Pickup frequency response calculator for guitar freaks

[hermetico]

I've found this link that can be of interest to guitar freaks:
http://guitarnuts2.proboards.com/index.cgi?board=reference&action=display&thread=3627

You can download the excel sheet there and start playing with it.


In my current Antiquity II surf set, I am ok with Neck and Middle pickups but, I am finding the bridge one as very bright, even piercing.
I have dedicated tone control for bridge pickup and the knob is always dialed to 8, with a 47 nF cap (0.047 uF).
I was curious about what's the effect that this particular setting has over the resonance frequency and resonance peak and, found it interesting.
Based on SD info, the bridge surf has a DC resistance of 6.3 K and an inductance of 2.87 H. Volume and Tone are 250K Ohm pots.
Modeled: 20 ft cable, no treble-bleed, strat b, single coil.

The interesting thing is that the tone pot at this spot isn't reducing the resonance frequency (around 2750 Hz) but, has a direct effect over the resonance peak, that drops from 4.99 dB to 3.62 dB. So, the resonance peak height is what hurts me.
Below the tone at 8, the resonance frequency changes to less than 2.7 KHz and, that explains why I am not rolling off the tone more than that.

Very interesting thing. I don't know how accurate that tool is but, it gave me some answers.

And now, the question for electronics wizards:


how do I reduce that resonance peak height (let say to 3.0dB) without affecting the resonance frequency, in a permanent way (I mean, with volume and tone controls at 10)?.

 

[Funkfingers]

Re: Pickup frequency response calculator for guitar freaks

Interesting software but where's the Mac version?

 

[Funkfingers]

Re: Pickup frequency response calculator for guitar freaks

how do I reduce that resonance peak height (let say to 3.0dB) without affecting the resonance frequency, in a permanent way (I mean, with volume and tone controls at 10)?.

H, you should have made this thread a poll. Forum members could have voted on which of our resident know-it-alls would be the first to answer your question.

 

[hermetico]

Re: Pickup frequency response calculator for guitar freaks

H, you should have made this thread a poll. Forum members could have voted on which of our resident know-it-alls would be the first to answer your question.

LOL
:friday::sword:

 

[freefrog]

Re: Pickup frequency response calculator for guitar freaks

how do I reduce that resonance peak height (let say to 3.0dB) without affecting the resonance frequency, in a permanent way (I mean, with volume and tone controls at 10)?.

1)By lowering the value of your tone pot. You can mount a pot whose resistance full up = the resistance of your current pot at 8/10... it's not that hard to find, knowing how actual pot resistance varies. For example, I've more than once measured supposed 500k pots which were actually 420k to 650k devices...
2) by mounting a resistor in parallel with the pickup (between the hot point of the pickup and the ground). Bill Lawrence recommends this solution and I've done it myself several times. It works well IME.

FWIW: typically, a tone pot does nothing else than lowering the resonant peak from 10 to approximatively 3. The resonant frequency of the tone cap starts to be prominent only below 3/10...

Hope to be useful.

 

[hermetico]

Re: Pickup frequency response calculator for guitar freaks

1)By lowering the value of your tone pot. You can mount a pot whose resistance full up = the resistance of your current pot at 8/10... it's not that hard to find, knowing how actual pot resistance varies. For example, I've more than once measured supposed 500k pots which were actually 420k to 650k devices...
2) by mounting a resistor in parallel with the pickup (between the hot point of the pickup and the ground). Bill Lawrence recommends this solution and I've done it myself several times. It works well IME.

FWIW: typically, a tone pot does nothing else than lowering the resonant peak from 10 to approximatively 3. The resonant frequency of the tone cap starts to be prominent only below 3/10...

Hope to be useful.

Indeed, very helpfull. It makes sense.
Thanks.

 

[robrob2]

Re: Pickup frequency response calculator for guitar freaks

Very cool spreadsheet. I had a several month old version of LibreOffice.org installed (free Office clone) and the spreadsheet wasn't displaying or functioning correctly. I downloaded and installed the latest version of LibreOffice, version 3.6.4, and it looks and functions great.

 

[uOpt]

Re: Pickup frequency response calculator for guitar freaks

how do I reduce that resonance peak height (let say to 3.0dB) without affecting the resonance frequency, in a permanent way (I mean, with volume and tone controls at 10)?.

A resistor across hot lowers the amplitude of the resonance peak. This is what your volume pot does. 250 has a lower amplitude for the resonance peak than 500 Kohm.

A capacitor across hot lowers the frequency of the resonance peak. Normally the only plain capacitor floating around there is the guitar cable, but you can turn your tone pot into a load capacitor by turning it to zero. People have been using direct load capacitors but not to great effect.

 

[Zerberus]

Re: Pickup frequency response calculator for guitar freaks

Nice little thing ya got there, Herm. Muchas Gracias for posting it. :beerchug:

H, you should have made this thread a poll. Forum members could have voted on which of our resident know-it-alls would be the first to answer your question.

But Hermetico started the thread, he´s the one I would have expected to know. Poll would definitely need 2 Rob options as a result (Standard and "I thought you were the electronics Guru") :laugh2:

 

[hermetico]

Re: Pickup frequency response calculator for guitar freaks

A resistor across hot lowers the amplitude of the resonance peak. This is what your volume pot does. 250 has a lower amplitude for the resonance peak than 500 Kohm.

A capacitor across hot lowers the frequency of the resonance peak. Normally the only plain capacitor floating around there is the guitar cable, but you can turn your tone pot into a load capacitor by turning it to zero. People have been using direct load capacitors but not to great effect.

Thanks uOpt. Valuable info, as ever.

 

[hermetico]

Re: Pickup frequency response calculator for guitar freaks

Nice little thing ya got there, Herm. Muchas Gracias for posting it. :beerchug:



But Hermetico started the thread, he´s the one I would have expected to know. Poll would definitely need 2 Rob options as a result (Standard and "I thought you were the electronics Guru") :laugh2:

Me?. Only real Wizard is ArtiToo.
I am a nut in electronics! (among, lot other things).