# Theoretical power question

Discussion in 'Amps and Cabs [BG]' started by Buzz Fretboard, Jun 29, 2002.

1. ### Buzz Fretboard

The subject of power and loudness has, to me, always been one of black magic rather than science, so here's probably a complicated question asked simply.

Suppose you want to build your own amp. You have a design for something that'll put 100 watts into 4 ohms. In theory, if you were to duplicate it, such that you had 2 4-ohm speakers in one cab, one pre-amp driving 2 power amps, and each amp putting 100 watts to one speaker, would you then have 200 watts, or two 100 watt sides?

I would like to build my own amp to be able to take to the occasional gig (I have no illusions of playing anything larger than a pub or club), but so far no one I've asked who went and bought something huge and, for me, WAY too expensive, has ever told me IF they gig, much less how big the audience is. So for my second question, does anyone gig with 200 watts or less? And if you do, what size of place are you gigging in?

Freddie singing, Jimi on lead, Keith on drums and now John on bass....now that'd be a gig!!

2. ### Rockin John

Dec 20, 2000
Leicestershire, UK.
You certainly would have 200 watts total. The fact that it's split into 2, 100 watt halves is by the by.

200 watts is, of course, not twice as loud as 100 Watts. It's a log10 thing so you'd need 1000 watts to be twice as loud as 100.

I've played small clubs with less than 100 watts. With 200, a decent preamp and good speakers there shouldn't be a problem.

Last week I rehersed with a 50 watt valve amp I'd repaired and restored (50 watt valve amps are good for about 35 watts RMS, clean signal). It wasn't loud enough, but not by that much.

Regards.

John