Savoie Drive Calibration
Calibration jig for our Savoie drive system. Oscilloscope not shown.
Read MoreJelco Arm Stub & Counterweight
Last July, we began prototyping our Jelco counterweight/arm stub modification (click here for part-1).
With prototyping complete, the mods are now in production.
We loved the prototype, but what caught us off guard was the further improvement in the production implementation. The improvements take the changes described in part-1 a bit further.
The Jelco's Strengths & Weaknesses
There are a few highly regarded after-market "modders" who are fabricating counterweight kits for various tonearms.
We had our own ideas about how best to implement this, but priorities continually pushed this project to the back of the queue, and we've been directing Jelco owners toward these other fabricators.
In general, these modders get it "right" - recognizing that when addressing the counterweight, the arm stub also requires attention.
The Jelco's fine, jeweled bearing deserves better than the design of the tonearm's rear section, and the arm stub is a critical weak link.
Complete Set
Mass Tuning
One thing these modders are overlooking however, is the concept of mass tuning, and this was one factor driving us toward realizing this design.
We're producing these weights in sets of three (custom weights are possible). Typically, only two weights are employed for any cartridge.
We've found experimentation with weight combinations yields good results, and with cartridge mass spanning a range of about 7 to 20 grams (and with varying compliance), multiple weight sets aid in matching your arm to your cartridge.
We're big fans of the Kuzma's threaded arm stub, which employs two or more weights which lock against each other.
In addition to the benefits multiple weights provide for mass tuning, this "dual locking" approach accomplishes two things: ease of adjustment, which in turn eliminates the necessity of a fine-adjust weight (a potential source of vibration).
The Finishing Touch
While we were at it, we sourced brass-tipped set screws for the VTA pillar.
If you've owned any tonearm which employs a set screw to lock the VTA pillar in place, you've no doubt become frustrated by the small "divots" that the cup pointed set screw creates in the pillar.
When you attempt to make a small height change, the set screw tends to "find" this adjacent divot, pulling the height setting back into its previous position.
The brass-tipped set screw mitigates this problem, and for the most part, it will improve the functioning of VTA pillars which have already been damaged.
Hats off to manufacturers who address this (Kuzma and Schröder to name but two).
So of course, any Jelco leaving our shop has this finishing touch.
What's the Big Deal?
Firstly, our stock of Jelcos is dwindling, and we're saving them for our current customers and for turntable packages.
This modification is a big deal. The presentation takes on an authority that approaches that of the "big boys", and this foundation creates a solid platform from which to launch the upper frequencies.
When asked about interim upgrades (a mid-point on the path to Schröder, Kuzma, Durand and such), we advise our customers to "stand pat". In general, we don't recommend incremental upgrades, but rather waiting until one can make one final leap.
Well, this arm stub/counterweight mod makes waiting easier, and frankly, I'd be surprised if any tonearm in the $2K to $3K price range can surpass this Jelco.
Oh yes ... don't ignore a quality tonearm interconnect. Your Jelco (and you) deserve it.
Related Posts
NiWatt Amplifier Build – Part 3
(click to enlarge)This is part 3 of our NiWatt build log (installment #2 is here). We’re nearing the finish line with about 3 hours’ work remaining for each amplifier. The observant reader will note that this is a photo of the right ampifier (note the binding post and output transformer location on the left side of
Read MoreNiWatt Amplifier Build – Part 2
NiWatt Build in Progress (click to enlarge)Part 2 of our NiWatt build log (installment #1 is here). At this point, in the build, about 7 hours’ work remains for each amplifier. Shown here are the glass/fiber epoxy boards after “staking” the turrets: 3 boards for each amplifier. Preparing boards to the point shown here
Read MoreA Pass Labs XA-25 Demo With Rockport Speakers
(click to enlarge)We just demo’d a Pass Labs XA-25 amplifier at a customer’s house. The amplifier showed its pedigree, with all of the clarity, delicacy and nuance you’d expect from a Pass Labs design. At the same time, the Rockport speakers showed how power hungry they are. While the amps never sounded stressed (up to sane, but loud
Read More