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Joined:
March 2007
Posts: 698
Location: Cork, Ireland | One for the electronics gurus:
I want to try and make a tone control to add to the Pacemaker. I know that to do but am not sure of the component values to use.
A book I have recommends a 0.02 microfarad capacitor in series with a 500K ohm pot, for use with a single coil pickup. Would these values work with the undersaddle pickup and preamp? Would it work best between the pickup and the pre-amp, or after the preamp? |
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Joined:
December 2006
Posts: 6268
Location: Florida Central Gulf Coast | Not sure if this will help ya, but here are some SCHEMATICS . |
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Joined:
October 2005
Posts: 4070
Location: Utah | f=1/(2PiRC), the low E string is 82 hz (or really close) and the high E string is about 326 hz. 12th fret E on the high string would be 656 hz. Figure out where you want the knee at full treble and go from there. I'd start with a guess of 15khz or maybe 20khz.
You could get fancy and use ganged pots and a BAxandall circuit to give true treble boost at one end and true bass boost at the other, with a flat response in the middle. Probably you'd want to buffer it with an op amp. Hey, now it's starting to look a lot like an active Ovation Breadwinner preamp.
Check out http://www.duncanamps.com/technical/tonestack.html for some info on tone stacks, and especially for the tone stack simulator that you can download free at the very bottom of the page. Though the circuits are designed for amps, the simulator might give you some ideas and a way to model what you might select.
Or, you could start with the 500k pot and buy a few capacitors to try out to see which works best. Caps are pretty cheap. |
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December 2003
Posts: 13996
Location: Upper Left USA | Or just grab an LR Baggs or Fishman EQ box that clips to your belt and allows you to make all the adjustments you need. |
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Joined:
March 2007
Posts: 698
Location: Cork, Ireland | Thanks guys. For a start I'm using bits that I have already - including a bagful of capacitors from my electronics store. Also I may mount the tone control in my home-made amp rather than doing any mods at all to the guitar. Flysig, thanks for the formula, never been able to find it for some reason.
Another Q, is a 50W soldering OK for such projects? Was thinking of getting a gas one and 50W seems the smallest compared to 25W or less for some mains ones |
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Joined:
December 2006
Posts: 6268
Location: Florida Central Gulf Coast | Originally posted by sycamore:
is a 50W soldering OK for such projects? I would go with the 25W. Just clean and prep the tip, components and wiring properly.
A higher compromise would be a 35W for larger discrete components. BUT be very careful, don't use it for chips unless you have above average soldering experience and ability! |
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Joined:
October 2005
Posts: 4070
Location: Utah | Keep in mind if you are crunching numbers that the pickup has a resistance or impedance that will affect a passive tone circuit. Trial and error might be easier, since you'll end up there anyhow. |
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Joined:
March 2007
Posts: 698
Location: Cork, Ireland | Taking my own post slightly OT, I first used the above 500K pot to add a volume control to my AA-31 which has a passive single-coil soundhole pickup. Previously there was about 12 inches of cable between the pickup and the output jack. Now there's an extra 6 inches or so of cable in the circuit. This resulted in a lot of buzz when plugged in. Could this be due to a poor quality pot (shouldn't be, it was not cheap) or the extra length of cable (which admittedly was cheap)? |
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Joined:
February 2002
Posts: 5750
Location: Scotland | probably a grounding issue. Try touching a metal part such as the shell of the jack plug or the nut on the jack socket while it's plugged-in. If the buzz goes away then it's an earth problem |
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Joined:
March 2007
Posts: 698
Location: Cork, Ireland | It gets worse when I touch the pot casing. |
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Making a Tone Control
