Threshold SA/3 Series II Optical Bias Pure Class A

A true classic! Threshold SA/3 Stasis Series II Optical Bias Power Amp. 50 watts per channel – Pure Class A. These amps do not come up for sale very often – for good reason.

Designed by Nelson Pass during Threshold’s heyday and considered to have very smooth sound, good thermal stability and more detail than Threshold’s earlier amps. Threshold referred to the sound of this SA series as “extraordinary musical accuracy”. The SA/3 is a favorite of Threshold lovers for its warm sound, and this amp is built like a tank.

Machined-aluminum faceplate and metal chassis. Gold-plated machined Teflon insulated input connectors, five-way binding posts with gold-plated contact surfaces, military grade glass epoxy circuit boards are all hand soldered, and assembly and final adjustment was completed under the supervision of Nelson Pass. It delivers 16 continuous amps and 80 peak amps per channel and will effortlessly drive most speakers. This particular amp drove Martin Logan electrostatic speakers, then Mirage M3’s with ease. I have paired with Magus tube pre-amp, Rotel CD player and Opus 21 DAC-CD player (with and without a pre-amp).

I am the second owner – bought it from a friend in 1990 (he bought a Threshold SA/4e). This amp has worked perfectly for me, I have never had it serviced (never needed to), and it sounds as good as the day I bought it. Has never been in a smoking environment and has seen little use for the past five years or so. I am finally getting over a sentimental attachment to it.

Condition is very good. I see no blemishes or marks on the faceplate or heat sinks. There is a faint mark on the right-side handle and a scratch and a few small nicks on the top plate – please see the photos. Original box, operating manual, promotional flyer and warranty card are included. Naturally, the warranty expired a long time ago and the box has seen better days (please see photo). I will ship UPS insured and double-boxed.

Buyer to pay actual shipping cost to your location (I will pay insurance add-on). Continental US only – no international shipment. Please add 3% for Paypal and thanks for looking.

For more about this amp, check out: http://www.vintageamprepair.net/archiveamps.html and http://www.thresholdlovers.com