Hullo! Well, at last there is a pcb for the clone of the very, Iomi-esque, tychobrahe parapedal available from Pedalpcb.https://www.pedalpcb.com/product-category/wah/ I was lucky to get a nice 2w dual gang 10k pot for my build.($16.99-ouch!)
I know Chicago Iron works has a dead on clone called the Parachute, but I am intrigued at the wilson effects clonehttp://www.wilsoneffects.com/FreakerWah.html and its mods, this from a description on the page, There is an added six position Q switch that adjusts the filter settings of the wah pedal. These range from a high filter sweep to a deep filter sweep and everything else in between. It doesn't stop there. There is also and added sweep knob that allows you to open up the Freaker's sweep to it's maximum width or narrow it down to a thin filter sweep. We have also added an external boost knob to boost the filter above unity gain if needed. The V2 has additional volume available via the volume/boost control at the heel of the pedal as well as a mini toggle located under the treadle of the pedal that allows the user to choose between the original function of the pedal or you can now eliminate the volume drop at the heel of the sweep via this toggle. I am wondering if they could be implemented on my clone build?Any Ideas would be greatly appreciated!
Building a clone of Tychobrahe Parapedal wah, some mods?
I think best course of action here is to get more general knowledge about how wahs work. I'll admit I don't know much about wahs, but if I wanted to know what you're asking, I'd start reading up on wah circuits, how they work, and how changing certain parameters affect the sound. Then I'd read about mods people are doing to other wahs, and see if and how I can implement them into the tycobrahe. My guess is there's going to be core similarities between wah circuits, and the way you change the filter frequency and/or range will be similar across most wahs. This is your classic "teach a man to fish" idea.
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mictester
- Old Solderhand
Information
There are (basically) three sorts of guitar wah circuits:
The simplest is the "Twin-T Filter". This can be done with just one transistor and gives a peaked response and a fairly good "wah" sound. Several manufacturers have used this approach for "inductor-less" wahs, and it has the advantage that the frequency is determined just by a single variable resistance - very convenient since you just need two wires to the frequency pot and you don't need much rotation to get enough value change if you use a high value pot!
The second circuit is the "Cry Baby" type - this uses an inductor and can thus be prone to hum pickup on electrically noisy stages! I had all sorts of grief trying to get the buzz of the dimmer packs out of one well-known guitarist's Clyde McCoy pedal. These are very open to modification - the inductor can be changed from the usual 500mH to a 680mH for a deeper "voice", and the usual tone-sucking low impedance input can be improved by the addition of a unity gain FET buffer. Other mods include the neat switching arrangement that Colorsound used in their Wah / Volume pedal to switch between the two functions.
The third and the most complex is the type that you're talking about in this thread - the "State-Variable Filter" type. The classic SVF has three output - high pass, low pass and band pass and every parameter can be tweaked - centre frequency, "Q" (filter shape), and bandwidth. The famous "Mutron" triggered wah used this approach and tuned the filter stages with light dependant resistors. This is also the type of circuit that Tychobrahe use for their Parapedal.
It's well worth reading up on the State Variable Filter since it's so open to modification and is relatively cheap to build. My take on the SVF uses four quad op-amp chips in the audio path, offers triggered and automatic wah of various types, offers LP, BP and HP outputs, does a "pseudo-phaser" effect, and also emulates the formant filters that were in the famous Colorsound "Dipthonizer". It can also have a "wah / anti-wah" effect that's quite close to the "talking" pedals that Electro Harmonix and others made. The big trick was making most parameters voltage-controlled....
The final kind of filters don't usually end up in guitar pedals - the Moog Ladder Filter and the Korg "Traveller". These were both developed for synthesisers, but there have been some rare examples of them used in guitar pedals. Back in the 70s, I had a Korg "Traveller" pedal and I wish I knew where it went to because it was superb! There are some other configurations of voltage-controlled filters that end up in more modern synthesisers, but most of them are just updated takes on the well-known older SVF and ladder types.
The simplest is the "Twin-T Filter". This can be done with just one transistor and gives a peaked response and a fairly good "wah" sound. Several manufacturers have used this approach for "inductor-less" wahs, and it has the advantage that the frequency is determined just by a single variable resistance - very convenient since you just need two wires to the frequency pot and you don't need much rotation to get enough value change if you use a high value pot!
The second circuit is the "Cry Baby" type - this uses an inductor and can thus be prone to hum pickup on electrically noisy stages! I had all sorts of grief trying to get the buzz of the dimmer packs out of one well-known guitarist's Clyde McCoy pedal. These are very open to modification - the inductor can be changed from the usual 500mH to a 680mH for a deeper "voice", and the usual tone-sucking low impedance input can be improved by the addition of a unity gain FET buffer. Other mods include the neat switching arrangement that Colorsound used in their Wah / Volume pedal to switch between the two functions.
The third and the most complex is the type that you're talking about in this thread - the "State-Variable Filter" type. The classic SVF has three output - high pass, low pass and band pass and every parameter can be tweaked - centre frequency, "Q" (filter shape), and bandwidth. The famous "Mutron" triggered wah used this approach and tuned the filter stages with light dependant resistors. This is also the type of circuit that Tychobrahe use for their Parapedal.
It's well worth reading up on the State Variable Filter since it's so open to modification and is relatively cheap to build. My take on the SVF uses four quad op-amp chips in the audio path, offers triggered and automatic wah of various types, offers LP, BP and HP outputs, does a "pseudo-phaser" effect, and also emulates the formant filters that were in the famous Colorsound "Dipthonizer". It can also have a "wah / anti-wah" effect that's quite close to the "talking" pedals that Electro Harmonix and others made. The big trick was making most parameters voltage-controlled....
The final kind of filters don't usually end up in guitar pedals - the Moog Ladder Filter and the Korg "Traveller". These were both developed for synthesisers, but there have been some rare examples of them used in guitar pedals. Back in the 70s, I had a Korg "Traveller" pedal and I wish I knew where it went to because it was superb! There are some other configurations of voltage-controlled filters that end up in more modern synthesisers, but most of them are just updated takes on the well-known older SVF and ladder types.
"Why is it humming?" "Because it doesn't know the words!"
Do you mind sharing where you scored the dual gang 10k pot? Had one of these on the backburner for a long time mostly on account of not being able to source a suitable pot with a proper sized shaft for the rack/pinyon.
Palelight, sheer,dumb search luck on Ebay. https://www.ebay.com/itm/10K-OHM-DUAL-L ... 2749.l2649 LAST ONE! B e prepared to fork over $ome cashola..palelight wrote:Do you mind sharing where you scored the dual gang 10k pot? Had one of these on the backburner for a long time mostly on account of not being able to source a suitable pot with a proper sized shaft for the rack/pinyon.
Thanks! I am going to get it going in the unmodded stage and then try incredibly hard NOTY to mod the beast,lol!mictester wrote:There are (basically) three sorts of guitar wah circuits:
The third and the most complex is the type that you're talking about in this thread - the "State-Variable Filter" type. The classic SVF has three output - high pass, low pass and band pass and every parameter can be tweaked - centre frequency, "Q" (filter shape), and bandwidth. The famous "Mutron" triggered wah used this approach and tuned the filter stages with light dependant resistors. This is also the type of circuit that Tychobrahe use for their Parapedal.
It's well worth reading up on the State Variable Filter since it's so open to modification and is relatively cheap to build. My take on the SVF uses four quad op-amp chips in the audio path, offers triggered and automatic wah of various types, offers LP, BP and HP outputs, does a "pseudo-phaser" effect, and also emulates the formant filters that were in the famous Colorsound "Dipthonizer". It can also have a "wah / anti-wah" effect that's quite close to the "talking" pedals that Electro Harmonix and others made. The big trick was making most parameters voltage-controlled....
The final kind of filters don't usually end up in guitar pedals - the Moog Ladder Filter and the Korg "Traveller". These were both developed for synthesisers, but there have been some rare examples of them used in guitar pedals. Back in the 70s, I had a Korg "Traveller" pedal and I wish I knew where it went to because it was superb! There are some other configurations of voltage-controlled filters that end up in more modern synthesisers, but most of them are just updated takes on the well-known older SVF and ladder types.