Quote:
Originally Posted by felim
If they're only getting 40 watts from a pair of EL34s, aren't they being underutilised? Biased very cold? What kind of effect would that have on the tone?
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Bias MAY not have anything to do with it. Power output has more to do with plate voltage and output transformer size. You can have a very low plate voltage for low output power, and still bias it correctly. In fact, EL34's and other power tubes should sound their best at low plate voltages and high currents as they are operating closer to class A like that.
The Marshall Artist 30 hybrid amp in the JCM800 line (op amp preamp and tube output stage) used EL34's with low plate voltages and a small output transformer, got only 30 watts output but sounded great.
Another example is to compare a Fender Bassman head and a Bandmaster head. These amps are very similar except the Bandmaster has a smaller output transformer. You will pull fewer watts from the Bandmaster because of the smaller transformer (40 vs. 50 for the Bassman), and the tone is a lot different.
Finally, Marshall has been rating the power of their amps a bit strangely lately. Remember the "100 Marshall watts" comments, where the 100W heads were WAY louder than expected? The Marshall heads of old would measure 50 to 100 watts clean power, where distorted it would go way up from that. But take say a Vintage Modern, the 100W model puts out only 80W clean, and 100W at full distortion. The 50W model puts out 35W clean. So it's very possible that the Haze 40 is actually a 25 to 30W clean output amp. We probably won't know unless somebody at Marshall spills the beans or a tech gets one and measures it (that'll be the first thing I do to one when I get my hands on it).