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Post subject: American Elite Precision Bass tone Pot
Posted: Sat Jan 14, 2017 7:05 am
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Hi

This is my 1rst message here, sorry to start with a question ;)

I own an MIM Precision deluxe, from '06 production, i'm pretty much happy with it. I plan to add a active/passive switch to it - that bass is currently always active, which is a bit of a shame for a PB. I guess Fender agrees as the current models feature that option.

Which leads me to the idea to replace the mid-control pot on my bass for a stacked one, in goal to add a passive tone control to the circuit. That would make something alike current American Elite Precision. Unfortunatley the part list does not quite give all the answers (especially part number, which would have helped my find a dealer to purchase it)...

http://www.fmicassets.com/Damroot/Origi ... -21-16.pdf

My guess is, to suit my needs, the pot should feature the mid-control above (i guess 100 K B with center clic), and a passive tone control below (i guess 250 K A, without center clic).

Does anyone have an idea ?


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Post subject: Re: American Elite Precision Bass tone Pot
Posted: Tue Jan 24, 2017 3:39 am
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The reason there are no part numbers for the control pots on that diagram is because the control pots are part of the active electronics printed circuit board assembly and are not separate pots at all. They are integral to and included with the PCB and are not separate parts available individually. This is a common practice on active Fender basses, other brands and also on many aftermarket preamps. Active/passive operation requires proprietary values in stacked pots based on the properties of the specific preamp characteristics. It is likely that your best option is to seek out an aftermarket solution that includes a new PCB with the required pots and active/passive switching already wired up and ready to mount such as the John East Uni-pre 01 4 knob bass preamp from the UK which sells for about 300 USD. If you want an active/passive it is usually best in the long run to buy an active/passive. Changing an active Fender to an active/passive by adding one switch and changing one pot would be nice but I personally would never try that. It is possible a top bass tech knows how to do that but nobody I know does.


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Post subject: Re: American Elite Precision Bass tone Pot
Posted: Wed Jan 25, 2017 4:32 am
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Thanks for your answer brotherdave. Indeed as an integral part of the circuitry it seems pretty logical that Fender does not list the part... I assume that the schematics of that board should be available somewhere, at the very least for authorized service center to perform maintenance when needed. Finally i'm not quite sure it would be that informative to me, as the specs of the pre may differ completely.

I spent hours on the web seeking to find a suitable part for my needs, as you would guess i didn't find any "stock" one - apart the 100 KB original stacked bass/treble control, which with little tweak on the taper and value could do... But i don't want a centre clic on the tone control. There also was the possibility to change wafers on one model that can safely be break apart (like on some CTS pots it appears) - which seems feasible if you don't have two left hands.

Still, i followed the idea i could order a custom pot. Which seemed easy at first sight, but many manufacturers doesn't even reply end-users requests, as they require a minimum order amount. One could find very attractive price on alibaba, some dealers there requiring less impressive quantities, but still too much for an hobbyist wanting to customize only one instrument.

I also heard of English manufacturer Omeg doing prototypes for less than hundred pound, but in the end of the day i had positive reply from germany : one from noll-electronic.de, and one from Banzaimusic.com. They both propose a custom pot service for less than 60 € (depending the options you need - for me it's 40 €). I choose Banzai as i was already customer there, and needed other parts, like cap, switch and some other things form them. They have a decent service so i'm confident that my order will be satisfying.

About modding the actual circuitry, i personally don't worry much, as the noiseless are passive microphones and the wiring don't look that complicated on my bass. Seems a bit of an hybrid, passive mixing going into an active preamp with EQ. Only the volume on those models is part of the circuitry, but looks like can be safely removed... anyway, adding a passive volume and passive tone, is not something very frightening.

As you point out, i cannot be 100% the result will be satisfying (even if with the noiseless, i think it will sound decent in passive mode)... But for the money i will spend on that, i think it worth the try.


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Post subject: Re: American Elite Precision Bass tone Pot
Posted: Sat May 06, 2017 8:49 am
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Few months later, the mod has been done and works pretty well. As a matter of fact now i am mostly playing passive, but i still like to use active on some situations. Mostly when using the JB mic (or a blend of PB/JB) active proves useful to compensate the loss of low end... And, of course, active is interresting whenever a more modern sound is needed (with those bright, open highs). Another funny difference, is that the embedded preamp kind of "compress" the sound, which could be interesting to use to get less differences between notes.

Anyhow, i encourage anyone who feels capable to do the active/passive mod, it is not that complicated, and works great. About the dual pot tones, the custom pot values i indicated above (100 K B with center clic/250 K A without center clic), are OK. Of course, i don't use the tone pot that much ;) If i can give any advice, is that you carefully check the available space in you bass to add that dual pot, as the jack port is really, really close.


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Post subject: Re: American Elite Precision Bass tone Pot
Posted: Fri Feb 07, 2020 11:15 am
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jefbass wrote:
Few months later, the mod has been done and works pretty well. ...
Anyhow, i encourage anyone who feels capable to do the active/passive mod, it is not that complicated, and works great. About the dual pot tones, the custom pot values i indicated above (100 K B with center clic/250 K A without center clic), are OK. Of course, i don't use the tone pot that much ;) If i can give any advice, is that you carefully check the available space in you bass to add that dual pot, as the jack port is really, really close.


Hello I'm trying to do something similar to this on a 2004 MIM Precision Deluxe Active, do you by any chance have any Diagrams on how you connected things? Im sorry to bother you win such an old post, but cannot find any information any where. Thank you


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Post subject: Re: American Elite Precision Bass tone Pot
Posted: Sun Feb 09, 2020 5:05 pm
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Hi Rikhernandez

Well, i don't have a ready-to-use schematic at hand. Sorry ! I remember starting from there for the conversion :

Image

It helped me to add the active/passive switch in a first place. Then i went from there to add a trimpot on the preamp (so to match preamp output with passive volume), basically in the place of the resistor replacing the 25k pot, as far as i remember.

For the abovementionned tone button... Looking at that schematic now, i'd say i wired it on the unused pin of the DPDT (i wanted it working only in passive mode, as you would expect). I'm not 100% sure of my memories, though.

I'll have to do some maintenance/Ugrades* in the weeks to come, so i'll check that...;)

Btw, if you want to keep the Fender preamp board, you may want to add the second battery. It supports 18V operation pretty well, you get more dynamic, less noisy sound. If your bass is anything like mine, the battery cavity should big enough for two batteries. Just wire a second battery clip in series from the first one, there you go ;)

* Pot to change, and probably some more upgrade i was thinking of, like replacing the DPDT for a 3PDT, so to have the ability to defeat the tone in the third position (active/passive with tone/passive without tone). I'm not afraid to overdo things :D I was also thinking of upgrading the original fender preamp for something different - Markbass just released one that caught my eye, actually. I usually go passive whenever i want a classic or vintage sound, and active for modern bright sound and slapping activities; so better looking something drastically modern, then ^^


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