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Post by blademaster2 on Mar 1, 2020 13:42:13 GMT -5
I spent a while yesterday debugging my 1970-era AMPEG V4. It suddenly sounded very dull and lifeless on Channel 1, and I first suspected the preamplifier 12AX7 since Channel 2 was fine. Opening it up, swapping the preamp tubes between the two channels showed that it was not the tubes (although the two had noticeably different tone, which surprised me that I could hear a difference. One was more edgy and the other more clear and crisp but both sound good). I ended up opening it up and spraying cleaner into the controls, which seemed to correct the initial problem I had. The thing is so darned heavy, even doing that is a major undertaking, but it is worth the effort. (It is still in excellent condition). Someday I might need to do a full re-cap, which will be very involved ...
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Post by blademaster2 on Feb 24, 2020 14:12:46 GMT -5
I re-installed a 'shortened' metal cover over the new SSL-1 pickup that I swapped in to one of my guitars in December. This was purely cosmetic, but I missed that clean look it used to have. I first tried it with tape holding the cover in place and played for a long while so I would know if any "eddy current" difference was audible in the high frequencies, but it still sounded good to me (but not like a Strat). This guitar is pretty bright anyway. I cut the sides lower on the metal cover (minimizing the metal needed) so it now sits just below the pickup mounting ring. wonder woman free svg file
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Post by blademaster2 on Feb 6, 2020 11:11:58 GMT -5
In an interview Brian shows the pickup combinations he has used in some famous songs and solos.
He used almost all of the available combinations in Bohemian Rhapsody throughout the song.
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Post by blademaster2 on Feb 4, 2020 17:33:39 GMT -5
On the long list of "maybe someday" projects, I had long thought of installing a set of the originals in a Strat, modifying the pickguard for fitment. So, my question would be, do these Strat-friendly ones faithfully replicate the original Tri-sonics? (I don't know if you had ever subjected the original models to testing, however.) I haven't tested the originals, but my guess is that they're constructed close enough to the originals. If they sound different than Brian May's Red Special, it's probably going to owe to all of the other differences between a Strat and that guitar. Brian May uses a treble booster in his setup, in addition to wiring them in series (I always figured that the treble booster was a way for Brian to get back the treble that was lost due to the series wiring, plus his use of a coin as a pick to get a sharp attack). Without that, ignoring the body construction differences with the Red Special, I would still expect the equivalent Burns pickups to sound different compared to the Red Special. I gather the closest anyone can get to the Red Special sound using a Strat is to wire the Burns pickups in series and also feed them into a treble booster (and then to a Vox AC30, cranked). The body construction difference - and the enormously thick neck Brian made - will still be missing, of course.
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Post by blademaster2 on Feb 3, 2020 18:02:01 GMT -5
I used to see a combination cable in stores, where a short portion of it was coiled and the rest was straight. That gave some strain relief without the annoyance and extra capacitance of the fully-coiled versions.
I gather they never sold well, since I seldom see anything like that in stores now. For my preferences, I would stick with straight cables but I recall that my first cable for my first guitar/amp was coiled.
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Post by blademaster2 on Feb 3, 2020 9:59:23 GMT -5
Frets, you are the only person I have ever heard of who actually fabricated capacitors on their own. That is impressive, and amazing. No "Cindi" quips would be appropriate in any situation (I would object to it regardless), but anyone inclined to show you such disrespect would have no basis to do it here.
Unless you used a lot of copper foil area and a very thin wax paper for the dielectric (not the kitchen variety) I would intuitively expect that the capacitance would be a pretty low value and not in the uF range. Hence my first suspicion is that the value was too low for the tone control to make a difference - and I cannot explain why the meter showed differently, but capacitance readings are more complex than resistance readings for these things and there are a few things that might explain it.
Otherwise, an open circuit as JohnH suggested might be the cause.
As to the idea that copper would be audibly better than other metals, I do not expect to hear it or see a measurable difference in instrumentation, but I would also never tell someone that they are not. Human hearing is one of the most fascinating senses.
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Post by blademaster2 on Jan 20, 2020 9:58:11 GMT -5
One benefit of active electronics is that the pickup can be loaded less with a higher input impedance feeding the preamplifier (like the 1Meg pots compared to 250k pots on passive electronics), can be shaped as Trag says, and in turn the amplified pickup signal at the output of a preamplifier can be much lower impedance such that you can use lower resistance pots to control the volume (or control it and subsequently buffer it so that a low impedance feeds the output of the guitar and makes the loading effect of cables less influential on the tone).
The drawback is noise and other non-idealities of the preamplifier circuitry in negative feedback topologies (slew rate and other transient response attributes that are the majority of what we call 'tone') and the need to put a battery in the instrument.
Given the subtleties of the tone of a guitar I could never prove it with instrumentation, but my impression from those I have tried is that the sound is okay in an active guitar but there is something missing or changed that I would prefer to use pedals if I want anything other than the passive signal feeding my amplifier.
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Post by blademaster2 on Jan 16, 2020 13:31:59 GMT -5
If the tab of the replacement pup still fits within the routed cavity under the guard, then can't a 2-screw pup be installed with only the need to drill a central hole? That would leave the other two holes there as decoration (or as 'features') and avoids the need to replace the pick guard just for that reason.
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Post by blademaster2 on Jan 15, 2020 8:49:31 GMT -5
I just used stiff cardboard with holes cut into it that matched the drilled holes of the wiring cavity. The top of a cardboard box works well if the edges are high enough for the pots to poke through and it can still sit on the edges of the box top. If you use stiff interconnecting wires then the whole assembly can retain that shape better and be inserted nicely where the pots/connectors line up with the holes easily.
I agree that it is far better to do this than to reach inside the cavity and risk damage to the guitar finish. I actually also used inline connectors (crimp type) for the pickup wire connections in one of my guitars so that I never need to do any soldering within the guitar cavity. It worked perfectly.
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Post by blademaster2 on Jan 14, 2020 10:01:14 GMT -5
A few days ago I picked up a replacement cable for my home set up due to a new piece of gear arriving at my studio - same as always at 15 foot length.
I plugged in a guitar that I have been playing a lot lately, and played through my Marshall combo (an amp that I always felt was a little dull, especially on clean settings). Not expecting a difference I started in playing my usual stuff, but then I noticed that the tone was noticeably better than I had heard when I last played that amp. I then used another 15 foot cable that I had used previously through that amplifier and I could detect a difference - it had gone back to the somewhat dull sound. As always, the difference is subtle and I might not hear it if recorded or if others were playing.
I know that antigua and others have shown plots of the loading effect of the cable on the frequency response so this might not surprise others, but I never expected the small difference (presumably in the capacitance) in a cable to make such a detectable difference in the sound.
I am going to buy two more of these same brand to swap out the others in my set up.
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Post by blademaster2 on Jan 8, 2020 17:03:41 GMT -5
I think what you are saying is correct - any metal in the vicinity of the modulated magnetic field will suck away some high frequencies from the signal due to eddy currents. I have experienced this myself when adding a metal cover to a pickup, which I subsequently removed because I could hear a sight difference. The different was pretty subtle, however, and it appears that the complete removal of all metal except for the poles themselves would similarly - but subtly - preserve the high frequencies.
I think the accepted response for a particular pickup design must include the effect of whatever metal is there, and perhaps it has the most profound effect when it is closest to the modulated region of the field (nearest the strings), which is why the usual place we see changes made is toward the top where covers can be either non-metal, removed entirely, or slotted metal (which might be due to eddy current losses but I do not have anything to confirm that). Perhaps the difference between metal and non-metal for the pickup base is less pronounced or imperceptible.
Then again, metal is the way we shield against electric-field-induced noise, so removing metal everywhere possible will lead to more noise (note that humbuckers address more of the magnetic-field-induced noise), so it becomes a trade-off. It seems that either way we do it, reducing noise ends up reducing high frequencies in some way.
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Post by blademaster2 on Jan 3, 2020 15:12:32 GMT -5
True, and thickness is hard to assess because - although it is blocked because I never use it - there is a route on the back of the maple guitar for a fender-style whammy, which reduces the thickness there beneath the pickups. The body of the maple guitar is actually thicker but locally this brings it down to be probably the same or thinner in that region.
Without building the guitars in advance with this experiment in mind and with the exact same body design I had no other option there. Still, I do feel that the penetration depth for many higher frequencies would be limited and have diminishing effect as you get farther away from the bridge and pickups (and yet, since I can feel the resonance, there is a significant amount of vibration propagating to the outside surfaces across a good amount of the range).
Dunno - I will remain a student of this stuff and I will never claim to be a master.
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Post by blademaster2 on Jan 3, 2020 14:19:39 GMT -5
Thanks!
Well, for an after-the-fact experiment I did not have the same body shape at my disposal but you make a valid point (especially at elevated volumes). Other than that, this was the most controlled experiment I can perform.
My sense is that beyond a limited 'penetration depth' the resonance due to the shape of the body outline will have decreasing effect and it will be mostly influenced by density and other material properties closer to the string and pickup anchor locations. However at elevated volumes I can easily imagine resonances of the various wings/protrusions bringing in something to add to the string vibrations. Then the pickups will sense any relative motion between their mounting point and the strings and this will be present there as well, which is why wood properties can have an effect (small in this case, but present nonetheless to my ears).
To be honest, I was a little surprised that I did not hear more difference than I did between the two, and I think this might be partly due to the brilliance of the SSL-1 pickups dominating the tone I heard. I also used my AMPEG V4 amplifier for this comparison, since it is the least "colouring" amp that I have and itself has a very clean high frequency response.
When I play either of these guitars I can feel the body surfaces vibrating in my hands, so by reciprocity these same surfaces must also couple the sound back into the bridge/pickups and strings. I *so* wish I could have cranked it up as part of the experiment (maybe I will someday).
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Post by blademaster2 on Jan 2, 2020 22:53:19 GMT -5
I believe that the advent of a slow-breaking diode is non-trivial. While speed counts in many applications (I mean, a very quick change over from one voltage level to another), there are times when a human-speed changeover would be nice.
Consider this component as a corollary of the slow-blow fuse compared to the regular circuit breaker - there are times when one or the other of them is better suited to the designer's intent and purpose. Same thing here. The fact that a distortion simulator seems to be the first real-world product is a bit of a stretch, I agree, but the nice man did say "The owner of the business plays guitar", that's a good enough reason for me.
sumgai
I have slowed the diode response using series resistors with diodes in the feedback path of an op amp (this was for a Wien Bridge Oscillator so it would produce a more pure sinusoidal output with fewer harmonics, but the basic principle still applies). Aren't semiconductor P-N junctions *all* molecular? To me this still sounds like snake oil intended to be comedy (or worse, a marketing ploy to sell a diode-clipped op amp distortion unit with a softened clipping response as if it is a new invention), but I am perfectly willing to be re-educated on it if I have missed something new in device physics. I can ask my university professor colleagues to see if they are aware of any such breakthrough in devices.
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Post by blademaster2 on Jan 2, 2020 22:03:13 GMT -5
In my ongoing research I decided to perform the best comparison I could between solid body guitar woods. I will refrain from calling this a 'tonewood' comparison, although that is essentially what this is. To do it with the fewest other factors that I could manage I did the following experiment: Similarities:- I installed Seymour Duncan SSL-1 pickups, each mounted into a neck-position humbucker mounting ring, into two solidbody guitars - Both guitars had pickup heights set to the same distance from the strings and very close in position along the string length - Both have Fender-style bridges, hard-tail mounted - Both have set necks - Both have rosewood fingerboards of the same density and of the same scale length - The electronics of the two guitars is of the same design. - Both had the same string gauges installed, and are (reasonably) new. - Both guitars are between 35-40 years old, so their relative aging/drying are pretty similar Differences:- One guitar is made from walnut and the other from birdseye maple. (Edit: the body shapes are different, of course, but the body thicknesses are approximately the same in the vicinity of the strings and pickups) Missing investigation:I never took the volume up such that the sound from the amplifier made a noticeable impact on the guitar response (I would love to, but neighbours may object). One slight headache was the need to deepen the pickup route for one of the guitars. I do not think I could perform a more controlled experiment (although I did not electrically measure and compare the two SSL-1 pickups as I assume that their manufacturing processes will bring them pretty close to each other in that regard). Results:- I would never expect to 'see' a difference if an oscilloscope or spectrometer was used (heck, I could not tell if a 'scope trace showed a guitar or a piano), so I never even tried that although I do own an oscilloscope. I rely on hearing and feel, over many minutes of playing. - I played both guitars through the same amplifier, same cable, same volume and tone settings, alternating between them. There *are* differences in tone, mostly on the attack, but they are subtle. I would say that they had very different 'personalities'in their tone, and I would be inspired differently when playing them. - The SSL-1 provided roughly the same glassy brilliant high frequencies for both guitars, but the slightly lower frequencies from those highs were stronger on the maple body than on the walnut body. - The maple body gave more crisp edge on the attack, whereas I heard a warmer smoother tone from the walnut guitar. If someone else was playing or if this was played through different amplifiers and different settings I might not hear these differences, but I am convinced that they were there in my comparison. Conclusions:This strengthens my belief that the body wood makes a difference even in solid body guitars, but this result also tells me that some opinions of 'cork-sniffing' enthusiasts may not be warranted. This difference is subtle, but I find it important in how I play and respond to the guitar. Nonetheless I would never try to tell people what they hear. This is my own finding, and others might have heard it differently (I would like to get other players to compare these same two instruments).
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Post by blademaster2 on Dec 21, 2019 16:55:33 GMT -5
Well, if it was still in the guitar I would first check switches and controls to see if debris caused them to open circuit on the signal path. If it is out of the guitar you can check with an ohmmeter to see if it is still an unbroken coil (should read below 10,000 ohms typically).
If you have no ohmmeter, then you can take the wires from the pickup and connect them (even with fingers) to the two contacts of a guitar cord plugged into an amplifier (not turned up too loud), and then tap on something that is ferrous (like a screwdriver or other metal object) using, say, a pencil in front of the pickup. It should make the tapping sound come through the amplifier. If that works then the pickup is working - and you can look at the more likely causes of no signal, such as the switches and control knobs (or broken wire in the cavity).
Good luck.
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Post by blademaster2 on Dec 21, 2019 15:25:47 GMT -5
I still think it is humour. Something like this:
or this:
Just imagine hooking up that Rockwell Retro Encabulator to your Marshall stack! Awesome!
Especially if the speaker cone was made from Prefamulated Amulite
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Post by blademaster2 on Dec 21, 2019 12:17:46 GMT -5
Hmmm - it sounds like he is describing a simple diode-clipped op amp circuit. Not exactly a breakthrough.
I am pretty sure this is intended to be humour. Maybe that is obvious to everyone else, but I did listen to get a sense of anything truly real, and I never got anything.
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Post by blademaster2 on Dec 21, 2019 8:48:11 GMT -5
I am impressed! I have heard of 'cigar-box ukeleles' before, but never a tube amp. I gather this is an effect unit or preamplifier, since it does not have an output stage for a speaker?
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Post by blademaster2 on Dec 20, 2019 15:29:18 GMT -5
It is sometimes held that a car battery is in essence little more than an enormous capacitor. Well anything with opposing polarities held separate satisfies that criterion and low leakage capacitors are indeed used for short term memory retention, but with all that in mind, I always thought of the Leyden Jar (or more simply the "Jar") as an earlier (if not the original) measure of capacitance? I shall revise that impression if the Jar was also a unit of electromotive force. This demonstrates to me that I'm not immune from holding unfounded ideas! Step forward Mr. Leyden! e&oe ...In point of fact, where the capacitor is nothing more than a "holder" of a charge, a battery (or more properly, a cell) actually does a chemical conversion of energy - it does not "just hold" an electrical charge in chemical form. Although if one really wants to get into it, the Laws of Energy Conservation could be invoked to mean that all energy can be converted to some other form, meaning that a "holding" action is really in play. As I learned it, way back when, a cap can only discharge what was put into in the first place, whereas a battery can be discharged quite often, and wonder of wonders, even without a direct recharge, it can actually deliver more energy, if it is given some time to "recover".
The obligatory car analogy: Let us assume that you use the car's battery to start the car every morning. It's near freezing outside, so the engine doesn't start immediately; it takes several seconds of turning over, and thus the battery is working pretty hard. If you run the motor for just 1 minute, that's not enough time for the alternator to send a charge back into the battery to completely replace what was used to start the motor. Yet, during the day, the battery is at rest, and when the next morning comes, it can do the job again. And again, and so on.
Start by measuring the initial amount of power it took to bring the battery to full charge, this will be your base line to measure against. Now, measure the amount of charge used by the starter each morning. Keep doing that every day, for a month. Totaling up those numbers will surprise you - said total is much greater than your initial power reading. Why? Because the chemical reaction can regain its potential simply by resting.
Now, that's a short-and-sweet story, and it breaks down under a deeper analysis. But the real point of the analgy is that if you compare that activity to a capacitor's capabilities, you'll see a marked difference. As in, the cap can't recuperate simply by 'resting'. In fact, for every electron discharged from the cap, said electron is gone. If you want another electron to be ready for discharging, the you're going to have to charge the cap with one, before the next discharge event.
In short, a cap does not do any 'energy conversion', it simply stores a charge of electrons on one of its plates, until a circuit is completed and the charge is dissipated into some other component/load.
Fun fact: In the very beginning, the pioneers called a capacitor an "accumulator". 'Struth!
Further fun fact: For some time after "accumulator" fell out of favor, the capacitor was called a "condensor" (or very occasionally, spelled as 'condenser'). Once in awhile, you still run across this nomenclature on old schematics.
HTH
sumgai
.... like 'condenser' microphones, which essentially works by charging up a capacitor (a.k.a condenser) that will change its capacitance value as the plates move back and forth with the sound waves hitting it. The signal coming from it is then essentially the displacement current from the biased capacitor at a fixed voltage as its capacitance is modulated. I bet nobody really wanted to hear that in this forum, but there it is.
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Post by blademaster2 on Dec 20, 2019 15:19:22 GMT -5
this is not true as, at least in the us, the neutral wire is tied to ground at the point where the power enters the building. there have been all sorts of fonky treatment of ac ground in amplifiers, including polarity switches which solve one problem (the high chance that the bar you're playing in was wired incorrectly by a patron willing to work for free booze) by causing another (the possibility of connecting the chassis to mains voltage) i would imagine all amps with a power transformer of some type would have to have a well-defined dc ground, no? that may or may not be the same as ac ground. many of the solid state amps I've dealt with have bipolar supplies so dc ground is halfway between (in theory) the negative and positive power rails In actuallity, blademaster2 is correct, even though he takes an unfortunate shortcut, leaving out an important word, like so: ... are grounded directly to Earth but only if... In all cases, since the time of the first amplifier (and not just for guitars, I mean all amps period), the chassis was connected to "ground" as in it was connected to Earth. Why? Because this was the way that radios worked. Recall that you can make a very simple "razor blade radio", just like the G.I.s of WWII fame, but that's about the only kind of radio lash-up that doesn't need a wire going to ground. (It was also called a 'crystal radio' among the hobbyists who could afford more than just a razor blade.)
In the beginning, there were batteries (Leyden jars) powering the nascent radios and such. Not much chance of AC shock there. But if we skip forward a decade or two, we see that Westinghouse has won the "power wars", and AC is the name of the game. Now we have some safety issues, but they aren't apparent to the average householder and family.... yet. But in the meantime, because radio waves travel between the atmosphere and the Earth (the ground itself), we maintain the need for grounding all such electrical devices. It soon develops that doing so provides a convenient reference point, against which we can measure things, and we can be assured that the same measurements will give the same results no matter where on the globe (on land, of course) we might be situated.
This is why, before the advent of the third wire, two wires were used to bring power to a building. But immediately, one wire, designated as Neutral, was connected to the Earth ground. Againg, why? And also again, because of commonality - being able to run one wire instead of two, and having the "other" wire being brought around for us via the nice "feature" of having lots of metal nearby, that was pretty nifty in those days. But your final question, why use the Earth for a power carrier?, well that's obvious - the Earth ground is a massive resistance to DC and low frequencies. A second wire is needed to supply power over long runs, but not for short distances, say several feet.
Please don't get me started on the alleged safety of the third wire, I'll wear down the markings on my keyboard the rest of the way to invisibility if I have to provide that particular rant.
HTH
sumgai
Yes, I did ignore the neutral-to-ground connection - mostly because the voltage on it is highly variable depending on the noise it carries from other loads and the current being drawn by other loads on the same chain of connections. So in that sense it is *not* ground despite the wired connection it has to ground. If *zero*current is flowing anywhere, then the neutral is identical to ground (Earth). In all other cases there is something of a voltage and signal on it relative to ground. The actual third-prong ground is supposed to have no current flowing at all times and therefore sits at the zero-volt Earth voltage, which is why it is safest to connect the exposed external metal of appliances to it: there will then be no voltage difference between any two appliances and/or plumbing in the home. Neutral lines cannot make that guarantee, and even if the voltage is at times rather low on the neutral line it has a very low impedance and therefore a lot of current can flow from it to the actual ground (Earth). On that basis, I do recognize the safety of the third wire in a correctly-wired home. If sumgai has a different take on this then I am interested to hear it (rant or otherwise). :-)
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Post by blademaster2 on Dec 11, 2019 10:01:20 GMT -5
All voltage is relative. Ground is whatever point in your circuit that you choose to be the reference point against which all others are measured. It doesn’t have to have anything to do with the actual earth. Edit - Did I ever tell you about the theory that there was some planet-sized object that ejected from Jupiter, careened across the solar system, and came pretty close to the earth? From what I read it had a large enough charge difference from us that there was a big old arc that may have been the column of fire which destroyed pharoa’s army in the biblical story. True. For systems on Earth, ground is loosely used to refer to the common reference point of voltage to which all current returns, and sometimes it is actually connected to the Earth (as in buildings, homes, ...). For shielding noise, the Earth is good also but if a voltage is measured differentially (looking only at the difference between to connections, which applies to a battery-powered amplifier) then it need not be. Guitar amplifiers are usually grounded to Earth but only if a third prong exists on the amplifier. If not then it is only looking at the guitar signal differentially and the shield is simply the common reference point. In spacecraft, of course, the spacecraft structure is usually defined as "ground" and there is no connection to the Earth (duh). In space a charge can build up to be very large if a part of a spacecraft is not connected ('galvanically isolated') to the spacecraft ground. When it is big enough it can arc, just like lightning.
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Post by blademaster2 on Dec 6, 2019 13:23:15 GMT -5
Mr. sumgai, meet Mr. JohnH. He says that they should be swapped around with the .047 on the other one, and you say that it's too big and you wouldn't even bother testing it. This is turning into fun. My Beringer had 500k tone pots with .047 caps, so put that in your pipe and smoke it. Nobody argues with Beringer. As for me, I'm still trying to work up the ambition to test the bass-cut tone control discussed in another thread, now well down the list. I've got the circuit made up, with input and output jacks and little alligator clips to hold the capacitor and resistor for quick changes. Now I just have to tear myself away from the computer long enough to test about 20 different combinations to see if any of them work. That's enough for now. I used 0.047 in all of my homemade guitars, and I put up with them like that but I sometimes feel that they roll off too low and that I would be happier with 0.022 (or maybe 0.033). I mostly keep Tone controls at 10, but that might be why since it gets too muffled too quickly when I turn the Tone down at all.
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Post by blademaster2 on Nov 27, 2019 15:27:21 GMT -5
Posted as requested:
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Post by blademaster2 on Nov 18, 2019 12:39:46 GMT -5
Can you share the diagram? What are the capacitor and resistor values so I can try them? Thank you! The Hagstrom II schematic shows this. The resistor is 12kOhm (if I read the writing correctly) and the capacitor is 3000pF. The "Mute" switch invokes the low-pass response and the "Tone" switch invokes the high-pass response. Personally I am not in love with the result when both are switched, but it does boost the mids (actually cuts the highs and lows to achieve a similar result). high quality image hosting
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Post by blademaster2 on Nov 14, 2019 12:35:30 GMT -5
I have used - in my own guitars - a 1000mH inductor to give a mid-cut in place of a traditional tone control (I sometimes call it a "fatness" control), but I have not tried it for mid-boost. This inductor was pretty costly because it was very small, but the older post on this thread identifies other devices that might be cheaper
As an alternative, for mid-boost I have a Hagstrom guitar that uses both a series capacitor and a shunt resistor (switchable on separate switches, and it has no tone control knob), which is simpler than using an inductor, although it might not give you as much boost as a second-order boost circuit could. Essentially you are using the inductance of the pickups themselves in conjunction with the capacitor/resistor.
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Post by blademaster2 on Oct 23, 2019 13:40:00 GMT -5
I think most players prefer simple classic wirings that they are used to. Plus, this wasn't invented in the 1960's! There shouldn't be any particular losses with it. LOL. Actually, reading Brian May's book tells me that this *was* invented in the 1960's by Brian and his father. Around 1963, IIRC. I always felt that Brian's tone was a little nasal, and not so crisp for a guitar with single coil pups. This is despite his use of a treble booster in the set up. Perhaps the added inductance of the three pups in series on some settings exacerbated this loss of highs. Having never tried the Burns pups myself I cannot say much more about it. One other factor that would dissuade me from this configuration is that the reliability of the switches plays a more influential role (the reliability prediction would be worse for this since there are more single-point-failures, any one of which results in silence from the guitar). Then again, I had a Hagstrom F12-S that used sliders that were terrible, and that might be causing me to have more negativity on this than justified - after all, it worked for Brian!
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Post by blademaster2 on Oct 7, 2019 21:41:36 GMT -5
In August I completed a nut replacement for an Epiphone Les Paul for a friend's son, but no photos and it already went back to the owner (it turned out really well, and is better now with the bone nut than the plastic one that came with it). More recently I decided to re-install the frets on my first guitar, sort of a celebration for its 40th birthday (now I feel old ...). The original frets were too loose because I had not cut the slots myself and the luthier who did it for me assumed I would glue them in. As a result it played well, but the frets never seemed 'solid', and over its age the fret profile changed and the fingerboard probably settled and I would get choking on the high notes here and there. Also, as I hand-sanded the radius by eye as a teenager I have found it is too round (tighter than 7.25" especially at the nut) and I also noted that it was a compound radius that I created even before I knew what that was called. I also did not flat-file it but rather attacked each buzz one-by-one with a file. There is a lot of sentimentality tied up with those frets, all hand-filed and shaped, so I thought I would first try removing and *reinstalling* the same ones (since they gripped so lightly they came out with no bending and very little wood chipping!). Here is the process I followed: 1) Remove the frets and keep them in sequence 2) Clamp the neck to be held as straight as possible 3) Re-shape/resurface the fingerboard using a 7.25" radius sanding block (StewMac product). This was my chance to remove the slight ski-jump that formed at the high frets due to the need to shim the pocket when the neck goes back in (it was never shimmed, but there was a tongue on the end of the neck that rested on the body surface and might have caused the skip-jump to form, so a shim will remove that pressure and it will hopefully remain with the profile I created) 4) Snip off the very edges of the fret tangs so that I could used wood-filler at the ends, and shed less blood from sharp fret ends. This involved a SteMac fret tang nipper 5) Crimp the fret tangs so they would go back in tighter using a fret tang crimper (another StewMac product) and Hand-bend these frets to match the new, fixed radius. 6) Use the brass, 7.25 radiused fret press insert with the plastic-tipped hammer so that the frets would preserve their radius as they are being tapped back in (yep, another StewMac product) 7) Re-flatten the re-installed frets using the same radiused sanding block and very fine sandpaper. I am in the process of doing this today .... Next steps:8) Make a shim to remove the pressure at the end of the fretboard where it rests on the body when the neck screws are tightened 9) Re-install the neck and (hopefully) discover that the guitar plays great, no buzzing, smooth action ..... I already love the tone from this mahogany-with-inset-maple body and the DiMarzio Dual Sound pickups, so the guitar will be much improved for the *next* 40 years ..... Photos of the process (so far) follow: As the frets came out, only a few minor chips were created and I glued them back. Sanding to reprofile the board took ages since I needed to remove the too-round compound radius to bring it all into 7.25". I considered going flatter but I did not since I wanted to change it as little as possible from my highschool effort. All smooth now with a fixed radius and that lovely, almost perfectly-black ebony. The first few frets have gone back in on the above image and I am very pleased with the StewMac tools and the process I am following. The neck overlaps the body to provide the upper frets, and it looked great but I suspect that there was a small gap in the pocket that created the ski-jump. Perhaps the larger contact area was a good thing for tone but I did not want any more choking on high notes and bends than usual for a 7.25" radius. I can add a shim and try it out, and remove it if I am dissatisfied. Tapping in the frets was pretty gentle, with just-enough tightness after crimping the tangs. I worked hard to match the new radius, so using the brass 7.25" fret-press insert with the hammer preserved the bend during fret reinstallation.
Here is the neck fully refretted, awaiting final truing. I am optimistic that this will improve the playability greatly - and I loved the crisp/warm tone of this guitar already so it will be even better (fingers-crossed)
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Post by blademaster2 on Sept 13, 2019 9:25:32 GMT -5
... which is a sign of excellent soldering workmanship.
Good job, and beautiful layout.
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Post by blademaster2 on Sept 10, 2019 16:29:27 GMT -5
I am late to this party, but I never saw anything in my engineering courses that said a passive circuit *must* have its maximum signal amplitude defined as 0dB. Usually, the 0dB level is defined for convenience as a reference level, and that anything above or below it is either amplified or attenuated relative to that reference (after all, dB is only an expression of a ratio). As such it was always perfectly acceptable to define a passive circuit with 0dB from DC up to frequencies of interest where filters and other frequency-related effects start to have an impact. Insertion loss may or may not be present, and it did not not matter either way. Also, a peak resonance amplitude has never, in my history, been defined to be 0dB as a mandatory thing (perhaps my history starts at a very different timeline than that to which Sumgai refers). A transformer is an example of a passive circuit that certainly can amplify the output voltage level above the input voltage. The key here, about "not getting something for nothing", is *power* and not voltage. The transformer provides lower current when it is providing higher voltage. No passive circuit can amplify power, of course. An acoustic guitar is said to "amplify" the string sound, but it is passive adds no energy. In reality an acoustic guitar is a "mechanical transformer" that matches the string energy to the impedance of the air for propagation at higher volume - it increases the pressure level much like an electrical transformer can increase voltage. In resonant circuits I need to dig deeper to confirm this, but I can easily imagine a similar relationship where a resonant peak generates higher voltage compared to the input, but with a higher Thevenin impedance. That would be consistent with the voltage gain of a transformer (but as I said, I need to dig into this before I can make that claim with any confidence). If the resonant circuit had only inductances and capacitances then there would be no insertion losses (at least not at DC) but the voltage could still be amplified. I have wondered if this is why in guitar pickup response curves we see so much sensitivity to things like eddy current losses. The peak level is generated with a high Thevenin impedance and can be reduced dramatically when loaded by even small loads ( ).
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