TS-808 MOD actual work
100 ohm resistor
10 Kohm resistor
8pin DIP IC socket
TS-9 Reissue PCB
Changing OP amp
Removing solder completely from 8 legs of OP amp at the back side of the board by solder wick (solder remover wire). Before removing OP amp, remember the position of pin number 1.
Inserting IC socket to the position where the OP amp was and soldering it. Taking care of the direction of the IC socket not to be confused later. Inserting JRC 4558D to right direction.
Changing resistors of output stage
Changing two resistors makes a TS-9 become the same as TS=808 as a circuit diagram. This modification is called "Brown Mod" and the result make the TS-9 sound smoother. I am not sure if Stevie Ray modified output resistors of his TS-9.
According to http://www.custom-sounds.com/srv.htm Stevie told around 1983 that he preferred TS-9 rather than TS-808. His TS-9 might not be modified. Anyway I tried the sound of TS-808 modification.
Removing 470 ohm with 100 ohm, and 100 Kohm with 10 Kohm. That was easy.
Comparing with original TS-9！
Modified TS-9 sound seems to became purer, wilder and something like vintage. Someday after that, when I tried vintage Vibroverb at a musical instrument shop , I tried original TS-9 and TS-808 they have as well. Original TS-9 and TS-808 were not the same as my modified TS-9. My TS-9 MOD was 70% of them. I was disappointed very much.
I got it ! Original TS-9
I won an auction for 1982 original TS-9.
Original (Upper) and reissue (Lower)
Original TS-9 has "The sound" of Stevie Ray. It has JRC 4558D of course. And type of some caps are different from caps of reissued TS-9. Perhaps, big sound difference comes from the caps and active part's parameter dispersion.
Buying original TS-9 is the only way to get Stevie Ray sound ? The combination of Vibroverb clone and original TS-9 come closer to his sound.
To be continued
Now I research original TS-9 to reach 100%
To TS-9MOD Advanced