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Post by Rhythmark on Jan 31, 2018 22:51:30 GMT -7
Need some advice I just bought a preowend 2017 DR. Z Zlux- There is a LOUD hum/buzz coming from the amp. If I pull V-3 ( 3rd from the right preamp tube) the buzz is gone. Tremolo still is fine amp is quiet.of coarse reverb doesn't work. So i assume thats a reverb tube. I tried some various tubes I have around but all of them buzzed - not the tube - the noise is coming out the speaker. So is something wrong with the tube plug or is there a magic tube I need ? I have a jan 12 AT7 philipsecg - and its bad noisy.
should I buy a new tube to solve this or should I consider returning this amp? Any help would be great!
Oh and its louder in 40w than 20w. as to be expected. thanks!!!
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Post by DRZ on Feb 1, 2018 4:15:15 GMT -7
The Z Lux reverb should not hum under normal operation. Check the footswitch as the Reverb connection must be a shielded wire or it will hum. Also check the RCA cables from the chassis to the reverb tub and make sure they are tightly connected. Did the seller report this problem? If not contact him and inquire.
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Post by Rhythmark on Feb 1, 2018 6:18:11 GMT -7
The Z Lux reverb should not hum under normal operation. Check the footswitch as the Reverb connection must be a shielded wire or it will hum. Also check the RCA cables from the chassis to the reverb tub and make sure they are tightly connected. Did the seller report this problem? If not contact him and inquire. Thanks z The seller had no hum- The footswitch is conncted proper- shield to reverb. The hum is there even when the pedal is disconnected. As long as a tube is in that socket- i have hum. Ill check the reverb tank wires- they go into the chassis- And make sure they are tight.
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Post by Rhythmark on Feb 1, 2018 6:31:13 GMT -7
I checked the reverb rca wires and they are seated and tight. I think ill pull the chassis and see if i have a cracked solder joint in there-? The packing was ok but loose- but the amp arrived in one piece. And looks good. And sounds great if v3 is pulled. IIf the seller is being honest it must have gotten jarred in shipping? Any other ideas. Ill pull the chassis a bit later - im off work today:)
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Post by Rhythmark on Feb 1, 2018 7:37:23 GMT -7
Ok i pulled the chassis. And all contacts look solid . I nudged all the wires to tube socket s and no problem. My other preamp tubes may not be good either. Im hoping this is just a tube issue. What is the proper tube for v3? So the grainy hum is there- even when the pedal is disconnected. If i turn the reverb knob ( off) the hum is gone. And when i pull the tube the amp is dead quite. Besides the fan.
The wiring looks amazing by the way!! Very clean !!
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Post by Rhythmark on Feb 1, 2018 9:39:14 GMT -7
New Report!
I swapped tubes around and put them all back in, the noise is only when the reverb is turned off . When the reverb switch is on the noise is gone. If i unplug the foot switch-. the noise is quieter but there but if i turn the reverb knob down its quiet.
I think im going to check grounding points.
please let me know if any ideas jump out -- i may have to return this to the seller- honestly this is my 4th Z and I know its not the build-- Ill swap the tube with my super reverb and see if those change anything-- but the noise is gone with reverb and there when turned off????hmmmm
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Post by Rhythmark on Feb 1, 2018 12:30:13 GMT -7
tube swaps helped a little- but there is a noise factor here. Its when the reverb is switched off the noise intensifies ? and the Reverb knob turned down cuts the hum off. But if you turn up the reverb the noise is louder and changes in tone as the reverb knob is turned. The reverb orca connecter needed solder but wasn't the cure for the noise.
I just dont have a full tube set to swap all these. It seems it would have to be the tubes.. My Cure is dead quiet, and the wreck was pretty quite. and my super reverb thats 53 is super quiet... And Ive heard the Zlux is to be the same...
So what do you guys think- should I keep it and Buy a new tube set to start fresh? Or should I return it?
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Post by daddyelmis (Greg) on Feb 1, 2018 14:52:37 GMT -7
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Post by Rhythmark on Feb 1, 2018 15:13:55 GMT -7
I definitely want to keep it. Does it make sense the noise would be louder when the reverb is off? I know weird noises are tubes most of the time.
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Post by Jaguarguy (Mike) on Feb 1, 2018 15:42:35 GMT -7
I can tell you that mine is quiet. Does anything happen if you play with treble and/or cut positions?
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Post by DRZ on Feb 1, 2018 17:28:25 GMT -7
I definitely want to keep it. Does it make sense the noise would be louder when the reverb is off? I know weird noises are tubes most of the time. That statement alone says the cables are reversed from your dual foot switch. Non shielded Trem cable is plugged into the Reverb Rear plug.
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Post by Rhythmark on Feb 1, 2018 18:03:34 GMT -7
This is how its plugged in. Note the noise is there with the foot switch unplugged as well. But goes away if I turn the reverb knob down.
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Post by headshrinker (Marc) on Feb 1, 2018 18:43:31 GMT -7
The shield on the reverb cable looks awfully frayed to me. May not explain the noise when not plugged in, but may contribute to it when it is.
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Post by Rhythmark on Feb 1, 2018 20:40:25 GMT -7
its pulled apart a bit but its all there. Im not new to amps , I work on vintage fender on occasion . Im by no means a Pro and dont know all there is.But I have a grasp. I believe this was knocked around during shipping, not enough for any visible damage. I looked over the chassis and it beautiful in there and everything looks solid. The one grey wire from the top of the board going to V3 seemed noisy so I resoldered it. No change.
Im just thinking that since the problem exists without the foot switch in we can rule that out, The problem revolves around the tubes in my novice opinion as everything else looks good. I did find a loose nut with a connected washer inside one of the transformers I could hear it sliding around. I got it out of there. But didn't see anything in the chassis missing a nut?? Unless it came from under the turret board. Im going to try to post a video of whats going on- since writing about is just that.
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Post by Rhythmark on Feb 1, 2018 21:45:22 GMT -7
I don't think I can post a video , i use imgur but dont think they support video?
Anywho-- As you can see the wires are correct, so what is the next possibility ? No joke when using reverb its quieter and when NOT using reverb its a noise? Should I just swap all the tubes and go from there? The seller is being very open and communication is great. Just to be sure though , this amp is usually quiet with no inst. cord plugged in? the Cure and Super are dead quiet on the same outlet when tried. I had a Rivera amp think it was a club50 but that thing was noisy and I guess they where made like that. Im hoping for a quieter amp! Plus the seller said it was perfect before shipping.
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Post by DRZ on Feb 2, 2018 8:54:12 GMT -7
rhythmark, we are trying to wrap are heads around your problem as we haven't seen an issue as your stating and it is very hard to diagnose via a keyboard. The last thing you want to do is swap out your complete set of tubes. That will be throwing out the baby with the bathwater. It will cause more issues. Your best bet is send the chassis in for repair and we'll suss it out for probable less then a compete set of Z Lux tubes. Also keep in mind that is a tube reverb circuit so a little noise is normal when you crank the Reverb pot. If it is a tube just replace that one faulty one.
Z
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bradm
Junior Member
Posts: 74
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Post by bradm on Feb 2, 2018 11:52:06 GMT -7
One very easy thing to check that most won't...the speaker jacks are grounded direct to chassis. Any oxidation between the jack mount and chassis can induce hum via a ground loop creation. I've personally seen this in Jaz 20/40. The fix was simple and this won't take you more than 5-10 min total...power-removed, caps drained...pull the nuts off the speaker jacks (any chassis grounded jack) and hit the hole surround (and jack) with DeOxit. (I was out of DeOxit at the time so I alcohol-cleaned the jack and took 440 grit cloth to the chassis jack hole on the inside. Reassembled...hum gone.
I know this is a new(er) amp, but I've had "new" parts come in and still see oxide...even visibly sometimes. One way to test that to even see if it's a culprit...take a nylon adjustment tool and just give a little pressure on the inside chassis of the jack (you'd do this live to hear the change so safety foremost...probe with right hand & left hand in back pocket)...hear a change? Then clean it. Every Z amp that's ever been on my bench ends up hum-free. Just a little TLC in the right spot sometimes.
Ha, one example of where those things weren't the culprit...I had an 80's JCM900 on the bench. Low level hum...swapped out a tube at a time...no change. Checked the jacks, solder joints, grounding scheme (not the best in that amp, btw)...nothing made an audible change. Finally just said, the heck with it...replaced ALL the preamp tubes with some JJ's I had on hand...problem gone. The issue? A particular SovTek 12ax7 that...no matter what preamp (or PI) position it was in...induced hum in the output...at the same level! Put just one back in anywhere...there it is again. Remove? Hum free. My guess was the tube physical construction in connection with the transformers magnetic field were contributing. But, I had no time to experiment further. Once it's resolved...it's out the door.
All the best!
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Post by Rhythmark on Feb 2, 2018 13:03:55 GMT -7
One very easy thing to check that most won't...the speaker jacks are grounded direct to chassis. Any oxidation between the jack mount and chassis can induce hum via a ground loop creation. I've personally seen this in Jaz 20/40. The fix was simple and this won't take you more than 5-10 min total...power-removed, caps drained...pull the nuts off the speaker jacks (any chassis grounded jack) and hit the hole surround (and jack) with DeOxit. (I was out of DeOxit at the time so I alcohol-cleaned the jack and took 440 grit cloth to the chassis jack hole on the inside. Reassembled...hum gone. I know this is a new(er) amp, but I've had "new" parts come in and still see oxide...even visibly sometimes. One way to test that to even see if it's a culprit...take a nylon adjustment tool and just give a little pressure on the inside chassis of the jack (you'd do this live to hear the change so safety foremost...probe with right hand & left hand in back pocket)...hear a change? Then clean it. Every Z amp that's ever been on my bench ends up hum-free. Just a little TLC in the right spot sometimes. Ha, one example of where those things weren't the culprit...I had an 80's JCM900 on the bench. Low level hum...swapped out a tube at a time...no change. Checked the jacks, solder joints, grounding scheme (not the best in that amp, btw)...nothing made an audible change. Finally just said, the heck with it...replaced ALL the preamp tubes with some JJ's I had on hand...problem gone. The issue? A particular SovTek 12ax7 that...no matter what preamp (or PI) position it was in...induced hum in the output...at the same level! Put just one back in anywhere...there it is again. Remove? Hum free. My guess was the tube physical construction in connection with the transformers magnetic field were contributing. But, I had no time to experiment further. Once it's resolved...it's out the door. All the best! Thanks for that info-- the amp is now making a crackling sound- so its seems to grow!! I have a youtube video so it can be heard.
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Post by Rhythmark on Feb 2, 2018 13:06:56 GMT -7
rhythmark, we are trying to wrap are heads around your problem as we haven't seen an issue as your stating and it is very hard to diagnose via a keyboard. The last thing you want to do is swap out your complete set of tubes. That will be throwing out the baby with the bathwater. It will cause more issues. Your best bet is send the chassis in for repair and we'll suss it out for probable less then a compete set of Z Lux tubes. Also keep in mind that is a tube reverb circuit so a little noise is normal when you crank the Reverb pot. If it is a tube just replace that one faulty one. Z I get the whole over the keyboard thing! Impossible- I think this amp needs a look over by the pros- I posted a video in this thread to hear the problem- it seems to be evolving- there is a crakling noise that made its appearance on the video. I wonder if the reverb tank could have gotten bumped too hard??
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Post by Rhythmark on Feb 2, 2018 15:08:57 GMT -7
I agree that my phone was making that static noise. Turned it back on without the phone and its just back to the hum.
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Post by Rhythmark on Feb 2, 2018 16:32:57 GMT -7
Bradm- Thanks again for the suggestions! But hum remains. I did swap each tube one at a time To no avail. Ill try all my super reverb pre amp tubes just for a listen once i get home tonight. Its sounds like something is ungrounded? Cant find any finicky points I tried a different speaker and power cord- nothing?
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Post by Rhythmark on Feb 3, 2018 0:13:16 GMT -7
Update- Its late but I had to try to see if some thing was ungrounded. And that nut I spoke of earlier that was in the transformer. There is a ground lug with a cap on that transformers bolt. So it was just on the bolt loose. I put the nut back on. And the amp seems better. There is hum but its more even across the different settings. If I play with vol and master at 9 O'clock I can't hear any hum. But if I near 12 o'clock the hum is there, not as loud I can play way louder than the hum. But because of the circumstances Im not sure if the amp is fine and has noise at 11-12 and louder as turned up. And the hum is still louder/different tone when turning off reverb with the foot switch. when that is off the reverb control changes the tone of the amp similar to a tone control but not as wide range.
Can anyone say if there lux is quiet at master and vol at noon, or is some hum normal? My super reverb has similar features and is just a soft hiss at full volume, With this amp on noon I can't hear the fender anymore. Its like you can hear the power . In a live setting I could play and not think about it. I think I better just send this in and be done, otherwise I just going to worry about for the rest of my life! The tone Im getting is awesome - Love the bottom end, im getting nice reverb and trem as well..
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Post by purpletele on Feb 3, 2018 4:00:25 GMT -7
Update- Its late but I had to try to see if some thing was ungrounded. And that nut I spoke of earlier that was in the transformer. There is a ground lug with a cap on that transformers bolt. So it was just on the bolt loose. I put the nut back on. And the amp seems better. There is hum but its more even across the different settings. If I play with vol and master at 9 O'clock I can't hear any hum. But if I near 12 o'clock the hum is there, not as loud I can play way louder than the hum. But because of the circumstances Im not sure if the amp is fine and has noise at 11-12 and louder as turned up. And the hum is still louder/different tone when turning off reverb with the foot switch. when that is off the reverb control changes the tone of the amp similar to a tone control but not as wide range. Can anyone say if there lux is quiet at master and vol at noon, or is some hum normal? My super reverb has similar features and is just a soft hiss at full volume, With this amp on noon I can't hear the fender anymore. Its like you can hear the power . In a live setting I could play and not think about it. I think I better just send this in and be done, otherwise I just going to worry about for the rest of my life! The tone Im getting is awesome - Love the bottom end, im getting nice reverb and trem as well.. Great work!
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Post by Rockerfeller on Feb 3, 2018 6:37:25 GMT -7
Update- Its late but I had to try to see if some thing was ungrounded. And that nut I spoke of earlier that was in the transformer. There is a ground lug with a cap on that transformers bolt. So it was just on the bolt loose. I put the nut back on. And the amp seems better. There is hum but its more even across the different settings. If I play with vol and master at 9 O'clock I can't hear any hum. But if I near 12 o'clock the hum is there, not as loud I can play way louder than the hum. But because of the circumstances Im not sure if the amp is fine and has noise at 11-12 and louder as turned up. And the hum is still louder/different tone when turning off reverb with the foot switch. when that is off the reverb control changes the tone of the amp similar to a tone control but not as wide range. Can anyone say if there lux is quiet at master and vol at noon, or is some hum normal? My super reverb has similar features and is just a soft hiss at full volume, With this amp on noon I can't hear the fender anymore. Its like you can hear the power . In a live setting I could play and not think about it. I think I better just send this in and be done, otherwise I just going to worry about for the rest of my life! The tone Im getting is awesome - Love the bottom end, im getting nice reverb and trem as well.. I have never noticed a hum in my Zlux. But I just went in to the studio and fired her up. Of course it is 6:30am and the house is deadly quiet. When I dimed the master and volume in full power and half power it was definitely not quiet and when I had them both at noon there was also some noise. But it is your typical "amp" sounds, I would never notice that at a gig. If that is what your hearing, I would say that is normal.
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Post by Maddog on Feb 3, 2018 8:21:45 GMT -7
Can anyone say if there lux is quiet at master and vol at noon, or is some hum normal? It's so subjective asking / answering if this amp or that amp is noisy....I would say my Lux is very quiet, but that might not be your idea of "quiet." So I made a little video of my amp with NOTHING plugged into the input.... Hope it helps!
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Post by Rhythmark on Feb 3, 2018 11:31:45 GMT -7
Can anyone say if there lux is quiet at master and vol at noon, or is some hum normal? It's so subjective asking / answering if this amp or that amp is noisy....I would say my Lux is very quiet, but that might not be your idea of "quiet." So I made a little video of my amp with NOTHING plugged into the input.... Hope it helps!
Thanks zbro! Im thinking this amp is ok. I know different anps have differing levels of ( noise) and i know this reverb stage has a little noise. Im going to listen to your video on headphones. But from what i think im hearing is very similar. And like i said the amp sounds freaking awesome! I think that nut solved the problem. Ill check it out later today. Thanks so much for posting that video- it helps!
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Post by Rhythmark on Feb 3, 2018 11:34:31 GMT -7
Update- Its late but I had to try to see if some thing was ungrounded. And that nut I spoke of earlier that was in the transformer. There is a ground lug with a cap on that transformers bolt. So it was just on the bolt loose. I put the nut back on. And the amp seems better. There is hum but its more even across the different settings. If I play with vol and master at 9 O'clock I can't hear any hum. But if I near 12 o'clock the hum is there, not as loud I can play way louder than the hum. But because of the circumstances Im not sure if the amp is fine and has noise at 11-12 and louder as turned up. And the hum is still louder/different tone when turning off reverb with the foot switch. when that is off the reverb control changes the tone of the amp similar to a tone control but not as wide range. Can anyone say if there lux is quiet at master and vol at noon, or is some hum normal? My super reverb has similar features and is just a soft hiss at full volume, With this amp on noon I can't hear the fender anymore. Its like you can hear the power . In a live setting I could play and not think about it. I think I better just send this in and be done, otherwise I just going to worry about for the rest of my life! The tone Im getting is awesome - Love the bottom end, im getting nice reverb and trem as well.. I have never noticed a hum in my Zlux. But I just went in to the studio and fired her up. Of course it is 6:30am and the house is deadly quiet. When I dimed the master and volume in full power and half power it was definitely not quiet and when I had them both at noon there was also some noise. But it is your typical "amp" sounds, I would never notice that at a gig. If that is what your hearing, I would say that is normal. Thanks for the info- it seems the amp is ok- im going to do another run with it later just to verify!! Thanks for posting your comment! It’s helpful!!
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Post by Rhythmark on Feb 3, 2018 15:17:21 GMT -7
ok Ran the amp again listened closely to the other video and Id say the amps sound near identical now.! Im still going to get some new tubes, due to just getting the right v3 tube and at v1 seems microphonic... But otherwise I think thats it- after i get the new tubes in Ill play it for a while and if I feel i need to Ill send the amp in for an inspection. Thanks for all your replies and help.. I did clean the jack area as described earlier, but it didn't help this case- the amp is exactly 1 year old-doest even have its first tooth yet!
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Post by Chilly Gibbons (Todd T.) on Feb 3, 2018 16:24:58 GMT -7
A loose ground point will cause all sorts of noise and other issues. Im surprised the noise wasn’t worse given the lug was just hanging onto the tranny bolt and not secured by the nut. Then there’s the fact that you had a highly conductive part that could have caused some real fireworks had it shifted to a hot zone! Glad you tackled it, Godspeed!
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bradm
Junior Member
Posts: 74
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Post by bradm on Feb 3, 2018 18:34:40 GMT -7
Interesting where the loose bolt was With the amp on, put your finger on the transfer and chassis around it and see if you can actually feel the transformer vibrating. If it's noticeable, it will fail over time. That can happen when the insulating shellac between the transformation laminations start to crack and breakdown. When it does, you'll start to notice an actual mechanical "hum" coming from the transformer. I've seen one old Marshall where it was really loud...inducing the hum physically into the chassis at a pretty good volume.
It one ground repair (loose nut) quieted it...I'd loosen and check them all plus any other jacks you may not have checked. ?
Good job finding the mechanical issues!
BradM
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