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I recently picked up a 1967 Traynor YGM-2 from L&M. Because I bought it through them, the amp comes with a warranty so I had the amp serviced by Traynor and, after doing some work on it, they gave it a clean bill of health (if it matters for the purposes of the issue described in this post, I can detail everything Traynor did to the amp). But despite them giving it a clean bill of health, I am still getting hiss/white noise when using it which gets louder as the volume is turned up. It is worse when I put a pedal in front of the amp.

It is entirely possible that this is being caused by the electricity in my home, or perhaps by the area in which I am using the amp as there is a stereo, two computers (a desktop and a laptop), a TV, a cable box, a DVD player, etc. all within close proximity to the amp (within ten feet). My Marshall is fine when played in the same spot, but the Traynor is noisy. I have tried the Traynor in another room which doesn't contain any electronics except for lights and the noise is still there, but in that case it is much quieter and doesn't get louder until the amp is cranked up to 9-10 on the volume.

Does anyone have any idea what might be causing this or a suggestion for how I can get rid of that noise?

When reading about this kind of issue online, a common answer is to replace the pre-amp tubes but if there was a problem with those Traynor would have replaced them when servicing it because they replaced the power tubes.

Would a noise pedal help? I've never used one so honestly have no idea what they do.
 

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I recently picked up a 1967 Traynor YGM-2 from L&M. Because I bought it through them, the amp comes with a warranty so I had the amp serviced by Traynor and, after doing some work on it, they gave it a clean bill of health (if it matters for the purposes of the issue described in this post, I can detail everything Traynor did to the amp). But despite them giving it a clean bill of health, I am still getting hiss/white noise when using it which gets louder as the volume is turned up. It is worse when I put a pedal in front of the amp.

It is entirely possible that this is being caused by the electricity in my home, or perhaps by the area in which I am using the amp as there is a stereo, two computers (a desktop and a laptop), a TV, a cable box, a DVD player, etc. all within close proximity to the amp (within ten feet). My Marshall is fine when played in the same spot, but the Traynor is noisy. I have tried the Traynor in another room which doesn't contain any electronics except for lights and the noise is still there, but in that case it is much quieter and doesn't get louder until the amp is cranked up to 9-10 on the volume.

Does anyone have any idea what might be causing this or a suggestion for how I can get rid of that noise?

When reading about this kind of issue online, a common answer is to replace the pre-amp tubes but if there was a problem with those Traynor would have replaced them when servicing it because they replaced the power tubes.

Would a noise pedal help? I've never used one so honestly have no idea what they do.
Isn’t it a common (substantiated?) belief that old carbon resistors are a source of noise?
 

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Doing some serious guessing here. Since the tone controls don't make it worse, then you can rule out the first tube stage. Also since it seems to be picking up the noise (less when you moved it to another room, correct?), You either have a funky volume control, or the 1 meg resistor on the grid of the second stage is open or off spec.
The only other thing I can think of, is it is picking up noise somewhere in the tone stack, either an open or failing pot, or a bad cap.
I'm afraid this is going to be one of those trial and error type of diagnosis.
Does the treble boost switch make any difference?
 

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Discussion Starter #8
Doing some serious guessing here. Since the tone controls don't make it worse, then you can rule out the first tube stage. Also since it seems to be picking up the noise (less when you moved it to another room, correct?), You either have a funky volume control, or the 1 meg resistor on the grid of the second stage is open or off spec.
The only other thing I can think of, is it is picking up noise somewhere in the tone stack, either an open or failing pot, or a bad cap.
I'm afraid this is going to be one of those trial and error type of diagnosis.
Does the treble boost switch make any difference?

Thinking about it more, I honestly can't remember if I adjusted the tone controls. I think I did, but cannot remember, so I might have been wrong about that point.

If I remember correctly, the treble boost switch made it a bit worse.

And yes, the noise was significantly lessened when it was in another room. The noise did get louder, but not until I turned it up to 9-10 on the volume dial.
 

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Thinking about it more, I honestly can't remember if I adjusted the tone controls. I think I did, but cannot remember, so I might have been wrong about that point.

If I remember correctly, the treble boost switch made it a bit worse.

And yes, the noise was significantly lessened when it was in another room. The noise did get louder, but not until I turned it up to 9-10 on the volume dial.
Considering it was worse in a room with a lot of RF, I would guess shielding. As much as people go on about hand-wired turret board amps, that is a downside to them. If the amp isn't well shielded and the wires have been moved around you may hit a certain mode where they are picking up stray RF and it's coming through as noise.

Does the amp have the removable lid? Does it still have a layer of tin foil and is that foil somehow connected to a ground when the top is on? Those are the sorts of things I would be looking at, considering the change in noise in different locations.
 

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Discussion Starter #13
No, it is a very early model so does not have a removable lid. I can get the noise dealt with under warranty, but it might be simpler to have a friend who is an amp tech take care of it for me.
 

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There are several possibilities, it would be good to rule out the location issue, it could be the marshall is less susceptible to some type of interference and the problem is actually external. However, you did say even in the other location the noise is still there, just less, but I assume still an objectionable amount?
Number one thing to check would be for a noisy preamp tube. Tubes can be bad brand new out of the box, but they can also go bad from one moment to the next. So perhaps it was fine at Yorkville, or they did not check it for noise level in a nice quiet area.
Mark the preamp tubes somehow so you can put them back in the exact same spots. Remove them and try them one at a time in the socket closest to the power tubes (leave the other 2 preamp sockets empty). Is one noticeably louder than the others?
That test still might not find a noisy one, try each in a sensitive socket of your marshall, usually the socket closest to the input jack. Any one noisier than the others?
Or you could try one of your marshall preamp tubes in the Traynor, one socket at a time.
 

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Just a side question if I may, based on @jb welder comment above. I often see suggestions to "leave a tube socket empty" when testing or even playing stuff. Is this OK to do with the amp off standby, fully powered. Is it tube dependent?
 

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It's usually ok, especially if it's just a couple preamp tubes.
As you remove tubes, the power supply voltages will rise a bit as there is less loading on the supply. So removing all the tubes, or all the power tubes can sometimes be a problem. This is because the supply capacitors may not be rated at a high enough voltage to withstand the now higher voltage levels. Especially with old equipment that was designed for lower line voltages (115VAC vs modern 125VAC).
So no problem removing a few preamp tubes. Usually no problem even removing all the tubes, which is how some troubleshooting needs to be done in repair work.
 

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Is the noise there when no guitar is plugged in? I would get one new 12ax7 and swap it out one at a time with whats in there now.
 

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My YGM2 was incredibly noisy as you describe. I plugged in a foot switch and disabled the tremolo, which solved the majority of my problem. Have you tried plugging one in?

W.
 
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