Can you add a resonant filter to a guitar?

[cmscss]

Hi there,

The title says it all, I’m guessing a 9v battery is needed but can you add a resonant filter to a Strat?

The only thing I found was this but don’t understand how (or if) it could be added to a Strat: 
www.cycfi-research.com/product/resonant-filter/

Any pointers in the right direction would be much appreciated. 

Cheers

[sumgai]

ben,


What that link described was nothing more than what you already have - pickups and tone controls. The keyword was "low-pass" filter, which is the exact description of a standard tone control - it reduces the amount of high frequencies, or stated in filter terms, it passes low frequencies.

Where the term 'resonance' comes in is the fact that a slight increase in loudness of a certain, narrow band of frequencies occurs just below the point where the frequencies are reduced in loudness. But rather than post any kind of chart to illustrate this point, let me avoid the redundancy and instead refer you to a good treatise by our very own JohnH:

Tone Control Discussions

This is a good starting point. When that starts to make sense to you, then we can move on to other kinds of tone controls, including bass-cut, mid-boost and others. But in each case, do keep in mind that these are all known as filters, and within each filter, there will be some resonance factor.

HTH

sumgai

[cmscss]

Thanks for the reply,

So does that mean there’s a way to make passive tone controls behave like a synth’s resonant filter?

I didn’t think you could boost frequencies withot power and my (limited) understanding of the Cycfi system is that it’s active (their pickups are).

[reTrEaD]

Jul 2, 2018 3:35:06 GMT -5 cmscss said:

I’m guessing a 9v battery is needed

Yes. The mention of an op-amp in that link makes that a certainty.

The Resonant Filter allows you to dial in the characteristics of virtually any pickup with two high quality dual-ganged Bourns® potentiometers. The Resonant Filter offers independent control of the cutoff-frequency and resonance (Q). The Resonant Filter is a single opamp VCVS second-order low-pass filter design with variable frequency, and variable resonance with constant gain compensation. The circuit utilizes the audiophile grade OPA209, a modern precision operational amplifier with very low voltage noise density of 2.2nV/√Hz, and a rail-to-rail output swing with a supply voltage from 4.5 to 36 volts — maximizing the dynamic range. The Resonant Filter module utilizes high quality gold-plated pin connectors.

That company has some interesting products. The pickups they make use of the same concept as the "Sidewinder" pickups Gibson used in their EB series basses, but they're shrunk down to fit into a SC form factor.

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In terms of passive designs, it is possible to create resonant filters. The Gibson Varitone is a prime example of a resonant notch filter. A bandpass filter could be made by reconfiguring the components. Instead of the capacitor and inductor being in series with each other, place them in parallel. ie: a tank circuit.

[sumgai]

reTrEaD,


I was in a hurry yesterday, and just plain forgot to include any mention of the op-amp and battery power - thanks for saving the day!

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Ben,


In essence, you're speaking to narrowing down the full spectrum of frequencies that can be heard from the pickups. Strictly speaking, this is not resonance, it's nothing more than what reTrEaD says, a "bandpass" filter. In and of itself, it's not resonating with anything, it's merely lowering the perceptable volume of the lower and higher frequencies, leaving only the mids to be heard (with ease).

As far as sounding like a synth goes, that's a different kettle of fish. Within a synth circuit, we're not just dealing with raw frequencies, but with distorted waveforms too. By that I mean, the resultant tones are not only not sinusoidal, but they are reshaped on purpose to produce a specific tonality. This is a heady topic for guitarists, to be sure. Nonetheless, it can be done, but at somewhat more expense than most mods to one's axe.

Of course, at this time in any of my postings dealing with this type of topic, I must now interject that the easiest way to achieve your desired "synth" filter tones is to simply install a divided (or "hex") pickup from Roland, connect it to anything from Roland's GR family of guitar synth systems, and have at it. Your wallet may gripe and grumble about it, but your ears will thank you and bless you for years to come.... trust me on this one.

Alternatively, you might achieve the desired tone with one of Roland's modelers from the VG series.  These units do have rudimentary filter patches that might serve your needs, and are somewhat cheaper, and more easily found on eBay or craigslist.  (Best of both worlds: The GR-55, containing both modelers (yes, that was plural, there are two of them) and a synth.  But still a bit pricey.)

HTH





sumgai

[cmscss]

Thanks heaps guys, great community here.

To be clear, I'm not after the sound of a synth per se, my GR-300 is a bit fragile/valuable for live, and I miss the GR-300's guitar-based adjustment (knobs) when using a Boss SY-300.

BANDPASS:
After more research, I've come to understand that you're right, I actually want two bandpass filters that can also boost frequencies (this sounds 'resonant' to me, even though resonant probably describes a certain circuit).

EXAMPLE CIRCUIT:
I found this schematic here: www.electronics-tutorials.ws/filter/filter_7.html





QUESTIONS:

• Would this achieve what I'm after?
• Could it be integrated into a guitar using a 9v battery?
• I also don't understand where the power goes - is the 0v ground?
• Is DesignSpark PCB (or similar) how you convert schematics into a PCBs?

Hope that makes sense.

Cheers

Ben

[cmscss]

Have concluded that a couple of these might be better: www.guitarfetish.com/Onboard-Switchable-Wah-Wah-Midrange-Booster-Complete-Kit_p_573.html

Cheers

[sumgai]

Ben,


Sorry for missing your post (Reply #5), but the circuit you posted is exactly what we call a band-pass filter. And no, it's not what you're after, you were right to question it's suitability for your purposes.

However, your latest link, to the "Wah-wah In Your Guitar" circuit, that'll do the job. And for 50 smackers, that's not a bad deal at all. Around here we tend to say nice things about Guitar Fetish, so you should be well satisfied with this item. But for Pete's sake, post before and after mod videos, or at least sound clips... please.





sumgai

[thetragichero]

looking around some of the diy fx sites and depending on how handy you are with a soldering iron/what spare parts you have on hand, this could be a fun and cheap diy project
the colorsound wash doesn't even need an inductor! effectslayouts.blogspot.com/2015/07/colorsound-wah-wah.html?m=1

I've read some people were happy with a maestro circuit. looks like some threads were spawned after wanting to copy zappa's two band parametric eq he had wired on all his guitars