Post by antigua on Nov 2, 2016 22:33:02 GMT -5
www.tvjones.com/tv-ht-pickups.html
This is a single coil pickup in a Filter'tron style housing, with the large 1/4 AlNiCo bar laid beside the coil, with six screws through the coil that extent all the way down to the base plate.
These pickup sound a lot like regular Filter'tron despite having only one coil. The inductance and DC resistance suggests that the might cram as many wind around the one bobbin in the TV-HT as they do both bobbins of a Filter'tron.
TV Jones TV-HT Bridge
Resistance: 4.26k ohms
Inductance: 2.492H @120hz, 1.857H @1khz (TV Jones reports 1.85H)
Gauss: 300G
Unloaded: dV: -5.6dB f: 9.48kHz (black)
Loaded (200k & 470pF): dV: -4.5dB f: 4.41kHz (red)
TV Jones TV-HT Neck
Resistance: 3.427k ohms
Inductance: 1.729H @120hz, 1.286H @1khz (TV Jones reports 1.22H)
Gauss: 300G
Unloaded: dV:-6.6dB f: 10.6kHz (green)
Loaded (200k & 470pF): dV:-5.3dB f: 5.12kHz (gray)
A note about the inductance measurement, the Extech 380193 is an industry standard LCR meter. It features measurements capabilities at both 120Hz and 1kHz. Helmuth Lemme has suggested measuring at 120Hz to avoid inaccuracies in relation to eddy current losses www.planetz.com/wp-content/uploads/2014/10/Pickup_Measuring_Technique.pdf , skip to page 4. Mike Sulzer, a very smart guy, also details the reason for it here. Since the 120Hz and the 1kHz measurements disagreed to such a great extent with this pickup, I documented both values above, though it's likely that the 120Hz value is the most accurate.
Looking about the bode plot below, there is a large drop off at 200Hz. 120Hz is within the baseline, before the eddy currents become highly reactive, while 1kHz intersects a 2.5dB loss in amplitude, so it's not at all surprising that the Extech measured very different values there. This gives me a lot of confidence that the 120Hz measurement is more accurate, but the overall low Q factor of the pickup makes me wary of the 120Hz measurement as well.
Note that TV Jones' inductance values measures match my 1kHz measurements almost identically. I believe it's very likely that they use an Extech 380193, as it is industry standard, and that they measure their pickup's inductance at 1khz, though it appears to me that measurements at this frequency are erroneous.
Bode plot:
It's clear to see that all the metal involved with the TV-HT causes eddy current losses that greatly exceed those of any Filter'tron style pickup tested to date.
To my ears, it seems that these produce a sound very similar to Filter'trons, same EQ profile, but you can tell they're voiced more like a single coil, either because they read a smaller segment of the string, or because they lack the comb filtering of a humbucker. The 5dB drop off from 200Hz up to the resonance is not readily obvious to my ears, but it might well be the reason these pickups have a full sound than say, a Strat pickup wound to 4k with 1.7H inductance.
A gratuitous amount of metal has been cited as a reason why the pickups that came in a lot of 70's / 80's import guitars sounded so bad, but IMO, this goes to show that even a pickup that involves substantial eddy current losses can be made to sound good, with thoughtful design.
I'm impressed that the Gauss readings at the pole tops measured around 300G, that's about typical for the slugs of a PAF, but in this case, the magnet is not even directly touching the screws, half of the coil sits in between them, though there is a bent steel keeper bar that snakes around the bottom of the coil .
Pics:
This is a single coil pickup in a Filter'tron style housing, with the large 1/4 AlNiCo bar laid beside the coil, with six screws through the coil that extent all the way down to the base plate.
These pickup sound a lot like regular Filter'tron despite having only one coil. The inductance and DC resistance suggests that the might cram as many wind around the one bobbin in the TV-HT as they do both bobbins of a Filter'tron.
TV Jones TV-HT Bridge
Resistance: 4.26k ohms
Inductance: 2.492H @120hz, 1.857H @1khz (TV Jones reports 1.85H)
Gauss: 300G
Unloaded: dV: -5.6dB f: 9.48kHz (black)
Loaded (200k & 470pF): dV: -4.5dB f: 4.41kHz (red)
TV Jones TV-HT Neck
Resistance: 3.427k ohms
Inductance: 1.729H @120hz, 1.286H @1khz (TV Jones reports 1.22H)
Gauss: 300G
Unloaded: dV:-6.6dB f: 10.6kHz (green)
Loaded (200k & 470pF): dV:-5.3dB f: 5.12kHz (gray)
A note about the inductance measurement, the Extech 380193 is an industry standard LCR meter. It features measurements capabilities at both 120Hz and 1kHz. Helmuth Lemme has suggested measuring at 120Hz to avoid inaccuracies in relation to eddy current losses www.planetz.com/wp-content/uploads/2014/10/Pickup_Measuring_Technique.pdf , skip to page 4. Mike Sulzer, a very smart guy, also details the reason for it here. Since the 120Hz and the 1kHz measurements disagreed to such a great extent with this pickup, I documented both values above, though it's likely that the 120Hz value is the most accurate.
Looking about the bode plot below, there is a large drop off at 200Hz. 120Hz is within the baseline, before the eddy currents become highly reactive, while 1kHz intersects a 2.5dB loss in amplitude, so it's not at all surprising that the Extech measured very different values there. This gives me a lot of confidence that the 120Hz measurement is more accurate, but the overall low Q factor of the pickup makes me wary of the 120Hz measurement as well.
Note that TV Jones' inductance values measures match my 1kHz measurements almost identically. I believe it's very likely that they use an Extech 380193, as it is industry standard, and that they measure their pickup's inductance at 1khz, though it appears to me that measurements at this frequency are erroneous.
Bode plot:
It's clear to see that all the metal involved with the TV-HT causes eddy current losses that greatly exceed those of any Filter'tron style pickup tested to date.
To my ears, it seems that these produce a sound very similar to Filter'trons, same EQ profile, but you can tell they're voiced more like a single coil, either because they read a smaller segment of the string, or because they lack the comb filtering of a humbucker. The 5dB drop off from 200Hz up to the resonance is not readily obvious to my ears, but it might well be the reason these pickups have a full sound than say, a Strat pickup wound to 4k with 1.7H inductance.
A gratuitous amount of metal has been cited as a reason why the pickups that came in a lot of 70's / 80's import guitars sounded so bad, but IMO, this goes to show that even a pickup that involves substantial eddy current losses can be made to sound good, with thoughtful design.
I'm impressed that the Gauss readings at the pole tops measured around 300G, that's about typical for the slugs of a PAF, but in this case, the magnet is not even directly touching the screws, half of the coil sits in between them, though there is a bent steel keeper bar that snakes around the bottom of the coil .
Pics:
