images via this auctionBe sure to read the details on this one if you are considering picking it up. The follow are just the mods:
" * CV and Gate inputs.
* CV input to turn on Slide. (V2.1D onwards: > 2.3 volts turns on the Slide circuit and > 4 volts turns on Gate to tie notes together.)
* CV input for Accent.
* CV input for Filter Frequency.
* Output for Accent.
* Audio In to filter.
* Audio In to frequency modulate the filter.
* Audio Out from filter (pre-VCA).
* Overdrive pot to control the level of oscillator going to the filter: zero to 66.6 times normal level.
* Separate control of Main Envelope Generator times in accented and non-accented notes.
* Volume envelope is no longer fixed, and can be varied from 16 msec through 3 seconds - and to no decay at all, i.e. for notes which last indefinitely.
* Soft Attack control gives attack times between 0.3 and 30 msec. (TB-303 attack was ~3 msec.)
* Slide time is variable to five times longer than normal.
* Variable Filter Tracking causes the oscillator CV to control the filter frequency.
* Internal Filter FM: a unique approach of AC coupled Filter FM from the audio output of the VCA.
* The Muffler is a unique post-VCA soft-clip distortion circuit which retains bass response.
* Push-button to manually activate Accent.
* Filter can be switched to self resonance.
* Accent Sweep has three modes and can be disabled.
* Filter Cut Off pot range doubled to 5 kHz max, and widened to include much lower frequencies.
* Env Mod pot range extended to include zero and go as high as three times the normal maximum.
* Bass response is improved.
* Lithium battery for at least ten years battery backup, so there is no need to install C-cell batteries.
* The six TB-303 knobs Tuning to Accent are mounted about 1.5mm higher than normal, which makes them easier to turn."
