SD-1 turns 'on' when guitar cord is plugged in. Help Please

[Gilmorian Knight]

Hello,

Please help.  I've got a minor issue with a BOSS SD-1 Pedal.  It turns 'on' just by inserting a guitar cord into the input jack on the SD-1.  All of my other Boss Pedals do not do this.  I even have a second DS-1 that operates correctly.  Other than this issue, the pedal works just fine.  The foot switch can turn the unit off/on.  Does anyboy know how to make this Boss SD-1 behave just like all of my other Boss Pedals?  I have a SD-1 schematic/soldering skills and can work on whatever is suggested.  Is there a previous thread that somebody can point me to?  Sorry for being so fussy.  Any help is appreciated.  Thank You.

Best regards,

Gilmorian Knight.

[RDV]

I know I'm gonna regret this but here goes. All Boss pedals(and almost every other one in the world) are turned on when you plug them in. If you mean that the light comes on every time you plug it in then that's another matter, though I don't see the problem exactly.

Regards

RDV

[petemoore]

Functionally it works perfectly?

[Xlrator]

I had a DOD FX-56 that did that. When you inserted the in jack, the distortion went on. If I hit the switch to turn it off it would go off and never back on again. I had to re-plug the in jack to get the effect back on. :x

I scrapped it for opamps and caps.

[Mark Hammer]

I don't see what the problem is either, but here goes.

The electronic switching is done by a "mirror-image" type circuit called a flip flop.  Whatever state one half of the circuit is in, the other is in the opposite state.  Each circuit can put out a control signal which is used to turn on an FET, which reduces its resistance.  In some instances that reduced resistance is a resistance to ground so that something is shunted out of the signal path, but in the overwhelming majority (see I spelt it right this time!) of instances the FET is in the signal path so that turning the FET "on" allows signal to pass through a low resistance, and turning the FET "off" imposes a very high resistance so that the signal is, for all intents and purposes, blocked.

Presumably, the pedal "wakes up" with one half of the flip-flop circuit in an "on" state and the other half in the "off" state.  Essentially what you want to do is switch the FET connections around so that instead of the pedal waking up with the distortion-allowing FETs "on" (because of which half of the flip-flop they are connected to) and the clean-only FETs "off", you get the reverse.

So....

If you look at the board so that the components are facing you, and the leads for the controls are at the "top" (i.e., away from you rather than closer to you), you will see a diode labelled D7 along the left side halfway down.  A bit below that and closer to the middle of the board, you'll see another diode labelled D8.  What you will want to do is cut the connection between the pad where non-stripe end of the diode goes to, and the other component pads linked to it, for each diode.  Now run a suitably insulated lead from the  recently severed diode pad to the pads of the components for the *other* diode so that each diode is now receiving the control signal the other one used to get.  Just for confirmation purposes, those diodes are connected to the junction of a .047uf cap and a 1m resistor.

There.  That's it.  Your flip now flops, and your flop now flips, and your pedal *should* boot up as "asleep" rather than "awake".

[smoguzbenjamin]

My metalzone does this when I plug my wallwart into the wall (I daisy chain my pedals) and I just stomp it off.

[Gilmorian Knight]

Guys,

Thanks for the quick replies.  Yes, the pedal works perfectly except for this minor irritation.  With the guitar cord plugged in, it turns the unit and LED 'ON'.  I can then use the foot pedal to toggle it off and then back on again if I wish, just like all of my other BOSS pedals.  I am especially thankful for Mr. Mark Hammer's reply.  Very concise and candid.  One last question,  how could this have occured?  It was that way since new.  Could it be component tolerance creep or is one FET more sensitive due to other connected components?  Another interesting thing that I noticed is that most times all I have to do is just put the guitar cord in just ever so slightly to where the TIP just toutches the contact in the recepticle and the 'ON' LED illuminates.  Once I push the plug in a little further, the LED/unit goes 'OFF' and then back  'ON" when fully seated.  Any ideas?  Thanks again for all who have replied.  This is a very nice Forum.  I just joined today and the activity is on topic.  Warmest regards to All.

Respectfully,

Gilmorian Knight

[smoguzbenjamin]

That's because the ground is being connected, and when you push it through the jack stops 'shorting' as it were. Then you push it into its final position where the pedal can be turned on normally.

[Exactopposite]

I know I'm gonna regret this but here goes. All Boss pedals(and almost every other one in the world) are turned on when you plug them in. If you mean that the light comes on every time you plug it in then that's another matter, though I don't see the problem exactly.

Regards

RDV

i have  a boss bd-2 that i just bought a couple of monthes ago and every time i plug a cord into the input the light comes on but it turns off with the swithc. no big deal to me......i dunno

[gtrmac]

My Boss DS-1 wakes up "on" also. No big deal to me.

[The Tone God]

I wrote an small article about this. Included is a small circuit to control the start up state. Its called "Lost In State". Its intened for people with pedalboards and switching systems so when they turn everything on they can set whats on and off.

Andrew

[Gilmorian Knight]

Dear Tone,

Can you please point me into the direction on where your article is located?  I tried a search here and could not find it.  Thank You.

V/r,

Gilmorian Knight

[RDV]

Dear Tone,

Can you please point me into the direction on where your article is located?  I tried a search here and could not find it.  Thank You.

V/r,

Gilmorian Knight

It's on his website. Here's a link. http://www.geocities.com/thetonegod/state/state.html

Regards

RDV

[jplaudio]

Pedals that use a discrete bistable multivibrator(flip flop) can be modified to power up in the off state by switching the positions of the flip flop transistors.
The power up state is determined by the small differences in the two transistors. There is an article on my website in the DIY page that touches on this in the notes section near the end of the article.
http://www.jpl-audio.com/images/alwayson.pdf
flip the positions of the two transistors and your pedal will power up in the off state.

[casey]

my boss dd-5 does the same thing.  it takes it a while, and then i just
stomp it off.  ive had my sd-1 do that too.

[modmod]

i did the mod in sd-1 from fuzzcentral,my sd-1 now will power up in "off" state, before that it will power up in the "on" state,can anyone kindly explain that ?  :?:

[toneman]

check your 9V battery.
don't use a NiCad "9V" batt.
these R actually 7.2V.
tb

[Steve C]

I have a Boss CS-2 that does the same thing, but only if the other end of the cable I plug into the pedal is already plugged into my guitar.  If I plug a cable in that's from another pedal in front, it doesn't start off on, only if it's plugged into my guitar, and it doesn't matter which guitar I use, I get the same results.

[12StringStratMaker]

flip the positions of the two transistors and your pedal will power up in the off state.

I just tried this on my Blues Driver and it didn't fix anything.  I'm sure it might work in some cases, but for anyone else out there who might do this, I want the search thread to actually acknowledge that it might not work.

[burnt fingers]

I don't really see the problem.  You plug your cord in, the effect is on, you stomp the switch, it goes off.  It works, sounds good,so don't worry about it.  Just play and enjoy. 

Scott