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Mods and Modified Versions

Conversion to TS808 - this seems to be a perennial hot one. Simple... just locate the 470 ohm and 100k resistors on the output buffer transistor, tracing back from the output jack, and replace them with a 100 ohm and a 10K. Bang, instant 808. If you're doing this to a TS 10, short out the 1K resistor leading to pin 3 of the dual opamp as well. A variation of this mod is to add more bass response as in the next mod. This is sometimes referred to as making it have a "browner" sound.

More bass - remember that 4.7K/0.047uF network on the (-) input of the clipping amp? To give yourself more bass, increase that cap to about 0.1uF. The (-) input is pin 2.

More distortion - everybody's favorite. No problem here. If you want more distortion, lower that 4.7K to get more gain when the drive control is maxxed out. If you don't also want to change the bass/treble response, you will need to change the capacitor as well. If you half the resistor, double the capacitor to keep the same overall frequency response.

It is theoretically possible to just use a higher value pot in the drive control, but you're unlikely to find a replacement for the micro-sized pots used in the original case. This is a possibility if you rip the circuit board out of the original box and install it in another box of your own choosing. This is not as crazy as it sounds, especially for the potato-bug TS5 as the plastic case is essentially useless no matter how good the circuit sounds. This leaves room for a true bypass switch as well.

Note that if you take the step to go to a box that lets you use different pots, you can also add switches for other functions like changing the bass response by switching in another capacitor, switching in other gain resistors or pots for various degrees of gain, or other tone control pots for changing the treble response.

Note that in going to higher gains, you will inevitably increase the noise in the output. This may be curable to a degree by changing the input transistor to a quieter part (MPSA18 or 2N5089 is good) as well as swapping to a more modern and quieter opamp like the LM833 or both.

Sweeter distortion - the stock units use a pair of silicon signal diodes, which look identical to the 1N914/1N4148 devices. If you change one of these diodes, chances are that the resulting pair will not clip at the same voltage for positive and negative signals, giving you asymetrical clipping, and the resulting even order distortion. If you pick something close, like maybe a silicon power diode like the 1N400x series for the second diode, the resulting second harmonic will be very subtle, not audible as an octave effect at all, just a "sweeter" or more liquid tone.

You can try a number of things like putting one germanium (1N34A from Radio Shack works) diode in series with one of the silicons to add a bit more threshold voltage to one side. A more radical treatment would replace one of the silicons with three germaniums; even more radical would replace one of the silicons with TWO silicons. These last will start to make an octave effect just barely audible at some notes on the guitar neck.

I've even heard of using LED's in there for the clipping diodes. Go wild here.