My second express, a little help please

[Mont]

First of all thanks again to all the guys at TAG for helping me with my first wreck. it's been kicking some ass for over a year now. I just finished my second express and everything is great except the more I turn it up, the flatter it sounds. any suggestions?

[selloutrr]

leaky cap?

lame preamp tube?

stressed speaker?

ear fatigue?

[Mont]

It reacts the same with no matter what tubes are in it or what speaker cab I use.

[passfan]

Have you gone through yet and matched voltages to the chart to see if anything is off?

[selloutrr]

I know you said you have tried other tubes - power tubes as well?
could be the power tubes compressing?

if it's not the power tubes look for a leaky cap.

did you meter and test your parts before you soldered them in place?

[Mont]

Yeah, I tested all the parts both caps and resistors and everything met or exceeded the tolerances on the franchesca build. and yes i tried 3 different sets of power tubes. the amp sounds great till I get it about half way up and then it goes flat. no gain just loud and flat.

[Mont]

And yeah all my voltages are good.

[JamesHealey]

Bad volume pot?

[ampmike]

I had a somthing like that and it was the ground on the vol pot.Mayby a bad solder,Good Luck,Mikey

[Ian444]

What do you mean by flat? No more volume, or compressed, or lack of treble response? Is the amp making the expected power?

[KellyBass]

Did you try another PI tube when you tried different preamp tubes?

[Mont]

I did change the pi tube as well when I tried other tubes. switching out volume pots had no effect. a friend told me sometimes when an amp has too much gain it will still be loud but sound flat and dull when it is cranked. any thoughts on this?

[Mont]

everything is reading right, all voltages. it is just as loud as my first express build. but once I start turning it up past 6 it starts to lose tone and no harmonic content whatsoever. just dull and loud

[guitarmike2107]

are you saying it is loosing the high end?

What output transformer have you used?

[Mont]

yeah, it has no high end, no gain. it sounds woofy, if that makes any sense. the trannies are both heyboer.