Fender Vintage Noiseless, Analysis and Review

[antigua]

shop.fender.com/en-US/accessories/pickups/fender-vintage-noiseless-strat-pickups/product-0992115.html

It's been a long time since I've heard these pickups in person. I remember thinking they sounded a bit dark and weak, and it was as though the pick attack was somehow muffled. The all around bad experience made me lose interest in stacked humbuckers altogether.

The individual coil bobbins look similar to a PAF coil, but they're actually about 4/5th's the height, and the plastic is not as thick, either. The bottom coil has two smaller steel poles between the AlNiCo poles, one between the A and D, and one between the G and B. I have no idea what purpose they serve.

Electrical

It turns out that all three pickups are essentially identical. The measurements actually put the peak resonance really high, at about 13.7kHz, a good 3 to 5kHz above most Strat sets, but the loaded peak comes all the way down to 4kHz, which is typical of a glassy Strat pickup. The reason is that the initial capacitance is extremely low at an estimated 33pF. A typical Strat pickup has between 90 and 120pF capacitance, so their lower resonant peaks can be blamed on a higher initial capacitance. Once you add a theoretical guitar cable, everything evens out. 

Magnets

Fender claims these are AlNiCo 2, but only one of the three pickups measures a Gauss that says this is possible, showing an expected Gauss around 850, but the other two measure well above 1200G, meaning they must be AlNiCo 5.

The AlNiCo 5 pole pieces are actually very strong, measuring between 1200G and 1450G, but it's not because it's some strange allow of AlNiCo 5, but just because they are very tall pole pieces, much taller than a typical Strat pole piece. The tall D pole measures 0.8145", whereas the typical height is about 0.72". 

The six AlNiCo poles run all the way through the pickup, top coil to bottom coil. This is a good design, because it helps ensure that both coils will have matching inductances that are attributable to the AlNiCo cores, but also bad, because they will inductively couple where the two coils meet, but with opposing magnetic phases, causing an impedance.

Noiseless vs Vintage

So, in summary, here are a few things that make these pickups especially unlike a vintage spec Strat pickup, in no particular order:

- A loaded (470pF & 220k) Q factor of 1.2, down from a more typical 1.8. That's a dramatic drop, as these things go. Expect a darker higher end.

- The bottom coil cancels the sound of the top coil. They do their best to put that coil further away, and there's a ferrous plate between the coils, which I doubt makes much of a difference.

- The pole pieces more strongly magnetize the strings due to that 20% - 25% higher Gauss, or flux density.

- You only get about half the generated current, since half of the copper involved is playing the role of 'dummy coil' on the underside of the pickup. The stronger magnetism will make up for it a little, but  then the bottom coil is cancelling some of it out again.

All these factors combine to make a pickup that is "close, but no cigar".

Fender Noiseless Bridge

DC Resistance (series): 10.27K

 top: 5.14K

 bot: 5.18K

Inductance (series):  2.592 H

 top: 1.445H

 bot: 1.591H

Resonant Peak: 13.7kHz kHz

Calculated C: 32pF (52-20)

Coil width: top: 0.6090" bottom: 0.5870"

Fender Noiseless Middle

DC Resistance: 10.00K

 top: 5.05K

 bot: 4.95K

Inductance: 2.623 H

 top: 1.470H

 bot: 1.612H

Resonant Peak: 13.3 kHz

Calculated C: 35pF (55-20)

Coil width: top: 0.5985" bottom: 0.5850"

Fender Noiseless Neck

DC Resistance: 10.19K

 top: 5.10K

 bot: 5.09K

Inductance: 2.555 H

 top: 1.398H

 bot: 1.588H

Resonant Peak: 13.7 kHz

Calculated C: 33pF (53-20)

Coil width: top: 0.5954" bottom: .5880"

Voltage to frequency bode plots:

Here is an analysis if the "bridge" pickup, measuring both coils in series, and each coil by itself:

You can see that when the top coil (green line) is induced with voltage, it's actually stronger than both coils together (black line). This is because when wire in series, the bottom coil cancels out the top coil. This graph might exaggerate the actual amount of difference between the top coil versus combined coil output, because the driver coil has a higher flux density than will guitar strings, meaning greater cancellation at the bottom, but all the same, it's a not-so-secret secret that you can get a volume bump out of a noiseless stack by splitting to the top coil alone. 

The bottom coil has a pronounced kink, or a sort of dual peak, but that appears to be the result of interference from the top coil. If the driver coil is placed at the bottom, then the bottom coil reads almost identical to the top coil.

Setup details:

Bode plots are made with a Velleman PCSGU250 and the supplied probes in 10x mode, with the function generator feeding a driver coil of 0.48mH, placed on top of the pickup and driven with 2Vpp. The pickup is connected to an integrator circuit, designed by Ken Willmottkenwillmott.com/blog/, with a Velleman 10x probe, and fed back into the Velleman PCSGU250. I measured the probes' capacitance at 20pF, so that amount is subtracted from the capacitance calculation.

The inductance and Q measurements are made with an Extech 380193 in "SER" series mode, and the mean value between the 1kHz and 120Hz modes is recorded. The capacitance value is derived from the inductance and measured resonant peak.

Magnets are tested with a Spin Doctor ER gravitastech.weebly.com/spin-doctor-er.html

[antigua]

Regarding the output of a stacked humbucker compared to a "traditional" single coil, I just did a side by side test between a Seymour Duncan SSL-1 and a Fender Noiseless. Both pickups have an identical inductance of 2.6H. The SSL-1 has a DC resistance of about 6.5k and the Noiseless about 10k.

Here's the result:



Using the Noiseless as the baseline, for a given input excitation of 4Vpp with the exciter coil, the SSL-1 produced +2.8dBV, and the top coil by itself produces +2.4dBV. So the humbucking mode definitely causes a small output drop, but it appears that using the top coil alone produces just about as much voltage as the SSL-1. The interesting thing about that is that the SSL-1 has twice the inductance and probably twice as many turns of wire as the top coil of the Fender Noiseless, and yet it makes only a tiny difference in terms of the output voltage. 

Now for the resonance differences:




When in series, the higher series resistance and maybe some mutual inductance between the top and bottom coils of the Noiseless cause a lower +5.0dB boost at resonance, where as both the top coil by itself and the SSL-1 produce +7.0dB at resonance. Of course, the inductance of the top coil by itself is only about 1.5H, so the loaded resonant peak is 5.67kHz, quite a bit higher than a typical Strat pickup, and likely to sound very bright.

The Fender Noiseless' 2.8dB drop in output voltage compared to the SSL-1 is not very much, and if the small difference in resonant Q factor is audible, that could be compensated for by using a 500k ohm tone or volume pot.