Stax · Electrostatic · 1975 (Mk3 Pro from 1985)
The SR-X Mk3 is the third version of an electrostatic line Stax started in 1970. The Mk2 followed in 1972 and the Mk3 in 1975, and owners still commonly run it from an SRD-7 transformer box wired to a receiver's speaker outputs. Stax kept the design going into the Pro-bias era with the SR-X Mk3 Pro of 1985, which used a 1.5-micron diaphragm. That later version matters when you buy, because the two look alike but don't take the same energizer socket. The Mk3 has a 6-pin Normal plug and the Mk3 Pro a 5-pin Pro plug. Stax has ended repairs on every SR-X version, so buy one that plays cleanly on both sides.
Before you plug in
Should come with it
Check the listing photos against this list, and ask the seller about anything you can’t see. A missing piece should come off the price.
Nothing model-specific is documented. Stax has ended repairs on all SR-X versions, with no drivers, pads, cables or headbands, and electrostatics dislike damp and dust.
New to used headphones? How to check a used pair covers pads, cables, channel dropouts and fakes, and impedance and your amp explains what will drive it.
Buying guide
We'd buy the SR-X Mk3 titled excellent and very clean at $240 delivered from a US seller at 99.7%, and if you need something to drive it, watch the auction with an SRD-7 adapter, now $322 delivered with no bids. Only 4 are for sale, at $240–322 delivered, so the $250–280 band isn't a market read. It won't play from a headphone jack, phone or ordinary amp, and the Mk3 needs a Normal-bias (6-pin) source, such as an SRD-7 or SRD-6 box wired to a receiver's speaker outputs, an SRM-1, or the Normal socket on an SRM-1/MK-2 Pro, SRM-T1 or SRM-T1S. Count the plug's pins in the photos, since 6 means the Normal Mk3 and 5 means the 1985 Mk3 Pro, which needs a Pro socket. Stax has ended repairs on every SR-X and none here is titled tested, so ask for a note that both sides play evenly, and skip the box-only photo from a 97.9% seller.
$240.00est. delivered
The lowest delivered SR-X Mk3 here at $240, titled excellent and very clean. It's the earspeaker alone and needs a Normal-bias source such as an SRD-7 box, so count six pins on the plug in the photos.
Stax Electronic Ear Speakers Headphones SR-X Mark-3 Exc Cond Very Clean
$240.00est. delivered
Under the $250–280 band from a 99.7% seller, with clean condition in the title. Stax has ended SR-X repairs and it isn't titled tested, so get a note that both sides play evenly with no crackle before you buy.
Stax Electronic Ear Speakers Headphones SR-X Mark-3 Exc Cond Very Clean
Delivered prices include shipping as eBay quoted it to a US address on Oct 14, 2026. Many sellers charge by distance, so your total may differ. eBay shows yours before you pay.
Snapshot
Checked . Some may have sold.
Delivered prices include shipping as eBay quoted it to a US address on Oct 14, 2026. Many sellers charge by distance, so your total may differ. eBay shows yours before you pay.
Used$240.00est. delivered
$225.00 + $15.00 shipping
Buy It Now$225.00
This seller takes offers, and many sellers accept less than the asking price.
Fine if you might miss it? Send an offer first. Someone else can still buy it while you wait for a reply.
Want it for sure? Use Buy It Now.
Good buy
Titled excellent and very clean. Earspeaker alone.
Seller: cliv87
99.7% positive
Used$256.14est. delivered
$250.00 + $6.14 shipping
Auction · no bids yet · ends in 3d 11h
Our take
SR-X Mk3 box in the photo. Auction, no bids yet, so the price will climb.
Seller: jdlad1976
100% positive
Used$321.80est. delivered
$300.00 + $21.80 shipping
Auction · no bids yet · ends in 9d 12h
Our take
With an SRD-7 adapter in the title and photo. Auction, no bids yet, so the price will climb.
Seller: mleotta1
99.7% positive
Open box$260.27est. delivered
$246.20 + $14.07 shipping
Buy It Now$246.20
This seller takes offers, and many sellers accept less than the asking price.
Fine if you might miss it? Send an offer first. Someone else can still buy it while you wait for a reply.
Want it for sure? Use Buy It Now.
Check the seller
Titled new open box mint, but the photo shows only a box. Seller at 97.9%, in Canada.
Seller: tristantcg
97.9% positive
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