OS-2 remove fet switching?

[comfortably_numb]

What would one need to remove/replace in order to disconnect the JFET switching in this pedal while leaving it in the "ON" position?



CJD

[cd]

The pic you posted is terrible, but replace the top two FETs with jumpers from D to S, and remove the bottom FET completely.

[wampcat1]

The pic you posted is terrible, but replace the top two FETs with jumpers from D to S, and remove the bottom FET completely.

http://www.freeinfosociety.com/electronics/schematics/audio/pictures/bossos2.gif

[wampcat1]

Here is what I would do:
(edit: fixed link)
http://aronnelson.com/gallery/Brian-Wampler-Indyguitarist/temp_boss_os2_truebypass?full=1



bw

[cd]

Here is what I would do:
http://aronnelson.com/gallery/album15/temp_boss_os2_truebypass

bw

Bzzt!  You lose, the bypass path is still connected.  Depending on the startup state of the pedal, the clean signal will still be heard.  Next time you ripoff an idea be sure to follow ALL instructions:

replace the top two FETs with jumpers from D to S, and remove the bottom FET completely.

[wampcat1]

Here is what I would do:
http://aronnelson.com/gallery/album15/temp_boss_os2_truebypass

bw

Bzzt!  I hate you Brian Wampler!! Please have pity on me in spite of my own self!!

replace the top two FETs with jumpers from D to S, and remove the bottom FET completely.

I'll check the schem again...that's what I get for trying to help someone real quick. 

(edit, reviewing circuit)...
Let's see... buffer, to clipping circuits...to buffer ... to output.
Uh...yeeeaah. Ok. Take some more meds!! How's that bipolarisim working for ya?! 

[comfortably_numb]

Wampcat, thanks a lot for the help and for being generous enough with your time to draw up a diagram.  It is much appriciated, as is your good attitude.   

[wampcat1]

Wampcat, thanks a lot for the help and for being generous enough with your time to draw up a diagram.  It is much appriciated, as is your good attitude.   

Not a problem, ignore CD (MANNNN I wish there was an "ignore" function on the boards here!  ), he's usually quite the arrogant ass and most of us just realize it and ignore it.

The way I 'drew' it, I just removed the jfets and jumper the connections. The one at the bottom is yet another buffer, I just eliminated it, but you can keep it by doing what goober was talking about.

Have fun,
Brian

[Mark Hammer]

Let's take a step or two back, breath deep, and ask the question "Why do you want to do this?".  That is, what are you trying to accomplish, or what do you *think* you will be accomplishing by doing this.  It may well have very different repercussions than you think, so before you go ripping things apart, please answer that question for me.

P.S.: If you DO wish to keep the board relatively intact, once you identify the FETs in question, wire jumpers can be added on the copper side of the board to connect drain and source.  Then they can be easily removed to restore the board to stock if need be.

P.P.S.:  While Brian's suggestion "works" you lost the advantages posed by the FET input buffer on the pedal.  That's why I'm asking about your motivation.  If you're rationale is to improve sonic cleanliness, sidestepping a perfectly good FET buffer is not the optimum strategy to do that.

[jxoco]

Let's take a step or two back, breath deep, and ask the question "Why do you want to do this?".  That is, what are you trying to accomplish, or what do you *think* you will be accomplishing by doing this.  It may well have very different repercussions than you think, so before you go ripping things apart, please answer that question for me.

I think that the original post is 'so that it is on all the time'.
Maybe just a pull up resistor on Q8 or Q9's  base would do that.

[Satch12879]

I don't get this mod request; if one wanted it on all the time, why wouldn't one just leave it on all the time?

[comfortably_numb]

The rational is two fold.  I want to install a true bypass, and I want to put the thing in another box.  So, getting rid of the FET switching and any problems that it causes, adding true bypass, and a new enclosure.  Being on all the time was simply an easy way of getting around the rest of it.  I know how to wire true bypass, just not how to remove a FET switching mechanism.

I would like to keep the input buffer if possible.

Thanks all

[aziltz]

Has anyone built one of these?  i heard the stock pedal was pretty good?

[wampcat1]

My apologies...I had assumed this fellow was wanting to True bypass it, which is why people usually do the 'always on' mod.

Mark, Looking at the schem there still shows the input AND output buffer there, even after we jumper that jfet there

[Mark Hammer]

Okay, pretty much as I figured things would turn out.  So, why do you feel you need to true bypass it and rehouse it?  How many other pedal in your signal chain are true bypassed, and what sort of cable length do you run?

[comfortably_numb]

This I expected also   I know the opinions around here about the boss bypass, but the main concern is, as you said, rehousing.  I want to do this mostly for the experience.  I want a different box for a different look, and a different switch for a different feel.  Also, this is to bring attention to the fact that these pedals are modified (I would do the BD-2 also).  I suppose if one could still use the FET switching with a metal stomp switch, the FET could remain.

To answer your questions, I've got all of my gear on a pedalboard, as economically spaced as possible and all but two Boss effects are indeed true bypass.  <Ernie Ball Volume, OZ comp, OS-2, BD-2, AMP - effects loop - Line6 DDL-4 - AMP>

Longest cable is 10 feet.