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Any chance someone with skill could redraw the TC booster line driver and distortion
without the switching and boost options as a straight true bypass distortion pedal diy?
Just love the sound of it and really miss mine. I'll jump on building one promptly.
Thanks

I started looking at it. I'm not sure how Q4 is orientated based on the schematic, (Weird symbol). Ill use a BC549.
I'm thinking I can build from input through to the eq input leaving off the bypass and noise gate for now
to see if the basic sound is there through a DOD FX40b.
Am I correct that in distortion mode all 4 diodes are in play, while in boost mode the gain is too low for the
diodes to have any effect, in addition to bypassing the distortion pot (gain).

screamersusa wrote:Am I correct that in distortion mode all 4 diodes are in play, while in boost mode the gain is too low for the
diodes to have any effect, in addition to bypassing the distortion pot (gain).

Only 2 diodes clip signal... (D14 and 15 are just there for protection) In boost mode IC1b is just a buffer and diodes are bypassed.

Q4 buffers bias voltage

You'd better build a D+ with asym clipping and a baxandall tone control.
Far easier

Hmmm.. My old rig from way back was a pair of TC BLD, An original Rat, A TC chorus (the big one), and two memory mans running
into the clean input on one of Robert Fripps old Carvin X100b. (All lost or stolen due to Divorce and homlessness).
I'm trying to replicate one of the tones I used then with the TC's and The memory man.
Kind of like U2, Cure and Cult mixed with A hard rock toned ryth player.
How close would the D+ get to the TC tone?
I'm thinking I'll probably want to toss an SHO in front as a pre boost which would pull those protection diodes
into play as well. The one thing I wish the old BLD had was a boost like the VPD-1.
This will mate with a Dragon armor (slap echo in loop)and a TC VPD-1 and will have a loop as well for the analog delay.
Basically an op amp version of my tube rig that I can't use in the house.

screamersusa wrote:How close would the D+ get to the TC tone?

Well...
for what I can see on BLD schematic IC1b has 470K feedback resistor instead of D+ 1M, then a Ge diode + sil. instead of D+ Ge + Ge diodes, D+ will have more treble since its feedback cap to GND is smaller than BLD's electro...
the following LP filter is far different since it has 2 resistors + cap instead of D+ cap to ground.

So far, so similar...

Then signal goes to an inverting op-amp for level control, and further to a baxandall treble/bass control...
I just don't know how much the noise suppressor might affect the tone....

while trying to lay out the "Mini BLD" I discovered the schematic and the
print of the board in the service manual......do not agree.
Hmmmm.. Is the Gain pot adjusting vbias through the transistor Q4 to the second stage b4 eq or
the transistor Q4 just part of the bypass switching (disabling the distortion)?
Or is it intended be part of the distortion tone like the electra for example?

Funny note: I pulled out the old modded deltalab rd1, it does sound quite similar to the sound
I used with the TC when I use my low gain mod. I've traced it almost a dozen times and it still
looks weird. I'll try to scan the RD1 trace and post it here as it may be a very good alternative
if I can make the my low gain switch work correctly.

OK , I got a couple of hours to muck around so I pulled out the Deltalab RD1 guts and trace drawings and tweaked it
against the BLD schematic. I lowered the input gain, added the silicon/germanium diode combo and raised the output gain.
Frankly I think it works as a poor man's BLD as it sounds a lot like I remember.
I pulled out some of my old tones I was searching for along with a couple I currently use. It'll work.
If a few people are interested in the mods, I'll post it in a new thread. Maybe someone can refine it a little.