OBP1 ADDING active/passive tone control???

[baloubass45]

Hi i want to know it's possible adding in one OBP1 one tone control for work in active and in passive mode?
thank

[basadam]

Yes, it is possible and AFAIK there are diagrams in Aguilar website.

[PilbaraBass]

it's not possible to use the OBP-1 tone controls in passive mode.

but what you can do, is to add an additional passive tone control to the preamp circuit such that it will work in both passive and active modes.

[mikezimmerman]

Didn't Dingwall have a wiring setup for the OBP-1 that enabled the Aggie treble boost when you turned the knob one way, and did a passive treble cut when you turned it the other?

Mike

[baloubass45]

Originally Posted by PilbaraBass

it's not possible to use the OBP-1 tone controls in passive mode.

but what you can do, is to add an additional passive tone control to the preamp circuit such that it will work in both passive and active modes.

yes that's it

[PilbaraBass]

Originally Posted by baloubass45

yes that's it

go to the aguilar website...there's a diagram for that, there.

[PilbaraBass]

Originally Posted by mikezimmerman

Didn't Dingwall have a wiring setup for the OBP-1 that enabled the Aggie treble boost when you turned the knob one way, and did a passive treble cut when you turned it the other?

Mike

I suppose you could do this...if you set up a gang pot a certain way...

Interesting...I have to think about this...it's a great idea and solves a dilemna I have on a future bass mod I'm working on (how to avoid another hole )

THANKS

Update:

I thought about it...sketch on the back of an envelope...a ganged pot WILL work...I'd probably use a suitably sized series resistor with the passive cap to prevent too much roll off affecting the treble boost (size about 1/10 the pot value)

[mikezimmerman]

Originally Posted by PilbaraBass

I suppose you could do this...if you set up a gang pot a certain way...

Interesting...I have to think about this...it's a great idea and solves a dilemna I have on a future bass mod I'm working on (how to avoid another hole )

THANKS

Update:

I thought about it...sketch on the back of an envelope...a ganged pot WILL work...I'd probably use a suitably sized series resistor with the passive cap to prevent too much roll off affecting the treble boost (size about 1/10 the pot value)

I always thought it'd be a cool approach with the OBP1 or the Sadowsky preamp, but was not clever enough to start thinking about how the circuit would go--let us know if you come up with something workable!

Mike

[PilbaraBass]

Originally Posted by mikezimmerman

I always thought it'd be a cool approach with the OBP1 or the Sadowsky preamp, but was not clever enough to start thinking about how the circuit would go--let us know if you come up with something workable!

Mike

I will let you know...

I've already got the basic preamp design sorted on paper (it's a 2-band boost-only a la Sadowsky & the OBP-1...a variation of the Fender tone stack without a mid control.)...time for a breadboard...

adding the passive tone control will be interesting...

the goal is to have the passive control counteract 1/2 the treble boost at centre detente...

shouldn't be too difficult.

[mgmadian]

Originally Posted by mikezimmerman

Didn't Dingwall have a wiring setup for the OBP-1 that enabled the Aggie treble boost when you turned the knob one way, and did a passive treble cut when you turned it the other?

I recall hearing about this, too. One thing I'll say tho, is that I actually find the tone very useful with bridge pickup on my 71 Jazz when I turn up the treble (and bass) somewhat on its OBP-1 and roll off the passive tone.

[PilbaraBass]

Originally Posted by mgmadian

I recall hearing about this, too. One thing I'll say tho, is that I actually find the tone very useful with bridge pickup on my 71 Jazz when I turn up the treble (and bass) somewhat on its OBP-1 and roll off the passive tone.

many Sadowsky users w/ VTC say similar things...

maybe the Dingwall setup isn't the most flexible...

it's certainly much easier to imlement a separate passive roll-off