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Post by antigua on May 30, 2022 20:05:18 GMT -5
I recently acquired a cheap Chinese guitar with cheap Firebird style pickups. This is the first time I've had a good excuse to look at Firebird pickups. They sounded alright, but with two real problems 1) too much feedback and 2) low output. Adding insult to injury, this style of guitar has the pickup set far from the string, even when the pickups are raised up as much as possible.  The core of the coils are ceramic magnets, and they show a high strength of 850 gauss, but because the ceramic has no permeability, and because the guitar strings are likely magnetically saturated, the overall output is surprisingly low given the magnetic strength. The coils seem to have a good amount of wire on them at 11k ohms DC resistance.   These pickups actually sound pretty nice, very clear. They're so microphonic though, that almost any amount of gain will cause them to squeal loudly. I could believe that they're microphonic to the point where some fraction of the output signal is acoustically as well as magnetically induced. That could be fixed with wax potting, but the overall low output of the pickups makes them not worth keeping in the guitar. Chinese Firebord Humbuckers
Bridge
- DC Resistance: 11.701K ohms
- Q @1khz: 0.823
- Measured L: 1.637H
- Calculated C: 97.38pF (with cable)
- Gauss: 850G (ceramic)
Neck
- DC Resistance: 11.947K ohms
- Q @1khz: 0.833
- Measured L: 1.670H
- Calculated C: 123.21pF (with cable)
- Gauss: 850G (ceramic)
Bridge unloaded: dV: 2.4dB f: 13.0kHz (black)
Bridge loaded (200k & 470pF): dV: 1.7dB f: 4.26kHz (blue)
Neck unloaded: dV: 3.7dB f: 11.1kHz (red)
Neck loaded (200k & 470pF): dV: 2.0dB f: 4.62kHz (green)
 Interestingly, even though the covers are solid and brass, the ceramic cores cause no eddy currents and so the loaded Q factor still manifests as a peak, and not a blunted curve. These are the replacements from Q Pickups on Reverb, reverb.com/item/8224072-firebird-pickups-set-2pcs-vintage-correct-mini-humbucker-chrome-gibson-by-q-pickups?utm_campaign=OrdersMailer%23shipped&utm_source=sendgrid&utm_medium=email from Croatia . They claim to be vintage correct, even having a steel strip over one of the string positions, under the cover, as is shown here www.stewmac.com/electronics/pickups/pickup-parts/mini-humbucker-pickup-parts/steel-plates-for-firebird-mini-humbucker/ . Previous testing showed that this steel strip probably slightly reduces the treble of the string that it's under.  As $200 per set, they're a pretty good deal, very good quality. Nickel silver all around, braided hookup cable, maple spacers, AlNiCo bars, and black paper tape that's neatly applied. They sound really good. The nickel silver / AlNiCo combo results in a much higher loaded Q factor 6dBV as compared to 2dBV. Both pickup sets have a loaded resonant peak around 4.25kHz, but I'd say the Q-Pickup Gibson replicas have a more traditional guitar sound, with that punched up resonance, were has the stock pickups had a very clear Danelectro lipstick-tube sound, with a softer roll off in the high end. I like the sound of both pickups in this Chinese guitar, but ultimately the Q-Pickup replacements are a lot more practical for rock music. I also have actual Gibson mini-humbuckers in an Epiphone Sheraton, and those are structured more like a miniature PAF, with an under magnet and pole pieces, but I might never be able to objectively compare the sounds since these sets are in such very different guitars with different pickup alignments... but I'll try my best. Q pickups Firebird Pickups
Bridge
- DC Resistance: 7.034K ohms
- Q @1khz: 1.693
- Measured L: 1.992H
- Calculated C: 109pF (with cable)
- Gauss: 250G (AlNiCo )
Neck
- DC Resistance: 6.260K ohms
- Q @1khz: 1.550
- Measured L: 1.623H
- Calculated C: 133pF (with cable)
- Gauss: 250G (AlNiCo )
Bridge unloaded: dV: 9.4dB f: 10.4 kHz (black)
Bridge loaded (200k & 470pF): dV: 6.3dB f: 4.36kHz (blue)
Neck unloaded: dV: 9.4dB f: 10.4 kHz (red)
Neck loaded (200k & 470pF): dV: 6.7dB f: 4.73kHz (green)   |
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log
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Post by log on Sept 15, 2022 6:19:07 GMT -5
I believe your specs are in error for the chinese set, as listed as AlNiCo.
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log
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Post by log on Sept 15, 2022 6:21:22 GMT -5
Also thankyou.
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Post by antigua on Sept 16, 2022 10:11:50 GMT -5
I believe your specs are in error for the chinese set, as listed as AlNiCo. Thanks for pointing that out. |
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Post by davidofchatham on Oct 6, 2022 12:09:36 GMT -5
antigua, thanks for sharing this. I've just become interested in Firebird and mini-humbucker pickups — I started listening to sound samples of bridge pickups, trying to find something I actually like, and those types caught my ear. Unfortunately, rarity aside, it seems quite difficult to find mounting rings to put them in a humbucker-routed guitar. Might one get similar results from a low-to-moderate-output humbucker wired in parallel?
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Post by gckelloch on Oct 6, 2022 15:24:09 GMT -5
Check out this page: www.guitarfetish.com/GFTron-Vintage-Pickups_c_838.htmlThe Vintage AII models sound great. Very low inductance, and you can adjust the pole screws per string. Granted, the Steel pole screws reduce the Q a lot, but they are low enough inductance that there's plenty o' high end. Sweet and chimey from what I hear in the demo. The flux power will be a lot lower than the original Firebirds with ceramic magnets-- the attack is milder, and the output lower. Maybe the mounting brackets will work with Firebird size pickups if you really want those. |
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Post by antigua on Oct 6, 2022 22:19:37 GMT -5
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Post by Yogi B on Oct 6, 2022 23:08:01 GMT -5
original Firebirds with ceramic magnets Don't you mean AlNiCo? Though "original" is a bit open to interpretation: if simply meaning made by Gibson, last I knew the current production Firebird pickups did have a (horizontal) ceramic magnet (paired with steel blade poles); but vintage '60s pickups are more or less identical to the above replacement set from Q pickups with an AlNiCo bar at the centre of each bobbin. From GFS's range my first thought was their Pro-Tube Lipstick Humbuckers because of lipsticks' similar coil-around-bar-magnet design. — though without mention of the tube material I'd guess it's brass. Or maybe another alternative from them: their "Metal Foil" Dual Coil Alnico V Humbuckers, depending upon both their actual internal construction and how that foil is for eddy currents. (Not that they're necessarily the same, but the foil plates sold by Axesrus are listed as aluminium, which seems like a lousy idea since it has a conductivity of around 2—2.5 times that of typical brasses.) |
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Post by gckelloch on Oct 7, 2022 9:53:37 GMT -5
original Firebirds with ceramic magnets Don't you mean AlNiCo? Though "original" is a bit open to interpretation: if simply meaning made by Gibson, last I knew the current production Firebird pickups did have a (horizontal) ceramic magnet (paired with steel blade poles); but vintage '60s pickups are more or less identical to the above replacement set from Q pickups with an AlNiCo bar at the centre of each bobbin. From GFS's range my first thought was their Pro-Tube Lipstick Humbuckers because of lipsticks' similar coil-around-bar-magnet design. — though without mention of the tube material I'd guess it's brass. Or maybe another alternative from them: their "Metal Foil" Dual Coil Alnico V Humbuckers, depending upon both their actual internal construction and how that foil is for eddy currents. (Not that they're necessarily the same, but the foil plates sold by Axesrus are listed as aluminium, which seems like a lousy idea since it has a conductivity of around 2—2.5 times that of typical brasses.) My bad. I thought they had ceramic bars in the coils. The covers may have been brass, so the Lipstick HB's might be a good option. Brass is diamagnetic. That would reduce the magnetic flux to and from the strings, as well as roll off the high end. Aluminum is Paramagnetic. Thick Aluminum shielding beside the coils causes some upper-mid loss. I doubt the thin foil above the coils in the GF's would have any significant tonal or flux power effect. The lower inductance HB versions might be nice. |
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Post by davidofchatham on Oct 7, 2022 13:29:31 GMT -5
Check out this page: www.guitarfetish.com/GFTron-Vintage-Pickups_c_838.htmlThe Vintage AII models sound great. Very low inductance, and you can adjust the pole screws per string. Granted, the Steel pole screws reduce the Q a lot, but they are low enough inductance that there's plenty o' high end. Sweet and chimey from what I hear in the demo. The flux power will be a lot lower than the original Firebirds with ceramic magnets-- the attack is milder, and the output lower. Maybe the mounting brackets will work with Firebird size pickups if you really want those. , my previous fascination was with Filtertrons, and I still plan to use one in the neck position in my guitar. I actually have three on hand now, one each from TV Jones, Odezza Pickups, and Gretsch — an older ceramic-mag one, which I was going to try but can't mount due to its baseplate. I've just gotten the TVJ and Odezza pickups mounted, and I'm waiting on parts to be able to wire them up and hear how I like them. Unfortunately there was a mix-up on cover finishes; one is chrome and one is nickel, so they don't look right together (yes, it bothers me!). I was thinking about what to do and got to wondering if I could find a bridge pickup that I like the sound of on its own, not only blended, and started hunting around again.... When I first looked at antigua's chart for the Q Firebird pickup above, I thought they looked very similar to his Filtertron measurements, but after a while I realized the vertical scale is different — the Filtertrons barely have a resonant peak at all. I think I might like the "top boost" from the stronger resonant peak. I know, EQ can do that too, but for other reasons I want a base sound that I like without pedals. But yeah, I need to experiment with what I have first! antigua, thanks for the suggestion! I was assuming that I'd need staggered, slanted-bottom pickup rings, partly because that's what I'm used to and partly because that style also exists for mini-humbuckers. But looking again at your guitar above, it has flat rings even with a wraparound bridge. I guess I could also cut down a flat adapter and put it inside a regular slanted humbucker ring.... Sounds like it's harder than I thought to duplicate that response profile. I'll see how I get on with the Filtertrons, then I may come back to Firebird or some other type of pickup. I'm also curious how the Q Firebird pickups compare in output to Filtertrons. I know from your thread on relative volume that there's a gain from side-by-side coils, and I think that having the coils closer together reduced the volume. The Firebird pickups look smaller than Filtertrons, but do their other characteristics make them as loud or louder, in your experience? I'm not asking for measurements! From GFS's range my first thought was their Pro-Tube Lipstick Humbuckers because of lipsticks' similar coil-around-bar-magnet design. — though without mention of the tube material I'd guess it's brass. Or maybe another alternative from them: their "Metal Foil" Dual Coil Alnico V Humbuckers, depending upon both their actual internal construction and how that foil is for eddy currents. (Not that they're necessarily the same, but the foil plates sold by Axesrus are listed as aluminium, which seems like a lousy idea since it has a conductivity of around 2—2.5 times that of typical brasses.) , thanks for your suggestions as well! I'd never considered the lipstick humbuckers — they're kind of interesting, but I'm not sure they're what I'm looking for from the few samples I've found. I did come across a demo of the GFS Goldfoil, Lipstick, and Dynasonic-style pickups by R.J. Ronquillo which I think is worth sharing in case anyone else reads this thread and is interested in them. Wish it had really clean samples, though. |
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Post by newey on Oct 7, 2022 18:08:56 GMT -5
I'd never considered the lipstick humbuckers — they're kind of interesting, but I'm not sure they're what I'm looking for from the few samples I've found. I have this, with a GFS lipstick-tube humbucker. I like the pickup a lot, it's one of my favorite guitars and gets played more than most of them. But take that with a grain of salt, 'cause I'm not really a humbucker guy, I like the brightness of single coils. For a HB, these are pretty bright. But, then again, I used a 1MΩ volume pot and a 500K tone pot, which certainly brightens things up quite a bit anyway.  |
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Post by gckelloch on Oct 7, 2022 19:09:24 GMT -5
Pickups can sound bright even with Brass covers if there's enough ~2kHz+. The GFS Lipstick HB's are wound higher than standard 42AWG. AlNiCo II bars in the core don't raise the inductance as much as Steel screws/slugs, and don't roll off the high-end nearly as much. The Brass covers do that and likely have some other effects like freq range cancelations and slight microphonics. I'd assume the flux power through the Brass covers ends up being close to AlNiCo II or V PAF levels. Assuming the inductance is in the 4~6H range, the output and Q should be pretty similar to typical PAF's, but there is a certain chime to them.
I'd assume the ferrite-powered Gold or Metal foils are louder than the AlNiCo V versions due to the much higher Permeance. The ones with the AlNiCo V or ferrite bars in the core would be lower inductance than the ones with Steel screws/slugs, the 4k likely well below 2H.
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Post by antigua on Oct 9, 2022 3:24:38 GMT -5
antigua, thanks for the suggestion! I was assuming that I'd need staggered, slanted-bottom pickup rings, partly because that's what I'm used to and partly because that style also exists for mini-humbuckers. But looking again at your guitar above, it has flat rings even with a wraparound bridge. I guess I could also cut down a flat adapter and put it inside a regular slanted humbucker ring.... Sounds like it's harder than I thought to duplicate that response profile. I'll see how I get on with the Filtertrons, then I may come back to Firebird or some other type of pickup. I'm also curious how the Q Firebird pickups compare in output to Filtertrons. I know from your thread on relative volume that there's a gain from side-by-side coils, and I think that having the coils closer together reduced the volume. The Firebird pickups look smaller than Filtertrons, but do their other characteristics make them as loud or louder, in your experience? I'm not asking for measurements! I've probably never said it this plainly before, but the resonant peak frequency matters a lot more than the Q factor, or the vertical scale, the reason being is that the resonant peak decides what you have to work with, because if the resonant peak cuts out the treble, there's no way to get it back, it's gone, and it has a noticeable impact on the timbre, and the initial pluck of the strings, because pickups with lower resonant peak frequencies end up omitting much of the treble that comes from the pick attack, making it sound more soft and punchy, like when you roll the tone control down to zero, but not to that extreme. The Q factor / vertical scale just sort sets the baseline for what proportion of the signal will be weighted towards bass versus treble. The fact that Filter'trons have a low Q factor means they're surprisingly bassy pickups, but because of their low inductance and resulting high resonant peak frequency, there's also treble content in the signal, just of a lower amplitude. The Firebird pickups have a higher Q factor, so the bass relative to the treble is lower, but in either case they can be made to sound nearly alike by just adjusting the bass on the guitar amp. You also have a lot of control over the Q factor by changing the values of the volume and tone pots, so it's less intrinsic to the pickup than the inductance. The Firebird pickup also has a stronger magnetic pull, though, that impacts the harmonics of the string, that adds some treble and a sharpness to the sound. I almost agree that a pickup with a low Q factor can have a lot of treble, but there are some Chinese Tele neck pickups with a low inductance, but they have steel pole pieces and thick brass covers, the combination of those two things cause such dramatic eddy currents that they sound very dull as a result, regardless of load. Here's the bode plot of that, notice how the loaded and unloaded plots are nearly the same.  If Filter'tron's didn't have that H pattern cut in the cover that breaks up eddy currents in the cover, they would probably sound a lot darker, too. I'm not sure what your guitar looks like that you'd put the pickups in, but I think that adapter ring is meant to just go directly on top of a standard PAF plastic ring. I see they have a bunch of color options here reverb.com/marketplace?query=Humbucker%20to%20Mini-Humbucker%20Adapter%20Pickup%20Ring |
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ahlios
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Post by ahlios on Dec 23, 2022 13:29:25 GMT -5
Hello Antigua,
thank you for the detailed analysis of the qpickups' firebird pickup.
Looking at the specs (about 2 Henries, about 6 kOhm, about 4.35 kHz resonance frequency loaded) I would like to know, how different these pickups are from strat pickups like 57/62 or CS 69 soundwise?
The plot makes me imagine a sound "in the ballpark" of these classic single coil pickups. Or am I wrong?
Karl
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Post by antigua on Dec 24, 2022 4:13:34 GMT -5
Hello Antigua, thank you for the detailed analysis of the qpickups' firebird pickup. Looking at the specs (about 2 Henries, about 6 kOhm, about 4.35 kHz resonance frequency loaded) I would like to know, how different these pickups are from strat pickups like 57/62 or CS 69 soundwise? The plot makes me imagine a sound "in the ballpark" of these classic single coil pickups. Or am I wrong? Karl Yeah the biggest difference is certainly how Firebird pickups are positioned in a guitar compared to Strat pickups. This blue space ship looking guitar I have in the pics places these pickups roughly in between where Strat pickups would be, so it's very different for that reason alone. So I'm kind of at a loss, I want to say Strat pickups like the CS 69 are harsher and peakier sounding, but I couldn't tell you if it were the pickups, or the placement of the pickups. The electrical properties say that these pickups have the same filtering properties both in terms of peak frequency and Q factor, so I trust that they sound pretty much the same when listener bias is removed. The two coils also cause some comb filtering that a single coil doesn't have, but the comb filtering is at high frequencies because the coils are very close together, but nevertheless it could impact the "pick attack", for that brief one or two cycles when high frequency is abundant in the signal. To the extent that it's audible, it would soften the pick attack. The two coils also diffuse the magnetic pull over a wider area. The single pole AlNiCo 5 pole pieces pull on the strings in a specific spot, and it induces harmonics when the pickup is underneath the antinode of the harmonic, but since the magnetic field of this pickup isn't as sharply focused, it won't alter the harmonics exactly the same way, but probably still very similar. I measured 850G over both bars, so the overall amount of pull is as strong, if not stronger, than single AlNiCo 5 pole pieces measuring 1050G, so overall I suspect they will sound nearly identical. These also humbuck, single coils don't, and I have got the feeling that people can judge a pickup to sound different than another, just for the fact that there is a lack of noise present. |
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Post by ahlios on Dec 24, 2022 4:56:25 GMT -5
Hello antigua,
thank you for the detailed additional information! I really appreciate it!
Karl
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Post by ms on Dec 24, 2022 6:30:38 GMT -5
The two coils also diffuse the magnetic pull over a wider area. The single pole AlNiCo 5 pole pieces pull on the strings in a specific spot, and it induces harmonics when the pickup is underneath the antinode of the harmonic, but since the magnetic field of this pickup isn't as sharply focused, it won't alter the harmonics exactly the same way, but probably still very similar. I think the magnetic pull is mostly over the two pieces. The pole piece causes magnetization in the string that is like two thin rod magnets (along the string) with like poles facing each other. The field from the string magnetization pointing toward the pole piece is over it as aquin43 has shown, for example, in the model plot here: guitarnuts2.proboards.com/post/104632/thread. |
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Post by antigua on Dec 25, 2022 2:15:22 GMT -5
I think the magnetic pull is mostly over the two pieces. The pole piece causes magnetization in the string that is like two thin rod magnets (along the string) with like poles facing each other. The field from the string magnetization pointing toward the pole piece is over it as aquin43 has shown, for example, in the model plot here: guitarnuts2.proboards.com/post/104632/thread. But still that's two points of attraction instead of one, so it would bend the string more broadly, like if you were to tug at the string with two fingers instead of one. |
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Post by ms on Dec 25, 2022 7:03:24 GMT -5
I think the magnetic pull is mostly over the two pieces. The pole piece causes magnetization in the string that is like two thin rod magnets (along the string) with like poles facing each other. The field from the string magnetization pointing toward the pole piece is over it as aquin43 has shown, for example, in the model plot here: guitarnuts2.proboards.com/post/104632/thread. But still that's two points of attraction instead of one, so it would bend the string more broadly, like if you were to tug at the string with two fingers instead of one. Yes, and I like that comparison. Merry Christmas! |
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