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P/J active preamp advice.


B.Flat
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I would be grateful to hear opinions on four-hole commercial preamps to be used in a P/J set-up.

I understand pickup choice is an important element of this, so pickup advice also if poss.

Question arises fro wanting to mod a '95 Warick Fortess One. The existing Warwick is OK but the Sadowsky, with passive tone control, beckons.

9 or 18 volt OK, I can modify the battery accomodation.

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OK ,BassBunny noted, I will investigate.

However, since I posted I have thought that maybe all I need to do is stack the bass/treble pots and wire in a passive tone before the preamp.                                                             Having said that, I have no idea how to wwire it.                                                                                                                                                                                                                                 Can anybody out there help with a laymans  diagram I could follow ?   

60004 Wiring SS1 SS2 Streamer Bolt-On Fortress One 1996.jpg

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That would work if you know the values of the bass/treble pots.

Regarding the passive part, the circuit is the same as a jazz/ p bass. The way John East does it is with a single spindle, dual pot so effectively a passive circuit for each pickup. Then simply wired into the inputs of the pre-amp. Or what would be even cooler is a standard 250k dual pot and you could have different passive effect on each pickup.

Edited by BassBunny
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Well, Bassbunny, the bass and treble pots are 100K linear, but the rest is a bit unclear for me. Are you saying the best would be to get a 250k dual pot and wire it between the existing volume pot and the preamp ? If yes  how would I do that. Is there any chance you could draw it on the circuit I included in my last post and post it back ?                               It is important that the passive tone works in both passive and active mode.

With regard to the active bass and treble I would obtain an MEC dual concentric 100k linear pot and copy thye connections on the diagram

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25 minutes ago, B.Flat said:

Well, Bassbunny, the bass and treble pots are 100K linear, but the rest is a bit unclear for me. Are you saying the best would be to get a 250k dual pot and wire it between the existing volume pot and the preamp ? If yes  how would I do that. Is there any chance you could draw it on the circuit I included in my last post and post it back ?                               It is important that the passive tone works in both passive and active mode.

With regard to the active bass and treble I would obtain an MEC dual concentric 100k linear pot and copy thye connections on the diagram

I'll see if I can update the diagram tomorrow. The passive element isn't wired between any part of the existing pre-amp. It's an additional control.

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16 minutes ago, BassBunny said:

I'll see if I can update the diagram tomorrow. The passive element isn't wired between any part of the existing pre-amp. It's an additional control.

Hi, OK I am grateful for any help you can give me but only when you have time to do it.

Thank you

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Right here we go and hope this makes sense. This is the way John East adds the passive control to his range of pre-amps as far as i can tell.  I've shown as 2 individual pots as I already had a diagram I could crop but these really represent a Dual Pot.

You can use a dual gang, if you want the same amount of treble bleed on each pickup or a dual concentric if you want to be able to vary the effect separately on each pickup, (that could be pretty cool actually).

Also if you want a greater effect, change the 0.047µF capacitor for a 0.1µF.

34889907_WarwickPassiveTone.thumb.jpg.cfcf88543adb12ffc96240ae3e5c415a.jpg

 

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That is really great, BB, it looks foolproof to me, and I am greatly indebted to you.                                                                                                                                                                              Thank you very much !!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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