This is my experience as well. However, George's comments reminded me that there are at least two different types of humbuckers - one type that has virtually identical magnetic pole-pieces and magnetic circuit through both coils, and one type that doesn't.
I've always interpreted guitar pickups as variable-reluctance magnetic circuits (return flux being through the guitar string and air gaps spacing the string from the polepieces). In my mental picture, then, there are equal flux changes running through both coils of the humbucker in response to string motion.
Perhaps this is less true of the asymmetrical humbuckers that have no externally visible pole-pieces for the second coil.
Any chance you could also take measurements with the pickup loaded with a 330k resistor and 470pF or 560 pF capacitor? This is to simulate a 500k volume pot turned up to full, a 1 mega ohm grid leak for the input 12AX7 triode, 100 pF of Miller input capacitance from the triode, and about 500 pF of cable capacitance in a typical 5 metre (~ 15 foot) guitar cable.
While it's interesting to find out the extreme limits of pickup output, I would like to also find out (roughly) the mean and standard deviation of the distribution - the most commonly encountered range of values. My hunch is that this will turn out to be somewhere between 100 mV and 20 mV.
IMO guitar is not an instrument with a wide dynamic range (which is why it is not called a pianoforte, though it existed long before the piano was invented!)
At one end of the guitar's dynamic range, thumps and bumps and squeaks from fingers on fretboard and strings limit how quiet you can go. At the other end, string buzz limits how hard you can hit the strings (Pete Townshend notwithstanding).
I think electric guitars can give the illusion of high dynamic range, mainly because you can plug the same guitar into anything from a 1 watt amplifier to 15 kilowatts of P.A. system. But if you try to play quietly through that 15 kW P.A. system (without turning down any knobs), you'll find out it cannot be done.
-Gnobuddy
Blackmore and Brian May were two of the kings of AC30 tone.
Rumors also say that Blackmore used an Aiwa tape machine as a booster.
This leads to "Noiseless single-coils", which are in fact just humbuckers, sometimes without a core in the second coil. A few guitars guitars feature a dummy coil underneath the pickguard, actually a separate pickup without magnets.
I remember once examining a Schaller humbucker, whose owner complained about its low output. He did not manage to wire ist correctly, either it was too quiet or picking up hum. It turned out that the magnets of both coils (it was a type with magnets inside the coils) had the same orientation, definitely a production error. It sounded as expected.
As I was told afterwards, the pickup had been bought second-hand and was already several years old before the owner fitted it to his instrument. I assume it had gone through the hands of several unsatisfied buyers before.
I have his book, For Guitar Players Only. There's some good instructional material, but the best part is the little stories he tells about some of his gigs.
I like the part where he talks about playing banjo, mandolin, bouzouki, balalaika, etc. He just tuned them like a guitar! "The producer never knew the difference"
Interesting! Based on that song, and keeping in mind the limitations of YouTube audio quality, I think that what you call "gling" is not at all the same thing as I have in my head when I think of good "valvey" clean tone.
To me, "Last Train" sounds like the combination of a stingingly bright Telecaster and the abrupt-onset relatively harsh distortion of a diode clipping circuit (tubescreamer et al), but occurring only at high frequencies; possibly there is some additional treble boost between the 'Tele and the stage generating that distortion.
I came somewhat close to your "gling" with my current project amp by adding the 33nF bright cap across the input JFET 10k source resistor for treble boost above 500 Hz, and then inserting no attenuation between the input JFET and the rest of the "de-nastifying filter". That generated a bit of the same crunchy distortion at high frequencies only.
It is actually not a sound I care for (it sounds harsh to me), so I will find some way to tame it, probably by reducing the 33nF cap to 16 nF, and inserting some fixed attenuation between the two JFET stages.
The "tubey" clean tone I like best involves no audible crunchiness at all. To me, it has a "singing" or "shimmering" quality, but I don't know if that makes sense to anyone else. Sadly, it's virtually impossible to describe a sound in words.
Based on some of my tinkering, the sound I like seems to involve some treble boost, as much as 25% - 35% of mostly second harmonic distortion , and very little of any higher order distortion.
My Super Champ XD, set to the clean channel, and pushed to near full power, has those shimmering, sweet cleans. I have also extracted them from a 6AG5 pentode (maybe beam tetrode) in a preamp design of my own.
Weirdly enough, I cannot get the same cleans from my 65 Princeton Reverb (reissue), though it has virtually the same power amp design as the Super Champ XD, and 12AX7 preamp stages preceding them, while the Super Champ has a sterile solid-state preamp.
This may have something to do with the JJ 6V6's in my Princeton Reverb, which seem to sound more sterile and solid-state than "real" 6V6's do. (The Super Champ has a non-JJ brand of 6V6's).
I don't want to start any conspiracy theories and "tube sniffing" contests, but take a look at the attached photos of the JJ 6V6S and JJ 7591. The plate structure looks identical to me. I think JJ simply took their existing 7591 valve, re-pinned the base, labelled it a "6V6S", and started selling it.
Also take a look at the original Tung Sol 6V6 and 7591 data sheets. Notice the THD specification: the 7591 generates much less THD, i.e. "sterile clean" from the point of electric guitar.
-Gnobuddy
Attachments
Free Form Guitar on the first Chicago Transit Authority album (1969) explained in the liner notes how Terry Kath got that overdriven sound by using an old Bogen (tube) PA amp as a preamp for his guitar amp. About a month later a friend brought me his Kustom solid state amp to fix......he had tried to emulate Kath and turned some silicon back to sand.
My parents got me an electric guitar (but no amp) for my birthday somewhere around age 7 or 8 (about 1960). They didn't get me an amp, but gave me their old Magnavox console HiFi when they upgraded to a Silvertone stereo. It took me about 10 minutes to cut a guitar cord in half and twist the wires to the wires in the tone arm of the Maggie......a few years later they probably regretted those actions, but kept taking me to guitar lessons well into high school.
Or-- you could look it up.
Candy Store Prophets, Louie Shelton guitar.
Whole thing parodies/plagiarizes the Beatles' Paperback Writer, which had a strong guitar riff (and wild-for-Beatles bass line).
The Monkees had a TV show in the late 60's. True trash, but my mom sucked it up. She was always complaining about the "noise" that I listened to and wondered why I wouldn't watch the Monkees on the family TV. I said that if you paid attention it wasn't hard to see that they weren't even playing their own instruments, but she refused to believe.
Sometime later a guitar playing friend asked me to go with him to a Monkees concert. I told him that he was nuts, but he had heard on the radio that the opening act featured an awesome unknown guitar player.....Armed with this information, I managed to convince my mom to let me go to the Monkees concert, and she even bought my ticket ($2 or $3 if I remember correctly).
That unknown guitar player made it clear to the three of us who went that we would never be rock stars.....his name was Jimi Hendrix!
Sometime later a guitar playing friend asked me to go with him to a Monkees concert. I told him that he was nuts, but he had heard on the radio that the opening act featured an awesome unknown guitar player.....Armed with this information, I managed to convince my mom to let me go to the Monkees concert, and she even bought my ticket ($2 or $3 if I remember correctly).
That unknown guitar player made it clear to the three of us who went that we would never be rock stars.....his name was Jimi Hendrix!
Maybe, but don't forget there is a huge difference between being a great musician and being a rock star. Just ask the Wrecking Crew members, or the Funk Brothers in Detroit, or any of the top-notch instrumentalists who never had popular success. Or Taylor Swift, who can barely sing or play, but is a star to millions.
People who become stars and celebrities are usually extremely self-obsessed. They may be either narcissistic or the opposite, extremely insecure.
Stardom is more likely to occur for the physically attractive, and even more likely for those with no normal sexual boundaries, frequently as a result of childhood sexual abuse (for example, Marilyn Monroe and countless others like her).
These days, having lots of expensive plastic surgery is also required.
Finally, having dubious ethics, i.e. being willing to do "whatever it takes" is a major asset.
"Stars" are almost always seriously damaged people. Far from being examples for society to follow, they are the opposite - exactly the kind of person that one hopes never to have the misfortune to become.
I will do my best to return this thread to its original topic tomorrow, when I should have some time to work on my amp some more.
-Gnobuddy
Yeah it's hard to find a good recorded example of gling.
Last train is an exaggerated example.
I have it on vinyl. Sounds pretty good to me. Maybe youtube version is a bit lacking in resolution.
Played by Louie Shelton: Thanks, PRR.
What I hear is a kind of "bloom" in the notes.
There's probably a compressor in the recording, but I can get pretty close with just a strat straight into a twin reverb. It's loud as hell because you need to crank the twin to get it to break up even a little bit.
If you could take the Last Train riff, turn down the treble a bit, and a little less gain, I think you would have your "valvey clean tone".
Really, I think we are on the same page with this. It's just hard to find a recorded example.
I think it's something you experience live more than something that can be recorded.
Sorry to hear about your JJ 6V6. Definitely try something else.
"Sterile" and "Princeton Reverb" should not be together in the same sentence.
Need to get out and finish clearing the driveway.
Hey PRR, did you get hammered up in Maine? We got clobbered pretty good in Mass.
It helps to have a huge marketing machine behind you. As mentioned, the Monkees were a prime example, as was Grand Funk Railroad with the huge stacks of (fake) amplifiers that could be climbed like stairs.......How many boy bands are a marketing PRODUCT of the Disney corporation?
As did many teenage kids, I had rock star dreams. Reality was brought to me through some friends who were short lived rock stars. There was a local band called Fantasy who had a radio hit in 1970. The picture here was taken on Miami Beach and is the center fold of their record album. This song was all over the radio in 1970. They recorded the demo material for their second album in the studio where I played Mr. Fixit, and master cable technician, as did Wishbone Ash for their Argus album.
YouTube
They had been signed to a two record contract and given an advance based on the airplay of Stoned Cowboy. The first record came out and sold well in Florida at least. The record company refused to accept ANY of the material for their second album. Once the deadline for the second album had passed the record company reposed all of the band's equipment, and even took their old Dodge van. The band was broken up since the girl (center of picture) had turned 18 and Janis Joplin had died, she was to join Big Brother and the Holding Company. That didn't work out, neither did a solo setup and Lydia died of a heart attack in her late 40's. The rest of the band played some local gigs with borrowed equipment, then reorganized with a new name, but never got anywhere.
Their treatment by the record company cured a few of us of our rock star dreams.
But they are exactly that: back to back diodes in the NFB loop of an Op Amp.
Only difference ... which is actually not a difference ... is that these are "amplified diodes" ; they behave exactly like their built-in BE diode, but "amplified by the 2 resistor attenuator.
Being symmetrical you can save one resistor, that does not change the way it behaves.
The only advantages are that you can scale the R network to let the Op Amp clip just before reaching rails, so typically they can put out up to 12 or 13V peak instead of 700 mV peak, and, what was not addressed above, clipping point may be set differently for positive and negative peaks, generating more even harmonics, and that´s the main feature.
But if you keep it symmetrical, they are just "louder diodes".
EDIT: and you have heard them
, they are used in Music Man amps, a couple Fender ones and massively in Crate ones.Maybe I'm wrong, but I don't think that's the case. Firstly, for some settings of the pot, the BJTs never turn on at all, and there is no distortion of the signal.
As you turn up the pot beyond that, the BJTs start to turn on partway through the cycle, and the LTSpice simulation shows rather gradual and minimal squashing of only the signal peaks. Turning up the pot more produces progressively more peak squashing.
Notice also that each BJT has a 100k resistor in series with its emitter. This stops it from being an amplified diode - there is local negative feedback applied to each BJT from that unbypassed 100k emitter resistor, so there is no longer a purely exponential relationship between base voltage and collector current.
Also, even when one of the BJT's is fully biased on, this resistor is in the opamp feedback network, so you never get the hard logarithmic clipping of back-to-back diodes - AC gain never falls below unity at any point of the cycle, even when driven hard.
I have not seen this kind of very progressive, subtle to severe clipping from back-to-back diodes. Those just spit out the absolute value of the logarithm of the input voltage, which is a nasty waveform riddled with every unwanted harmonic. Then you have to low-pass the heck out of it, and drown it in delay and reverb, so that the harshness is minimized and becomes tolerable. (If you're David Gilmour, you can even make it sound beautiful.)
I will add that I haven't built this circuit and listened to it (yet). So who knows, maybe it does sound just as nasty as logarithmic clipping diodes.
The issue of symmetrical vs asymmetrical distortion is another whole long discussion.
Based on my experiments so far, I think I prefer low-order asymmetrical (even harmonic) distortion for "clean" tones. But for large amounts of distortion, as in rock music, I seem to prefer symmetrical (only odd order) distortion.For me, one of the keys to a "mild to wild" guitar amp seems to be to have it transition from mostly even harmonic distortion for small signals, to mostly odd order harmonic distortion as the amount of overdrive goes up.
This seems to be possible if you allow the right amount of bias shift to occur during overdrive, for example warm-biasing a stage to produce asymmetrical clipping, and allowing the bias point to drift towards colder bias when overdriven (due to grid current flow through coupling caps), so that it starts to clip symmetrically when heavily overdriven.
Maybe I've heard them on some recordings, who knows. I've never encountered any of those amps in person.EDIT: and you have heard them
-Gnobuddy
But there is more to say.
Besides Hendrix there have been lots of real remarkable musicians all the time. I've read some about them, and often they decide in their very early childhold to become a rock star.
Real guitar heros are obsessed by their instrument, playing several hours each day. And that obsession may produce sometimes some extraordinaire artists.
And I agree - this obsession has its price - and ends more often then not in a destroyed personality.
Anyway I am convinced that on the long run these rare sparkling stars never have been the product of clever marketing.
Certainly there exist excellent unknown artists and bands.
You may have a look at "the hamsters", a fantastic UK live band, meanwhile retired.
Besides Hendrix there have been lots of real remarkable musicians all the time. I've read some about them, and often they decide in their very early childhold to become a rock star.
Real guitar heros are obsessed by their instrument, playing several hours each day. And that obsession may produce sometimes some extraordinaire artists.
And I agree - this obsession has its price - and ends more often then not in a destroyed personality.
Anyway I am convinced that on the long run these rare sparkling stars never have been the product of clever marketing.
Certainly there exist excellent unknown artists and bands.
You may have a look at "the hamsters", a fantastic UK live band, meanwhile retired.
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I agree entirely - I call these people virtuosos, not stars - and most never become "stars", in the sense of achieving widespread public recognition and acclaim.
For example, 99% of classical musicians fall in this category. Only the very best ones can find jobs these days, and they often study for a lifetime and practice for six to eight hours a day. And yet, nobody in the audience even knows the names of the hundred-odd musicians in the orchestra - at best, they may know the name of the conductor and the soloist.
Meantime, people will get extremely excited over some blues player who knows three chords in the key of E-major, and five notes out of the twelve available in the chromatic scale.
There have been a few virtuosos who also became stars. Paganini, in his day; Yngwie, in the 1980's; and a handful of others.
Then there have been virtuosos who achieved stardom, but not because of their virtuosity: George Benson, for instance, achieved popularity through singing pappy pop songs like "Give Me The Night", and not for his astonishing jazz guitar virtuosity.
And there are virtuosos who never achieve stardom, like all those classical musicians I mentioned, or people like Al De Meola, a staggeringly accomplished guitar player on both acoustic and electric guitar, whose astonishing technique inspired many who grew up to be shredders. As far as I know, he never achieved much stardom - certainly nothing remotely like the stardom achieved, for example, by the stunningly mediocre Taylor Swift.
Here's De Meola effortlessly doing what most guitarists can never even hope to accomplish on an acoustic guitar: YouTube
Agreed, nobody can fake a Yngwie or Al De Meola. But, at least in the USA, far more people were obsessed with the utterly unremarkable Kardashian family members for years on end...
I think you and I basically agree, we are just using the term "star" in different ways. I use "star" to mean tens of thousands of people show up at your concerts and scream for your autograph - and as we have seen (Taylor Swift, ahem), this takes little or no talent to accomplish.
-Gnobuddy
Sheldon re-plays Last Train, with comments (his first hit record, 3 guitarists, some words about gear at the end):
YouTube
Maybe a clearer tone than some low-fi rip.
You can't deny the echo of Paperback Writer guitar.
If you follow some clues there may be more material about it.
I agree that "Disney band" makes sense today, but aside from Annette {sigh}, Disney did little toward pop music in those days (they changed).
Rafelson and Schneider had worked as TV producers. Rafelson had also been an itinerant musician, and says he thought of a band-show before Hard Day's Night made the idea a hit. Which they pitched, and sold. They were unable to get either the Dave Clark Five or the Lovin' Spoonful for the show, so we got circus-boy, country musician, English singer, and that other guy. Another advantage is that these four had no leverage, could be worked cheap, and fired at will. Music director Don Kirshner hired competent hit-writers and booked studio musicians.
The TV show was lip-synced, of course. All had some musical background, but individually they were not experienced music performers, and they had not worked together at all when the show was started. There's a LOT of shots in each show, it would be humanly impossible to do all the monkee-bits and also do true music performances. And Don was selling the records, which had to be hits, and the TV had to sound *just* like the record. So they'd spin the 45 maybe 4 times with 3 cameras while the cast flapped their lips, done. Even the poor syncing fits the overall buffoonery.
Yes, the boys "could" play, and learned to play together, despite wide differences in style. This led to friction with Don, who won't take crap from anybody. Don saw it was gonna fall apart, but he could squeeze out one more year by letting the boys play their own work. Which came to a head in HEAD, the post-TV movie, which has moments but is mostly piffle.
And does not have any hooks like Seldon's "gling" or Boyce/Hart's Clarksville.
YouTube
Maybe a clearer tone than some low-fi rip.
You can't deny the echo of Paperback Writer guitar.
If you follow some clues there may be more material about it.
I agree that "Disney band" makes sense today, but aside from Annette {sigh}, Disney did little toward pop music in those days (they changed).
Rafelson and Schneider had worked as TV producers. Rafelson had also been an itinerant musician, and says he thought of a band-show before Hard Day's Night made the idea a hit. Which they pitched, and sold. They were unable to get either the Dave Clark Five or the Lovin' Spoonful for the show, so we got circus-boy, country musician, English singer, and that other guy. Another advantage is that these four had no leverage, could be worked cheap, and fired at will. Music director Don Kirshner hired competent hit-writers and booked studio musicians.
The TV show was lip-synced, of course. All had some musical background, but individually they were not experienced music performers, and they had not worked together at all when the show was started. There's a LOT of shots in each show, it would be humanly impossible to do all the monkee-bits and also do true music performances. And Don was selling the records, which had to be hits, and the TV had to sound *just* like the record. So they'd spin the 45 maybe 4 times with 3 cameras while the cast flapped their lips, done. Even the poor syncing fits the overall buffoonery.
Yes, the boys "could" play, and learned to play together, despite wide differences in style. This led to friction with Don, who won't take crap from anybody. Don saw it was gonna fall apart, but he could squeeze out one more year by letting the boys play their own work. Which came to a head in HEAD, the post-TV movie, which has moments but is mostly piffle.
And does not have any hooks like Seldon's "gling" or Boyce/Hart's Clarksville.
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