How to Make Boss DD-2 Always On (clip which resistor?)

[aviherman5]

Hi all,

I was wondering how to make the BOSS DD-2 always on? On most effects, there is clearly a resitor to clip, but the footswitch on this one has other functionalities, so I'm not too sure what to do here 

Here is the schematic:


Any ideas?

Thanks!

P.S. Just to throw it out - is it R30?

[Fancy Lime]

Just don't switch it off, maybe? I'm not sure what it is that you want to do. Just disable the foot switch in such a way that the effect is stuck on "on"? Can you explain why you want that? This may help to figure out how to do what you want without unwanted side effects.

Andy

[antonis]

Just to throw it out - is it R30?

I can't get what you really want but R30 (via Q7 & Q5) is onbe of the control items  for pre and de emphasis mixing..
If you want to make Q5 always ON, deleting any of R13, D1, R26, R34 or D2 components also could to the job..

[Fender3D]

Isn't it easier shorting Q5 and 8 D and S pins?
Of course, Direct out won't switch off direct signal from stereo out, and do not trust its LED anymore...

[aviherman5]

Just don't switch it off, maybe? I'm not sure what it is that you want to do. Just disable the foot switch in such a way that the effect is stuck on "on"? Can you explain why you want that? This may help to figure out how to do what you want without unwanted side effects.

Andy

Hi, you're absolutley right! I want to make it always on so I can add my boss true bypass relay switching system to it. For that, I need to make sure that the pedal is always on. The R30 resistor was just a guess.

Most boss pedals looks like this, and I just clip the following resistor which puts the pedal in an always on mode. It seems like the DD-2 has a different switching system, though.



With that being said, any suggestions?

[antonis]

I think it should be easier to just toggle between Direct and Main outputs..

[Fancy Lime]

Ah, I see. The switching is done with IC9, which is a BA634 flip-flop (bottom left in the circuit diagram). There is a thread on that thing: https://www.diystompboxes.com/smfforum/index.php?topic=116541.0
To turn the circuit on permanently, find transition Nr 3 from the main to the SW board and cut it. Solder the end of that that goes to the SW board to +9V. Transistion Nr 7 is the nearest access to +9V, probably. Now the circuit should be stuck on "on".

Disclaimer: this is what I deduced from the schematic but not tested. I have been known to make mistakes in the past. I would advise you only to proceed if someone with any modding experience at all ( mine = zero) concurs with my assessment or you feel particularly lucky and adventurous.

Andy

[aviherman5]

So just to clarify, you think that soldering Wire #3 from the switchboard to +9 will do it?

Of course, I understand the disclaimer, thank you!

[aviherman5]

Ah, I see. The switching is done with IC9, which is a BA634 flip-flop (bottom left in the circuit diagram). There is a thread on that thing: https://www.diystompboxes.com/smfforum/index.php?topic=116541.0
To turn the circuit on permanently, find transition Nr 3 from the main to the SW board and cut it. Solder the end of that that goes to the SW board to +9V. Transistion Nr 7 is the nearest access to +9V, probably. Now the circuit should be stuck on "on".

I can confirm this is correct and still maintains all of the functionality of the pedal!

It will work for the DD-2 and "Long-Chip" DD-3!

Thanks, Fancy Lime!

[Fancy Lime]

Glad if I could help!

[Processaurus]

Ah, I see. The switching is done with IC9, which is a BA634 flip-flop (bottom left in the circuit diagram). There is a thread on that thing: https://www.diystompboxes.com/smfforum/index.php?topic=116541.0
To turn the circuit on permanently, find transition Nr 3 from the main to the SW board and cut it. Solder the end of that that goes to the SW board to +9V. Transistion Nr 7 is the nearest access to +9V, probably. Now the circuit should be stuck on "on".

I can confirm this is correct and still maintains all of the functionality of the pedal!

It will work for the DD-2 and "Long-Chip" DD-3!

Thanks, Fancy Lime!

Does the hold mode work right?

[Processaurus]

The bypass on this one is quite unusual.  Not the typical Boss buffered dry path and effect path that is alternated with FET switches. In this one, the dry is always on (provided nothing is plugged into the 'direct out'), and Q8 mutes the delay sound going to the level and regen pots. Muting the regen in bypass is nice. So is the FET switching because it fades in over a few ms and doesn't pop and send pops through the regen when you turn it on.

If a plug is plugged into the 'direct out', Q5 mutes the dry in the dry/wet mixer at IC1a, but unmutes the dry when in bypass, opposite Q8.

The bypass signal does go through a lot of stuff, not just the buffer, but a pre-emphasis (IC1b) and de-emphasis (IC1a) that I didn't notice sounding terrible on my DD2, but, I don't think it is crazy that guitarists might object to having to run through all that stuff in bypass.

There's a bunch of functionality that is lost by true bypassing by disabling the FET switching and BA634 flip flop- you lose muting the regen, you lose the popless transition when the delay gets switched on, I'm pretty sure the hold won't work right because the there is no input to the delay buffer before you hit the switch, and the relay doesn't know to switch momentary in hold mode.

A 'truer to the original design' way to do a relay bypass would be to do the classic "tone sucking" bypass, where you are always feeding the effect input, and switch the output jack from pedal input jack  to effect out, with one SPDT switch.  Don't worry about tone sucking because the input impedance is nice and high, 1M. Control the relay with the 0/+9v logic at wire connection #1 on the SW BOARD (the common of S1 Mode switch, top throw on the schematic).

That logic has the bypass to go with the LED, and does the momentary thing when in Hold mode.  Also in this configuration the direct out works as intended, making the effect output wet only, when a cable is plugged in. Hold mode should work right because you are always feeding the buffer.

[aviherman5]

Ah, I see. The switching is done with IC9, which is a BA634 flip-flop (bottom left in the circuit diagram). There is a thread on that thing: https://www.diystompboxes.com/smfforum/index.php?topic=116541.0
To turn the circuit on permanently, find transition Nr 3 from the main to the SW board and cut it. Solder the end of that that goes to the SW board to +9V. Transistion Nr 7 is the nearest access to +9V, probably. Now the circuit should be stuck on "on".

I can confirm this is correct and still maintains all of the functionality of the pedal!

It will work for the DD-2 and "Long-Chip" DD-3!

Thanks, Fancy Lime!

Does the hold mode work right?

Yes!

[Processaurus]

Ah, I see. The switching is done with IC9, which is a BA634 flip-flop (bottom left in the circuit diagram). There is a thread on that thing: https://www.diystompboxes.com/smfforum/index.php?topic=116541.0
To turn the circuit on permanently, find transition Nr 3 from the main to the SW board and cut it. Solder the end of that that goes to the SW board to +9V. Transistion Nr 7 is the nearest access to +9V, probably. Now the circuit should be stuck on "on".

I can confirm this is correct and still maintains all of the functionality of the pedal!

It will work for the DD-2 and "Long-Chip" DD-3!

Thanks, Fancy Lime!

Does the hold mode work right?

Yes!

With the true bypass circuit installed, or just with the BA634 disabled? The latter I could see, since the top pole of the mode switch uses the BA634 output for bypass in mode 1,2,3, but changes to the momentary footswitch state for mode 4, the hold setting.

[aviherman5]

I wired the output of the BA634 to +9v which has the pedal always on, but have yet to install the relay TB unit.

For now the hold mode works, but I think you're right that I'll lose the hold mode functionality. I'm thinking of inventing something to make it work, so will keep you updated!