Stax SR-Λ Signature
←Older revision | Newer revision→
SR-Λ Signature (SR-Lambda Signature) - Overview
SR-Λ Signature replaced SR-Λ Pro as the TOTL Lambda model in 1987. Both models were produced together with SR-Lambda Pro becoming the second best in the line of Lambda frame based headphones (SR-Λ, SR-Λ Pro and SR-Λ Signature).
SR-Λ Signature shares its drivers with SR-Σ PRO. Those drivers have the distinction of using the thinnest, lightest diaphragm Stax ever used in a production electrostatic. It is not clear if SR-Σ PRO was positioned by Stax as the top Stax model at the time, but according to the brochures SR-Σ PRO was more expensive and should be considered the TOTL Stax headphone.
SR-Λ Signature has an extra-thin 1 micron diaphragm and an electrode gap of 0.5 mm. The company used the research that went into SR-Λ Pro to create the Signature model by supplying a new low-capacitance cable, removing all mechanical damping, and using a diaphragm only half as thick as the SR-Λ Pro's. However, the resulting extension of the treble response produced the famous "Stax etch" a treble peak that could be fatiguing with wide-range program material; regardless, SR-Λ Signature is considered one of the best Lambdas because of the speed and incredible level of details it is able to present if given the opportunity.
General Description of the Sound
Though its ability to retrieve detail and present it with authority is beyond question, there's no doubt that the Lambda Signature is a bright headphone, as its frequency-response graph plainly shows. Owners discreetly turn the treble down about 3 dB and prepare to enjoy the sound of the most massless of all Stax diaphragms.
Low diaphragm mass in an electrostat enhances bass damping (without which there is no such thing as bass "slam"), because ideally an electrostatic diaphragm is damped by the air load on either face. Until the Signature, all Stax headphones used acoustic resistances, mineral-wool pads fixed just behind the diaphragm, to both absorb some midrange backwave and supply mechanical damping for the bass frequencies. The tradeoff was a loss of the sensation of complete openness that the Lambda frame's design promised.
The air load is the only damping provided in the Signature. It was the first Stax headphone to use no mechanical damping whatsoever, and all future Lambdas up to the present are built this way. Having said that, the Signature's bass is good but not as well defined as later Lambda models with heavier diaphragms. This is not due to the low mass per se but most probably to the unavoidable stretchiness of the ultrathin PET films available at the time. After the Signature and Sigma Pro, Stax went back to 1.5 and 2.0 micron diaphragms until 1999's SR-303 and 404, which brought the thickness back down to a reasonable 1.35 micron.
The thinness of the Signature's diaphragm and the low capacitance of its special cable also ruthlessly revealed all the defects in the Lambda stator design-- Stax would be sure to correct this in the next generation, the Nova series.
Pricing & Other Data of Interest
SR-Λ Signature price on today's used market ranges from $400 to $550 depending on condition.
Name: SR-Lambda Signature
Transducer shape: Elliptical/Oval
Electrode type: Perforated metal plate
Diaphragm thickness (micron): 1
Electrostatic Capacity: 122 pF
Impedance: 129 kOhm
Electrode gap: 0.5 mm (580 V)
Bias Voltage: 580 V
Frequency Response: 7-41,000 Hz
Signal cord: 5-pin PC-OCC
Weight: 450 g (with cord)
There are 12 Stax headphones based on the Lambda frame:
- SR-Λ PRO
- SR-Λ Signature
- SR-Λ Nova Signature
- SR-Λ Nova Classic
- SR-Λ Nova Basic
- SR-Λ Spirit
- Airbow SC-1 - modified SR-404
Back to Stax Earspeakers Overview