kamadude1216
New member
UPDATE guys!! This was typed on my phone so the structure may be a bit messy, but here ya go!
Trombetta Rotobone Y-input rotary caps:
0.0082 uF/8.2 nF (yellow Cornell dubilier cylinder style) OR 10 nF since label is MKT .01
0.012 uF/12 nF (poly)
0.022 uF/22 nF (poly)
0.047 uF/47 nF (poly)
0.068 uF/68 nF (grey film)
0.082 uF/82 nF (poly)
Trombetta Rotobone X-output rotary caps:
0.0082 uF/8.2 nF (yellow Cornell dubilier cylinder style) OR 10 nF since label is MKT .01
0.022 uF/22 nF (poly)
0.047 uF/47 nF (poly)
0.068 uF/68 nF (grey film)
0.082 uF/82 nF (poly)
0.22 uF (poly)
Tested with Peak Atlas DCA55
Q1 transistors (NPN)
Si 2N5088: Hfe - 424; 0 mA leakage
Ge AC130 Hfe -109; 0.010 mA leakage
Q2 transistors (PNP)
Si 2N2907A: Hfe -225; 0 mA leakage
Ge 2N404: Hfe - 174; 0.137 mA leakage
Other important circuit notes (may be all over the place but I think I covered everything/most)
Diodes: 1N4148 symmetrical but opposite directional arrangement after Q2E but before Vol.
Input-Y and Output-X rotaries in parallel w/input and output caps
*I believe in the V1 Rotobone, the Presence switch is an SPDT On/Off/On with a 1n cap wired in Up position, and a 2n2 cap in Down position, just like the Minibone. Location is after the Volume pot but before the Output .
In either Rotobone version, 1n Output cap wired after Vol. Pot Lug 2/Middle Lug
22n cap wired in series off Q1B 560k ohm resistor
560k/150k ohm voltage divider on Q1B
Q1E to SPDT switch(Q1E to middle common lug and 1.2k ohm resistor wired to terminal ends for Hi/Lo power switch)
Second 560k ohm resistor in series with 560k ohm resistor off Q1B voltage divider section AND Q1C 3.3k ohm resistor
Input signal into 2k ohm resistor and other end of resistor goes into Gain pot "In" Lug (left most lug if viewing pot from the underside)
2k ohm resistor between ground and ground lug (right most lug of Octave pot when viewed from underside). Middle lug connected to Q2C? (I may be getting slightly confused since this portion is PNP transistors. It's either off Emitter or Collector, whichever is electrically correct). The experts can help clarify this one for me lol.
Here's a recap list of all the resistors used in Rotobone V2:
x2 560k ohm 1% tol.
x1 150k ohm 5% tol.
x1 3.3k ohm 5% tol.
x1 1.2M ohm 1% tol. (I believe this one is wired near input to prevent pops when switching the pedal on/off)
x1 1.2k ohm 5% tol. (for Q1E)
x2 2k ohm 5% tol. (one for the Gain pot and the other for the Octave pot)
Apologies on any confusing details. I'm no expert on schematics but I think I know enough to be able to decipher most of a somewhat simple circuit. The existing Trumpeter/Minibone PCB should be able to do the Rotobone V2 circuit. Some resistors may be ever so slightly different, but the overall wiring and configuration is the same.
You'll just have to find a way to do the input and output rotaries and the transistor switching. Vol and Gain are wired the same (more or less). On Rotobone, there's no Bone pot (which looks just like a simple tone panning switch to me like in the MK3 Tonebender/Buzzaround circuits). Octave is essentially an external Bias pot off Q2 and the Hi/Lo is just a switch off Q1, which I believe coltonius has implemented a very similar function in his modded Minibone/Rotoclone builds.
The only thing I haven't done is take voltage readings off Q1 and Q2 with the circuit activated, but I'd be glad to take those if needed. I just need some guidance on what ranges to look for.
Hope this gives the experts enough to work with!
*Anyone willing to return the favor by offering up a Tornita/Tornita KS2 circuit next? Pretty please? Lol
@coltonius @PedalBuilder @Robert
Trombetta Rotobone Y-input rotary caps:
0.0082 uF/8.2 nF (yellow Cornell dubilier cylinder style) OR 10 nF since label is MKT .01
0.012 uF/12 nF (poly)
0.022 uF/22 nF (poly)
0.047 uF/47 nF (poly)
0.068 uF/68 nF (grey film)
0.082 uF/82 nF (poly)
Trombetta Rotobone X-output rotary caps:
0.0082 uF/8.2 nF (yellow Cornell dubilier cylinder style) OR 10 nF since label is MKT .01
0.022 uF/22 nF (poly)
0.047 uF/47 nF (poly)
0.068 uF/68 nF (grey film)
0.082 uF/82 nF (poly)
0.22 uF (poly)
Tested with Peak Atlas DCA55
Q1 transistors (NPN)
Si 2N5088: Hfe - 424; 0 mA leakage
Ge AC130 Hfe -109; 0.010 mA leakage
Q2 transistors (PNP)
Si 2N2907A: Hfe -225; 0 mA leakage
Ge 2N404: Hfe - 174; 0.137 mA leakage
Other important circuit notes (may be all over the place but I think I covered everything/most)
Diodes: 1N4148 symmetrical but opposite directional arrangement after Q2E but before Vol.
Input-Y and Output-X rotaries in parallel w/input and output caps
*I believe in the V1 Rotobone, the Presence switch is an SPDT On/Off/On with a 1n cap wired in Up position, and a 2n2 cap in Down position, just like the Minibone. Location is after the Volume pot but before the Output .
In either Rotobone version, 1n Output cap wired after Vol. Pot Lug 2/Middle Lug
22n cap wired in series off Q1B 560k ohm resistor
560k/150k ohm voltage divider on Q1B
Q1E to SPDT switch(Q1E to middle common lug and 1.2k ohm resistor wired to terminal ends for Hi/Lo power switch)
Second 560k ohm resistor in series with 560k ohm resistor off Q1B voltage divider section AND Q1C 3.3k ohm resistor
Input signal into 2k ohm resistor and other end of resistor goes into Gain pot "In" Lug (left most lug if viewing pot from the underside)
2k ohm resistor between ground and ground lug (right most lug of Octave pot when viewed from underside). Middle lug connected to Q2C? (I may be getting slightly confused since this portion is PNP transistors. It's either off Emitter or Collector, whichever is electrically correct). The experts can help clarify this one for me lol.
Here's a recap list of all the resistors used in Rotobone V2:
x2 560k ohm 1% tol.
x1 150k ohm 5% tol.
x1 3.3k ohm 5% tol.
x1 1.2M ohm 1% tol. (I believe this one is wired near input to prevent pops when switching the pedal on/off)
x1 1.2k ohm 5% tol. (for Q1E)
x2 2k ohm 5% tol. (one for the Gain pot and the other for the Octave pot)
Apologies on any confusing details. I'm no expert on schematics but I think I know enough to be able to decipher most of a somewhat simple circuit. The existing Trumpeter/Minibone PCB should be able to do the Rotobone V2 circuit. Some resistors may be ever so slightly different, but the overall wiring and configuration is the same.
You'll just have to find a way to do the input and output rotaries and the transistor switching. Vol and Gain are wired the same (more or less). On Rotobone, there's no Bone pot (which looks just like a simple tone panning switch to me like in the MK3 Tonebender/Buzzaround circuits). Octave is essentially an external Bias pot off Q2 and the Hi/Lo is just a switch off Q1, which I believe coltonius has implemented a very similar function in his modded Minibone/Rotoclone builds.
The only thing I haven't done is take voltage readings off Q1 and Q2 with the circuit activated, but I'd be glad to take those if needed. I just need some guidance on what ranges to look for.
Hope this gives the experts enough to work with!
*Anyone willing to return the favor by offering up a Tornita/Tornita KS2 circuit next? Pretty please? Lol
@coltonius @PedalBuilder @Robert
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