Stax · Electrostatic · 1979–1982
Stax's SR-Lambda, officially the SR-Λ, came out in 1979, the same year as Stax's first solid-state energizer, the SRM-1. It introduced what Stax called semi-panoramic sound, with oval drivers set slightly forward to line up with the ear, and it won a design and engineering award at the 1981 Chicago Consumer Electronics Show. This is the original Normal-bias version, running at about 230 volts with a 6-pin plug. From 1982 the Lambda moved to Pro bias, so a Normal Lambda needs an energizer with a Normal socket. That's easier than it sounds, because many later Stax units kept one alongside their Pro sockets. Sellers often just write Stax Lambda, so count the pins on the plug.
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.
A Normal-bias Lambda can play louder on one side for a while after switch-on, until both diaphragms charge, and that's normal. With age a channel can fail and the pad foam crumbles, and Stax no longer repairs it.
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-Lambda titled 6 pin Normal bias at $475 delivered from a seller in Iceland, who also has a second pair titled Normal bias at $555. There are at least 5 for sale at $475–1,094 delivered, too few for the $550–1,025 band to be a market read. It won't play from a headphone jack, phone or ordinary amp, and it needs a Stax energizer or SRD box with a Normal (6-pin, about 230 V) socket, such as an SRM-1, an SRD-7, or the Normal socket on an SRM-1/MK-2 Pro, SRM-T1 or SRM-T1S. The SRM-1/MK-2 PP and current Stax energizers have none. Sellers often just write Stax Lambda, so count the plug's pins in the photos (6 for Normal, 5 for Pro) and ask for a photo of the nameplate on top of the cup, which is blank on a Normal Lambda. Skip the two SRM-T1S systems from Japan that share one photo, and remember a Japanese energizer runs on 100 V and needs a step-down transformer on US mains.
$475.00est. delivered
The lowest delivered pair here at $475, and the only one titled with a 6-pin plug and Normal bias. It's the earspeaker alone and needs a Normal-socket Stax energizer or SRD box, and it isn't titled tested, so ask for a note that both sides play evenly once warmed up.
Stax SR-Lambda 6 pin Normal bias headphones
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$475.00est. delivered
$445.00 + $30.00 shipping
Buy It Now$445.00
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 6 pin Normal bias. Earspeaker alone, ships from Iceland.
Seller: mjolnir-audio
98.6% positive
Used$555.00est. delivered
$525.00 + $30.00 shipping
Buy It Now$525.00
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.
Our take
Titled Normal bias, same Iceland seller. Count the plug pins in the photos.
Seller: mjolnir-audio
98.6% positive
Used$685.00est. delivered
$645.00 + $40.00 shipping
Buy It Now$645.00
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.
Our take
Bias not titled, from Japan. Count the plug pins and ask for the nameplate.
Seller: vamvam-audio-japan
100% positive
Used$1,009.99delivered
$1,009.99 · free shipping
Buy It Now$1,009.99
Check the seller
SRM-T1S system titled working and tested, from Japan. Same photo as another seller's listing, and the 100 V energizer needs a step-down transformer in the US.
Seller: yumekoichi
99.3% positive
Used$1,094.33est. delivered
$936.83 + $157.50 shipping
Buy It Now$936.83
Check the seller
SRM-T1S system titled working and tested, from Japan with $158 shipping. Same photo as another seller's listing, and the 100 V energizer needs a step-down transformer in the US.
Seller: b-lead_japan
99.7% positive
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