PRS Silver Sky 635JM vs. 635JM “S”

The PRS Silver Sky has to be one of the most controversial models that Paul Reed Smith has ever released. Some people love it, others love to hate it. Some think it’s just a Strat copy, and others think it’s something more. If you’re reading this article, you’re likely a fan – and you’re in good company. I can state from personal experience with my own Midnight Rose Silver Sky, it’s a great guitar. 

However, it doesn’t come cheap. Lucky for us, the Silver Sky SE was finally released in January 2022. The debate still remains, do they sound the same? Both models are different in several ways, from the body wood, fingerboard radius, and most notably, the pickups. Since very little data exists for either the 635JM or the 635JM “S”, we took it upon ourselves to test both. Before we jump in, an important note is that both the Silver Sky and Silver Sky SE use identical pickups for each position, with the only caveat being the middle position is reverse-wound, reverse-polarity (RWRP) for hum-free 2nd and 4th pickup selector positions. The data below will apply to the bridge, middle, and neck positions.

PRS Silver Sky SE 635JM "S"
PRS Silver Sky 635JM

Visually, there are several noticeable differences. Most obviously, the pole piece radius is different. This makes sense, as the Silver Sky and Silver Sky SE have different fingerboard radius values. Less noticeably though, the magnets of the 635JM “S” are slightly thicker and taller than it’s sibling, 4.96mm x 18.67mm vs. 4.74mm x 17.67mm. Neither are beveled, and both keep the magnet height consistent across. The 635JM removes the bobbin extension for the leads, while the 635JM “S” keeps traditional bottom flatwork. Lastly, the cover colors are incredibly close, but the 635JM “S” appears to have a very small tint of amber compared to the 635JM. Flipping them over reveals an unexpected factor. 

PRS Silver Sky SE 635JM "S" - bottom view
PRS Silver Sky 635JM - bottom view

While the 635JM appears as expected, the 635JM “S” has metal inserts in between each pole piece. This is very similar to DiMarzio’s Virtual Vintage technology, where they add metal slugs in between pole pieces. This patent is expired, so it’s fair game for other companies to take advantage of. By adding extra ferrous metal within the pickup’s core, the inductance values will increase, decreasing the resonant peak. 

Finally, let’s see how these differences affected the resonance curve and specs:

635JM vs 635JM S
Resonance curve captured includes a load to represent 2 x 250K pots and cable/amp capacitance.
635JM “S” 635JM
DC Resistance 7.45 K 6.43 K
Magnet Type Alnico 5 Alnico 5
Inductance 2.72 H 2.33 H
Resonant Peak 3.5 kHz 3.9 kHz


Both of these pickups achieve exactly what they aim for – to make awesome Strat sounds. They get there in different ways, and they end in different spots. Will these pickups sound the same within the same guitar? No. They are different in almost every measurable way – DC resistance, inductance, resonant peak, Q-factor, the list goes on. It’s possible that the Silver Sky SE uses different parts that create a brighter tonality, in which case the differences were created intentionally. From Paul Reed Smith’s reputation, I wouldn’t dismiss this notion. Overall, the 635JM “S” will have a bit less high end and a slightly smoother tonality as compared to the 635JM. This may actually be preferable in many situations. As always, try before you buy. 

13 thoughts on “PRS Silver Sky 635JM vs. 635JM “S””

  1. The original SS used a 300k volume pot with a 2.7 meg resistor to get to a goal of 270k+-, which should roll off some high end. I don’t know how the SE SS is wired, but I suspect the pickups were designed to do that without the creative wiring.

    1. Hi AJ,
      The USA 635JM is 17.8mm L x 84mm W x 16.3mm H (or 20.26mm including the wire terminal). The 635JM “S” is 17.7mm L (or 24.74mm at the base) x 83.5mm W x 17.22mm H. Both screw holes are the same distance, roughly 76mm from center to center. They should both fit in similar pickguards.

      1. How wide is the cover over the bobbins area? Meaning how wide would the hole in the pick guard need to be?

  2. The steel does more than boost inductance, it is attracted to the magnet poles, itself becoming a temporary magnet. This stops the like poles of the six Alnico rods from trying to repel one another. The consequences on internal phase are quite large.

    Do you know what type of wire is wound on these pickups?

    Cheers, Ben Bailey 👍

    1. Without cutting the wire and measuring we can’t be sure. However, based on its DCR and resonant frequency our expectation would be 42AWG. If it were 43AWG, we would expect a much higher resonant frequency.

      1. I meant wire type (Insulation being Poly, Plain enamel, FormVar) not gauge. It would be a squeeze to get 7.4k on those bobbins with 42awg, indeed. Cheers Ben Bailey 👍

      2. Definitely poly wire. We compared our 635JM “S” to our Fender Player Series Strat Neck pickup which is also around 7.5k, and the PRS pickup definitely had a fuller bobbin. This leads us to the conclusion that the PRS uses 42AWG.

    1. Hi there! We’re developing a graphical comparison tool to add each resonance curve to the pickups we’ve tested. We believe that will be much more useful and manageable than just providing images.

    1. Hi Adrian – we posted the dimensions in a previous comment. They are very consistent with a standard Strat pickup. We don’t see anything that makes them super unique from their dimensions. The USA 635JM has a nearly identical coil height to a Seymour Duncan SSL-1.

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