Boss TB-2W Photos
- Thread starter Robert
- Start date
benny_profane
Well-known member
Keep in mind that there’s buffered bypass with FET switching and true bypass as well as on-board Vc selection. Those circuit blocks will add a decent amount of components.
Robert
Reverse Engineer
The left half of the board is all power supply. This uses a buck converter and programmable voltage regulator instead of the typical charge pump arrangement we usually see.
It doesn't have the usual transistor based flip-flop circuit used in most Boss pedals, instead it uses a flip-flip IC.
Bypass switching is done with the relay in both true-bypass and buffered modes. The slide switch activates an "always-on" buffer on the output.
It doesn't have the usual transistor based flip-flop circuit used in most Boss pedals, instead it uses a flip-flip IC.
Bypass switching is done with the relay in both true-bypass and buffered modes. The slide switch activates an "always-on" buffer on the output.
Wow, those are just some generic transistors. Figured they’d be using some OC75’s at least. Talk about bs hype 
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(To be clear, I’d be interested in a project with some of the options they’ve added, but I’m just surprised these are commanding thousands when the “rare germanium transistors tested for optimum tone” seem to be a big part of the price tag).
.(To be clear, I’d be interested in a project with some of the options they’ve added, but I’m just surprised these are commanding thousands when the “rare germanium transistors tested for optimum tone” seem to be a big part of the price tag).
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Sorry for warming up this old post...
In the booklet of the Boss TB-2W there is this schematic. There is something like a JFET between Q1 and Q2. This is likely not to be original to the Tonebender circuit. Doe anybody know the function of it?
Further more, it looks to me, that the Boss R26 is the original R1. And Boss uses 10k (103 on the smd) instead of 100k there, resulting in quite high 9,57V collector voltage at Q1. Me, I am struggling with the value of the R1: 100k -> great deep sound and sustain, but a hell of buzz (sounding nearly like a ground loop) on single coils. 10k -> very silent pedal, even with single coils, but less sustain and less depth on the sound.
In the booklet of the Boss TB-2W there is this schematic. There is something like a JFET between Q1 and Q2. This is likely not to be original to the Tonebender circuit. Doe anybody know the function of it?
Further more, it looks to me, that the Boss R26 is the original R1. And Boss uses 10k (103 on the smd) instead of 100k there, resulting in quite high 9,57V collector voltage at Q1. Me, I am struggling with the value of the R1: 100k -> great deep sound and sustain, but a hell of buzz (sounding nearly like a ground loop) on single coils. 10k -> very silent pedal, even with single coils, but less sustain and less depth on the sound.
Robert
Reverse Engineer
I never even opened the damned booklet....
The JFET is a 2SK209-G.
R26 isn't part of the original Tone Bender circuit, it's the low side of a voltage divider used to bias the switchable buffer.
R1 is R1, and is 22K.
Thank you for this clarification! ...so it's amazing, that Boss tweaked the original circuit quite a lot. (I suppose that this JFET works as a fourth amplification component.) And it's interesting to see, that with modern germanium transistors a value far below 100k seems often to be a good choice for R1.
