Herbert loose bottom end...need help-solved-

Just picked up a Herbert mkii loaded with JJ KT77's and JJ 12ax7's in the preamp. Channel two sounds like it's lacking attack and girth, channel three has a loose low end while palm muting. The note return is sluggish and fuzzy. I'm playing through a Mesa 4x12 traditional cab. In comparison, my EVH 5150iii has more attack and tighter more brutal bottom end while palm muting. My first guess is that it needs new tubes in the preamp since v1 is microphonic. There might be others that are bad too. The guy I bought it from (online sale, bought used, so I never heard it prior) said it was fine and the tubes are only 3 months old. Also when on channel three, if I drop guitar volume and increase master volume on the amp, a terrible high pitch ring/oscillation ensues.

Would bad preamp tubes cause the Herbert to react this way - aside from the microphonics...loose bottom end, lack luster attack, etc?

Please help!

There is honestly a lot of factors that would cause a loose bottom end man. Are you playing the evh through the same cab, what are the herberts eq settings since different amps respond differently in the eq, amount of gain being used... Beyond the tubes theres a whole mess of things that can cause it.

The herbert is definitely not a super loose amp though

Playing the EVH thru same cab, guitar, room. The Herbert bass setting is very very low around 9 o'clock and the depth is all the way off! I have tried various eq settings to see how the Herbert reacts and its still boomy and sags. Gain is around 11 or 12 o'clock so it's pretty conservative. Treble is around 1 o'clock or so and mids around 12.

The Herbert definitely has an inherent sag/squish to the initial attack of the note. The boominess and particularly the oscillation sound like it could be a tube issue, though. But it could be other things.

I like a little sag but this is too saggy, Rectifier saggy.

(Edit) Please contact me:

peterdiezel (at) diezelamplification (dot) com

Replaced the tube in v1...problem solved! Amp is breathing fire!

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Good news - normally it's tubes, modern tubes can be pretty poor in terms of quality! I always go with Papa's recommended tubes in my Herbert, no issues so far, it's a monster amp!!!

I can second this, I usually play strong tested vintage tubes, if they've lasted this long. And still test as new.....

I've tested more new tubes that test below new than vintage tubes