Why does my amp get dirtier the longer I leave it on?

Mark I's, II's, III's and the almight IV

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camsna
Mark IV
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Joined: Thu Feb 21, 2008 1:51 pm

Why does my amp get dirtier the longer I leave it on?

Post by camsna » Fri Oct 06, 2017 7:42 am

I had never experienced this before. Start the amp (Mk III) beautiful, sparkling cleans. After about an hour, still beautiful, but not sparkling; crunching.

Weird.

Put it in standby for 40 minutes — sparkling again.

As long as I turn the amp off or put it on standby between sets, it stays clean. Leave it on and it goes dirty after and hour or so. And not subtly so. Clean channel is like R2 crunchy.

What gives?

treedroppings
Mark II
Posts: 137
Joined: Sat Aug 05, 2006 11:15 pm
Location: San Jose, CA

Re: Why does my amp get dirtier the longer I leave it on?

Post by treedroppings » Wed Oct 18, 2017 4:41 am

maybe you need a mark 1

I used my mark 3 in 1988 to play Slayer and Judas Priest songs with a Jackson
2006 Fender Lite Ash Strat
2012 US Gibson Firebird V
1990 Boogie Mark 1 Reissue
2-12 Sapele Cab

Music: from blues to thrash and back! (allman bros, exodus, saxon, tcf, robert johnson)

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Markedman
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Location: Norfolk, CT

Re: Why does my amp get dirtier the longer I leave it on?

Post by Markedman » Thu Oct 19, 2017 1:42 pm

[quote=

I used my mark 3 in 1988 to play Slayer and Judas Priest songs with a Jackson[/quote]

You lucky dog! Mesa/Boogie and Jackson ruled back then. I had 2 custom made Jacksons, well, still have them, back then but couldn't afford the Mesa so I went with a Marshall JCM 800.

I never played a Mesa until about 5 years ago when I stumbled upon a Mark IV at a pawn shop for $650. I sold off most of my Marshall and Fender amps last year as they were collecting dust. I'll be keeping the Jackson guitars though they never get played anymore. I like my Steinberger GR4 guitars today.

As for the OP, something in your amp is old and needs to be replaced. Don't try to fix it yourself, you'll just get shocked! It's tune up time, just do it, now is not the time to procrastinate over something this important. When the amp comes back and you are howling/barking at the moon, we'll share a drink.
JP2C, Mark llC++ DG, Mark IV-A/B.

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screamingdaisy
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Location: South of Heaven

Re: Why does my amp get dirtier the longer I leave it on?

Post by screamingdaisy » Fri Oct 20, 2017 7:40 pm

Every Mesa I've owned starts off stiff and harsh while cold, then starts to get smoother and more compressed as they heat up. Usually takes about 15-20 minutes of playing before they get hot enough to compress.

The trick is to dial the amp in while hot.
Ignore the hype and trust your ears. Play more, buy less = better tone.

treedroppings
Mark II
Posts: 137
Joined: Sat Aug 05, 2006 11:15 pm
Location: San Jose, CA

Re: Why does my amp get dirtier the longer I leave it on?

Post by treedroppings » Sat Oct 21, 2017 1:39 am

Time to check out the clean channel and try a tube screamer until you can afford repairs. I know it's blasphemy,but you said you wanted a clean sound. And if it gets dirty on that channel you know you've got a problem.

Play with every switch/knob and see what happens, you could also take a chopstick and hit the tubes to see if any one of them makes a strange noise.

My Mark 1 is a '91 and I had to get the filter caps replaced because I got it in 2009, sounded like 80 dB on Ten! I got it for a Triple XXX combo straight trade, but a Boogie is so much louder after it was repaired 8) !
2006 Fender Lite Ash Strat
2012 US Gibson Firebird V
1990 Boogie Mark 1 Reissue
2-12 Sapele Cab

Music: from blues to thrash and back! (allman bros, exodus, saxon, tcf, robert johnson)

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