How about a 20 Watt speaker in a Tweed Deluxe

[d. spree]

I am about to start an amp build - Tweed Deluxe - having recently received tha chassis kit from Bruce at Mission Amps. I have been busy working on the cabinet and am almost ready to think about mounting a speaker. The cabinet is a standard Tweed Deluxe cab set up for a 12" speaker.

I have have available two 12" speakers. The first is an 8 ohm 50 watt MOD speaker which in my view is not particularly great and not the best speaker for this amp.

The second - which I would prefer to use is an 8 ohm 20 watt Weber AlNiCo 12A125A Vintage Series. I understand that the Tweed Deluxe amp produces about 12 watts (maybe a little more). I would like to use the Weber AlNiCo as it is a much better quality speaker. I don't want to destroy the speaker and wonder if it is sufficient for teh amp's output. Any thoughts on the suitability of the Weber with its 20 watt rating?

[Jazz P Bass]

A 20 watt speaker driven by a 12 watt amp.
Sounds like a safe bet.

[tubeswell]

Yes I'd try the Weber first and see how you like it. If it isn't already broken in, it will sound a bit funny for a wee while at first. A 5E3 is more typically around 15-18W, but the Weber should still be fine. Don't dime it to begin with. If it starts to make funny noises at louder volumes, then try something else.

[pdf64]

A 5E3 is more typically around 15-18W

That's more than I'd expect? The RI schematic advises 12.5 watts @370vB+.
http://support.fender.com/schematics..._schematic.pdf
Pete.

[wyatt]

The Webers are generally rated for RMS wattage.

His 20-watt speakers will be perfectly fine in a 5E3, which if stock is around 12-15 watts RMS. Actually the Weber 12A125 is probably one of the most popular speaker for a 5E3, it's closer to a vintage P12Q than the Jensen RI.

[greekie]

The stock wattage is usually what the amp can do relatively clean. The number varies - some measure at 1% THD some at 10% THD. Go figure.

How ever, when an amp like this is dimed and overdriving, it might deliver twice the rated amount. This is indeed true for many older 50 watt Marshalls that can sure cook a pair of Greenbacks!

[pdf64]

My findings are that a 5E3 doesn't put out much more overdriven power than clean power, due to squish and sag constricting the B+ available for signal swing, both at the plate and screen nodes (measured with a true rms meter).
But the point about putting 50 watts of speaker on to a regular 50 watt amp is worth making! Pete.

[greekie]

OK - to be honest, I haven't measured a 5E3. But I'm always a bit cautious with stuff like that. Put a 100 ohm 10W resistor over the 8 ohm tap - that'll keep you somewhat safe if the speaker fails.