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Post by jdcox3333 on Apr 29, 2017 13:34:31 GMT -7
I have a very low (but audible) hum coming from the Maz. Is it normal or is there something I should be looking at?
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Post by benttop (Steve) on Apr 30, 2017 5:32:28 GMT -7
Well I don't hear anything on that video other than the sound of the standby switch. Pull the PI tube - does the hum disappear? If so, it's probably a preamp tube. If not, you might need to replace the power tubes. Check the troubleshooting on the Z Amps site too: drzamps.com/info/faq-troubleshoot/
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Post by KeithA on Apr 30, 2017 5:38:38 GMT -7
Well I don't hear anything on that video other than the sound of the standby switch. Pull the PI tube - does the hum disappear? If so, it's probably a preamp tube. If not, you might need to replace the power tubes. Check the troubleshooting on the Z Amps site too: drzamps.com/info/faq-troubleshoot/I couldn't hear the hum at first either, but upon putting the iPad speaker closer to my ear I could hear it.
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Post by jdcox3333 on Apr 30, 2017 9:30:50 GMT -7
I know it's kinda hard to hear... So, I've tried swapping all the tubes with a known good set I have. Installed a new rectifier tube. Tried removing the PI tube and the hum is still there. Is this a "normal" hum of this amp? I can't remember it being there when I first got it. Any ideas are welcome. Thanks
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Post by benttop (Steve) on Apr 30, 2017 12:43:18 GMT -7
I know it's kinda hard to hear... So, I've tried swapping all the tubes with a known good set I have. Installed a new rectifier tube. Tried removing the PI tube and the hum is still there. Is this a "normal" hum of this amp? I can't remember it being there when I first got it. Any ideas are welcome. Thanks Well that indicates power amp or power supply. How old is your Maz? My 38 NR was very quiet, so I would say no, it is not "normal" to have any hum. But you may be more sensitive than I am (or your hearing may be better - in fact, I'm certain it is). If it's an older Maz, you may need updated filter caps in the power supply. If it's a newer Maz, I'm still thinking power tubes. You may have got a bad one in a new set.
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Post by jdcox3333 on May 17, 2017 14:08:21 GMT -7
Well... It was bad rectifier and power tubes. Thanks for the help!
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Post by BritInvasion on May 17, 2017 18:47:59 GMT -7
Maybe the bias has drifted. Possibly a resistor has aged and gone out of spec.
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