SUBSCRIBE FOR UPDATES
Instant access to research, reviews, and website updates.
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.
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.
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 “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 |
Summary
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.
30 thoughts on “PRS Silver Sky 635JM vs. 635JM “S””
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.
Or maybe PRS purposefully made the “import” pickups darker so they can upsell the US model for its “clarity”.
Hi. What are the dimensions of the two pickups? Screw holes?
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.
How wide is the cover over the bobbins area? Meaning how wide would the hole in the pick guard need to be?
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 👍
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.
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 👍
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.
HI!
Why the resonance curve is not added to a pickup specs?
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.
Any chance you could compare the physical dimensions of each pickup (and perhaps also to a standard Strat pickup)?
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.
Hello. I saw information that you wanted to compare these pickups in an independent guitar and record a video.
Please tell me, do you have the result of this work? How can I find this video?
If this is still in progress, please tell me when you plan to release the video?
Thank you!
Hi Bogdan – We are actively working on that video! Hopefully should be available in a week or so. Please subscribe to our YouTube channel for the fastest notification time.
The specs of the 635JM pickups in the Silver Sky changed rather dramatically starting in 2021. The DC resistance is now around 5.6K rather than 6.4K, and the output is lower, as you’d expect. See Justin Jeske’s video: https://youtu.be/-FNVbE1XluY?t=411
For a sound comparison between the pre and post 2021 SS models, see: https://youtu.be/1S-ZnAA-Z1A
I’d be really interested to see your measurements of a current version 635JM pickup if you can get your hands on one. BTW, love your website and what you’re doing!
Thanks Ben! This is fantastic info. I’ve heard rumors about the change, but hadn’t looked into it enough. My Silver Sky was a 2020 model, so that makes sense why it has the 6.4K version. It’s really frustrating that they made a change this big and decided to say nothing, and even left it as the same model name. Changing it to 5.6K also negates the “635” name, since the whole point was for it to essentially be a 63′-64′ style strat pickup, and 5.6K is much more of a 50’s spec. Funny enough though, neither of the USA versions are close to the SE model.
If I can get my hands on a new one I’ll measure it and go over the differences. I really love the 6.4K model, it’s got a ton of power and sounds glorious with gain. I bet the 5.6K version works better with John’s latest music he’s been playing, which has been very clean.
I agree, I think the 6.4K and 5.6K SS pickups are so different that they deserve different names. As you point out, a 5.6K pickup doesn’t fit the ‘63/’64 spec at all. I think both versions are compelling for different reasons. I agree, the punch and power of the 6.4K PUPs are fantastic, and I love the dynamic range and glassiness of the new ones. As Justin Jeske observed, the current 5.6K PUPs are quite similar to the PUPs in John’s Black1 guitar. The main difference is that the SS PUPs have significantly reduced ice pick frequencies (lower resonant peak presumably) vs those in the Black1.
I have a Silver Sky made in November 2022. Each of the pickups has a resistor and capacitor (I think) soldered to it. I had never seen this before on any pickup and asked PRS support who confirmed this as normal for the guitar.
I’d love to see a picture of that. PRS has been doing this for other guitars to modify how pickups sound when split, but I haven’t seen them directly solder any resistors or caps directly do the pickup itself. If you read my article about PRS TCI, there’s a section that discusses that.
I would be very interested in this too to learn if there’s actually a difference between the old and current Silver Sky pick-ups. Somewhere I feel they haven’t actually changed the pick-up themselves, but did some other wiring tricks (which those caps + resistors could be a perfect example of) to alter the sound/output somewhat. I’ve got a 2019 Silver Sky myself and really like the old style pick-ups for what they are: strong, modern and punchy. I think it complements Fenders more whereas the new direction is more Fender style.
If you watch this YouTube video, you can hear the differences: https://youtu.be/1S-ZnAA-Z1A
The sound difference is pretty clear. I haven’t played the newer one, but I agree with you that the 6.2k version is awesome.
I’ve watched all those comparison videos, but I’m still not sure whether the sound of the pick-ups is all that different. For sure there’s less output and top end, but couldn’t this simply be a result of the different wiring?
If there was different wiring, that could absolutely play a factor. I haven’t seen any confirmation on that side though. What I have seen consistently is that the original pickups were around 6.2k, and the newer ones are 5.6k. Small changes in DCR will always make subtle changes, but it seems like you noticed the difference already, mentioning the output and top end. If I had access to a newer model and could see the wiring, I could make a better judgement on it.
https://postimg.cc/9zbgCNvq
That’s so strange. Can you read what the values are?
No. And it‘s back in the guitar 🙂
Hi, thank you for this amazing study of these pickups.
Do you remember from which year were the 635JM pickups, please? (because it seems like they’ve changed over the years:
https://www.youtube.com/watch?v=-FNVbE1XluY )
Cheers
Mine were from 2020, so they were the original set PRS released. The latest one I believe was released in 2021, and is a lower DCR. My guess is that the new version lines up better with the import variant.
Thanks for your answer. Mine are also from 2020 so they should read the same as the ones you measured (cool! 🙂