80 watt speakers/ SS rectifier to add headroom to 40 watt amp?

[telerocker5150]

I recently acquired a SF pro reverb that im going to have rewired to blackface specs, therefore lowering it to 40 watts. In order to add clean headroom to those 40 watts, Would changing the speakers to weber californias (80 watt JBL d-120 clones) give me more headroom before it starts to break up? Ive also considering going to a solid state rectifier for the same reasons. The amp is currently 70 watts which is too much but id like to lower it to 40 yet still retain plenty of clean headroom for live playing. For those who have tried tube and solid state rectifiers, What are you thoughts?
Thanks

[Tim Armstrong]

It'll take more than rewiring to make a 70 watt Pro Reverb into a 40 watter! You'll have to change the output transformer, too, at the very least!

Can't say weather you'll get more headroom from those speakers, since I don't know what speakers you have presently.

Seriously, I wouldn't try to blackface that amp. It's got a whole lot of clean headroom as-is. The only reason to make it less powerful would be to dirty it up...

Tim

[telerocker5150]

The reason im having it blackfaced is because 70 watts is more than i want. I played a kustom coupe 36 for about 2 and a half years straight and it was plenty. I want it blackfaced and back to 40 watts, but i want the cleanest forty watts possible

[Tim Armstrong]

The cleanest 40 watts possible would be your amp turned down to 7.

Seriously, a 70 watt amp is only a little bit louder than a 40 watt amp. To double the volume of a 40 watt amp, you need an amp that puts out around 400 watts.

Besides, the 70 watt version of the Pro Reverb can't really BE turned into a 40 watt BF version without basically ripping it apart and redoing the whole power amp portion. It's a whole different amp, compared to the earlier 40 watt BF and SF Pro Reverb.

If you want clean headroom, you already have an amp that's gonna provide it.

Tim

[marshman]

Well, the power rating of the speakers doesn't really tell you how 'loud' they're gonna be--for that you need efficiency, rated in dB. Since it's unlikely you'll have reasonable data for the speakers currently in the amp (but presuming they're 30+ year-old originals), I'd say you're looking for something in the 99db and above range, perhaps more.

Tim is right, of course. Trying to reduce power output and then counter that by modifications that increase headroom is a lot of money spent on going literally nowhere. You may be able to tweak a little, but to truly BF that amp it's going to require a serious overhaul, including AT LEAST new OT.

Why not just pretend it's a Twin and call it a day?

[telerocker5150]

Thats what i will most likely do. It seems that will be the most simple way to do it. Thanks