Does anyone else's Mark V do this?

I recently noticed this weird "issue" that happens with both of Mark V amps, under the same circumstances. It's on channel 1, using a really clean "fat" John Petrucci clean setting. Have the EQ set to footswitch, with the preset/slider knob set to preset, and the preset depth maxed out.

Try playing some chords on the clean channel, and switch the preset/slider switch back and forth (but don't actually have the EQ activated) and see if there's not a faint amount of crackling in the background of your playing when the switch is on "preset" mode? It's faint but it's definitely there on both amps, but ONLY when it's switched to preset, with the depth maxed, and the EQ itself off. It's really strange and I'm not sure what to make of it given the fact that you'd think adjusting knobs and switches while they're not actually affecting the tone wouldn't cause any additional noise.

Thw fact it's happening with both amps makes me think it's an overlooked design flaw and not an issue with an individual amp. Anyone else try this and get the same results?

I wasn't able to reproduce it but I didn't have the volume up very loud.

jaslan said:

I wasn't able to reproduce it but I didn't have the volume up very loud.

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Interesting. I didn't have mine terribly loud either but I had it on these settings:

Channel 1 -
Gain: 10 o'clock
Master: 12
Presence: 12:30
Treble: 1:30
Mid: 9
Bass: 11
Fat
EQ footswitch
Any watt
Bold
V30 Orange cab

Ok. I "think" I can hear a slight "pfft" when I switch from "preset" to "sliders".
I have to be honest though, I am not sure why this is a concern.

I'm not talking about the sound when you actually flip the switch, I'm talking about a light crackling/distortion on an otherwise clean channel. Only when its switched to preset with the depth maxed, but not with the eq actually activated, if that makes sense.

It's not a big concern, but it is strange as it sort of makes the clean channel less than clean when those settings are in place.

Hi.

I don’t know technical implementation of the preset eq but theoretically, if the preset eq is a mid cut eq which has make-up gain it may overload (distort) the circuit after the eq. That would kinda explain the situation but I have no clue about the schematics so... :lol: it’s just a thought. The GEQ circuit OTOH doesn’t have such a feature.

... yet if my memory serves me at all correctly the sound with preset maxed would be already too well in the no-mids-land for my tastes :mrgreen:

Eevil said:

Hi.

I don’t know technical implementation of the preset eq but theoretically, if the preset eq is a mid cut eq which has make-up gain it may overload (distort) the circuit after the eq. That would kinda explain the situation but I have no clue about the schematics so... :lol: it’s just a thought. The GEQ circuit OTOH doesn’t have such a feature.

... yet if my memory serves me at all correctly the sound with preset maxed would be already too well in the no-mids-land for my tastes :mrgreen:

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That's quite a theory lol. Do you think that could be the cause of additional gain occurring even when the channel theoretically shouldn't be affected, since it only occurs when the preset EQ is not activated?

I have an older Mark V 90, and I do not have that noise at all.

I did have odd noises at one time in different settings.
Cleaning all tubes and sockets with DeOxit, got rid of any weird noises however.

I got the same problem on my 90w Mark V, with the preset eq depth turned up on ch1, but eq not activated, I will get the crackling/breakup noise over what is otherwise a perfectly clean sound. I have to keep the ch1 preset depth at 0 to stop the noise.

seems like a design/component flaw if multiple amps are having the exact same issue.

Manehead said:

I got the same problem on my 90w Mark V, with the preset eq depth turned up on ch1, but eq not activated, I will get the crackling/breakup noise over what is otherwise a perfectly clean sound. I have to keep the ch1 preset depth at 0 to stop the noise.

seems like a design/component flaw if multiple amps are having the exact same issue.

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Have to check how my amp behaves

FWIW my V:90 had a similar cracking/whoosh noise which was intermittent... most noticeable after power-up and then would slowly dissipate. Lived with it for a quite a while. Then one day it was persistent... isolated the preamp via the FX send... no noise. Playing into the power section with FX return and noise was there. Pulled the power tubes, cleaned the leads and it went away at that time. Came back. Would juggle the tubes and it would come and go.

Opened it up and upon inspection found a power tube socket with no solder to the PCB. Can only assume it was missed during assembly. A dab of solder and it's been great ever since. Surely an isolated incident but it helps to see if it is preamp or power amp related.

Manehead said:

I got the same problem on my 90w Mark V, with the preset eq depth turned up on ch1, but eq not activated, I will get the crackling/breakup noise over what is otherwise a perfectly clean sound. I have to keep the ch1 preset depth at 0 to stop the noise.

seems like a design/component flaw if multiple amps are having the exact same issue.

Click to expand...

Tested this today and my amp has no such an issue no effect in tone if the eq is not active