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Post by gfreak on Jan 27, 2019 17:05:47 GMT -7
My Z-Plus started making intermittent static noise, even with no guitar plugged in(stand by is off.) I tapped the preamp tubes and the 12AT7 was microphonic. Replaced the tube but I still got the static. So I replaced the V1 and V2 and the static noise went away. The problem now is if I turn the reverb up to 3 o'clock on the dial it starts to feedback. 2 o'clock is fine and I can play all day. I tried 3 different 12 AT7's with the same result. I even swapped the 12AT7 from my Maz 8, which I can turn the reverb up all the way with not feedback.
What can be causing the feedback? I rarely turn the reverb up past 9 o'clock on the dial. Noon is a lot of reverb for me, so it is not that big of a deal but it bothers me.
Thanks for any help.
Rich S
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Post by purpletele on Jan 27, 2019 18:02:01 GMT -7
Gfreak,
You may need to try a 12Ay7 or a 5751 in V1. Just a thought. Maybe a 12AY7 in the phase inverter position.
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Post by DRZ on Jan 28, 2019 1:24:01 GMT -7
Rich, why don't you contact Don in the repairs dept. repairs@drzamps.com he can guide you through some tests of your Z Plus. My feeling is it's not a tube causing the feedback but a faulty reverb tank.
Z
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Post by gfreak on Jan 28, 2019 8:22:20 GMT -7
Thanks! I sent him a email.
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Post by gfreak on Jan 29, 2019 14:10:31 GMT -7
Had some time today so I put the Z-Plus back to back with the Maz8 and plugged in the Maz8 reverb tank into the Z-Plus. I cranked the reverb and there was no feedback!
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Post by purpletele on Jan 29, 2019 14:12:03 GMT -7
Had some time today so I put the Z-Plus back to back with the Maz8 and plugged in the Maz8 reverb tank into the Z-Plus. I cranked the reverb and there was no feedback! I was curious about that. Easy fix!!
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Post by simpleton on Jan 29, 2019 14:25:31 GMT -7
My Z Verb has had a similar issue.... need some tubes first but now I know about the tank idea as well.
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