taming the liverpool high end?

[pinkmarkos]

hello everybody- i built a liverpool a few months back, and i have tried everything i can think of and have seen mentioned in other posts to try to tame the high end in the liverpool. i like everything about this amp except the fact that it seems to have just a little too much high end. for R7/C8 i have 68k/.0047 and that helped a little bit. i also put a 500pf cap into C2 ala the express, but that didn't do much. i tried 100pf, 500pf, and even a .001 for the bright cap values. 500pf is very close to how i like it to sound, just a little too piercing, and with the bright switch off, it is just a tad muddy, but also close to what i'm looking for.
ironically, my express doesn't have this problem even though i have the pre wired up the same, maybe its the difference between the el34s and the el84s.
i play through a closed 2x12 with a v30 and a g12h30, which i realize aren't really known for their "mellow" tone, but i was hoping i could make a cheaper fix than two new speakers. any advice from the TW sages would be much appreciated.

[ckpop]

Here are a couple of things to try to see if they work. You can use a female to female coupler and extend the lenght of your guitar cable to roll a little of the high end off.
Second I'm not a big fan of a power attenuator on the Express but on a Liverpool one or two clicks down works great. The high end of the Liverpool and the slight roll off of the attenuator balance out nicely.
The third is your fizz cap in the phase inverter I stuck with the orginal 100pf instead of 47pf. This is a slight difference but another trick to tame the harshness of the top end slightly.

I do find the Liverpool to be a brighter amp then the Express mainly due to the EL84's and the vox like EQ. Sometimes bright can be good to really cut in the mix of a band as long as it is not harsh sounding. The trick is the right balance to retain definition and brightness and eliminate the harshness.

[El_Martin]

Hi!

Try searching "conjunctive AND filter". Ho about different speakers? Or some additional damping cloth in front of the speaker? Easy to try and removable.
Whats good for living rooms might not be good on stage...

Ciao
Martin

[pinkmarkos]

thanks for the suggestions- i think i will try the longer guitar cords with the coupler, i just remembered that glen does this to reduce the high end. also- i did (re)search the conjunctive filter and i am curious if anyone else is using this method, and what their results were.
lastly, what is the expected effect of putting caps across the plate resistors? i saw this technique on some of the blues express schems and am curious.
thanks again!

[pinkmarkos]

ckpop- thanks for your suggestion about the PI cap- i changed mine to 100pf, put a 500pf cap back in the bright switch- and now I have complete awesomeness. finally unlocked the tone i knew was hiding in this amp. it's like a perfect marriage of a non-master marshall and a cranked AC30. its brilliant. thanks again for everyone's help