MartyGrass

The secret remains.

Ren wouldn't divulge his secret on HRWs. But I have talked about it with him and with his long-time co-workers. He would only smile when asked about what he did to Schallers. My guess is that they took a bath in liquid nitrogen. I highly doubt he did a partial uncoiling for several reasons. The first is the lack of any hum. The second is that a cryo treatment is an established way to modify a pickup. The third is that cryo treating is clean and relatively easy. Why did Heritage promote the HRW? The best answer I can come up with is because they could, especially is the process is secret. Here is what I got from AI. Cryogenic treatment for guitar pickups involves deep-freezing the components (typically to around or ) to permanently improve their molecular grain structure. Proponents claim this process relieves internal stresses in the metal parts, such as magnets and copper wire, resulting in enhanced clarity, smoother frequency response, and increased output. ProjectGuitar.com +4 Claimed Benefits While controversial in the guitar community, those who offer cryo-treated pickups cite several specific tonal and physical improvements: Enhanced Clarity & Definition: Treating materials like copper and silver is said to improve string definition and provide "faster" transients. Smoother Overtones: The process aims to align the molecular structure to be more uniform, which some makers claim makes overdriven tones smoother and more "in tune" by reducing dissonant overtones. Increased Output: Some manufacturers report measurable increases in output (up to 18%) because the treatment potentially lowers electrical resistance and improves conductivity. "Turbo-Aging": For hardware and magnets, cryo-treatment is often marketed as a way to replicate the "relaxed" feel of vintage parts that have naturally settled over decades. Brands & Services Several high-end and boutique brands incorporate cryogenic treatment into their products: Seymour Duncan: Offers the Zephyr Silver series, which uses cryogenically treated silver wire and magnets for maximum expression and detail. Lindy Fralin / Callaham: Features the Callaham Cryogenic Fralin pickups. Callaham has also been known to offer treatment services for customer-supplied parts. V.I.P. Pickups: Uses a "cryo-tuning" process for their LOVERS PAF-style humbuckers to achieve a more transparent, vintage sound. Faber Guitar: Provides cryogenic treatment for various guitar hardware and components to minimize "bad" overtones. Nitrofreeze: An industrial service provider often used by boutique builders to treat electronic and musical components. Scientific & Practical Considerations Skepticism: Critics often point to a lack of peer-reviewed data supporting tonal claims, suggesting that perceived improvements may be due to psychological factors or "marketing hype". Risk of Damage: Extreme cooling can sometimes cause plastic parts (like bobbins) or adhesives to crack if the process isn't carefully controlled. Metal vs. Wood: While the effect on ferrous metals (steel) is well-documented in industrial settings for hardening, its effect on non-ferrous metals like copper is more debated in the audio world.

Highly unlikely that bobbins were wound at Heritage. Ren is a clever person. I'd bet on the cryo treatment. If not that, it's something that can change the sound but doesn't require a lot of labor. Is It Cool or Not? Cryogenically Frozen Gear Explained | Ultimate Guitar

To be candid about this, around a decade ago I really didn't like HRWs, at least in the bridge position in solid bodies. The high frequency output was too sharp to my ears. Eventually I sorted it out. The neck position was always fine. It's odd to me because I've never had an issue with Schallers. I'm pretty sure HRWs were cryo treated. I asked Ren once. He just smiled. In that particular context it would have been easy for him to say something like there's more to the story. He didn't. This conversation occured when I brought in a Johnny Smith with a Floating #3 pickup and asked about getting a tone control added. He did the work while I was there, which took maybe 15-20 minutes. He charged very little, no more than $50.

Where did this idea come from?

You're right about the dot. I've put HRWs in my guitars a couple of times and did this. Clever guys!

We've gone down this path.

I have always liked HRWs sometimes! The right guitar and amp settings can bring out a very pleasant brightness and sparkle. The secret about making these pickups, as best I can guess, is a cryo treatment of the magnets. I've asked Ren Wall a couple of times over the years about cryo treatment. He just smiled and wouldn't comment further. I'd like to put this to rest. What's the truth?