Stax · Electrostatic · From 1982
Stax built the SR-Lambda Pro, officially the SR-Λ Professional, at the request of Daimler-Benz. Its acoustics lab played back dummy-head recordings of engine, transmission and suspension noise on Lambdas, and it wanted response below 8 Hz and above 50 kHz with 7 dB more dynamic range. Stax thinned the diaphragm, widened the gap between the stators and launched it in 1982 with the SRM-1/MK-2 Pro, its first Pro-bias system. Pro bias means about 580 volts and a 5-pin plug, and owners say every Lambda since has used it. Stax later sold a diffuse-field equalizer made just for this model. It's the classic Lambda that plugs straight into a modern Pro energizer.
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.
After many years one channel can go quiet or fail, and the foam in the pads crumbles. Stax Japan has ended repairs for this model and takes no repairs from outside Japan, so parts and fixes come from third parties.
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 Pro that comes with its SRM-1/MK-2 Pro energizer at $897 delivered from a US seller, a complete system for about $230 more than the cheapest earspeaker alone. There are at least 11 for sale and most ask $750–1,125 delivered, with earspeakers alone from $669 and a Japanese SRM-T1 system at the top. Like every Stax it won't play from a headphone jack, phone or ordinary amp, and it needs a Pro-bias Stax energizer (about 580 V) such as the SRM-1/MK-2 Pro, SRM-T1, SRM-T1S or SRD-X Pro, so count the plug's pins in the photos (5 for Pro, 6 for a Normal-bias Lambda). Stax no longer repairs it or supplies pads, so ask the seller to confirm both sides play evenly with no crackle, and check the pad foam in the photos. A Japanese energizer runs on 100 V and needs a step-down transformer on US mains, and the two Japan listings sharing one photo are worth skipping.
$669.08est. delivered
The lowest delivered pair here at $669, from a US seller, with its box and a Stax stand, and the photo shows an SR-Λ Professional manual. It's the earspeaker alone and the title only says SR-Lambda, so count five pins on the plug and plan on a Pro-bias Stax energizer.
Vintage Stax SR-Lambda ORIGINAL Electrostatic Headphones Box w/ Stax Stand
$897.43est. delivered
A complete system at $897 delivered from a US seller, with the SRM-1/MK-2 Pro energizer Stax launched this model with in 1982 (the photo shows its Professional label). It's titled Ex, not tested, so ask for a note that both sides play evenly.
Stax Lambda Pro Electrostatic Headphones Earspeakers with SRM-1/MK2 Interface Ex
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$669.08est. delivered
$650.00 + $19.08 shipping
Buy It Now$650.00
Good buy
Box, Stax stand and an SR-Λ Professional manual in the photo. The title doesn't say Pro, so count the plug pins.
Seller: nervis7
99% positive
Used$897.43est. delivered
$859.99 + $37.44 shipping
Buy It Now$859.99
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
With an SRM-1/MK-2 energizer, labeled Professional in the photo. Titled Ex, not tested.
Seller: hifistasha222
100% positive
Used$780.00est. delivered
$750.00 + $30.00 shipping
Buy It Now$750.00
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
Earspeaker alone, from a US seller. No condition claim.
Seller: musiquevive
100% positive
Used$932.27est. delivered
$907.22 + $25.05 shipping
Buy It Now$907.22
Our take
Earspeaker alone, shown on a Stax wooden stand; ask if the stand is included. Ships from Australia.
Seller: jabba8
100% positive
Used$1,159.24est. delivered
$1,050.00 + $109.24 shipping
Buy It Now$1,050.00
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
With an SRM-1 MK-2 Pro energizer, from a US seller. No condition claim.
Seller: vbak3594
100% positive
Used$699.99delivered
$699.99 · free shipping
Buy It Now$699.99
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 fully working, from Japan. Same photo as another seller's listing here.
Seller: marubows_japan
100% positive
Used$748.82delivered
$748.82 · free shipping
Buy It Now$748.82
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 1982, with the terminals cleaned with DeoxIT. Seller at 95.5%, and the photo matches another seller's listing.
Seller: sa218132
95.5% positive
Used$1,775.00est. delivered
$1,495.00 + $280.00 shipping
Buy It Now$1,495.00
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.
Priced high
SRM-T1 system from Japan with $280 shipping, about 1.9 times the median. The 100 V energizer needs a step-down transformer in the US.
Seller: at_shop_12
98.8% positive
Prices change daily. The live eBay search shows everything listed now, including anything new since Oct 14, 2026.
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