Running jcm 800 at half power?

[rocksoldier]

What would the difference in sound be?
I just thought it could be a good way to get a little more power tube breakup at lower volume, (not bedroom low, but the drummer doens´t like when i krank it...:P)
Also, could i just pull the outer or inner tubes and strart playing, or is bias adjustment or whatever required?
So tell me what you think.

[shreder75]

Re: Running jcm 800 at half power?

pull the two outter tubes, then halve the impedence on the head from whatever you have it at at full power

[ErikH]

Re: Running jcm 800 at half power?

If that doesn't work, get an attenuator.

You play with a drummer that doesn't like it cranked up? Man, all the drummers I've played with prefer it that way.

[shreder75]

Re: Running jcm 800 at half power?

tell the drummer to turn down..oh that's right, they can't! lol...

tell him to stop being a girlie man and suck it up ;0)

[DesertRose]

Re: Running jcm 800 at half power?

mine has just 2 power valves. nothing to pull out I guess

[shredaholic]

Re: Running jcm 800 at half power?

You probably won't even notice a volume reduction, just a change in tone. It'd be much more worthwhile to install a pentode/triode switch and run the amp on triode mode, then the actual volume (not wattage) will be about 60% what it was before.

[DesertRose]

Re: Running jcm 800 at half power?

heard that 25 watts is 78% of 50watts or something like that. So not really much in diff

[shreder75]

Re: Running jcm 800 at half power?

heard that 25 watts is 78% of 50watts or something like that. So not really much in diff

yeah, that's about right...

u lose more headroom than volume....I don't even boether with half power on my quick rod anymore...it sounds fuller at full power...heh, that's ironic...lol..


anywho, it's not worth the volume difference to me

[Koreldyre]

Re: Running jcm 800 at half power?

What would the difference in sound be?
I just thought it could be a good way to get a little more power tube breakup at lower volume, (not bedroom low, but the drummer doens´t like when i krank it...:P)
Also, could i just pull the outer or inner tubes and strart playing, or is bias adjustment or whatever required?
So tell me what you think.

You could pull out the outer two tubes to run at half power, however what you're seeking to do is overload the output transformer. To do that, you need to run it at 100-watt capacity. You will find it difficult to saturate a 100w transformer running at 50w.