screamermods

Asymmetric Clipping:

This is probably the favorite of the
serious builder because it is the
clipping stage where you can make
the most difference in the
characteristics of the distortion.

Your mod kit comes with one 1N4001
diode. Replace one of the 1N914
diodes. It doesn't matter which one,
as long as you put the 1N4001 in the
same direction as the 1N914 that you
took out. This will give you very light
second order harmonics (assymetrical
clipping). If you want more
pronounced asymmetrical clipping just
keep adding extra diods in series to
one side of the clipping stage...that
is...solder them end to end. to make
one long diode. This will also
increase your volume and decrease
distortion. This is what is going on
with many of the boutique overdrives
that are know for their transparent
boost properties such as Klon. You
can also use an LED instead of the
1N4001 because after all, an LED IS
just a diode. This is the formula for the
clipping stage of a Langraff overdrive -
1N914 + yellow LED.




To say that there are a lot of mods to do to a tube screamer is an understatement. I'm going to go over the 3 major ones and touch on 2 others. The first and easiest (only because you have an op amp socket :^) !) is changing the op amp. The original ts808 came with the JRC4558D op amp. A lot of the popular boutique pedal modders claim that the texas intruments RC4558P will make great improvements in tone. You can actually use any DUAL op amp such as TL072 or LM833...it really doesn't matter as long as the op amp is a DUAL DIP8 op amp. Before I get into the other mods, I want to talk about desoldering. If you have desoldering braid or a desoldering gun, then by all means...use it. But if you don't, it is not necessary for these mods. You only NEED to desolder if the component you are removing has 3 or more leads...and since the only components you will be removing are diodes and caps, you won't need to desolder. HOWEVER...you need to be very careful...not so much when removing the old component, but when replacing the new component, because you can rip the trice right off the circuit board if you try to push the leads into an existing solder joint that isn't thoroughly melted. So just be very gentle when removing and replacing components.


		Increasing frequency response and decreasing mid range hump: This is probably the most popular. Most people's beef with the TS series is the mid range hump. Replacing the .047uF cap with with a .22uF will give you more full range response and flatten out the mids.




	You can also swap the transistors. The MPSA18's are low gain, low noise. You can use any NPN transitor you like. 2N5088's are good. IMO, the 2N3904 is a good replacement. They are a little noisier, but I think they make the pedal a little more ballsier. You will need to desolder to change transistors though. This is not a popular mod and it is the general concensus that lower noise, lower gain transistors are better. Another mod that is very common when modifying stock Ibanez tubescreamers is lowering the 4.7K resistor for more distortion. Increasing the A500K pot to a A1MEG pot will do the same thing too. You can try it if you like, but I don't supply a lower value resistor in the mod kit and I do not recomend it. The reason is that your TS808 clone is true bypass and the mass produced Ibanez tubescreamers are not. Since some of the guitar signal is deminished by the JFET switch, increasing the gain doesn't really "increase the gain"....it only brings it back around to where it would be if it were true bypass. Lowering the 4.7K resistor on your true bypass ts808 will just create a lot of hiss.