The most popular was the TS-9 tube screamer, which is almost the same as the TS-808 internally.
Externally the on/off switch grew to fill about 1/3 of the effect.
SRV used the TS-808 for his trademark juicy strat tone.
This is also Jim Weider's favorite chip in the King Of Tone pedal.
Some of the early TS-808s also have a nut holding the power adaptor jack on, while later ones have no nut and a flush adaptor jack. You can see one of the Narrow Euro TS-808 pedals, it's the leftmost of the TS-808s. The bottom right is the original orange Ibanez Overdrive, with the slightly later OVERDRIVE-II on it's left, with the last version OVERDRIVE-II one more to the left.
The most popular use of a tube screamer is to push a tube amp to make it overdrive more, but they sound good through almost anything.
If you are a geek like we are, check out this awesome article Tube Screamers Secret for some cool info about why the tube screamer circuit sounds so good.
The main change in the TS-9 circuit is in the output section.
This caused the tube screamer to be a bit brighter and less "smooth".
Also the LEVEL knob on these is labeled BALANCE and the external 9V power jack is on the side next to the input jack.
It used the same case as the earlier OVERDRIVE and OVERDRIVE-II pedals which used stomp switches. This board can also be found in some old Maxon OD-808 OVERDRIVE pedals which had a TS808 style switch and a power jack on the side (not to be confused with the 2000-era Maxon OD808).
Please feel free to use info from this web site on ebay or other websites, but please give credit to analogman.com, thanks!
An Ibanez Tube Screamer is an overdrive/distortion pedal that is mild compared to many, but allows the true sound of the guitar and player's technique to come through.
The TS-808 and its generation have small square metal on/off touch-buttons. There were some TS-808s made in the 1979 period, mostly for other than USA markets, that came in a narrower box.