Wiadomość #15331

[lord_awesomeguy]

Znalazłem coś ciekawego:

Alu wrote:I could give you some stupid tips about what you can do to "electronically" change the sound on MKIII...

1) Want a slighty different sound? Really simple, change the character of the tubes! It makes a pretty audible difference, expecially on the Power Amp section... I usually set the first preamp stage as "bright" to get more bite/clarity... if it is not enough I set to bright the second stage and so on...
I do not set the power amp tubes to "bright" cause it will sound too fizzy, I prefer "Clean" or "Round"

2a) Want more or less gain? Ok, then click on "Edit Internals..." and mess around with the MU parameter. MU represents the amplification factor (theorically 100 for 12AX7), so increase it to have more gain, decrease it to have less gain...

2b) Want more gain and a different distortion character? Go into the third gain stage where you can find the 39K cathode resistor and lower the value to 10K for example... this should give you more distortion and a different saturation type (kinda more symmetrical)...

3) Want less gain to get more clarity? Ok, go into the second stage and switch the tube to 12AU7... 12AU7 tubes have a lot less gain (just check the MU parameter :wink: ) compared to 12AX7, but they work good with Peavey hi-gain amps cause they're all overgained (basically Soldano SLO copies with shitty components and more (useless) gain stages :roll: )

4) Want less fizzyness? Increase the Grid Resistor value... the grid resistor, paired with the Miller capacitance of the tubes, makes a RC filter... changing the resistor you can change the cut frequency: let's say the cut starts at 2.2KHz (classic 470KOhm resistor used on hi gain amps) then higher resistor value = cut earlier than 2.2KHz (ex. 1KHz) = less fizzyness, lower resistor value = cut after 2.2KHz (ex. 3.5KHz) = more fizzyness/brightness
Basically, f = 1/(2*pi*R*C) where f is the cut frequency described above, pi = 3.14, R = grid resistor value, and C is around 150 picoFarad for standard 12AX7 tubes.
On the first tube stage you have 68KOhm on the grid resistor, this is a common standard for more or less all the amplifiers and I think is right as is... if you want to change it, do it slightly, or you could easily kill the sound (you're basically tweaking your guitar clean signal before it hits the tubes!)

5) Want more gain and more lows? Increase the value for the cathode capacitor... Want less gain and less lows, do the opposite!

6) Want a tight and clear low end response...? theorically, setting the rectifier of the power supply to "Ideal power supply" should do the trick... setting the output transformer to Overmatched or more (Solid or Transparent) should help too...

7a) Want more clear/tight/modern sound? Increase the plate voltage

7b) Want a kinda "brown" sound? Decrease the plate voltage

This is how real tubes SHOULD work more or less (I'm not 100% sure cause I'm still learning, these are all infos I've taken from the net during my studies to build tube preamps... so just try by yourself )