Originally Posted by
Rockfactor
In the late 90's I had to have a Marshall amplifier so grabbed a JCM900, 50W dual reverb with 2 x 12" speakers. Never really liked it too much and couldn't get the sounds I need.
I now use a modeller straight into the FOH desk 99.5% of the time. At two venues I plug the modeller into the fx return of the amp bypassing the preamp straight into the power amp section with the power switch set to 25W and the volume set to 2 1/2, so barely ticking over.
This now has me thinking, I'm not attached to the amp so maybe I could rebuild it into something more suitable. As an electrician come electrical engineer I know my way around electricity safely and have a fairly rudimentary understanding of tube amps so am contemplating rebuilding it as a 15W - 18W?
This would allow me to build the power amp section so I could use it with my modeller and then build some preamp modules to suit the sounds I'm looking for.
I replaced the 5881 valves with EL34s previously so I have a lead in question. As stated my understanding of valve amps is rudimentary at best but if all else stayed the same and I halved the amplifier voltage, this in turn would have the current so it would seem this would result in 1/4 the power output. Is this correct? I'm just contemplating if I can use the EL34 in a lower wattage amp or do I investigate using EL84?
Anyway I'm only at the maybe/what if stage so any thoughts, suggestions or harebrained schemes welcome.
Robbo
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