MP1 Preamp Tubes for Metal?

[toilinthedark]

So glad to see this forum back up!
I have an MP1 from way back. Only mod is a factory modded rear jack.
Not that happy with my tone, right now.
Rig: MP1, BBE 822, Mesa Simul-Class 295, Marshall 1960 4x12
I have always found that the BBE is essential with the MP1 to get the big, tight low end that I need for metal.
I have EMG 81's in my guitars and have not found gain to be wanting with the stock MP1.
Tunings - Standard E down to Drop A#
Was interested in modding the MP1, but wanted to start with tubes first. Swapped out the Groove Tubes for Mesa Boogie 12AX7 that I had lying around and the tone improved, but it's still not where I want it.

What I hear right now:
Distortion is fizzy
Power chords sound great, but palm muted notes are really weak. They just die instead of jumping out of the speaker. This is worse on the low string.
Overly compressed distortion
Single note leads don't sing. The sustain is poor and the tone is brittle.

I have been reading a lot about tube recommendations for the MP1 here and other forums. Was looking at the JJ. Was unsure of 83 or 803.
I have also read about making sure the gain rate is at least 110 Mu. How do I make sure a tube has this gain rate?
Thanks!!

[toilinthedark]

I do realize that some of these tonal shortfalls might be best addressed by some mods, but I wanted to start with a good preamp baseline.
The more I read, the more I am leaning to the JJ gold pin 803

[MarshallJMP]

Dougs tubes sells tubes with gain ratings over 110.You won't find these in off the shelf tubes.He doesn't sell the 803 but he has the ECC83S.These are Ruby branded but they are JJ's.

http://www.dougstubes.com/brands/ruby-tubes/ruby-12ax7-acz-high-grade.html

[ERX-71]

same hers i have a couple old ada's and love metal!!!the bbe sonic max is a must along with a alesis Quadraverb.  i just replaced tne pre tubes in one w/genalex-gold-lion and they are mean.  boogie ada marshall all in one
wonder if anyone else has tried them? lookin forward to hearing them in my 3tm mod

[Iperfungus]

Hi there!

In my MP-1 I tested many tubes and this is what my conclusions are:

1) I do not like Russian-made tubes inside the MP-1 (EHX, Sovtek, TungSol): they can make it sound a little "muddy" on some settings (expecially if you like basses)
2) beside the original red-label chinese 12AX7A tubes, the ones I love more are Ruby's Selected JJs ECC83s: plenty of gain and dynamics, good for rock and metal
3) Ei ECC83 tubes are great as well, less aggressive
4) Groove Tubes GT-7025 works fine inside the MP-1

Some TAD tubes (chinese) can do a good job with the MP-1, but I preferred them inside the Marshall JMP1.

Never tried Genalex.