Edit: Don’t know what our admin did, but I can finally post again after several months!

For reference:

https://strandbergguitars.com/product/strandberg-hsx-hyper-single-coil-circuit/

https://support.strandbergguitars.com/article/106-the-hsx-module-looks-exciting-please-tell-me-more-about-it

https://strandbergguitars.com/wp-content/uploads/2020/11/el-hsh5-03-r1_hsh_wiring_mf_pickups.pdf

First-off, the HSX (or “Hyper Single Coil”) circuit is just a passive RC filter for humbucker series connections to pass through on their way to ground. What it does differently from most I’ve seen, however, is have a component to it that runs in parallel between the input and output lugs of the volume pot, as well.

The hype on the Strandberg site gives the impression that the HSX is filtering each of the two coils separately; so the resulting series-connected signal processed in parallel adds up to a facsimile of a single coil EQ curve, with minimal decibel loss. In reality, I suspect that the HSX is just two common RC filters - acting as a series connection shunt (As you find in PRS coil splits) and treble bleed (a mod becoming more and more common in production guitars) - gooped together in a $44 disc shape, for the sake of making inferring the dollar’s worth of resistor and capacitor values superficially more difficult.

As novel as the approach is said to be, I’m afraid my first-hand impressions are not positive - In fact, I’d go so far as to say that the MFB-designed “Fusion” pickups currently paired with the circuit in its exclusive offering from Strandberg are the worst set anyone could have chosen to demo this filter; because the two products are not in any way optimized for one another.

In my previous experiments shunting humbucker series connections through C and RC filters, the depth of the desired midrange cut had to be tuned by mating the appropriate component value(s) to the voicing of the pickup being affected. In addition to being a case-by-case basis, the pickup being in neck or bridge position will also dictate how much cut feels necessary to suit each player’s needs.

The HSX, however, is one-size-fits-all. The result, in the case of this unfortunate pairing, is that the humbuckers included in the Strandberg Fusion (hot-rodded with cranked mids and subdued highs for the sake of emulating Allan Holdsworth’s post-amp graphic EQ settings) don’t receive sufficient mid-scoop from the HSX component values to seem in any way “single coil-like.” In fact, even a full coil split results in honky mids from these pickups.

I feel the HSX could shine, so long as it was prescribed for use with a four-conductor PAF or other lower-output humbucker style that suffers from anemic split tones. But why spend $44 + tax on a dollar’s worth of components to share between two humbuckers, when you could just buy the dollar’s worth of components in the first place?

My verdict is that a few cheap components purchased after reading this RC-tuned coil shunting article by Dirk Wacker are a far better investment than a gooped disc branded “MFB”:

https://www.premierguitar.com/diy/mod-garage/jazzmaster-mods

That said, I’ll update this thread after trying the circuit with some “vintage”-output Dimarzio offerings.