#1
I am wondering how does the tube poweramp affects the quality (not quantity) of the sound on an amp.

What would happen if someone would modify 100W AMP JCM 800 and replace the 100W poweramp witha 5W power amp,

would it sound the same but quieter ? when cranked all the way up
#3
The power amp tubes are what colors the amps sound. If you did that modification, if it worked, yes it would be quiter, but that's not done by changing anything with the tubes. I don't know for certain, but I imagine that lots of other things would need changed also, like the resistance of the circuit and the biasing of the tubes. Your best bet would be to buy or build an attenuator if your amp doesn't have a master volume. I can't imagine modifying it like that would be a good thing though, and it probably would affect the sound and not for the better.
Last edited by Kentris.5 at Feb 20, 2008,
#4
It would of course sound different, but it's impossible to tell how. The change would depend on the circuit, and you can't just magically knock a 100w circuit down to 5w. It's not actually something you can do anyway, since modding the power section that much would cost more than the amp itself.

Assuming you made the circuit sound similar to the original, a smaller power section would be quieter when cranked, less headroom, less bass, etc.

Basically I tried to answer your question theoretically, since in reality it's a dumb idea.
#5
Quote by Roc8995
It would of course sound different, but it's impossible to tell how. The change would depend on the circuit, and you can't just magically knock a 100w circuit down to 5w. It's not actually something you can do anyway, since modding the power section that much would cost more than the amp itself.

Assuming you made the circuit sound similar to the original, a smaller power section would be quieter when cranked, less headroom, less bass, etc.

Basically I tried to answer your question theoretically, since in reality it's a dumb idea.


I found a website that shows sells the kit to build your own jcm 800, it comes with schematics for the power amp and preamp. I am just wondering if anyone had tried building the preamp (preamps process the sound at 1 watt level) and send that to a smaller poweramp sinted of 100 W, 5W, or 1 W.
#6
The power amp tubes are what colors the amps sound.


The pre-amp shapes the sound. The power-amp boosts the signal to a level high enough to drive the speakers. Though keep in mind that amps like the JCM 800 derive the majority of their tone through pushing the power tubes.
Someones knowledge of guitar companies spelling determines what amps you can own. Really smart people can own things like Framus because they sound like they might be spelled with a "y" but they aren't.
#7
Quote by DrEvil
I found a website that shows sells the kit to build your own jcm 800, it comes with schematics for the power amp and preamp. I am just wondering if anyone had tried building the preamp (preamps process the sound at 1 watt level) and send that to a smaller poweramp sinted of 100 W, 5W, or 1 W.


It won't sound like a JCM800 anymore. Half the amp's sound (or more) is in the poweramp section.

Fenders are a good example. They have nearly the same preamp in most models, yet they all sound different (speakers play a big part here too).