For Halloween: Re-animating the JVC HA-RX330
Nov 3, 2018 at 12:44 AM Thread Starter Post #1 of 4


New Head-Fier
May 24, 2013
Northern California
So, for Halloween, I decided to do a small audio project - to BRING the DEAD back to LIFE! Perhaps worse than dead, take a dull, lifeless sounding headphone and turn it into a real killer...

The Victim: I found a clearance JVC HA-RX330 at my local Fry's for the undead price of $4.99! I snatched it up, and gave it a test run, only to find the sound lame - boring, flat, thin, heavily veiled and generally cheap and unappealing. However, the design of the headphone bodies is rather exceptional - they have large, (4") ear openings with an unusual slightly slanted mount of the speakers themselves to better angle the driver at the sensitive part of your ear. They share this design with higher JVC headphones, with only a reduction in material quality (cheap plastic). The cans themselves are quite good looking, with large synthetic pads, very large ear openings, and a unique swivel mechanism to allow a natural angle change on each side to better fit various head shapes. They are exceptionally light headphones, and extremely comfortable. Apart from the appalling sound, they're quite good!

The Donor: I am super high on the Kramer Mod Koss headphone sound - I have a Kramer PortaPro (Kramerized mylar drivers), a Kramer KSC75, and a Kramer Koss Titanium KTXPRO1's with multiple sets of Kramer mod grilles, for different tunings. I've always had problems with the KTXPRO1's headphone design - poor pressure for my head, poor angles to keep the drivers properly placed, and a limited pad set from the (poor) pad anchor design... super great Koss titanium drivers, lousy headset... Hmmmmm...

Question: What if I were to remove the BRAIN (drivers) from the KTXPRO1and place it in the BODY of the JVC? Would I get Abby Normal? Or Hans Delbruk?

Time for surgery: I opened each side of the JVC, useing a jewelry screwdriver to gently pry the lame drivers out of their sockets, measured, and found the widths of the sockets to exactly match those of the KTXPRO1 drivers - bingo! I used superglue to mount the Koss drivers into the JVC sockets, carefully threading the wires through the wire slots *** important *** these are a particularly good match as both the Koss and the JVC are two-wired headphones, not single sided - this means the wires don't have to be rerouted through the JVC head strap - they exit out the bottom of the cans as designed. An added bonus is the existing Koss wires contain an inline volume control :wink:

The KTXPRO1 housings fit into the JVC can housings with only a single modification - the faceplate screw hole slightly overlaps with the Koss driver body, so a small file for two minutes is needed to clear the area.

Performance: (my tests are conducted with 16 bit FLAC music files, Android running Meridian Player, plus a JDSLabs cMoyBB v2.03 amp) Initial tests yielded an "imperfect DNA match" - the Koss's bring superb bass, but some of that energy is absorbed by the cheap plastic bodies of the large JVC cans. Simple solution was to add a small amount of polyfill to the headphones to dampen the vibrations. It took several attempts to yield the best bass performance - too much polyfill steals the bass entirely while not enough allows the plastic vibration mud. Next the clear, bright, articulate highs and mids of the Koss have to reach perhaps a half inch further, which gains them down a bit - solution there was to remove the Kramer mod covers all together and run them "naked". In addition, I carefully cut out the fabric separator sewn into the earpads to further recapture a touch of the lost gain. This not only works effectively, but creates an impressively beautiful look inside, as the naked titanium drivers are clearly visible when gazed upon. And as usual, the JDSLabs amp tightens the bass, sharpens the mids, and significantly improves this setup (highly recommended unit).

Results: Ultimately the cheap plastic of the JVC bodies does steal a touch of the clarity of the mids and highs, and creates a hint of congestion in the midbass. And with its substantially larger enclosure, the lower bass simply doesn't extend quite as low as in it's original configuration. I'd estimate a loss of 5-10db at the lowest frequencies. The overall effect is a subtle veiling of the sound, similar to my Pioneer SE-A1000. However, an interesting artifact is that the soundstage is noticeably wider - instruments "hang in the air" several inches wider than in the KTXPRO1 configuration, a very appealing improvement as I love recordings which separate instruments in the soundstage.

However, don't get me wrong - the Koss driver's brilliance is mostly preserved, enhanced in soundstage width, the drivers are now visibly on display to impress my friends, and I can wear them for hours in supreme comfort - JVC really killed it in the basic design of the headphone structure. The sonic signature is sanded down a bit for Koss, which actually makes them even better for long listening sessions. The project turned out so good it's spooky! And the price ($5 for the JVC, $20 years ago for the Koss, plus an hour of elbow grease) yields a unique, impressive, customized listening device with comfort for hours. You might say it's to die for... :wink:

(once I figure out how to post pictures, I will)
Nov 3, 2018 at 1:14 AM Post #2 of 4
IMG_20181102_215425.jpg IMG_20181102_215554.jpg
L: Very good looking body upon which to graft a new BRAIN (notice JVC and Koss logos together);
R: Attractive and terrific Koss Titanium drivers "naked" through JVC spider supports
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Nov 3, 2018 at 10:51 PM Post #3 of 4
IMG_20181102_215450.jpg IMG_20181102_215541.jpg
L: Koss wiring looks perfectly factory through JVC wire leads. Koss volume control a plus;
R: Another look at the "naked" Koss drivers; notice the slightly angled driver offset within the housing
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Nov 3, 2018 at 10:52 PM Post #4 of 4
IMG_20181102_215354.jpg IMG_20181102_215405.jpg
Slick JVC can design - L: cans pivoted out; R: cans pivoted in.
Pads are also angled in fore/aft, this shows wider back side
Combined with ultra-low weight, overall comfort is excellent.
I'm betting pads are standard size/easily upgradeable as well.
Only thing missing is a nice sheepskin wrap for the head braces - perhaps an aftermarket seatbelt pad...?
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