sd-1 true bypass

[slammer]

hi
I need sd-1 true bypass, but I don't have too much knowledge, so please someone can edit schematic and post it ? please don't write how to do this, my english isn't so good, can someone edit this schematic and post it again ? thanks.

[shredgd]

Just take the standard Tubescreamer schematic and change the values according to this schematic you posted.

[sevenisthenumber]

check this out
http://www.diystompboxes.com/smfforum/index.php?topic=61035.0

someone did an sd-1 as well because i followed thier thread.

[petemoore]

  To question the motivation...why is true bypass needed ?
  Just seems like a lot to mess with and...
  The SD-1 could be less useful or damaged by the intrusions.
  Building an SD-1 with TB would allow comparing SD-1 to SD-1 -true bypass, admittedly at greater expense and probably more time.
  You'd end up with your choice of the SD-1 you have, and the SD-1 modified for TB.
 

[slammer]

thanks, i'll try. but if i had a truebypass schematic, it would be better. thanks

[sevenisthenumber]

have you tried the simple sd-1 bypass bleed mod?

[slammer]

have you tried the simple sd-1 bypass bleed mod?

no, what is it ?

[slammer]

is that right? in ts808 there's no resistor between 2sk30 but in this schematic, there's 2 x 22k what about them ?

[sevenisthenumber]

this is much easier and fixes the problem of high gain coming through the bypass when the pedal is off. The boss buffers are very clean and dont color your tone. This is the way to go!

[slammer]

but i'll build it (diy) so I want to make it true bypass. anyone help me ?

[sevenisthenumber]

oh!!

Just locate the input cap and the output.. ?

[reverbie]

I think that bypass bleed fix was actually figured out by analoguru over at the FSB board, not indyguitarist, but I could be wrong. Anyone know?  Just to give the right guy credit since indy is advertising his business wbesite in a giant font on an image showing someone else's hard work.

[sevenisthenumber]

the image clearly says thanks to the people who made the mod???

[reverbie]

I heard that is was singularly analogguru over at a completely different forum but whatever. Giving a general thanks to everyone at this board is cool, but not necessarily credit given where credit was deserved especially if the solution was one guy's who isn't even part of this forum. Indy probably found it here, just making a note of the originator. No skin off my back!

[slammer]

so, there's no truebypass ? I know I can build this sch. and use dpdt to connect input to output this is a true bypass also, but because I'll build it why I have to use an unnecessary bypass module  It makes my pcb bigger and takes more spaces in my box etc.... Please anyone can convert it true bypass ? It also looks like ts808 but, in ts808 there's no resistor between bypass FETs, but in this there're 2 of 22k between 2sk30, what about them ?

[sevenisthenumber]

You should just build the tonepad Tubescreamer to these specs. It even says you can build the SD-1 on the board!!

[MikeH]

The schematic as you have it above will work fine for true bypass.  You smudged out everting in the FET switching except the 0.047uf cap right after the first buffer that was going to the FET switching.  Just use a dpdt or 3pdt to switch the input and output and you're all good.  And as others have stated, you can use ANY tubescreamer layout (GGG and Tonepad come to mind) to make an SD-1.  Just look at the schematic for the tubescreamer and figure out the parts substitutions.  It will also give you a good idea of what your schematic is supposed to look like.

[ayayay!]

Why don't you just do what Moro did? 

http://www.diystompboxes.com/smfforum/index.php?topic=60631.msg475140

[slammer]

yeah! tonepad. thanks, I did ts808 but didn't realized    so, I don't have to use those 22k res. I'll go over the ts808 sch. thanks.