Passive MFD's with tone pot?

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Passive MFD's with tone pot?

Postby Freddels » Tue Mar 27, 2012 2:00 pm

I usually play my L2000 in passive mode. I was thinking that a tone pot could add some variations. Has anyone added a tone pot or removed the preamp and just went with vol/vol/tone? Or something like that?

I wonder what the MFD's would sound like without the bass knob.
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Re: Passive MFD's with tone pot?

Postby Ken Baker » Tue Mar 27, 2012 6:05 pm

A classic tone control, such as found in a Jazz Bass, is a 250K audio taper pot with a .047mfd cap. Treble cut. That is what the L-200 uses right out of the factory as its treble control.

So...

Pull the battery, set the active/passive switch to passive, and dime the bass control. Under these conditions the bass is as close to the preamp being gone as you can get without physically removing it, and the bass control is effectively out of circuit when dimed.

If you end up liking it and want to mod the bass, it's easily done.

Ken...
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Re: Passive MFD's with tone pot?

Postby ghiadub » Tue Mar 27, 2012 6:34 pm

I have removed the pre from my 2500 and had my local guy wire it like a L-1000. It was epic, I got the diagrams from the G&L forum sticky. I think Harleyyy might still have it.
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Re: Passive MFD's with tone pot?

Postby Freddels » Tue Mar 27, 2012 7:15 pm

I was thinking of something like the ToneStyler tone pot to get more variations from it.

How did the wiring for the L1K mod go?
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Passive MFD's with tone pot?

Postby ghiadub » Tue Mar 27, 2012 11:53 pm

I had three way micros for each coil selection for each pickup and a three way pickup selector. Then the usual vol/treble/bass controls.

My guy built all the tone controls out of orange drop caps of various values that were in an old blaupunkt radio.

I think the thread with pics might be here somewhere.
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Re: Passive MFD's with tone pot?

Postby harleyyy » Wed Mar 28, 2012 8:12 am

ghiadub wrote:I have removed the pre from my 2500 and had my local guy wire it like a L-1000. It was epic, I got the diagrams from the G&L forum sticky. I think Harleyyy might still have it.



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Re: Passive MFD's with tone pot?

Postby Freddels » Fri Mar 30, 2012 5:20 am

I've removed the battery as Ken has suggested. I've been playing it off and on for the past few days and I really like the tone of it (especially in single coil mode). I would think with a ToneStyler tone knob, the variations would be very pleasing. Now, I have to decide whether or not I want to have the preamp removed. If I do remove it, I'll keep it ready to put back in if I ever want to do that.

What is the L1K mod? Doesn't the OMG switch really just boost the lows and highs and scoop the mids? I remember on the L1K that I had, it really seemed to lose the mids when that was engaged.
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Re: Passive MFD's with tone pot?

Postby Freddels » Fri Apr 26, 2013 11:42 am

Ken Baker wrote:A classic tone control, such as found in a Jazz Bass, is a 250K audio taper pot with a .047mfd cap. Treble cut. That is what the L-200 uses right out of the factory as its treble control.

So...

Pull the battery, set the active/passive switch to passive, and dime the bass control. Under these conditions the bass is as close to the preamp being gone as you can get without physically removing it, and the bass control is effectively out of circuit when dimed.

If you end up liking it and want to mod the bass, it's easily done.

Ken...


I'm still thinking about modding one of my L2K's. Can the factory installed tone cap be removed and substituted with another (e.g. a .1 mfd cap)?

What does the bass knob actually do? Does it cut or boost?

If I was to remove the preamp and all the guts and make it V/V/T, would the pickups sound like they do now with the bass all the way on or all the way off?

I was thinking of having it done V/V/T, with a 3-way for each pickup (outer coil, both, inner coil) and a series/parallel switch.

Any thoughts?
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Re: Passive MFD's with tone pot?

Postby Ken Baker » Fri Apr 26, 2013 10:33 pm

Freddels wrote:I'm still thinking about modding one of my L2K's. Can the factory installed tone cap be removed and substituted with another (e.g. a .1 mfd cap)?


Yup. Look for the .047mfd cap on the treble control. Swap it out. Nothing fancy in the way of a cap is required. .1mfd/50v poly would be fine.

What does the bass knob actually do? Does it cut or boost?


In the factory Tri-Tone circuit, both the bass and treble controls are cut only. With both controls dimed, you're getting the full frequency spectrum of the pickups.

If I was to remove the preamp and all the guts and make it V/V/T, would the pickups sound like they do now with the bass all the way on or all the way off?


If the tone control in your circuit is dimed it would sound nearly the same as the stock circuit with both bass and treble dimed. I say nearly because even with the battery removed and in passive mode, the preamp is still physically connected and having a tiny effect on the tone. Example: When I remove the stock preamp from my L-2500 and replaced it with an OBP-3, I wired to have passive mode that completely isolates the preamp. The difference stock to what I have now (in passive mode) is very slight, but it's there.

I was thinking of having it done V/V/T, with a 3-way for each pickup (outer coil, both, inner coil) and a series/parallel switch.

Any thoughts?


Sounds like an interesting project. I'd like to hear YOUR thoughts if you do it.

Ken...
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