Tube Screamer TS-9 Mods

  • Conversion to TS-808 Specs
  • Bass Boost (aka Brown Sound)
  • Footswitchable level bypass (big switch in center) gives you a second channel for soloing!
  • Asymmetrical Distortion mod for a bright, British sound
The TS-808, Bass Boost and Distortion mods and schematics were based on ideas I found here. The level bypass mod is of my own design. IBANEZ, TUBE SCREAMER, TS-9, TS-808 AND TS-9R ARE TRADEMARKS OF THE IBANEZ CORPORATION AND ARE USED FOR REFERENCE ONLY. THIS SITE IS NOT AFFILIATED WITH THE IBANEZ CORPORATION IN ANY WAY.


Here's the schematic for the guts of a TS-808 or TS-9/TS-9R (click on the image to enlarge). This circuit omits the footswitch and its circuit and it omits the Half-Supply resistor divider. The nodes marked Vhs are connected to half-supply or 4.5V here.

NOTE: The only difference in the TS-808 and TS-9 is in the output buffer circuit. These include two resistors in the output, R1 and R2 here.

  • The conversion to TS-808 involves swapping out the above resistors
  • The TS-808 and original TS-9's used a JRC4885 Op-Amp - this needs to be changed out if it is not the same type to get back to TS-808/TS-9 reference
  • The Distortion Mod involves switching in 3 diodes in series into one of the diode-feedback branches, resulting in asymmetric clipping and a brighter, more British sound
  • The Bass Boost (aka Brown Sound) is done by modifying the 0.047uF capacitor on the inverting input which sets the low frequency rolloff of the distortion stage
  • The Level Bypass shorts across the output (level) control giving a full-out setting. By using a second footswitch, this make a Solo-Boost footswitch - or allows two different output volume settings, footswitchable.
Home | Schematics | Disassembly | TS-808 | Bass Boost | Level Bypass | Distortion