Updated: Annoying Noise on All Channels of New Mark V

[pwoz]

Hi all,

I've been lurking for a while, but now I had a reason to register. I wanted to ask you here before I contacted Mesa tomorrow. I play high gain, and I have always had some noise/hiss on ch 2 and 3 (3 more significant than 2), but the past few days have been quite bad.

I am not sure if it's a bad outlet (tried different ones, and I use a power conditioner) or some interference (though I haven't moved the amp). I'm plugged into a 1x12 wide body thiele. I bought the amp in January brand new. I've always had some noise when cranking the gain on ch 2 and especially 3 (noise is worse with the bright switch on ch 3) but not as bad as this week. I tried all my guitars, but it's loudest with my 7 string with the Crunch lab.

I uploaded some quick audio that I grabbed with my S5 to YouTube. I just had a cable going straight from guitar to amp (I use mogami everything). I get some noise on all channels.. 1 is hardly noticeable.. ch 2 is nothing crazy unless I add a boost (e.g. Flux Drive or TS), and ch 3 is what you will hear in that video. I know the tubes have 6 months warranty, but I have not touched/looked at them other than when I bought the amp and I made sure they were in there tight. I get the noise on all watt settings and my gain is at about 3 o'clock

I've only owned some Peavies in the past which were "set it and forget" so I don't mess with tubes except the changes every few years. I have a TC Elec Sentry noise gate that helps, but you still have noise in ch 3 with it enabled and the past few days, even the gate doesn't hide the noise in the video when you start playing.

I've watched other youtube videos and I only heard different sounds (which sounded a lot worse than mine). I've searched various forums and it seems it could be a bad ground (though the noise was not EVER this bad when I bought the amp) or a bad preamp tube.. perhaps V1?

Anyway, I appreciate any feedback. I love this amp, but I've been wanting to compliment it with a JP15 or Majesty and this noise is scaring me.

http://www.youtube.com/watch?v=fS1sz1CTrxM

I tried everything but tube changes, such as removing the footswitch cable and using the changer knob on the back, different cables, etc. When I plug nothing into the amp, I still get some noise (mostly noticeable in channel 3), but it gets as loud as you'll hear in the video the second I plug in my guitar, which makes me suspect V1 but only because that's a common problem it seems and I have very little knowledge about tubes.

Update: I contacted Mesa this morning and they got back to me very quickly. Based on my description and sound clip, it may be one of my preamp tubes. I do not have any spares (will try to find one locally) otherwise Mesa is sending me one and I will see if V4, V5, or V6 are the culprit. If one of those is not the problem, then I will try V1. I will update my progress in this thread, in case anyone else ever has a similar issue.

 

[pwoz]

Another update: I have not done a tube swap yet, but I did some more testing/troubleshooting this weekend.

I get the same (or very similar noise) in all channels in the following conditions:
Ch 1 - When I run any high gain distortion pedal, and when I boost the Ch 1 gain (especially the tweed channel)
Ch 2 - When I run at full gain, I get slight noise but a noise suppressor pedal gets rid of most of it, but once I start boosting Ch 2 with a flux drive or tube screamer (or any OD), I get the noise
Ch 3 - Noise is present from mid gain to full. It gets worse when I put the bright switch on.

So, I'm starting to think that the problem is V1 since that tube impacts all 3 channels and I get the noise on all the channels. Mesa sent me a tube that I'm still waiting for, but I also ordered a spare Mesa 12AX7 and a Mesa SPAX7 that are arriving today. I did let Mesa know about my new discovery and I'm still waiting for response, but I'm wondering what you guys think?

Should I try testing V4, V5, and V6 individually (since they are easier to get to than V1), or should I just try to replace V1 first?

 

[OryCheyne]

Yes try replacing V1 first.
Take note of the position of the valve cover when you remove it. From memory there are two little notches which face the front and back of the chassis. These need to be aligned when reinserting. Likewise take note of the position that the pins on the preamp tube are facing as this will also allow easier replacement.
I have found it easier to have the amp on a table so I can get both hands in their and feel both the edge of the socket and tube, and tube cover while reinserting. This helps me feel when the tube is fully seated, and likewise when the cover is flush before giving it a quarter twist to lock it in.
Not sure how big your hands are, mine aren't small, but I can get both in without removing the power tubes. You may find it easier to remove the power tubes for the first time.

Good luck.

 

[pwoz]

Yes try replacing V1 first.
Take note of the position of the valve cover when you remove it. From memory there are two little notches which face the front and back of the chassis. These need to be aligned when reinserting. Likewise take note of the position that the pins on the preamp tube are facing as this will also allow easier replacement.
I have found it easier to have the amp on a table so I can get both hands in their and feel both the edge of the socket and tube, and tube cover while reinserting. This helps me feel when the tube is fully seated, and likewise when the cover is flush before giving it a quarter twist to lock it in.
Not sure how big your hands are, mine aren't small, but I can get both in without removing the power tubes. You may find it easier to remove the power tubes for the first time.

Good luck.

I removed the the cage, power tubes, rectifier tube, and reverb tank, and I was able to get to V1 rather easily. I only had a little trouble with the one reverb tank screw and I had to go to home depot to get an offset screw driver. I replaced V1 with a SPAX7 but I still get noise.... not as much noise as my first video (no scratching just hiss/hum), but still... Mesa tech says it's normal considering the noise you get from pedals. I still get noise when going straight to amp but a little more noise w/ pedalboard.

https://www.youtube.com/watch?v=HSP_PDe8h2M

I don't feel like tinkering the rest of the night because I will just lose my temper. The noise suppressor makes it somewhat tolerable and I have a lot of **** in this room that might be interfering. I'll consider swapping V4, 5, or 6 if it still pisses me off. I also went from a furman surge protector to a power conditioner but it didn't seem to do much. There's quite a bit of buzz on ch 3 without the TC Sentry.

I will try another room and outlets tomorrow. The main reason this issue annoys me is that I just ordered a Torpedo Live and I want to start recording soon, but if I get all this noise, it's going to make recording extremely frustrating, otherwise I would not mind "normal" noise if I'm just practicing/riffing.

 

[OryCheyne]

I wonder if you may have an earth problem. You'll find out once you've tried it elsewhere. But careful the power circuits in an adjoining room may be the same as the one it's in now.

 

[pwoz]

I wonder if you may have an earth problem. You'll find out once you've tried it elsewhere. But careful the power circuits in an adjoining room may be the same as the one it's in now.

I'm suspecting a ground issue now, though I don't think the noise was this bad 2 months ago. I noticed yesterday that the noise would drop a bit when I touched one of my pedal switches with my finger. I'm going to buy an outlet tester to see how my grounds are... the house is about 25 years old. At least the scratchy sound from the first video is gone! Perhaps I had two problems.. bad V1 and grounding.

 

[Nicklotsaguitars]

I ask because I don't see it mentioned.
Have you tried a new lead? It's worth spending £5 on a cheap lead just to check.

 

[pwoz]

I ask because I don't see it mentioned.
Have you tried a new lead? It's worth spending £5 on a cheap lead just to check.

Is lead the same thing as a new cable? If so, then yes. I tried my usual mogamis, and a bunch of spare ones and no real difference.. except that my one 7 string is the most noisy.. could be grounding issue in that particular guitar. My other ones were not as loud in ch 2, but ch 3 is the loudest for everything. Maybe I will try a swap in V4, V5, or V6 later this week.

Oh, I also brought a ground tester and all my outlets are fine. I bought the amp for the purposes of the highest gain settings and the noise pedal makes it tolerable, but I'm worried how the recordings will sound.

 

[Nicklotsaguitars]

Well I wouldn't try to compare the levels of interference between home and studio environments.
I'd be looking at the guitars rather than the amp. In tracing noise problems. It's important to work systematically. In a specific order.
The biggest generator of noise is you. You're a great big antenna that channels all the noise around you, into the back of your guitar.
So when you touch the bridge or strings of the guitar. That noise is then sent from your body, into the ground side of the circuit. Along the lead, into the amp, out of the amp and into the electrical socket then into the earth.
I'd work my way along that chain in that order. As well as trying a different amp in a different location and then the same location.

 

[OldTelecasterMan]

Have you tried a power conditioner? Also my amp is dead quiet but if I get near a TV, computer or the like I get noise just like you are getting. Anything in the effects loop with the cable going by an outlet especially if there is something plugged in on the same circuit in another room that is inducing noise into the circuit.

 

[bandit2013]

Before jumping on your guitar or cables, leave the amp unplugged (nothing in the FXloop or input on the front of the amp). Keep the reverb circuit plugged in and make sure the speaker is plugged in too. Power up the amp as you would normally do and adjust the volume. If you still get noise you can easily rule out the external components.

I noticed in your first video, did not watch the other, that there was other noises present in the sound that would indicate a bad preamp tube. With the SPAX7 in V1 the noise should have been reduced. I would use the tube you removed from V1 and roll it through the tube chain (replace it with one of the preamp tubes already in the amp). Note that there will be some noise with the amp at high gain settings without signal but not quite like this. I typically find noise on CH1 and CH3 but CH2 remains very quiet due to the difference in the gain stage and tone control driver circuit. If you are using the FXloop set to active for use with the single master volume, turn it off and use the master controls on each channel. If the noise goes away, it would be related to V6. If no change, try turning off the EQ (use the footswitch or set the small toggle switch on each channel to turn off the EQ). If it goes away in doing this, call Mesa.

I would also consider earth grounding issue. Perhaps it is not your wall outlet but may be in the appliance power cord. What is the supply voltage? If it is too high, that may contribute to noise. A power conditioner will clean up the AC power considerably to remove line noise caused by typical motors (compressors for AC, Heat pumps, dishwashers, nearby manufacturing facilities that are polluting the line frequency).

I hope I could help but not sure in this case.

 

[pwoz]

I narrowed it down to a mix of grounding (I need to rewire a couple guitars with hot pickups) and interference from random crap around the house. I bought an outlet tester and all outlets are fine. I did buy a new JP15 guitar and the noise is not that bad except ch3 you get hum on really high gain, but that's expected for such high gain.

The noise almost goes away entirely with nothing plugged into the amp (just some noise on high gain ch3 and I think also if I use a high gain pedal on ch1 and boost ch2 (and I dime my gain on ch2 in crunch mode).

Before and after swapping out V1, fx loop on/off and EQ on/off made no difference.

Last week I did get a new random noise, but it only lasted a few minutes... I switched to tube rectifier mode in 45w, took the amp off standby and it made some strange noise.. ch1 sounded VERY weak and ch2 and ch3 were very weak.. but after about 10 minutes (and I was going from 10w/45w/90w testing various settings) the issue just went away and did not return.. I figured maybe the rectifier tube was just being a jerk for that moment. I did make a video of that sound and I can post it after work, but it hasn't returned and I have not thought about it until just now.