Vibrolux Headroom

[drewl]

Working on a silverface Vibrolux Reverb here that the customer wants more clean headroom.
It's a later one with the odd PI values, pull boost was removed sometime in it's lifetime so I'm going through it to make sure it's right.
Will changing the phase inverter to blackface specs give it any more clean headroom?
I recapped and biased it which helped a bit.
Any other suggestions without going nuts on it?
Thanks.
Andrew.

[MWJB]

BF PI won't necessarilly give a cleaner tone.

Quick & easy mods -try 12AT7 or GE5751 in the preamp (V1 or V2), maybe even a 12AU7 in the PI? SS rectifier, 100uf first filter cap, US made 7581A power tubes, reduce values of power supply dropping resistors to push up preamp voltages, cleaner speakers...and most importantly get the player to use tilt back legs or get the amp up at head height so they can properly hear what's coming out of the speakers, rather than have a cooling breeze around their ankles.

[Alex R]

I have had one of these around for a while. It has a great breakup sound. It's cleans are sweet, soft and springy. The owner and I have been playing around with it for a while. Blackface-type changes make it break up a little bit sooner still. A guy came in with a PRS and tried it and there were virtually no cleans at all, the output of that guitar was so high.

I think that MWJB's ideas will indeed give a bit more headroom, but I doubt it will satisfy the customer, as in trying for that you are working against the nature of the amp, particularly the lower voltages. This is just plain not an amp with loads of chimy Fender headroom. Lots of buyers think all Fenders give loud clean chime like a Twin, or even a Super, and it ain't so.

The Silverface circuit was after all arguably Fender's best shot at getting clean headroom from this class & size of amp.

People who like Fenders buy these - and Deluxes - and are surprised how early they break up. Well they're not Twins, say I. They are beautiful-sounding amps though, easy to find a place where a soft touch will play clean and sweet, whilst a stronger note will crunch nicely.