Post by antigua on Feb 24, 2019 18:41:22 GMT -5
I saw, on Amazon, some humbucker sets for really cheap boasting nickel silver base plates and reasonably good electrical values (not crazy hot)
www.amazon.com/gp/product/B074KHPVJ1/?tag=tdpri-20 , so I bought a couple sets. This one in particular is all black, DiMarzio style, with twelve hex screws, all black. Currently they're listing for $37 for both the neck and bridge pickups together as a set. Getting two nickel silver AlNiCo humbuckers for such a low price is almost unheard of. They're so cheap that if you add up all the individual parts involved from StewMac, these still come out a lot cheaper. They're so cheap that even if you buy all the tools necessary to mod these pickups to become what you want, wire snips, a soldering kit, chrome polish, you'd still have spent less than what a comparable domestic set would cost.
These hex poled style pickups are often associated with hot, high output pickups, but based on the measured values, they're in the "PAF" range. The bridge pickup has an inductance of 5.5H, which is the same range as the Seymour Duncan Pearly Gates bridge, a "hot PAF". The neck pickup has an inductance of 4.4H, which is the same measured value of a Seymour Duncan '59 neck PAF.
Overall, they looks like good pickups. I'm actually planning to replace a set of Seymour Duncan Pearly Gates with them, in part for something new, but also for the black-out aesthetic of these pickups, once the logos are cleaned off the tops.
LYTC Control HP5 Humbucker Set
Bridge
- DC Resistance: 9.153K ohms
- Measured L: 5.521H
- Calculated C: 177pF (187 - 10)
- Gauss: 230G AlNiCo
Bridge unloaded: dV: 5.9dB f: 4.95kHz (black)
w/ copper shield cut & disc. dV: 7.9dB f: 6.07kHz
Bridge loaded (200k & 470pF): dV: 1.7dB f: 2.52kHz (blue)
w/ copper shield cut & disc. dV: 2.0dB f: 2.67kHz
Br Split unloaded: dV: 4.4dB f: 9.59kHz (red)
Br Split loaded (200k & 470pF): dV: 1.5dB f: 4.36kHz (green)
Neck
- DC Resistance: 8.074K ohms
- Measured L: 4.425H
- Calculated C: 208pF (218 - 10)
- Gauss: 230G AlNiCo
Neck unloaded: dV: 4.4dB f: 5.12kHz (black)
Neck loaded (200k & 470pF): dV: 1.7dB f: 2.83kHz (blue)
Nk Split unloaded: dV: 3.5dB f: 10.3 kHz (red)
Nk Split loaded (200k & 470pF): dV: 1.9dB f: 4.84kHz (green)
Stock condition: dV: 5.9dB f: 4.95kHz (black)
Coil shield disconnected: dV: 5.7dB f: 6.07kHz (blue)
disconnected & cut: dV: 7.8dB f: 6.07kHz (red)
disconnected & removed: dV: 7.9dB f: 6.07kHz (green)
w/ 200k & 470pF load: dV: 2.0dB f: 2.67kHz (pink)
An interesting aspect of these pickups is that they show a strong second resonance beyond the primary resonant peak. This appears to be caused by a stronger-than-usual interaction between the two side-by-side coils, possibly caused by the copper shielding around the coils.
As for being vintage correct (as much as a pickup like this can be), the do something uncommon for U.S. made pickups, but apparently common with foreign made pickups, including the "Duncan Designed" pickups, and that is they put copper shielding around the coil, to help reduce noise, in theory. Their doing that introduces additional capacitance and eddy current losses to the pickup, though both effects are slight. The capacitance increases because you have a grounded metal right beside the coil, the positive side of the circuit, and so they capacitively couple. The eddy currents are caused by the fact that the shielding is essentially a second coil around the outside of the first coil, and so they magnetically interact, and that second coil acts as a load on the first coil.
The capacitance increases by about 60pF, while the eddy currents cause the peak amplitude to drop by about 2dB. With a test load, similar to a real guitar rig, the resonant peak only drops by 150Hz and the resonant amplitude drops by less than 1dB, compared to when the copper shielding is disconnected from ground and snipped in half (so that it doesn't have DC continuity all the way around, preventing it from behaving like a coil).
These differences, a ~150Hz drop in the resonant peak, are negligible, and so it's probably not worth removing the coil shielding, but if you wanted to take the shielding off, there is a layer of yellow protective tape between the coil and the copper shielding, so you can unsolder the shielding and pull it away from the coil without risk of damaging the fine coil wire. If helps to have some precision tools though, such as tweezers and a fine tip soldering pen, and a way to secure the pickup.
This plot below shows the pickups with the copper shield in place, and then in place but disconnected, disconnected and cut, and then disconnected and removed, as well as a loaded plot with the shielding disconnected and removed. Two interesting takeaways is that there is very little difference between cutting the shielding down the side, versus removing it entirely, which means the shielding can be made inert without having to fully dismantle the pickup. The other interesting thing is that the strong double resonance is great reduces when the shielding is cut or removed, suggesting that it's a strong contributor to the double resonant peak.
Copper shield and ground connection:
In the top pickup, you can see the solder blob that binds the shielding to itself, and in the bottom pickup the solder blob has been removed and the shielding has been lifted away from the coil. There is a yellow protective tape under the shielding and over the coil.
They spec it as having an AlNiCo 5 bar, but surprisingly, the flux density at the tops of the pole pieces is not especially strong, only abut 230 Gauss, where as a PAF with AlNiCo 5 usually comes closer to 300G to 350G. This is not a problem, it just means the pickup might sound more like it has an AlNiCo 2 or 3 bar underneath.
As you can see in the picture, the screws stick way out of the bottom of the pickup, by clipping those short, the flux density can be increased by about 200 to 300 Gauss. Since the magnet intersects the screws and their mid point, the lower half of the screws just serves to magnetically counteract the top half of the screws. Ridding the screw of the extra length increases the strength at the head end of the screw. There's a picture of the snipped screws below.
At first I tried using a Dremel to saw off the screw legs, but the head caused the black paint to smell very bad, and the steel shavings stuck to the pickup, so instead I used 7" wire snips, but that was still very difficult, so I've ordered some "high leverage" 11" wire snips to add to my tool box for situations like this.
These pickups, as you can see, come branded as "LYTC Control". If you don't like to see branding of any sort on your pickups, you're in luck, the painted on logo rubs right off with metal polish. Mother's Mag & Aluminum polish worked especially well. The plastic loses a little bit of gloss as a result, but it's not bad.
