New (untested pedal) -- Buckeroo (Humbucker simulator)

[slajeune]

Hi,

Here is the link to an untested pedal desing that I am working on.  The premise of the pedal is to boost the signal of a single coil by 6db and affecting its resonnance to resemble the output of a humbucker.

Here is the link to the design:

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

This is my first pedal design! With swicth S1, you can affect the resonnance of a single coil to sound a bit more like a humbucker.

I haven't tested the design yet (I am planning on trying it this weekend).  I am still learning about transistors and as such, I don't have a full grasp of how all of it works.  The transistor part is basically stock as is found on many web sites.  I am still learning how to bias a transistor correctly...

The resonance switch (with caps C3 and C4) were recently discussed in a thread in this forum.

Suggestions, comments are very welcomed!

Thanks,
Stephane.

[Marcos - Munky]

Your idea looks very cool. Hope it works. I have humbuckers now, but lots of people will like your circuit if he works right. Here is a suggestion for your next circuit: a single coil simulator, for the people that have guitar with humbuckers only (like me ).

[Ansil]

hey munky i will send tit to you.

[bwanasonic]

Stephane-

I admire your efforts, but if you have single-coils and wish to get a humbucker sound, the solution is clearly MORE GUITARS  

Kerry M

[Joep]

Hi Stephane,

You must place to two caps in front of the circuit, even before the 1uF cap. In this way the caps influence the resonance peak of the pickup. If you place them after the circuit, you "hide" you pickup behind the circuit and the caps only work as a low pass filter.

Also increase the resistors at least times 10 or even bigger.

Bye,

Joep

[slajeune]

Hi,

joep, Thanks for the insight!  I will modify the design so that I affect the resonnance before hitting the transistor.

bwanasonic, I agree with you, in a perfect world, I would own about 20 different guitars!  But, if you want an approximation to goof around with, this circuit could be useful

BTW, anybody knows a good tutorial on transistors (i.e. how to calculate the resistors)?  I am still looking for a good tutorial.

Thanks,
Stephane.

[Mark Hammer]

Craig Anderton had a design in Electronic Musician around 1986 or so that was an attempt to mimic different pickups.  It was essentially a bunch of specially-tuned parallel bandpass filters, whose outputs were mixed down to mono.  You "retuned" the effect by enabling a bunch of dipswitches.
In principle, this is not a whole lot different than what normally gets done with "acoustic simulators", and I wouldn't be surprised if you could even get some modest acoustic sounds from the circuit.

In theory, any suitable graphic EQ ought to be able to mimic this too, but the ability to completely cancel a range, rather than just trim it back 10db, provides more robust tonal differences.  Craig's design also includes a highpass filter to add in the sheen of single coils, and I think it also includes an inverting full-spectrum pathway so you can have either resonances or notches.

[Phorhas]

Hey slajeune,

The Link doesn't work, Can you send me the schematic, sounds interesting...

Phorhas@icqmail.com

Cheers, Dan.

[smoguzbenjamin]

Paste the link in a new window, geocities is a pain with links

[slajeune]

Hi All,

I will post a new version later on today (or before the end of this weekend).  Following some suggestions and a big design flaw, I have redrawn the circuit and will try to test it tonight (if I have the time).

Thanks,
Stephane.

[slajeune]

Hi All,

I have corrected the design and posted it:

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

I will try to breadboard it tonight and post an update if it works or not!

Thanks,
Stephane.

[Joep]

Hi Stephane,

This looks better, but you can raise  the value R1 and R2 even more. The imput impedance is set by these two resistors and less the 47k is still a "big" load for a guitar pickup. (R1 parallel to R2 set the input impedance of the circuit)

Try R1=1Meg and R2 is 220k. You can also use a better quality for C2 now because you can lower C2 to 100n now. Try playing with C2, if you lower it further you will loose bass.

The voltage gain is (roughly) set by R4/R3 if you don't bypass R3. Make sure The collector of Q2 is set around 6V, otherwise change R3. If you lower R3 the voltage on Q1 collector will drop, if you higher R3 the voltage will rise.

Good luck,

Joep

[slajeune]

Hi All,

I tested the circuit as posted (i.e. without increasing the resistors to 1M and 220k as suggested by joep).  I do see a slight increase in volume and also it does affect the resonance (becomes a bit less pronounced in the highs).  My question is how much louder should I expect it to be?  I know it's 6db between a single coil and a humbucker but is there a big difference in volume or is it slightly perceptible (i.e. it will drive the amp a bit harder, but it's very hard to tell the difference in volume by hear)?

joep, I will try your modifications.  I will need to recalculte R3 and R4.  Any hints where I can read up a good description of how I would go about calculating them (rather than trying different combinations)?

Thanks,
Stephane.

[Phorhas]

Thanx for the explenation, I got the file

[slajeune]

Hi Joep,

I found the math equations to help me solve the last two resistors.  The only problem is that I had to make an assumption for the collector current (what are appropriate values, I picked 1ma...).

Here are the values of the resistors:

R1 = 1M
R2 = 220k
R4 = 2k
R3 = 1k

Do these values make more sense?

I remember reading somewhere that transistors look very easy to work with but they are actually a lot more complicated!!!

Thanks,
Stephane.

[george]

Hi All,

I have corrected the design and posted it:

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

I will try to breadboard it tonight and post an update if it works or not!

Thanks,
Stephane.

link still doesn't work :-(

Can you email it to me? GistheW@hotmail.com

Thanks!

[slajeune]

Hi all,

since a lot of you have been having problems getting the PDF file, here is an HMTL page with the design:

http://www.geocities.com/slajeunesse/buckeroo.html

This is the version that I will test this weekend.  If everything goes fine, I will post the results here.

Cheers,
Stephane.

[Joep]

The problem is not in the PDF but with Geocities. You have to copy and paste the link in a new browser screen.

Stephane,

This looks fine. Smart of you to use a trim pot for the 1K, this will change the gain if you turn it. Let us know how it turns out.

Bye,

Joep

[smoguzbenjamin]

Joep, geocities does that to stop people using geocities for picture storage and linking from other sites

[Joep]

yeah, I know, still a problem....  :wink:

later!

Joep