A wide-band impedance plot would tell the tale. These days there are software tools that can make the measurement, and break it into resistive and inductive components (real and imaginary parts respectively.)
One could then look for any odd behaviour in those two components within the guitar frequency band. It's conceivable that there could be core losses that reduce inductance and increase lossy resistance by the time 20 kHz rolls around - but e-guitar really stops at about 5 or 6 kHz. Would there be noticeable losses by then? They'd have had to use a solid iron nail for the inductor core, which would be appallingly poor engineering.
I've heard tales of mysterious nonlinearities in magic inductors, but everything is linear for small enough disturbances. The current through a wah-wah inductor is milliamps or less, and I cannot think of a core material or core size small enough to become nonlinear under the influence of such tiny magnetic fields.
This too could be measured, if anyone were so interested. Drive the inductor with an AC current, use a second sensing coil wound over it to pick up the resulting magnetic field, and do an FFT on that sensed current to see if there are any harmonics of the original frequency present.
As I'm sure you've noticed, I tend to be extremely skeptical of most of these magic-mojo claims, in large part because I've never seen a shred of hard evidence for any of them. Only claims by self-proclaimed Golden Ears.
Shrubberies are good things - green, relaxing to the eye, they provide shelter for the last few insects and spiders still alive on our dying planet ( Plummeting insect numbers 'threaten collapse of nature' | Environment | The Guardian , https://www.washingtonpost.com/science/2018/10/15/hyperalarming-study-shows-massive-insect-loss/ ), and they make a little oxygen for our overheated atmosphere.we will probably end up with Shrubbery...
The funny thing is, bad engineering is exactly what's required for good guitar electronics!...bad engineer, no biscuit
-Gnobuddy
I did a little mechanical engineering for the EB VPJr to Big Baby conversion.
Attached is the drawing for the sheet metal. Three (3) Pot holes, a 9 V power adapter hole, and two (2) 1/4" phono jacks on front. On top the hole for the foot switch and on back two wiring holes.
I will be making my own, but thought if would be fun to get a quote from a couple of sheet metal places.........and that was a joke. A place called ProtoLabs quoted over $400.00, I mean really you expect someone to pay gold prices for 20 or 30 minutes worth of work.......of course "if I wanted production quantities" the price per part would be lower.....and they wonder why DIY guys don't use them.
I will post more later, the holiday caught up with me....as normal get a few days off work and end up being sick with the flu.......
I also did some Googling again, everything I wanted to do with my wah circuit has already been done by another place, and is sold in kit form.
Mojotone Wah Pedal Kit
But they are a little deceptive in the "advertising". You do not get a Fasel Red inductor, you get a Dunlop Halo, and no schematic. Just a Parts list that says what reference designator to put the part in.
Overall the kit is pretty nice, and it saved me from having to order PCB's.
So I will be showing how all this will fit in the EB VPJr pedal....
Amazing how many have done this kind of work before........
Attached is the drawing for the sheet metal. Three (3) Pot holes, a 9 V power adapter hole, and two (2) 1/4" phono jacks on front. On top the hole for the foot switch and on back two wiring holes.
I will be making my own, but thought if would be fun to get a quote from a couple of sheet metal places.........and that was a joke. A place called ProtoLabs quoted over $400.00, I mean really you expect someone to pay gold prices for 20 or 30 minutes worth of work.......of course "if I wanted production quantities" the price per part would be lower.....and they wonder why DIY guys don't use them.
I will post more later, the holiday caught up with me....as normal get a few days off work and end up being sick with the flu.......
I also did some Googling again, everything I wanted to do with my wah circuit has already been done by another place, and is sold in kit form.
Mojotone Wah Pedal Kit
But they are a little deceptive in the "advertising". You do not get a Fasel Red inductor, you get a Dunlop Halo, and no schematic. Just a Parts list that says what reference designator to put the part in.
Overall the kit is pretty nice, and it saved me from having to order PCB's.
So I will be showing how all this will fit in the EB VPJr pedal....
Amazing how many have done this kind of work before........
And a schematic.
R6 5K pot adds a little mid-range, extremes of pot range can make it sound weird / bad....
R8 1K adjusts gain
R10 100K adjusts the Q (voice) of the mid peak, and extremes of pot range will sound bad....
R6 and R10 interact, adjusting one will change the other....
S1 will switch between bass or guitar, changes center frequency of the filter.
I have found zero sound difference using a Halo, Fasel, or any other inductor...but if you think you hear a difference then use what-ever makes you happy. This was tested with other people listening as well, all I asked was what sounds better (they did not know what inductor was in circuit). No one could tell a difference. Two inductors wired in with a on off on switch to select what was in circuit.
Oddly if I said here is a Fasel, or Halo.....well then it must of been something in the way I played because then they could.....psycho acoustics!!!!
I have done this test with cables before too, don't say whose and they cant tell.....say brand X and wow what a difference
Same goes for thinking you need to use PIO caps, you don't...but your money.
R6 5K pot adds a little mid-range, extremes of pot range can make it sound weird / bad....
R8 1K adjusts gain
R10 100K adjusts the Q (voice) of the mid peak, and extremes of pot range will sound bad....
R6 and R10 interact, adjusting one will change the other....
S1 will switch between bass or guitar, changes center frequency of the filter.
I have found zero sound difference using a Halo, Fasel, or any other inductor...but if you think you hear a difference then use what-ever makes you happy. This was tested with other people listening as well, all I asked was what sounds better (they did not know what inductor was in circuit). No one could tell a difference. Two inductors wired in with a on off on switch to select what was in circuit.
Oddly if I said here is a Fasel, or Halo.....well then it must of been something in the way I played because then they could.....psycho acoustics!!!!
I have done this test with cables before too, don't say whose and they cant tell.....say brand X and wow what a difference
Same goes for thinking you need to use PIO caps, you don't...but your money.
Firstly, thank you very much for doing the test! I appreciate it very much when someone makes the effort to dispel popular superstitions. The world desperately needs more rationality and less superstition.
And the results are exactly what I was expecting...even without double-blind testing (person conducting the test should not know which inductor is in use, because this might subliminally change his/her behaviour, which test subjects might pick up on. See "Clever Hans": Clever Hans - Simple English Wikipedia, the free encyclopedia ).
I fooled myself once, years ago; roped in a friend to run me through a series of tests, and my success rate dropped to the same as a coin-flip. I left humbler and wiser. There is no overcoming our intrinsic human nature.
Paper In Oil isn't good enough, but vintage Egyptian Papyrus-In-Mermaid-Oil (PIMO) caps are the bees knees!
They are very expensive, because mermaids are rare, and you have to find one and squeeze her through a wringer to extract the oil every time you make a batch of PIMO caps. But hey, what's the death of a few mermaids when better audio quality is the result?
Remember, you always get what you pay for! If you pay more for brand X snake oil, that must mean it's better snake oil!
-Gnobuddy
Of course! Remember "horse sense"? From the Longman Dictionary of Contemporary English: Horse sense: sensible judgement gained from experience, common sense.
If you doubt my veracity: horse sense | meaning of horse sense in Longman Dictionary of Contemporary English | LDOCE
-Gnobuddy
Firstly, thank you very much for doing the test! I appreciate it very much when someone makes the effort to dispel popular superstitions. The world desperately needs more rationality and less superstition.
And the results are exactly what I was expecting...even without double-blind testing (person conducting the test should not know which inductor is in use, because this might subliminally change his/her behaviour, which test subjects might pick up on. See "Clever Hans": Clever Hans - Simple English Wikipedia, the free encyclopedia ).
Remember, you always get what you pay for! If you pay more for brand X snake oil, that must mean it's better snake oil!
-Gnobuddy
No Problem, it was fun to do and similar to things I have done in the past. Yes Double Blind would of been better, but I did have some control of the "Hans bias" by following up with the "this is a Fasel / Halo" test.
On the Fasel / Halo test, as predicted Fasel won, yet no one could explain why it was better, just generalities like "it sounds warmer, has a more pleasing tone", or "I just like that better".........metal heads liked the Halo better though, "more of a heavy tone" was the proclamation.
I have some metal forming to do and then some rewiring before I can button up the Big Baby. But I do like this new Wah pedal.......the EB VPJr base has a better foot feel..........LOL
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