Peavey Classic 30 cant handle low end from 2001 Gibson R8 Les Paul

[cyclist]

My classic 30 has a celestion g12h30 70th anniversary speaker and toms tube tamer both fitted to it. My 2001 R8 les paul has florance voodoo 59 pafs fitted to it. I only use the clean channel on the amp , reverb off, bass 6.5 , mid 4.5 and treb 6. If I play below 4 on the master vol it is fine, but vols greater than 4 and on the neck pickup, if I play on the low E or A strings, the cabinet just cant handle it and it vibrates very audibly , a single coill strat doesnt exhibit this problem. There is a serious low end from this very resonant historic les paul indeed, is there any way to eliminate the cab vibration with a les paul being played at > 4 on the master vol ? the outputs of the pafs are 7.1 k / 7.9 k neck / bridge respectively.

All advice will be gratefully received.

[oc disorder]

I'll try to avoid being a smart Alec saying turn the bass control down to 2 although there is some merit in that!
The output tubes when worn can develop a rumbling sound even though you have
Toms Tube Tamer fitted.
To check this try tapping the output tubes with a pen or similar and see if they rumble.
Next (this will be a bit of a pain to do !) remove the amp chassis from the box extend the speaker wires and see if the rumble/vibration is just the box and speaker and not the amp (or tubes) vibrating in sympathy. You may have to construct some sorta
jig to rest the amp in (old text books or scaps of wood) so that it is physically seperated from the cabinet.
If it is just the box some additional bracing may be required.
Check that the baffle is fixed securely (the board the speaker is mounted on) and that the cabinet overall is solid.
It may be the resonance of the speaker combined with the resonance of the box are creating this.
Trying another speaker is another alternative...
I presume the impedence of the speaker is correct although I would think that would have a relatively minimal effect on the problem.

Thats about all I can think of...

[Enzo]

The Classic 30 has a tendency for the phase inverter to clip when turned above 4 or 5. COuld you be hearing that? The waveforms of low notes are much larger than the high notes and so would be more likely to clip that stage.

How does the original speaker perform?

[1ampman]

These amps are brutal on the EL84 outputs. Any brand of tubes get rattled to death in no time. I'd plug into an extension cab and see which is the problem? Also that Celestion is noted for more bottom end that others. Experiment till you pinpoint the problem. I don't think that amp is that robust to handle a good pounding for very long. They sound very nice. Lastly check the screws holding the speaker and baffle board. I'm curious to what you find?