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Post by modernfiction on Jan 18, 2021 18:59:54 GMT -7
I have a 1x10 Monza I just picked up and it has an brake lite and a master volume mod on it. I was trying to push it by opening the master all the way and bringing the volume up and it started Feeding back, so I rolled the guitar volume off and it kept feeding back.
I completely unplugged anything from the input and it would start feeding back the same. Eventually I noticed even with the master all the way down but not off, when the volume got to about 1:00 the amp would start screaming like a feedback.
I'm completely stumped on why it would be doing this?
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Post by DRZ on Jan 18, 2021 19:09:02 GMT -7
Best guess V1 preamp tube is microphonic.
Z
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Post by modernfiction on Jan 18, 2021 19:32:36 GMT -7
Hey Doc! I did swap out the preamp tubes and even went and swapped all of the tubes and got the same result.
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Post by Jaguarguy (Mike) on Jan 18, 2021 19:53:23 GMT -7
Here's Doc's trouble shooting video - usually help me when I have an issue.
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Post by DRZ on Jan 19, 2021 3:40:41 GMT -7
Hey Doc! I did swap out the preamp tubes and even went and swapped all of the tubes and got the same result. Well then I'm not sure of the cause, from your description I would say a bad pre-amp tube. This is not a typical problem with Monza's though they are high gain little amps. I guess I would have to bench it to solve the issue. Can you ask the previous owner you bought it from for some insight ?
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Post by pcns on Jan 19, 2021 7:25:26 GMT -7
Hey Doc! I did swap out the preamp tubes and even went and swapped all of the tubes and got the same result. it wouldn't be the first time that a replacement tube was bad too. They don't make 'em like they used too
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Post by modernfiction on Jan 19, 2021 7:28:13 GMT -7
I wish I could Doc, I picked it up from Guitar Center though, so the previous owner is a mystery.
The master volume mod is done as a knob in place on the on/off switch, which I thought was unique, curious myself if this was done by the Z shop or somewhere else since I haven't seen these modded like that before.
The amp sound amazing nonetheless, only stumbled upon this trying to see if the max volume could run with a full band unmic'd.
If that mod sounds uncommon for you shop, could be the issue. I think anyway I'll have to have the beauty sent down to you for a once over at some point.
Really appreciate the help! It's awesome having direct contact with the company.
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Post by pcns on Jan 19, 2021 7:40:40 GMT -7
I wish I could Doc, I picked it up from Guitar Center though, so the previous owner is a mystery. The master volume mod is done as a knob in place on the on/off switch, which I thought was unique, curious myself if this was done by the Z shop or somewhere else since I haven't seen these modded like that before. The amp sound amazing nonetheless, only stumbled upon this trying to see if the max volume could run with a full band unmic'd. If that mod sounds uncommon for you shop, could be the issue. I think anyway I'll have to have the beauty sent down to you for a once over at some point. Really appreciate the help! It's awesome having direct contact with the company. its very cool that the man himself steps in to answer questions
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Post by bubs42 on Jan 19, 2021 11:47:34 GMT -7
Both of those Monza's on GC's site had been modded. So you didn't buy the one with the extra switches on the back did you? That one was FS in Iowa for a while then ended up at GC for sale. I think it had a MV and Pent/Tri mode on the back.
I"m not an expert, but could it just be your guitar? That amp full out would be super hot anyway and if you pushing any kind of gain your going to get feedback. If your using anything in front of it like an OD then your compounding the likelihood of feedback.
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Post by modernfiction on Jan 19, 2021 12:01:10 GMT -7
That's the crazy thing, with nothing plugged into the amp it and the master at 0, as I turn up the volume knob it starts feeding back at about 1:00.
I even popped in 2 new gold lion 12ax7s and got the same result... Bizarre.
It was the little red combo with the white knob in place of the on switch... Which makes me question who did the MV mod... Might be the culprit.
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Post by adam on Jan 19, 2021 17:55:44 GMT -7
A couple things in your favor here. #1, if you don't want it, you can return it to any GC within 30 days I think. #2, you can send the amp to Z and have the experts fix it. That is one of the super cool things about Z.
I was going to say check your cable. Sometimes they can do really funny things. Maybe try it with another cable rather than no cable and see what happens. I once did a gig with a bassist and he couldn't figure out why he didn't have any low end and it turned out to be the cable. No clicks or pops or volume changes, just something partially shorted or something. Second experience was recent, had a lifelines cable which has an amp end and guitar end, and that was feeding back. Turned the cable around backwards from what it was supposed to be and the problem went away. And tubes, the replacement could be bad or you could have 2 bad or whatever. I guess plugins are good for something.
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