Anyone peeked inside a Seymour Duncan Pickup Booster...?

[Joep]

...it seems to be a really good device. It is able to "change" the resonance of a pickup to a lower frequence band. Together with some boost you can change the sound from a single coil into a humbucker.

Thanks,

Joep

[Brett Clark]

I don't know how the Pickup Booster does it, but you can change the resonance frequency of a pickup just by adding a small capacitor across it (from output to ground). Try a .001uF (that's also 1000 pF) cap to drop the resonance of a typical Strat pickup from about 6.5kHz to about 3kHz. You may also want to try the .001uF cap with a 4.7K to 47K resistor in series with it. Craig Anderton had some info on this in a Guitar Player article from LONG ago (1980 or so).

[bwanasonic]

I don't mean to sound like I know what I'm talking about, but I believe it might be a inductance/capacitance/resistor network (LCR network).  I really don't even know what this means, but I remember looking into these after reading about Bill Lawrence's *Q-Filter*. Maybe somebody who actually knows what they're talking about could provide some more info. But that's my story and I'm sticking with it.

Kerry M

[Ansil]

I don't mean to sound like I know what I'm talking about, but I believe it might be a inductance/capacitance/resistor network (LCR network).  I really don't even know what this means, but I remember looking into these after reading about Bill Lawrence's *Q-Filter*. Maybe somebody who actually knows what they're talking about could provide some more info. But that's my story and I'm sticking with it.

Kerry M

100pf and a 100 ohm in parallel connect pickup ground to this. and feed it to the bridge ground.

trust me. you will not be sorry


doing this creates a nice notch filter.   so you can do this to each pickup and tailor your sound.  or you can do it on say a six pos rotary switch and use it to notch the whole guitar.

[Boofhead]

I don't know the specifics but I have seen inside one.  It contains surface mount parts, so I don't think it had inductors of suitable size to do anything.  Didn't count the transistors or anything like that.

I suspect it's something quite simple:

Some sort of BJT or JFET or MOSFET preamp.   I know it's a clean preamp so it wouldn't matter if you sub'ed something else.  There's a good chance the first stage is a JFET buffer or JFET gain stage.

Not sure if the preamp uses feedback or is just open loop.  The gain control is either a feed back control, like, the MXR microamp, or, a variable resistor in series with a cap + resistor in the emitter/source circuit.

For resonance, a switch which shorts caps across the pickup say 1nF on one range and 2.2nF on another.

Only guessing.

[Joep]

Hi All,

Thanks for the answers.

Boofhead, if you see one again, can you take some pictures? I think I will experiment a bit with the suggestions you made.

My brother needs some Heavey Metal tone out of this stock Fender Strat. I already build him Mark Hammer's Chaos, but I think a humbucker like pickup will do more justice to a heavy metal sound.

There is some interesting stuff here too btw:
http://www.buildyourguitar.com/resources/lemme/

Bye,

Joep

[amz-fx]

There is more info on my page about pickup simulations:

http://www.muzique.com/lab/pickups.htm

-Jack

[javacody]

Jack, could I use that circuit to simulate a humbucker with my strat? Maybe some Allman Brothers "Live at the Fillmore East" type sound?

[bwanasonic]

Jack, could I use that circuit to simulate a humbucker with my strat? Maybe some Allman Brothers "Live at the Fillmore East" type sound?

Even putting an actual humbucker in a strat will not get that sound. Unless your strat has a glued in mahogany neck with a 24 3/4 " scale and mahogany body that has the dimensions of an SG or Les Paul. Believe me, I tried for years. If that sound is really important to you, you owe it to yourself to get a Gibson.

Kerry M

[javacody]

Sorry, but I'll never buy a name brand guitar again. I would rather build my own. In the meantime, I'll settle for "in the neighborhood of".  

[slajeune]

Hi,

I'm trying to modify the resonance of single coils and based on the information in this thread, I have attempted (please read failed) to change the resonance of my stratocaster.

Here is a schematic of what I have attempted:

http://www.geocities.com/slajeunesse/humbucker.pdf

I expected that when switch on is closed, I would hear a somewhat different sound.  I will have to check the circuit but, basically, either opened or closed, I hear no difference.  Is the capacitor the issue?  Can this circuit work passively?  Do I need to add resistors?  So many questions.

The capacitor I am using is 0.001uF non polarized.

Thanks all,
Stephane.

[Boofhead]

if you see one again, can you take some pictures?

Unfortunately, I don't when I will come across another one, it's was just by chance I got to see inside a unit- for a short time at that.

Because it's surface mount the cap values aren't readable and the pic would have to be *really*  zoomed in to see the tiny parts.  It would be easier to just trace from the original board, but to get the cap values you would have to pull the caps off the board and measure them.

I think I will experiment a bit with the suggestions you made.

It can't hurt, perhaps try 680p to 1n for the higher frequency range and, 1.5n to 2.2n for the lower range.

[Boofhead]

I have attempted (please read failed) to change the resonance of my stratocaster

Try a larger cap.

[Joep]

Hi Boofhead,

Thanks away! The SMD cap are a pain in the *ss. I have a Zoom TM-01 Tri-Metal full of them. They are indeed without values on them.

Stephane,

I just did a quick check by holding a 1n (0,001) and a 2n2 (0,0022) cap across the ground and signal of my guitar cable plug. There is definately a change in sound. (Supprisingly) you should notice less highs. I used a Squier Std strat to check this.

Part of the "simulation" of the humbucker is the boost, to distinguish between the (lower) output level of a single coil and the humbucker.

Regards,

Joep

[Ansil]

...it seems to be a really good device. It is able to "change" the resonance of a pickup to a lower frequence band. Together with some boost you can change the sound from a single coil into a humbucker.

Thanks,

Joep

try a varitone circuit.  if you need a single coil to sound like a humbucker. i know a pickup that you can drop in. it is a low impeadance. model with thicker wire.  and an active preamp voiced like a humbucker..  nice and cruncy.  or you can back off the vol and tone and get a creamy sound out of it.  i either use these or  carvins in my strat pickups. or i buy a stock humbucker and split it up as a single coil. but mostly i have the active bridge and neck set up like this.  really low noise too.  i used one of these in my yngwie clone guitar that is.

[slajeune]

Hi all,

ok, I found the problem.  The switch I was using wasn't working...  Anyways, it is now working fine!  Nice sounds for such a simple circuit.

Cheers,
Stephane.

[tclixx]

I use a SD booster the first thing in my chain and it works exceptionally well. It is a lot better than having a cap mod on my strat which I don't like. If you could mod the pedal to be able to switch from setting to setting using your foot without having to bend over and switch it with your hand would be great.

[MR COFFEE]

I'm gonna be short, because it's late and I'm tired as hell from putting new shutters on the house all day.

To emulate a humbucker with a single coil strat, you must do three things

1) Increase the signal level ('cause 'buckers are louder)

and

2) Drop the resonance to around 2 to 2.7 khz (depending on the particular humbucker sound you are going for),

and

3) tame the resonance inherent in strat pickups, where the peak is about 4.5 khz, so you get a smooth rolloff of the very high end, just like the Gibson sound

#3 you do passive (cap across the pickup/input signal), #1 takes gain (as in active gain stage - a JFET is quite adequate), and #2 usually is done with a resonant high pass filter with a Q tweaked to your taste (which will be higher than the usually Butterworth maximally flat value unless you are a tasteless dolt) :lol:  (Hey, I'm being funny again - don't get sensitive on me).

[John G]

All,
The Duncan I had in the workshop last year had a hi input impedance of 1Meg ohm, and had a minimum of 6db gain.
It was all surface mount I didn't see any inductors. The cap selection(which I didn't measure.....drat) appear to be 1nF to 2n5F area. I made a quick mock up usung a MXR micro pre-amp set to 6db gain and about 2nF across the input, and selected via an loop f/sw pedal. Seemed to do the trick.
In fact I have built this effect into the front end of one of my home brew amps.
Of course this effect will only work if the guitar interfaces straight into the Duncan with no other effects inbetween.
Hope this helps,
John G

[Satch12879]

EMG makes a circuit that sounds similar called the SPC Strat Presence Control.  It essentially is an active EQ that bumps up the mids.