Marshall amp

I own a Jcm 2000 Dsl 100 Marshall Tube amp, everytime I turn it up pass 2 it begins to lose high end and sound less piercing, like it totally changes tone with the loudness, because when it is 2 or lower you get a nice crunch high end presence piercing sound thats sounds great, but I turn it up louder it loses it. This is on Distortion BTW. Is there something wrong with my Marshall Head? And how do I know if the tubes or a tube needs to be changed? I have little knowledge with tube amps

How do you have your EQ set?

this is why:

http://www.webervst.com/fm.htm

basically your perception of pitch changes with loudness

the answer is to just readjust your EQ

Your tubes probably don't need to be changed... but your observation is one of the main observations that people make about tube amps. Solid state amps tone is in a 1:1 ratio with volume. Meaning the tone will stay exactly the same at all volumes... it won't change the way your distortion sounds or anything it will just be louder... obviously distortion always sounds better when it's louder. With tube amps you need to "saturate" the tubes to get the full tone. When you have your volume turned way down (below 4 or so, but it varies from tube amp to tube amp) the tubes aren't pushing as much tone as they can. Your ear has become accustomed to this tone and that's what it prefers... Like the other guys said... you'll have to crank her up and twiddle with the eq. You'll also notice that your amp probably sounds the best when it's been on for about 10 minutes or so.... This is becuase the tubes have heated up and the current flows more fluidly through heated tubes. Most people that by tube amps just to have them never really know what they sound like because they never get to turn them up past 4. I have a JCM 800 2x12 and I use an attentuator with it so I can pump full current to my tubes and still control the volume.

Volume and pitch perseption are intimately linked hence the Equal loudness contours or Fletcher-Munson curves that are seen with increasing volume.


It matters not a dicky-bird wether the volume is produced by a tube amp or a solid state amp, a telephone, a PA or a boom box as the physics is the same.

If you dont have a lot of money to spend look into the valvestate models. I have one that only has a 12 inch speaker and 100 watts, and it gets plenty loud and never looses its tone.