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Post by Tom the Guitar Guy on May 11, 2012 17:47:07 GMT -7
Ok, so I fired up my Mini Z that's been sitting on the shelf for a while.
The last time I played it, sounded great.
Now, I get this loud hum - even without a cable plugged into the instrument jack.
I thought it could be the cabinet (just built a cab w/ a 12" and 10" in it), so I hooked up another amp to the cab - no hum.
I even plugged the Mini into another cab, but still got the hum.
Any ideas of what it may be? I tried changing preamp and power tube with known good ones.
Any ideas would be appreciated. Thanks!
Tom
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Post by bluzman on May 18, 2012 10:45:50 GMT -7
I'd start by cleaning the input and speaker jacks along with the tube sockets. Visual check the sockets to make sure the pin connectors are where they should be.
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Post by Tom the Guitar Guy on May 21, 2012 6:49:00 GMT -7
Thanks! I will give it a check!
Tom
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Post by Tom the Guitar Guy on May 13, 2013 12:01:46 GMT -7
Well, it's been awhile since I checked back... Honestly, I put the Mini Z away for a while and as I was re arranging things, I "discovered" it and decided to play around with it.
I did do some jack cleaning, but I'm still getting a hum -
One thing I'm remembering is that I had recently (last year when I was first reporting the hum) swapped cabinets with another Z brethren - traded my 2x10 combo cab for his head cab (from the sticker it was a Z28 head cabinet). I don't recall getting any hum until I put the Mini Z into the head cabinet.
Any (other) ideas?
Thanks in advance!
Tom
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Post by Stan on May 13, 2013 12:25:45 GMT -7
try a different guitar to rule out guitar ~ ~
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Post by Tom the Guitar Guy on May 13, 2013 13:52:17 GMT -7
Stan,
Already tried several guitars. It hums even when nothing is plugged into input jack.
Thanks.
Tom
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Post by Stan on May 13, 2013 14:08:01 GMT -7
any changes in wiring in the house, or new gadget in the house or neighbors
i know i'm thinking outside the amp
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Post by Tom the Guitar Guy on May 13, 2013 19:32:36 GMT -7
Nope. No new toys (I wish!)...
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Post by freddieg on May 13, 2013 20:09:34 GMT -7
Did you try a new outlet or plug it in at a friends house by chance?
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Post by Tom the Guitar Guy on May 13, 2013 22:30:57 GMT -7
I've tried different outlets including one that had nothing else on it, but none of my other amps hum. I even tried it through my Furman Rack Mount Power Conditioner, so I'm thinking it is in the amp and not the electrical circuit. When I first got it, there was no hum though . . .
Thanks for all the suggestions, please keep them coming if you can think of anything else . . .
Tom
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Post by Tom the Guitar Guy on May 16, 2013 12:55:53 GMT -7
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Hummmm....
May 17, 2013 17:39:36 GMT -7
via mobile
Post by LuckyBlackCat on May 17, 2013 17:39:36 GMT -7
Have you contacted Dr. Z about the issue? I had a noise problem with my Mini and they were very helpful over multiple phone calls and emails, helping me troubleshoot.
At the end if the day it turned out to be a bad volume pot. I sent it in and had it back in less than two weeks, good as new.
Call them!
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Post by Tom the Guitar Guy on May 17, 2013 23:49:26 GMT -7
No, I haven't contacted them yet - kinda hoping someone could give me a good idea to try that would fix it.
Thanks!
Tom
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Post by "Z" Steve on May 21, 2013 8:47:17 GMT -7
Hey Tom - good to hear from you. Hope you're still entertaining the Inland Empire. Just for the heck of it did you try taking the chassis back out and seeing if the hum disappears? You noted that it started when you did the swap:
One thing I'm remembering is that I had recently (last year when I was first reporting the hum) swapped cabinets with another Z brethren - traded my 2x10 combo cab for his head cab (from the sticker it was a Z28 head cabinet). I don't recall getting any hum until I put the Mini Z into the head cabinet.
That could rule out the cab change at least. But I would shoot an email to the Z service dept with your notes and see what they say.
Best of luck - Steve
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Post by Tom the Guitar Guy on May 21, 2013 14:04:13 GMT -7
Hi Steve,
Yeah, still out and about! What about you?
I've contacted Z, but they've been pretty busy so they have not had a chance to answer me yet. I thought about the cab, but in that case, what would I need to do to fix the head cab?
Tom
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Post by DRZ on May 27, 2013 14:58:47 GMT -7
A tube swap would be a good idea. First a good 12AX7. then the EL-84, see what that does.
Z
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Post by Tom the Guitar Guy on May 27, 2013 18:19:28 GMT -7
Thanks Doc! I'll try the tube swaps and report back!
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Post by Tom the Guitar Guy on Jul 1, 2013 9:32:00 GMT -7
Replaced both tubes (on at a time). Still humming ~ no change in volume level of the hum with the tube swap.
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Post by LuckyBlackCat on Jul 1, 2013 17:35:20 GMT -7
I'd just send it in, they will fix you up and you will have peace of mind. My mini was making crazy sounds intermittently and it turned out to be a bad volume pot. I can't say enough good things about the Z support--Don, the guy I communicated with at length, in particular. He walked me through some extensive troubleshooting by phone before arranging to send it to the shop.
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