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Old 3rd January 2018, 03:43 PM   #161
Tubelab_com is offline Tubelab_com  United States
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Somebody on Ebay will throw lots of money at you for them.
If I don't put them in a DIY project first, which is my intention.
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Old 3rd January 2018, 04:48 PM   #162
Gnobuddy is online now Gnobuddy  Canada
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Originally Posted by Michael Koster View Post
Everything else being equal, the signal from a humbucker will be stronger. As evidenced by the lower relative volume when using coil tap switches.
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.

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Originally Posted by Michael Koster View Post
I just built a guitar with some pretty hot pickups. At some point I'll do another capture and compare with my earlier measurements.
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
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Old 3rd January 2018, 05:39 PM   #163
GeorgK is offline GeorgK  Austria
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Originally Posted by mjd_tech View Post
Blackmore's tone and technique are near perfection on that album. Rumor has it he used an AC30 rather than the usual Marshalls.
For us connoisseurs of killer "low gain" overdriven tone, this has got to be one of the benchmarks.
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.

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Originally Posted by Gnobuddy View Post
Perhaps this is less true of the asymmetrical humbuckers that have no externally visible pole-pieces for the second coil.
-Gnobuddy
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.
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Old 3rd January 2018, 07:19 PM   #164
voltwide is offline voltwide  Ireland
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Originally Posted by spaceistheplace View Post
Eric Clapton was asked about how it felt to be the world's best guitarist. His response: "I don't know. Ask Prince"
And he was right!
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Old 3rd January 2018, 07:54 PM   #165
Michael Koster is offline Michael Koster  United States
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Originally Posted by mjd_tech View Post
For an example of the "gling" I keep yapping about, and please don't laugh too hard, the Monkees "Last train to Clarksville". Probably was played by the Wrecking Crew. Last train to Glingsville.
That would most likely be Tommy Tedesco.
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Old 3rd January 2018, 10:51 PM   #166
mjd_tech is offline mjd_tech  United States
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Originally Posted by Michael Koster View Post
That would most likely be Tommy Tedesco.
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"
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Old 4th January 2018, 11:16 PM   #167
Gnobuddy is online now Gnobuddy  Canada
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Originally Posted by mjd_tech View Post
For an example of ..."gling" ..."Last train to Clarksville"...
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
Attached Images
File Type: jpg JJ_6V6S.jpg (148.5 KB, 95 views)
File Type: jpg JJ_7591.jpg (70.1 KB, 94 views)
Attached Files
File Type: pdf Tung_Sol_6V6.pdf (173.6 KB, 3 views)
File Type: pdf Tung_Sol_7591.pdf (95.4 KB, 8 views)
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Old 5th January 2018, 01:13 AM   #168
Tubelab_com is offline Tubelab_com  United States
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Rumors also say that Blackmore used an Aiwa tape machine as a booster.
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.

Quote:
The Machine Head album is the one that really motivated me to get an electric guitar.
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.
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Old 5th January 2018, 04:05 AM   #169
PRR is offline PRR  United States
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Originally Posted by mjd_tech View Post
...Monkees "Last train to Clarksville". Probably was played by ....
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).
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Old 5th January 2018, 12:46 PM   #170
Tubelab_com is offline Tubelab_com  United States
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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!
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