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previous: Bill Williams Subject says it all. Can someone e... -- 1/28/1999 1:20 PM View Thread

Re: explain Mesa half power switch?

2/1/1999 1:49 PM
Re: explain Mesa half power switch?
The other guys have covered how this 1/2 power thing is accomplished.  
Removing or disconnecting two of the four tubes can't hurt anything in your Showman, and you can leave the speaker load mismatched. This will lower the maximum power the amp can produce, but you may not notice much in the way of actual loudness reduction, unless driving the amp hard.  
I put a half-power switch, lifting the cathodes of one p-p pair, in a Twin Reverb amp (basically same amp in combo format). I was rather disappointed that there wasn't much difference for the work I expended to do the job neatly.  
If you've upgraded to new speakers which are more efficient, this amp will be even louder than it was when it was new. As far as speakers go, a 6db increase in efficiency will double the sound output. I hope you're not using Vintage 30s!