My Mark V is irritating me... Snap, crackle, pop...

[jgcable]

I read that the new Mesa Mark VI doesn't have that problem. It has anti-crackle modulation circuitry.

[warlok]

Yell as loud as you can through your highest output pickup!! I'll translate for you... Hey Senior Burro Radioaficionado.... Callate!!! (Hey Mr. Jackass Radio Operator... Shut Up!!!)

[emperor_black]

it proly crackles 'cause you're trying to play jazz on it!

[Trussrod]

Maybe someone local is using ham radio equipment that isn't FCC compliant. It sounds more like a grounding issue and could be a component that is going bad.

[MakeAJazzNoiseHere]

Why don't you take it (I know the Mark V combos are heavy but still) to a friend's house and see if you get the same effect there?

I can't even get the same effect all the time at home, so what would that prove? :think:

Working fine again this morning...

Vass, I have been reading that thread you linked, thanks for the info. I suppose there could be some fault with the amp that makes it more susceptible to this kind of noise but I tend to think there's nothing wrong with it based on the fact it doesn't have any other symptoms (bad tone, loss of volume/power, etc.) that indicate a problem.

[toejam]

Send an email to Mesa and see if they can help. Their customer service is usually pretty good.

[Cygnus X1]

Have you opened it up?
Do you feel competent to do so?

Nearly all guitar amps have a resistor in line between the positive
of the input and the tube.
Normally 68K.
The reason that resistor is there is to cut down on external RF interference.
I'd look at that.

Another thing to consider-one of the input jacks shorting lugs designed
to turn that input "off" when not in use might be dirty and picking up
intermittent stray RF.
Spray a little contact cleaner in those jacks and fuggem with a cable.

[MakeAJazzNoiseHere]

Cygnus, I wouldn't mind opening it up but I don't know which caps/what to stay away from, so I'm not sure I'd want to touch anything. Definitely not going to solder anything, it's under warranty, and I'd like to keep it that way.

I've talked to MESA about it. They're willing to have me send it in, or there are two repair depots in the city, but said they don't think they'll find anything wrong, based on the fact that it can be used for hours and never have an issue.

I tend to agree with that - if you can't replicate the problem it is going to be pretty damned hard to track it down and fix it. :dunno:

If I was sure it was my wiring or someone with a radio transmitter nearby I'd just deal with it/forget about it/whatever but that's damned hard to prove without a 2nd amp.

[Cygnus X1]

I check input RF sensitivity using a cell phone.
Works every time.

I used to use a very old Texas Instruments calculator, vintage 1979...
press a key, and it would pick it up, or not, depending on the health
of the circuit in the amp.

Doesn't do you much good, you already know there's a problem.
Let Mesa look at it then.

Those techs sound like they're being lazy.

[MakeAJazzNoiseHere]

Oh, it definitely picks up cell phone interference. It would make sense that they should have something to generate interference.

Yeah, it's kind of got me worn out at the moment. I don't even feel like playing. But I did kick it on this evening and let it warm up for about 5 minutes, took it off standby and it was crackling again.

So, I'm 4 for 4 on evenings, 0 for 4 on mornings. I'm pretty sure I've been able to do it in the afternoon before, but it was on a weekend... Still got my radio operator theory on my mind.

There's a place across town that's been in business for a while, they're an authorized repair center, I kind of want to just go dump it off on them and let them deal with it. In fact I think I will.... There's got to be something they can do about this? :think:

[jgcable]

Just drop it off and stop worrying about it.
If you aren't a tech you aren't going to be able to diagnose or repair it.
Leave it to an authorized tech. They will figure it out and you can stop stressing about it.
It probably has a ground that has either a cold solder joint or a loose connection somewhere.
You are lucky to have an authorized place across town. Many people would have to send the amp out.

[Grim]

Just drop it off and stop worrying about it.
If you aren't a tech you aren't going to be able to diagnose or repair it.
Leave it to an authorized tech. They will figure it out and you can stop stressing about it.
It probably has a ground that has either a cold solder joint or a loose connection somewhere.
You are lucky to have an authorized place across town. Many people would have to send the amp out.

Seconded. Just get it checked out. The closest Mesa dealer to me is

Well, it's 10 minutes away, but that's not the point. That is a long haul in a Canadian winter!

[Trussrod]

I'd expect more RFI in the evening, too. Have it serviced and if that doesn't fix it have Mesa exchange it.

[MakeAJazzNoiseHere]

I just wanted to rule out the possibility of a bad tube being a cause, because that's easy to fix. I don't really want to take it in to the repair depot for a month to hear "it was a bad preamp tube" or "we couldn't replicate the problem."

[Vass]

I think we have a winner. Your comment regarding when you have the problem is as close to a smoking gun as you're going to get without running some sort of test yourself.

Shortwave reception is much better at night than it is during the day. Early evening in fact can be some of the best of all.

I know this because my grandfather is/was a big shortwave guy.... Has the huge aerial in the yard, the whole thing.

Based on the observation that you're having problems at night, I'd feel confident telling them, as a place to start, that whatever they use to attenuate shortwave in their amps isn't working properly.

You could wrap your whole amp in tin foil as an alternative.... But you'd have to run it on battery and wrap that too to keep the signal out