|
Post by "Z" Steve on Feb 29, 2024 7:51:53 GMT -7
My Maz 8 combo is producing a fairly loud humming noise when there is nothing plugged into it. I've replaced each tube one at a time twice to make sure it isn't tube related, and when turning the amp on or off of standby the noise will increase then decrease (but still there). I moved the amp to another location in the house with no change, and my Cure sits next to the 8 while making no noise at all.
I appreciate any thoughts and/or suggestions! Steve
|
|
|
Post by dcarver on Feb 29, 2024 11:29:30 GMT -7
Hi Steve
Could it possibly be a grounding issue? Have you tried Docs yearly maintenance suggestions (great AMA for that). ie: clean the pots with Deoxit and re snug the nuts.
Have you taken the chassis out and looked for a toasted resistor, or a swollen cap, or something else that looks suspicious ? Maybe a lead on one of the caps has broken.
If it's not tubes, and it's not corrosion or a bad ground somewhere, it seems like it would probably be a worn out component, or bad connection somewhere.
Good luck. Let us know what you find. Cheers DC
|
|
|
Post by frankie on Feb 29, 2024 12:04:05 GMT -7
My Maz 8 combo is producing a fairly loud humming noise when there is nothing plugged into it. I've replaced each tube one at a time twice to make sure it isn't tube related, and when turning the amp on or off of standby the noise will increase then decrease (but still there). I moved the amp to another location in the house with no change, and my Cure sits next to the 8 while making no noise at all. I appreciate any thoughts and/or suggestions! Steve Steve, does it track with the volume knob (as in get quieter or louder as you turn it)? I will second making sure grounds are secured on the pots and jacks with a socket wrench. Especially the input jack.
|
|
|
Post by "Z" Steve on Feb 29, 2024 12:46:51 GMT -7
It only becomes louder when taken off of standby, otherwise it stays the same. I will pull the chassis out to see if there's anything obviously looking wrong or bad as well as check for loose connections or hardware.
Thanks Frankie & DC. I will update with my findings!
|
|
|
Post by "Z" Steve on Feb 29, 2024 18:09:43 GMT -7
I pulled out the chassis and the only thing that was visible was a burnt spot on the board where I had a 2 resistors give up the ghost about 7 years ago, and I sent it into the shop for Don to repair. I DeOxed the tube sockets and input jacks and made sure all the nuts and bolts were tightened. Unfortunately, there was no change as far as the noise, but all other maintenance was completed! I did record the noise, but the file is too large on my new Samsung phone to send without trimming. I will wait to hear from Don re my email and play it over the phone for him.
Thanks again!
|
|
|
Post by premiumplus (Dave) on Mar 13, 2024 9:48:08 GMT -7
The input jack has a set of contacts on it that ground the input when there's nothing plugged into the jack. Sometimes those contacts get oxidized and won't properly ground the input, and the amp hums.
I use a strip of paper maybe 1/4" wide that is soaked in DeOxit or some other contact cleaner, and put it between the contacts with a plug in the jack. Remove the plug and then pull the paper through the contacts. Hope this helps.
|
|
|
Post by "Z" Steve on Mar 13, 2024 10:35:57 GMT -7
The input jack has a set of contacts on it that ground the input when there's nothing plugged into the jack. Sometimes those contacts get oxidized and won't properly ground the input, and the amp hums. I use a strip of paper maybe 1/4" wide that is soaked in DeOxit or some other contact cleaner, and put it between the contacts with a plug in the jack. Remove the plug and then pull the paper through the contacts. Hope this helps. Thanks Dave, I will try that. I am currently not playing much electric since I've moved, and I have my Cure if needed so I'm not too pressed re the "fix", but I still like to maintain my gear so I'm ready if/when the call comes in!
|
|
|
Post by "Z" Steve on Mar 13, 2024 11:05:38 GMT -7
So, I tried what Dave suggested, but now the hum is only on the Triode setting, not Pentode. I traded out the power amp tube while doing my 1st trouble shoot and the noise was obvious in both settings.
|
|