Can anybody tell me how I can mod my Boss SD1 to the Ibanez TS808 specs?

[circuithealer]

Can anybody tell me how I can mod my Boss SD1 to the Ibanez TS808 specs? It would be great to try.

Thanks a lot!!!



Paul.

[warioblast]

http://www.guitarfaq.com/index_v2-7-5.html

[circuithealer]

Thanks a lot. I though however that a lot of components needed to be changed. Any other mod around?

Thanks,

Iván.

[Gus]

Sell the sd 1 and buy a ts 5 or ts 7 and mod that.

I still don't understand why someone wants to turn a sd 1 to a ts circuit.

[Mark Hammer]

There are a number of differences between the SD-1 and the TS-9/808/7/5/10, etc etc.  Some of them will only matter in certain setups, and some will matter regardless of what you plug into them and what you plug them into.

The two biggest differences, however, will be the use of an asymmetric diode arrangement in the SD-1 (2+1, compared to 1+1 in the TS), and a hotter gain structure.  A quick comparison can be done looking at these two simplified schematics.
http://users.sa.chariot.net.au/~gmarts/pix/a_ibanezts.gif
http://users.sa.chariot.net.au/~gmarts/pix/a_bossod.gif

The two units both use a .047uf cap and 4k7 resistor to ground from the '-' pin of the clipping stage.  However, the SD-1 uses a 33k resistor and 1M pot in the feedback loop, compared to the 51k and 500k in the TS-808.  This results in a maximum gain of 220 vs 118, which is pushing the diodes a little harder and should result in greater clipping.  Because the SD-1 uses 2 diodes in series for one half of the waveform, that half is less subject to clipping.  Of course you still have the single diode being pushed twice as hard due to the increased gain.  The result is a sound that is less compressed in the SD-1, but has the potential to be a little fuzzier.

Consequently, the simplest conceivable SD-to-TS mod (and keep in mind this disregards a whole whack of other differences that purists will make a big deal of) is to use one toggle switch to shunt one of those 2 diodes in series (i.e., provide a straight wire path around it so that it doesn't "count" any more), and another to drop the pot value down by half (with a 1M fixed resistor in parallel with the pot) so that it becomes easier to dial in lower-gain settings.  In fact, a single DPST toggle (4 pins) could do this with ease in a single action.  Again, this would not do ALL the changes but would quickly and painlessly do two of the standout differences and achieve a different feel.

You will notice a few differences.  First, with less gain you won't be able to get it quite as loud and raunchy.  Second, you will notice a more compressed spongy feel, where digging into notes gets you more clipping but not necessarily more volume.  Both diode arrangements (2+1, and 1+1) have their advantages and disadvantages in this regard.

[cd]

Sell the sd 1 and buy a ts 5 or ts 7 and mod that.

I still don't understand why someone wants to turn a sd 1 to a ts circuit.

Though I'd generally agree from a tonal standpoint, the switching system (physically) is far more robust on a BOSS pedal compared to the TS-5, -7, or even -9.