Quick TS-808 question

[scottosan]

I love the sound of my clone, but I have noticed that it seems as if some frequencies of the signal is distorted and a some aren't.  If I really dig into the strings, it seems as if part of the signal it wet and some is dry. Is this normal?

[stm]

Yes, its normal. It is a consequence of the OpAmp configured in a non-inverting fashion, where the output signal is composed of the input signal plus a clipped version at the diodes' threshold. If the input signal is strong enough, the clean (dry) part of the output will dominate over the clipped part.

One way of reducing the effect of the clean signal being too strong is dropping the guitar volume knob a little (perhaps to 60% of its full rotation), and then moving the gain knob on the TS higher to compensate.  You will see the overall structure of the output is different.

EDIT: Perhaps you are using a very hot pickup, a booster in front of the TS, or another effect that increased the guitar's level.

Regards,

STM

[scottosan]

Yes, its normal. It is a consequence of the OpAmp configured in a non-inverting fashion, where the output signal is composed of the input signal plus a clipped version at the diodes' threshold. If the input signal is strong enough, the clean (dry) part of the output will dominate over the clipped part.

One way of reducing the effect of the clean signal being too strong is dropping the guitar volume knob a little (perhaps to 60% of its full rotation), and then moving the gain knob on the TS higher to compensate.  You will see the overall structure of the output is different.

EDIT: Perhaps you are using a very hot pickup, a booster in front of the TS, or another effect that increased the guitar's level.

Regards,

STM

I get the same effect with all of my guitars.  Could I possibly cahnge a value on the input impedance

[stm]

Point me to the schematic you are using and I could suggest a way to deal with it.

STM.

[scottosan]

Point me to the schematic you are using and I could suggest a way to deal with it.

STM.

http://www.generalguitargadgets.com/diagrams/ts-808_sc.gif

thanks

[stm]

There are several ways to reduce the "clean signal feedthrough" effect you mention, and all of them I will mention will reduce somewhat the maximum gain of the pedal (slightly). Try the following (one at a time):

1) Increase R1 to 510k

2) Place two 1N4148 in series in D1 and two series 1N4148 in D2

3) Replace D1 and D2 by red LED's (will increase apparent level as well)

Take notice that what you want to get rid of is normal and characteristic to the tube screamer. TAken alone, it is a "soft" distortion device.  If you want it to sound more overdriven/edgy you should use it to effectively overdrive a REAL VALVE guitar amp.

I rather think that you could be better with a heavier device like a DS-1 or Blue Clipper (see ROG and Tonepad).

Regards,

STM