Channel 1 Distorting??

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paulg2uk
Mark III
Posts: 266
Joined: Wed Jun 24, 2009 1:13 pm

Channel 1 Distorting??

Post by paulg2uk » Sun Dec 22, 2013 8:47 am

Hi Guys,

Anyone come across channel 1 on their mark v distorting a little.I'm not sure if this is a tube problem or possibly my 1x12 cab. I'm getting a a little bit of a distorted signal coming from the clean channel it almost sounds a bit gritty to my ears. I have just racked my TC g system and the mark v now sits on top of my rack which is sitting on my 1x12 cab.

It's almost like the signal is too hot and is driving a little. This only occurs on the clean channel with or without the g system or effects and even plugged straight into the amp. In fact when an effect is on like chorus it makes it sound even more gritty. I'm on the tweed setting but have always got a really sparkling clean sound from this channel. I've been using the g sys for years with the mark v and it was previously on the floor connected up with no issues.

What do you guys think?

Many thanks
Paul

bdubbs
Mark II
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Re: Channel 1 Distorting??

Post by bdubbs » Sun Dec 22, 2013 10:54 am

Tweed breaks up for me really easily. How old are your power tubes?

paulg2uk
Mark III
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Re: Channel 1 Distorting??

Post by paulg2uk » Sun Dec 22, 2013 11:02 am

bdubbs wrote:Tweed breaks up for me really easily. How old are your power tubes?
It's the same on the clean setting and on any wattage. Power tubes are only a couple of months old really. I used to have the compressor on the g system engage which beefed up my signal quite nicely. Now I just leave it pretty low or off and i still get a bit of distortion. Is it worth me changing the power tubes again do you think?

Chester
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Re: Channel 1 Distorting??

Post by Chester » Sun Dec 22, 2013 12:23 pm

paulg2uk wrote:
bdubbs wrote:Tweed breaks up for me really easily. How old are your power tubes?
It's the same on the clean setting and on any wattage. Power tubes are only a couple of months old really. I used to have the compressor on the g system engage which beefed up my signal quite nicely. Now I just leave it pretty low or off and i still get a bit of distortion. Is it worth me changing the power tubes again do you think?
I had a similar issue recently on my Roadster - slight unwanted distortion on clean notes, almost subtely a slight buzz. Went mad rolling every tube in the amp which cured nothing. Turned out to be sockets / jacks which I now clean regularly - no more subtle farting through any of my Mesas :wink:
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paulg2uk
Mark III
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Re: Channel 1 Distorting??

Post by paulg2uk » Mon Dec 23, 2013 5:24 am

Chester wrote:
paulg2uk wrote:
bdubbs wrote:Tweed breaks up for me really easily. How old are your power tubes?
It's the same on the clean setting and on any wattage. Power tubes are only a couple of months old really. I used to have the compressor on the g system engage which beefed up my signal quite nicely. Now I just leave it pretty low or off and i still get a bit of distortion. Is it worth me changing the power tubes again do you think?
I had a similar issue recently on my Roadster - slight unwanted distortion on clean notes, almost subtely a slight buzz. Went mad rolling every tube in the amp which cured nothing. Turned out to be sockets / jacks which I now clean regularly - no more subtle farting through any of my Mesas :wink:
I turned the compressor off on my G system and it seems to have helped little. Seems strange though as my compressor has been on the same setting for the past 2 years and then when I rack everything it changes. Very odd.

bdubbs
Mark II
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Re: Channel 1 Distorting??

Post by bdubbs » Tue Dec 24, 2013 1:29 pm

did you check your loop gain knob?

paulg2uk
Mark III
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Re: Channel 1 Distorting??

Post by paulg2uk » Tue Dec 24, 2013 1:39 pm

bdubbs wrote:did you check your loop gain knob?
I did it's at 12 o clock where it's always been set and turning it down doesn't make a difference. I got a feeling it was the compressor on my g sys.

DangerMoney
Mark II
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Re: Channel 1 Distorting??

Post by DangerMoney » Sun Jan 26, 2014 11:01 pm

Switch it to "loop bypass" on the back of the amp and let us know what you find.

paulg2uk
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Re: Channel 1 Distorting??

Post by paulg2uk » Tue Jan 28, 2014 5:15 am

DangerMoney wrote:Switch it to "loop bypass" on the back of the amp and let us know what you find.
I'll give that a go tonight. I'm gonna try a different jack to jack cable as well and see if that makes a difference.

KyleT
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Re: Channel 1 Distorting??

Post by KyleT » Sun Mar 24, 2019 11:33 am

Sorry for resurrecting an old thread... I am trouble shooting this same issue and having no luck. I purchased a Mark V head from Sweetwater that had the same problem. I contacted customer service. They had me send that one in and they sent me another new Mark V. Got the amp plugged into my Mesa 2x12 rectifier cab set at 8 ohms. I am running Channel One on "Clean" mode, no graphic EQ and 90 watts. Gain is set at 10:30 and Master around 11:00ish. Set to "Normal". Should be pristine clean. I have the Loop activated as to use the Master volume feature.(I have tried running the amp with the Loop bypassed but get the same results) I am getting just a tiny bit of breakup. Sounds like the input is set too high or pickups are too hot. I have a Music Man JP13 with stock PU's and a Fender Strat with the Gilmour EMG set. The JP is a lot more noticeable but it is still present with the Strat. The issue is present when running either guitar straight into the amp or guitar > pedal board > amp... I did noticed it doesn't happen during single note stuff. However, if you arpeggiate a chord it is very apparent. After about the 3rd or 4th note you can hear it. Its like after you introduce just enough signal you hear the break up. I have eliminated the guitars as possible problems. My practice rig consists of a iRig Pro/iPad and I have had no issues. I also tried running through a Focusrite Scarlet 2i2 interface. Again, zero issues. Changed 9volts etc... I have used multiple cables. I have cleaned the jacks on the guitars with contact cleaner.

I had a few spare standard Mesa 12AX7 tubes so I swapped one in for V1. Nothing! I have no problems with any of the other channels. Anyone have any ideas???

Rider1260
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Re: Channel 1 Distorting??

Post by Rider1260 » Sat Jul 13, 2019 8:23 pm

I had the loop send / return set to high on mine ALL better after I lowered the level I was clipping the input of my TC Electronics Nova system I have in the effects loop
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KyleT
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Re: Channel 1 Distorting??

Post by KyleT » Fri Oct 11, 2019 6:26 pm

I believe I have answered my own question. Would like to see if any of you here on the forum can help me validate it.

After troubleshooting every possible combination of things I have found the issue. It is the "Preset Depth" knob for channel one. I had channel one setup so I could footswitch in the graphic EQ on Channel one if I wanted a more scooped tone. I was leaving the Preset Depth knob at 12:00 for a modest classic V scoop and had the channel set to Preset (obviously). I noticed through trial and error that when the EQ was turned on the distorted sound disappeared. Next step was to turn the preset knob level all the way up. When I did this the distortion/crackle was very, very apparent. But as soon as I engaged the eq it completely disappeared. I thought maybe engaging the eq dropped the signal level a little bit due to scooping it. I turned the preset level off and tried it again. With the preset level rolled all the way off the distorted sound was 99% gone. You could barely here it. And once again, when the eq was switched on I had a pristine clean. Not sure what to make of this. It's like the preset depth knob is tied to the channel input level or something and causing it to clip. I have tried with the FX loop on and run through my pedal board. I've tried it in "Bypass" mode. I've tried it with just a patch cable connecting the send to the return(nothing in the loop). I believe I have ruled out the FX loop. My fix has been to have preset selected, turn the preset level all the way off and have the graphic eq engaged when on channel one. This gives me beautiful cleans. Kind of defeats the purpose of having that option though. This same issue was present on the other Mark V I sent back for this exact reason. I can't say for sure it was the same problem but I am 99.9% sure. Can anyone test this theory for me..

Mesa Marvk V Head - Full Power - Channel 1 - Bold - Clean - EQ FS - 90W, plugged into a 2x12 rectifier cab (horizontal) at 8 ohms. Settings are the Petrucci clean settings from the Mark V video.

Turn the EQ selection switch to "Preset" and then turn the "Preset Depth" knob all the way up. Don't engage the eq on the footswitch just yet. Play something and see if you are getting any distorted sound. If so, then switch in the EQ and see if it goes away.

Thanks for any help in this matter. It has aggravated me to the point of selling the amp...
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mace
Mark III
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Re: Channel 1 Distorting??

Post by mace » Mon Oct 14, 2019 9:19 pm

I tried this tonight and could not duplicate it. With the EQ disengaged and Ch1 EQ set to PRESET I moved the dial on the PRESET from zero to full and back and forth. The tone stayed clean. I did the same with the EQ engaged and the tone stayed clean (but responded to the PRESET dial).

As best I could tell the sound did not distort. GAIN was about 10 o’clock, FAT, BOLD. 90W, full power.
Rankings: #1 Mark V head, #1b TC50 combo, #3 Rectoverb 25 head

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