead of a lightning bolt of potentially fatal current. jlh
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