DIYstompboxes.com

DIY Stompboxes => Building your own stompbox => Topic started by: bassplayer on January 27, 2011, 10:42:01 AM

Title: DOD FX25B - Force to power up in off.
Post by: bassplayer on January 27, 2011, 10:42:01 AM
When the FX25B powers up it's on.
Is there a mod to force the CD4007 to power up in off mode instead?
Title: Re: DOD FX25B - Force to power up in off.
Post by: runmikeyrun on January 27, 2011, 06:07:31 PM
all i can think of is a switch connecting the battery ground to circuit ground on the input jack, because how the pedal turns on- when you plug a guitar into it the two terminals connect on the sleeve of the plug.  If you had a switch you could flip it on and it would make the connection for you, which would turn the pedal on.  I don't know if there's really a way to turn on just the chip, unless maybe you wired that switch to the chip's ground.  But why would you want to only turn on the chip? 
Title: Re: DOD FX25B - Force to power up in off.
Post by: bassplayer on January 27, 2011, 06:49:47 PM
Quote from: runmikeyrun on January 27, 2011, 06:07:31 PM
all i can think of is a switch connecting the battery ground to circuit ground on the input jack, because how the pedal turns on- when you plug a guitar into it the two terminals connect on the sleeve of the plug.  If you had a switch you could flip it on and it would make the connection for you, which would turn the pedal on.  I don't know if there's really a way to turn on just the chip, unless maybe you wired that switch to the chip's ground.  But why would you want to only turn on the chip? 

I mean:

"on" = effect in
"off" = bypass

The pedals power up default is "effect in". I simply wanna modify it to "bypass".
Title: Re: DOD FX25B - Force to power up in off.
Post by: twabelljr on January 27, 2011, 08:01:28 PM
My Boss pedals do that. When the board is powered up all of the Boss pedals turn on automatically and I have to turn them off. My Tubescreamer uses jfet switching also and it is off until I turn it on. Making the pedal true bypass would solve the problem, if you want to add switches and drill holes in your pedal. This article explains the Boss and Ibanez jfet switching. Maybe someone will know why one powers up engaged and the other powers up bypassed. I don't. http://www.geofex.com/Article_Folders/bosstech.pdf (http://www.geofex.com/Article_Folders/bosstech.pdf). I am curious if there is a mod for this. I have not searched, I just understand your complaint. Not sure how DOD switching works.
Title: Re: DOD FX25B - Force to power up in off.
Post by: SISKO on January 27, 2011, 08:26:47 PM
Read this, it will probaly be of some help
http://www.thetonegod.com/tech/state/state.html
Title: Re: DOD FX25B - Force to power up in off.
Post by: bassplayer on January 28, 2011, 05:32:51 AM
Quote from: twabelljr on January 27, 2011, 08:01:28 PM
My Boss pedals do that. When the board is powered up all of the Boss pedals turn on automatically and I have to turn them off. My Tubescreamer uses jfet switching also and it is off until I turn it on. Making the pedal true bypass would solve the problem, if you want to add switches and drill holes in your pedal. This article explains the Boss and Ibanez jfet switching. Maybe someone will know why one powers up engaged and the other powers up bypassed. I don't. http://www.geofex.com/Article_Folders/bosstech.pdf (http://www.geofex.com/Article_Folders/bosstech.pdf). I am curious if there is a mod for this. I have not searched, I just understand your complaint. Not sure how DOD switching works.

There are info out there how to change the default state for the Boss flipflop circuit. It's a matter of changing the balance between "flip" och "flop". For instance I have a bassmodded BD-2. In that case I was rude with a soldering iron to one resistor. It was enough to change the balance.

This is another great article:
http://www.bossarea.com/forum/topic.asp?TOPIC_ID=1036

Quote from: SISKO on January 27, 2011, 08:26:47 PM
Read this, it will probaly be of some help
http://www.thetonegod.com/tech/state/state.html

Thanks mate, I'll look into it.