Why are Expresses so unstable?

[M Fowler]

I don't understand why people want a balanced PI in musical instrument amplification?

[matt h]

(deleted)

[EtherealWidow]

I just love how this amp breaks a lot of text book rules but sounds amazing.

[Mark]

I haven't found Liverpool amps to be unstable, I haven't thought Express amps to be unstable provided you follow good lead dress.

[cbass]

I think they're unstable cause both transformers are on the same side.making it want to tip if you grab it by the middle.

[jelle]

Also, the chassis on those is quite thin. Be careful throwing it into the tourbus!

[martin manning]

I've often wondered if that flimsy chassis wasn't responsible for some harmonic content.

[John_P_WI]

I've often wondered if that flimsy chassis wasn't responsible for some harmonic content.

+1, like the trem springs on a strat....

[vibratoking]

I've often wondered if that flimsy chassis wasn't responsible for some harmonic content.

Can I ask more about your theory? What is the mechanism? IMO, my Express sounds the same whether it's sitting on the speaker cab or away from it, unless I have noisy tubes subject to vibration. Also seems like the harmonic content would change depending on how tightly the chassis is bolted to the cab. Just wondering about your thoughts.

[kwijabo]

i've never used the thin chassis, but i too have wondered if that leads to some issues.

I haven't found Liverpool amps to be unstable, I haven't thought Express amps to be unstable provided you follow good lead dress

i've done two liverpools and one express. neither liverpool gave me any issues and one of them deviated from lead-dress to a high degree. not sure why but the express seemed to be more particular to what pre-amp tubes were used. strange since they're preamp and PI layouts are so similar.

[BIG Dave]

I think they're unstable cause both transformers are on the same side.making it want to tip if you grab it by the middle.

That was very funny!