High pitched squeal in a MKIII??

[Psyence88]

Hey there, I just obtained a '86 MKIII Blue stripe combo with Simulclass, reverb, EQ... etc... and I have to say it's pretty nice. Though when I went to crank it, I ended up getting this really, really loud high pitched squeal, I isolated the issue and it was completely from the amp(no guitar or cords or anything plugged in) I'm assuming the tubes are microphonic because I tapped the top of the amp and I could hear it being amplified. Thing is, I just re-tubed all the preamp tubes, so I'm guessing it could be the poweramp tubes? There is a good bit of hum going on as well, when the lead gain is brought up to around 8 or 10... There are some audible artifacts, I'm not sure how to describe it really, but they are there.

Also, can anyone recommend me a really good tube setup for some crushing metal tones? I bought a set of mesa boogie 12ax7s, they sound great but they sound a bit loose to me, any recommendations?

 

[MrMarkIII]

Hey there, I just obtained a '86 MKIII Blue stripe combo with Simulclass, reverb, EQ... etc... and I have to say it's pretty nice. Though when I went to crank it, I ended up getting this really, really loud high pitched squeal, I isolated the issue and it was completely from the amp(no guitar or cords or anything plugged in) I'm assuming the tubes are microphonic because I tapped the top of the amp and I could hear it being amplified. Thing is, I just re-tubed all the preamp tubes, so I'm guessing it could be the poweramp tubes? There is a good bit of hum going on as well, when the lead gain is brought up to around 8 or 10... There are some audible artifacts, I'm not sure how to describe it really, but they are there.

Also, can anyone recommend me a really good tube setup for some crushing metal tones? I bought a set of mesa boogie 12ax7s, they sound great but they sound a bit loose to me, any recommendations?

Any of the following controls: Volume, Treble, Master, Lead Drive, Lead Master, and Presence run at 8 or above simultaneously can lead to squealing, 'specially if any Pull Brights are also engaged. It's normal, normally. Try running it like this: Volume @ 10, Treble @ 7 (Pulled), Bass @ 2 (Pulled), Middle @ 7, Lead Gain @ 6, Lead Master @ 5, Master @ 5 (Pulled), Graphic in the classic "V", Presence @ 5. If this ain't metal (or loud) enuff, you need a Rectumfrier.

 

[Psyence88]

Hey there, I just obtained a '86 MKIII Blue stripe combo with Simulclass, reverb, EQ... etc... and I have to say it's pretty nice. Though when I went to crank it, I ended up getting this really, really loud high pitched squeal, I isolated the issue and it was completely from the amp(no guitar or cords or anything plugged in) I'm assuming the tubes are microphonic because I tapped the top of the amp and I could hear it being amplified. Thing is, I just re-tubed all the preamp tubes, so I'm guessing it could be the poweramp tubes? There is a good bit of hum going on as well, when the lead gain is brought up to around 8 or 10... There are some audible artifacts, I'm not sure how to describe it really, but they are there.

Also, can anyone recommend me a really good tube setup for some crushing metal tones? I bought a set of mesa boogie 12ax7s, they sound great but they sound a bit loose to me, any recommendations?

Any of the following controls: Volume, Treble, Master, Lead Drive, Lead Master, and Presence run at 8 or above simultaneously can lead to squealing, 'specially if any Pull Brights are also engaged. It's normal, normally. Try running it like this: Volume @ 10, Treble @ 7 (Pulled), Bass @ 2 (Pulled), Middle @ 7, Lead Gain @ 6, Lead Master @ 5, Master @ 5 (Pulled), Graphic in the classic "V", Presence @ 5. If this ain't metal (or loud) enuff, you need a Rectumfrier.

Very nice! Thank you, I will try this tomorrow when theres nobody home. Ha! Rectumfrier, hahaha... I think this could be the culprit because when I bring the EQ slider on the treble side all the way down it goes away, but as it gets louder it comes back, but when I bring down the next slider, it goes away... etc...

I'm not looking for anything extreme, just good metal, perhaps as crunchy as Petrucci's tone on Images and Words.