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Post by blademaster2 on Mar 31, 2021 8:35:07 GMT -5
I've been more interested in a tigher (higher Q?) notch filter to center around 300Hz - this seems to get the frequency cut I like to cut some mud out of a neck pickup. Ive had better luck modeling in GuitarFreak with the 3H Wilde-Lawrence Q-Filter. Also considering a Framus filter - seems to look promising. Anyone wire a Framus filter on a guitar? I have a Framus Nashville, which has a 800mH inductor in the tone circuit (air-core bobbin with what appears to be pickup wire windings). It cuts the mids while leaving the clarity of the signal. I like it and replicated something like it on my own guitars, although it does not sound like the typical thick 'jazz guitar' tone that other tone circuits give me so I only use it on one of the two pickups (bridge).
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Post by blademaster2 on Mar 17, 2021 21:31:05 GMT -5
Very interesting. Is it possible that the difference between these cases, in db, would become a lot less when plugged in? I would like to see the same plots done when you have a cable loading the guitar signal. (I presume that the 'brown' plot is with the Ni/Ag cover but no Al guard, but was labelled as BLACK in error?)
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Post by blademaster2 on Mar 4, 2021 16:40:41 GMT -5
Hi there,
I would have expected to hear the difference, but I purchased a set of Strat-type replacement pickups from StewMac a few years back (Golden Age pickups) for my brother in law and installed them. They had copper tape around them, connected to ground. Comparing their sound to the Seymour Duncan SSL-1 pickups I have used in my own guitars, and a set of Tonerider Surfari's in another guitar I own, I cannot say that this was in any reducing the high frequencies that I could discern. All of them had the expected glassy-highs I have come to know in Strats.
In theory any metal nearby in the changing magnetic field will introduce more eddy current losses and reduce the high frequencies. I understand that it varies depending on the metal used, so perhaps copper is not as sensitive.
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Post by blademaster2 on Feb 17, 2021 18:04:17 GMT -5
That is great to hear. I have long imagined trying this, but only as an experiment (like all of my guitar innovations, so it takes ages to hear the results) and have never yet done it.
Knowing that you have a result of something along those lines is encouraging, especially when you said you would have it in all of your guitars and that it replaces real SPL. Excellent.
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Post by blademaster2 on Feb 17, 2021 17:58:50 GMT -5
Without a photo or equivalent schematic I am a little lost, but I can possibly see it as a way to save adding a wire, or using capacitors that are on hand to achieve the value that was not in the available parts. Could that be it?
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Post by blademaster2 on Feb 16, 2021 13:08:39 GMT -5
Warning understood, although the notion of exciting the body mechanically with the amplified signal is not the same as - nor trying to emulate - what a sustainer would do.
Maybe it could be used that way (inadvisably), but as I see it the aim is to add body resonance to the signal as if the system was turned up much louder than it is.
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Post by blademaster2 on Feb 16, 2021 12:59:05 GMT -5
If he really wants such low noise then he is probably barking up the wrong tree to go with single coil pickups in the first place. Also, adding the capacitance of the close-hugging shield will only make things more low-pass filtered - and if the cavity shielding was done well it likely adds little benefit (some, but little).
Cloth insulation might in theory change the capacitance of the cables to the shields, which I doubt *I* could hear but it probably gets swamped by adding the shield around the wires that he wants.
IMHO test added bang for the buck is probably twisting the conductors of each pickup, which only slightly increases the capacitance and rejects some of the picked up EM noise.
Then he plugs it all into a cable that dominates the capacitance before the signal gets to the amp....
Maybe tell him that there is a new type of wire you will use, with a new type of insulation made from 100% pure placebo. That seems to work pretty well.
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Post by blademaster2 on Feb 16, 2021 0:44:38 GMT -5
Well, you will be able to achieve what I have not been if you *do* get to try this. My family and day job have kept getting in the way just like yours.
I have wanted to try an embedded exciter for years on a solid body electric, just to see what it would do when the body wood gets the equivalent stimulus of a loud amplifier in the room - while not needing to risk my hearing and police visits.
Good luck with it, and with the Texas cold weather. Here in Canada our homes are built for it but yours are not.
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Post by blademaster2 on Feb 16, 2021 0:39:38 GMT -5
True, the 0.4uT was the lower limit of the reported concern but I took it to at least strongly imply that the level of sensitivity for health concerns was on that order.
It certainly seems from the few papers I scanned that levels that low are not at all well correlated to any negative health effects, and again I would want to see levels versus wavelength in order to see what type of emissions are of a concern.
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Post by blademaster2 on Feb 14, 2021 23:43:45 GMT -5
I am fascinated by this, and I eagerly hope to hear how your experimental results work out.
I hope you can avoid all electronic feedback and simply excite the body with this vibration. That will be awesome.
Very cool stuff.
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Post by blademaster2 on Feb 14, 2021 23:39:10 GMT -5
Hmmmm:
"It is generally recognized that neuronal cells are very susceptible to oxidative injury and, in addition, some studies have evidenced greater incidence of tumors in human nervous system after exposure to ELF-EMF (re-viewed by Fe y c h t i n g et al., 2005). Results of Fa l o n e et al., (2007) sup-port redox-mediated ELF-EMF biological effects. They observed a positive modulation of antioxidant defenses as well as a shift of cellular environment towards a more reduced state after exposure to these fields. The results obtained in this study may be significant in the light of evidence that Parkinson’s disease causes reduction in total number of cells in basal ganglia. Nowadays, Parkinson’s disease almost becomes epidemic and cannot be interpreted only by extended life span of human race, but also by drawing attention to the environmental factors, such as electromagnetic fields present in highly urban society."
This was caused by 50-500uT exposure for 7 hrs/day, 5 days/week, which is 100x to 1000x the 0.4uT field strength that you cited, which came from a paper that said something like this I presume:
" ... 0.4 μT represents a very weak field strength, especially when compared with the Earth's 100 fold stronger static magnetic field, to which all of us are exposed all the time. Second, a doubling of the relative risk represents only a weak association in epidemiological terms. For example, Doll & Hill's (1964) epidemiological study of the link between smoking and lung cancer revealed at least a 10 fold greater relative risk. To express a doubling of the risk of childhood leukaemia in another way, this corresponds to an extra two cases each year in addition to the UK's annual average of 500 cases .... two scientific insights need to be factored into this discussion. The first of these is that there is no known direct physical mechanism by which a field strength as low as 0.4 μT can invoke a biological response. That is not to say that such a mechanism does not exist, but if it does, we currently have no knowledge of it. The second insight concerns the quality of the data and conclusions derived from a host of laboratory experiments that have sought to determine whether ELF-EMFs induce biological responses."
That last sentence gently implies a possible confirmation bias in the research.
Nonetheless, any result that suggests a biological response is interesting since it is not at all clear what is happening in the body. From the above, I am not inclined to be terribly concerned for my family's health but it does bear some further research into the topic.
Thank you for pointing me to this eye-opening information.
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Post by blademaster2 on Feb 14, 2021 19:51:07 GMT -5
Well I would never make a claim if evidence suggested to the contrary. What I was stating was the facts (physics and what is currently done for testing), plus what I believe is defendable statement that if risk was very high we would be looking at far higher correlation than we currently see.
I will look at the other articles you linked.
The path length of blood vessels, or wires in a pickup, needs to translate to a wavelength for resonance and absorption so it does not immediately translate one for one between the two.
No one wants to take risks with their family's health, and I would certainly take heed if evidence was strongly supporting that 0.4uT was harmful, but I would still need to ask what frequency/wavelength is represented by that - there is a plethora of incorrect and misleading information out there. Long wavelengths like heat/IR would represent very different risks compared to shorter wavelengths like RF, microwaves or X-rays at the same field strength. By comparison, I still understand that 60Hz is almost DC and that health risks are pretty minimal if not nonexistent.
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Post by blademaster2 on Feb 14, 2021 12:27:21 GMT -5
The way to reduce EMI fields is traditionally to twist wires (cancels magnetic field portion of the EM wave) and surround the twisted wire with a shield (grounds out electric field portion of the EM wave). This works in both directions, making emissions lower and reducing the ability for it to pick up waves from other emitters. The shield has to be grounded to the amplifier or other receiver's reference, or earth ground.
For a guitar, which is a relatively high impedance signal, shielding is the usual method and twisting like microphone cables use for their lower impedance signals is not done. You do not generally want to have a lot of capacitance to the guitar signal because of its high impedance, which starts to lose high frequencies more with capacitance than a low impedance mic signal.
It sounds like your concern is also for health and safety, and for that you also need to consider the frequency of the EM fields, too. For 50/60 Hz the wavelength is very long ( several kilometers for a difference between, say, human tissue and earth). The thing is, nobody's body is large enough for this to create a voltage difference *across* the tissues of it, so our entire body goes along with the voltage wave up and down like a boat floating on large water waves with little or no difference across it. It is almost the same as DC fields. Much higher frequencies, like those of a microwave oven or your smartphone/wifi, are on the order of 6-12 cm so even that does not create a potential difference across cells - but what it does do is warm up the dielectrics of water and fats (cooking the food, or tissues). When we test for the effect of emissions on tissues in labs for health and safety it is measured in terms of the heating effect. Strong fields are not a good thing, but your daughter's brain gets much warmer locally by using a hair dryer than by using a smart phone.
The debate rages on about the health effects of EMI, and there are lots of myths and misinformation out there (like smartphones hard-boiling an egg). If EM fields were truly a significant health concern there would be irrefutable evidence by now given the ubiquitous presence of it, and we simply do not see that.
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Post by blademaster2 on Feb 11, 2021 10:27:15 GMT -5
Quick note: It looks to me like the pickup selector output is shown going straight to ground on the volume pot, and you will get no signal from it. It needs to go to the other side of the pot.
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Post by blademaster2 on Feb 5, 2021 16:37:43 GMT -5
To me the benefit of the lug is that you can solder the ground wire to it before it gets installed, so the soldering heat is no longer a worry.
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Post by blademaster2 on Feb 5, 2021 8:56:05 GMT -5
Wow - I wish I had that much free time.
Although I do not think I would spend it that way myself, it is great to have tinkering and innovation done to inspire new ideas.
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Post by blademaster2 on Feb 1, 2021 22:05:12 GMT -5
Unless one is trying to stick with a vintage look inside on'e guitar, I'd stay away from the braided shield stuff. As frets notes, it's a pain to work with, and if one is concerned about noise from the short wire runs out to the output jack (unlikely to be a source of noise in any event), better to use some other type of shielded cable. with a separte shield, rather than using the braided cable to both conduct the signal negative and shield the run as well. Any 2- conductor shielded cable will work, or you can salvage multi-conductor cable , like from old computer cables, and just use 2 of the conductors, jus tcut the extra ones off. The shield would then get grounded to one's grounding point, wherever that may be, and the two conductors make the jack connections. There are reasons that modern guitars (and modern pickups) don't use the single-conductor-with-braided-shiled wiring anymore. Good reasons. To add to Newey's comment, for the geometries in a guitar you really get little benefit from a shield braid, and if there is a solid wire within the shield then that is the one to solder. It might be good for noise to twist solid wires with a ground wire (loose twist), however, but that increases the capacitance and might reduce some high frequencies (although I doubt it would be noticeable). It is probably better to shield the entire cavity instead.
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Post by blademaster2 on Feb 1, 2021 9:28:44 GMT -5
My Teisco MJ-2L is different from that.
It has the Pickups switched to ground when off, and the signal is passed through 50k isolation resistors before joining at the output jack (so one pickup's switch does not kill the other pickup's signal). So in that case they are in parallel. My MJ-2L also has volume and tone separate for each pickup (tone wired to operate backwards, which Teisco did).
That Lynx is a very nice looking guitar!
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Post by blademaster2 on Jan 26, 2021 20:00:21 GMT -5
I must say that I absolutely *love* the results you had with those colours! That is one beautiful piece of wood, and the guitar is so much nicer looking than most other refins I have seen - ever.
Well done!
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Post by blademaster2 on Jan 26, 2021 19:57:17 GMT -5
Blade, The excitable topic of cap construction has caused some lively debates. And I’m not going to beat a dead horse. I did a blind test with friends a long time ago and could not differentiate between polypropelene, styrene, or polyester. I could pick the PIO most of the time. I could tell a ceramic and definitely wax paper. I have a favorite Gudeman PIO that has followed in my favorite guitars over the years. It is one sweet cap. I bet others on here have their one favorite cap. Oh, I do know that. The fact that *I* would not expect to hear a difference does not say that others do not or cannot. Having said that, I generally until recently keep my tone knob at full, so there was little likelihood of hearing any differences anyway. Lately I turn it down to 40-50% (since I installed "ice-pick single coils" in two of my guitars in the neck position and it needs the top end shaved off when playing clean) so I might be at a point where I could experiment and see if I can hear it myself. The first thing would be to ensure that the values of the two type of caps were essentially the same before any other comparison would hold water. How would you describe the difference of tone of PIO compared against, say, a ceramic or wax paper? If I were to be a skeptic, I might first assert/suspect that the tolerance of the capacitance for the ones where you could hear a difference might still have dominated the result more than the dielectric material - but I would never claim that with any certainty.
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Post by blademaster2 on Jan 26, 2021 13:19:01 GMT -5
I can certainly see that there is higher capacitance for paraffin potting compared to air (if the gaps are there at all and are filled with the paraffin).
Paraffin will double or even triple/quadruple the capacitance value of the interwinding capacitance in the coil compared to the same coil with air. That would have to affect the frequency response of the pickup. Tighter winding would reduce this impact, since there is no air gap (or less of an air gap) to be filled with the paraffin.
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Post by blademaster2 on Jan 25, 2021 17:15:47 GMT -5
Hi Joe, Yes, the traditional values per G&L are .022 (22nF) for the Treble Cut Pot and .0022 (2.2nF) for the Bass Cut Pot. You can use just about any construction type of a tone cap although I would avoid ceramics or electrolytic. You can use polyester (greenies), polypropelene (Orange Drops), PIO (paper in oil), or wax caps. Definitely agreed about avoiding ceramic caps (poor tolerance, varying value as they age, intermodulation but to a lesser extent), although I have seen Gibson Les Pauls that used them, and other brands like Hagstrom. I have used polyester in my guitars. To be honest about it, however, I probably myself could not hear what type was in a guitar I was playing.
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Post by blademaster2 on Jan 25, 2021 15:19:53 GMT -5
Many thanks!
I think we had it the same way, so that is good news.
The old DiMarzio wiring was a little restricting, but workable. I like their sound, especially on split coil.
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Post by blademaster2 on Jan 22, 2021 10:49:37 GMT -5
The article is certainly convincing-sounding. Perhaps that is why there is so much variation in the market: Some Fender amps have no standby switch, the AMPEG V4 has one and the manual suggests 30 seconds before applying the high voltage, and the VOX AC15 manual say to wait a full 3 minutes before applying the high voltage.
I always figured it was driven by the particular differences between the circuitry rather than misunderstanding/misinformation and tradition, but now I do not know. I have also read articles that sounded equally credible that explain why the standby switch is important and needed (I cannot recall the details just now), so I will still use mine but I will not leave them in that state for extended time periods.
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Post by blademaster2 on Jan 3, 2021 23:28:51 GMT -5
Retread,
So sorry to hear that.
I do hope your friend can make a good recovery. I am no medical expert but I have heard of new drugs and treatments that can reverse a lot of the effects of a stroke.
Speedy and full recovery are in my thoughts.
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Post by blademaster2 on Dec 27, 2020 0:00:45 GMT -5
I finally disconnected the soldering that I did in high school to find out what was really going on with the pickups in my first guitar I built.
These were purchased in 1978 and were called "Dual Sound", which was essentially a splittable Super Distortion Humbucker. They had three wires (white, red, black) plus a bare ground wire. DiMarzio still makes "Dual Sound" pickups, which appears to be the same thing but now they have 4 wires (green, red, white, black) plus a bare ground wire.
I was unable to find anything on the meaning of the wire colours on these models on the web, and I was not getting the sounds I expected with the wiring I had constructed (which was done exactly as the instructions said since I knew nothing back then about this topic).
So here is the answer (found using an ohmmeter):
Coil A: White is signal, and the other 'negative' end of this coil is permanently connected to shield/ground Coil B: Red is 'positive' and Back is 'negative' relative to the white wire on coil A
The original wiring I used, which I understood to be a series/parallel switch, was actually only giving me parallel/single coil. I liked the sound, but I thought I was getting something else. Now I have the neck pickup configured for Series ("Super Distortion", highest output) or single coil (the inner coil, so someday I might rotate the pickup so I get the single one to be the one closer to the neck). TBH, I am not terribly pleased with the duller series tone on its own but I left the bridge pickup with my original parallel/single coil so I could preserve that clarity as I mix the two and it gives me the most variety.
It is like a whole different guitar now, with more variety of tone than ever before.
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Post by blademaster2 on Dec 5, 2020 12:52:39 GMT -5
Many of out members may be too young to remember who Rube Goldberg was, but this is a perfect example. Although some pretty solid engineering had to go into this thing: Very impressive, and a heck of a lot of effort that went into it. I gather he cannot take requests for a different musical number .....
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Post by blademaster2 on Dec 4, 2020 16:18:57 GMT -5
Thanks Ash, No one has ever described it to me like that. I find it to be the most useful way to think about how a filter works. “Everything useful is a voltage divider”. Figure out what makes the top of the divider and what makes the bottom. Caps get big at low frequencies. Inductors get big at high frequencies. When you start mixing them, things can get complex (like literally complex as in imaginary numbers and vector math) which can lead to resonances and such, but for quick “back of envelope” eyeballing, it is a good way to get a general idea of what’s happening. That is a beautiful and simple way to look at it. I think of it that way myself.
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Post by blademaster2 on Oct 29, 2020 20:21:10 GMT -5
That 1-2 Mohm reading must mean that a pickup coil or external connection to it is broken (open-circuited) and you are reading whatever else is in the circuit in parallel (likely volume knobs) depending where you are probing to make your measurement.
The mysterious aspect appears to be still hearing a signal from something that is supposed to be "broken", but perhaps if you traced the circuit you could discover that you are getting the signal from a good pickup feeding through the circuitry when you have it switched to the 'broken' pickup. Some people call that a 'sneak circuit'.
For sure, any pickup truly reading such a high dc resistance must be dead.
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Post by blademaster2 on Oct 12, 2020 14:42:03 GMT -5
That would only hold true if a condenser microphone worked without phantom power. With no phantom power to offer a DC bias the change in capacitance cannot (should not be able to) generate a signal. My understanding is that "microphonic pickups" do indeed work the same way that a dynamic microphone does - any ability for the coil wires to move even a little within the magnetic field of the pickup will generate a signal. The resonance of these small, short spans of wire within the windings creates a fairly high shriek sound to most ears. That is why wax potting (or epoxy/araldite potting) reduces this effect by hold them more-or-less motionless relative to the magnet.
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