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Post by s3mamill on Aug 16, 2018 7:44:07 GMT -7
Hey guys, new to the boards here. Got my first Z amp last week, an EMS head and cab. Its amazing sounding!
... Except for one thing that's bugging me. There is like a hiss or rattle when I'm playing a low G and some other notes. Its definitely coming from inside the amp head. I've played another head with the cab and its not there with the other head. I can't tell if its something weird with the power tubes, or maybe the springs in the preamp tube shields rattling in harmony with the note.
I've had a number of other amps and I haven't noticed this before. I haven't opened it up yet to investigate. I thought I might ask around first before I do. Any thoughts would be appreciated!
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Post by Jaguarguy (Mike) on Aug 16, 2018 8:03:36 GMT -7
Welcome to the Forum - a lot of great information and people here. Was this a new amp or did you buy it used? Could be a tube - not sure that the tube shield springs would hiss (but they could rattle). I have an EMS and there is definitely no hiss or rattle. When you open it up, take a look/listen to see if the sound is coming from the shields. If not, try reseating all the tubes and see if that makes a difference. Only try one thing at a time so you can eliminate the root cause.
Also, you might want to shoot a quick video and post it - might be easier for us to hear (and hopefully diagnose) the problem.
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Post by s3mamill on Aug 16, 2018 9:40:09 GMT -7
I got it used, but the dude had just bought it and played it like 3 times. It seems to be in perfect shape. here is a link to a recording I made. You can hear it after the note. the little rattle/sizzle thing www.dropbox.com/s/kmhvqb0qnfen88q/Rattle.m4a?dl=0when you click the link dropbox says you should sign up but there is a "no thanks" button at the bottom of the notice to just listen without signing up FYI
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Post by purpletele on Aug 16, 2018 10:14:21 GMT -7
That's a new one on me. There is definitely something going on.
My first thought is that there could be a tube that has gone bad.
1. Switch the amp the SS rectifier and see if that does anything, that's the first tube test. 2. If that is good, then grab an 12AX7 and roll through the pre amp 3. Roll through the power tubes.
99% chance it is a tube.
I have a new EMS and I have a tube thing going on, and it needs to be addressed soon as well.
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Post by John on Aug 18, 2018 5:11:46 GMT -7
An additional thing:
is the head sitting on top of the cabinet? If so, move the head somewhere else. (floor or table/shelf) Anywhere but on top of the cabinet. If it stops, then to problem is being caused by the vibration of the cabinet. And if that's the case, it would lead me to believe it's a tube problem.
But either way, I think it's a tube. Get a 12ax7 tube you know to be good, and replace it in each preamp socket. Don't get three known good ones and replace all three at the same time. Because if it IS a bad tube, you won't know which one of the three. Do it one tube at a time. If that doesn't work, do the same things with the power tubes.
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Post by mudman on Aug 18, 2018 5:51:34 GMT -7
But replace the power tubes in pairs or quads. Don’t just replace one
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Post by nicholas on Aug 18, 2018 7:31:50 GMT -7
I listened to the link. That definitely sounds like a tube rattling. From the amount of tube rattles I've had, it sounds like a power tube or rectifier rattle to me.
One thing Ive been successful with is having an assistant play the note that always sets off the rattle while you lightly touch the top of each tube with your finger. Sometimes you can stop (or change) the rattle by touching it, then you know what one is the arrogant offending bastard. Just be careful with the power tubes as they get hot.
Just last week I had a preamp tube go bad and cause a rattle. I've become quite the rattle connoisseur. Apparently every tube made that will develop a rattle gets shipped to me.
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Post by s3mamill on Aug 18, 2018 12:47:26 GMT -7
Thanks for the replies guys! John, thanks for the advice, I'll go one tube at a time. and I'll try the head sitting on a table and off the cab just to see if it helps. Mudman says to swap the power tubes in a pair. I only have one extra EL34. Should be fine to swap them out one at a time with my other EL34, right, if I'm just looking for the rattle? The matched pair rule is only if you're putting in a new set for tone reasons, right? Nicholas, looks like I got one of your rattle-y tubes. I can send it back to you once I figure out which it is! Today I happened to pick up a 50's GE 5u4gb at a junk shop for 3$ so I'm hoping the issue is with the rectifier! I'm gonna try and get to this tomorrow.
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Post by mudman on Aug 18, 2018 16:27:30 GMT -7
Thanks for the replies guys! John, thanks for the advice, I'll go one tube at a time. and I'll try the head sitting on a table and off the cab just to see if it helps. Mudman says to swap the power tubes in a pair. I only have one extra EL34. Should be fine to swap them out one at a time with my other EL34, right, if I'm just looking for the rattle? The matched pair rule is only if you're putting in a new set for tone reasons, right? Nicholas, looks like I got one of your rattle-y tubes. I can send it back to you once I figure out which it is! Today I happened to pick up a 50's GE 5u4gb at a junk shop for 3$ so I'm hoping the issue is with the rectifier! I'm gonna try and get to this tomorrow. Negatory good buddy. It might be safe for a moment, but if the two tubes are too far out of spec from each other one will redplate and potentially foul up the amp. I’m not sure if the EMS is fixed bias (probably is given it’s a marshall style amp) but you would also need to rebias the amp for the new tubes. I really would not stick a random el34 in that amp.
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Post by nicholas on Aug 18, 2018 17:17:59 GMT -7
Nicholas, looks like I got one of your rattle-y tubes. I can send it back to you once I figure out which it is! Send it. Lol. Keep in mind this is a two part process. Once you identify the offending animal it's important to follow through on the procedure. Most folks skip this step, it is critical. You need to: - Put the offending tube in a zip lock bag. - Double bag it - Take it outside and "Gronk it". If you're unfamiliar with this procedure see below.
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Post by s3mamill on Aug 19, 2018 7:44:32 GMT -7
Nicholas, looks like I got one of your rattle-y tubes. I can send it back to you once I figure out which it is! Send it. Lol. Keep in mind this is a two part process. Once you identify the offending animal it's important to follow through on the procedure. Most folks skip this step, it is critical. You need to: - Put the offending tube in a zip lock bag. - Double bag it - Take it outside and "Gronk it". If you're unfamiliar with this procedure see below. oh I'm familiar, i live just outside of Boston, land of the gronk spike!
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Post by purpletele on Aug 19, 2018 8:20:50 GMT -7
Send it. Lol. Keep in mind this is a two part process. Once you identify the offending animal it's important to follow through on the procedure. Most folks skip this step, it is critical. You need to: - Put the offending tube in a zip lock bag. - Double bag it - Take it outside and "Gronk it". If you're unfamiliar with this procedure see below. oh I'm familiar, i live just outside of Boston, land of the gronk spike! That might be why you have a fickle tube
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Post by John on Aug 19, 2018 12:16:38 GMT -7
Thanks for the replies guys! John, thanks for the advice, I'll go one tube at a time. and I'll try the head sitting on a table and off the cab just to see if it helps. Mudman says to swap the power tubes in a pair. I only have one extra EL34. Should be fine to swap them out one at a time with my other EL34, right, if I'm just looking for the rattle? The matched pair rule is only if you're putting in a new set for tone reasons, right? Nicholas, looks like I got one of your rattle-y tubes. I can send it back to you once I figure out which it is! Today I happened to pick up a 50's GE 5u4gb at a junk shop for 3$ so I'm hoping the issue is with the rectifier! I'm gonna try and get to this tomorrow. Negatory good buddy. It might be safe for a moment, but if the two tubes are too far out of spec from each other one will redplate and potentially foul up the amp. I’m not sure if the EMS is fixed bias (probably is given it’s a marshall style amp) but you would also need to rebias the amp for the new tubes. I really would not stick a random el34 in that amp.
You should be able to get away with switching out one el34 at a time.....if you're only doing it for 30 seconds to see if the rattle goes away. But otherwise, matched power tubes are the way to go. If the rattle DOES go away when you switch out one el34....you will unfortunately need to buy a new matched pair.
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Post by s3mamill on Sept 2, 2018 12:15:39 GMT -7
Hey guys, just a quick update. I tried a few sets of EL34s. JJ's and an old set of JoLida's (Chinese made, prob from the 80's). The JJ's buzzed but on different notes (B vs G), the JoLida's didn't buzz. With the back of the amp still off, I popped the EHX tubes that came with the amp back in and they didn't buzz. I thought I had fixed the problem, and liked the tone of the EHX tubes the best. I popped the back of the amp back on, and plugged in and ... the buzzing was back. I played it some with the head off the cab and it buzzes still, but it seems to be less pronounced. I haven't tried swapping out the preamp tubes so maybe that's whats next. Other than the buzzing that amp sounds great. I think the design is so great, I'm able to get big tweed sounds out of it and all the way up to high gain. Really versatile! While I had the back of the head off I decided to take the chassis out and take a look at it. The lead dress is beautiful. Her birthday is 6/13/2017.
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Post by mudman on Sept 2, 2018 17:02:11 GMT -7
Have you tried the amp in a different room or even building? Different guitar cables? Different guitar? Have you tried isolating to make sure the buzz isn’t from the preamp? Switched to solid state rectifier to rule out the tube or vice versa?
If you did have a power tube eat it, it could take out a screen resistor which can cause buzzing.
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Post by Spidouz on Apr 15, 2023 11:08:12 GMT -7
I will reply here because I don’t know how to create a separate thread. I just received my EMS. Quickly plugged and try (I love it). However, I notice something and I wonder if it’s normal.
When I move the Presence knob, it does scratch (like an old pot), and when I fully turn it clockwise, I have a little hiss appearing. If I turn it back , the hiss disappears. Is that a normal behavior?
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Post by nmz on Apr 15, 2023 12:43:07 GMT -7
I will reply here because I don’t know how to create a separate thread. I just received my EMS. Quickly plugged and try (I love it). However, I notice something and I wonder if it’s normal. When I move the Presence knob, it does scratch (like an old pot), and when I fully turn it clockwise, I have a little hiss appearing. If I turn it back , the hiss disappears. Is that a normal behavior? I do know that the scratch from the presence knob is normal when adjusting, per Don. “the presence control will always sound that way. Because of how it operates, there ends up being DC on the pot which is what you hear as scratching”. The other I’m not sure, try tubes. Congrats on the EMS!
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Post by adam on Apr 15, 2023 16:06:51 GMT -7
When I move the Presence knob, it does scratch (like an old pot), and when I fully turn it clockwise, I have a little hiss appearing. If I turn it back , the hiss disappears. Is that a normal behavior? I have a bunch of amps which make noise like that on the presence control. Wouldn't worry about that. I don't think I ever turned the presence on 10 though!
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Post by Spidouz on Apr 16, 2023 2:18:58 GMT -7
When I move the Presence knob, it does scratch (like an old pot), and when I fully turn it clockwise, I have a little hiss appearing. If I turn it back , the hiss disappears. Is that a normal behavior? I have a bunch of amps which make noise like that on the presence control. Wouldn't worry about that. I don't think I ever turned the presence on 10 though! You’re right, me neither, and to be frank, I often left the presence at 12 o’clock. I was just trying the whole range to figure out the extend of the tone of the EMS, just discovering it. It was not a big issue, I dialed it slightly back and it was gone, so I continued playing. But I was just wondering if it’s normal (or not). For the scratching, like nmz said, I was expecting it to be normal, thinking it was related to the way it interacts with the circuit and tubes… So overall, it’s really not an issue, it was just trying to figure out since it’s my first Dr Z, and the only Marshall experience I had before was with the Victory Sheriff 44. But I have to say, I really like the EMS, so dynamic… and I could only try it with the volume between 7 and 8 o’clock so far (because it was late and I can’t bother neighbors too much). I absolutely don’t regret my purchase, and now it’s discontinued, it’s a collector
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Post by frankie on Jun 29, 2023 11:23:49 GMT -7
I have a bunch of amps which make noise like that on the presence control. Wouldn't worry about that. I don't think I ever turned the presence on 10 though! You’re right, me neither, and to be frank, I often left the presence at 12 o’clock. I was just trying the whole range to figure out the extend of the tone of the EMS, just discovering it. It was not a big issue, I dialed it slightly back and it was gone, so I continued playing. But I was just wondering if it’s normal (or not). For the scratching, like nmz said, I was expecting it to be normal, thinking it was related to the way it interacts with the circuit and tubes… So overall, it’s really not an issue, it was just trying to figure out since it’s my first Dr Z, and the only Marshall experience I had before was with the Victory Sheriff 44. But I have to say, I really like the EMS, so dynamic… and I could only try it with the volume between 7 and 8 o’clock so far (because it was late and I can’t bother neighbors too much). I absolutely don’t regret my purchase, and now it’s discontinued, it’s a collector Crackle on the presence is inherent in classic marshall circuits as there is a small amount of DC voltage that is on the pot.
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