Threshold SA-1

Threshold SA 1 famosa e rara coppia di finali in classe A pura.
160 watt RMS su 8 ohm, corrente di picco 150 ampere!
I più famosi gioielli di Nelson Pass.
Con i suoi imballi originali
Una coppia SEMPLICEMENTE straordinaria!

Rated at 160 watts per channel into 8 ohms in Class A, 320 watts into 4 ohms, 640 watts into 2 ohms, and capable of driving 1 ohm loads without issue.

Cosmetically, I'd say the condition is perfect.

As far as I can tell, there are no scratches on either amplifier, and they appear flawless, including the screws.
No blemishes, and the metalwork appears spotless.
The condition of these amplifiers would make a great display for a classic audio museum!
They are simply fantastic.
The amplifiers have always been stored in a temperature-controlled environment, away from smoke, children, pets, and wives. The SA/1 models are highly sought-after and are becoming very difficult to find on today's market.

The big difference is that the SA/1s are pure Class A and use a total of forty 20-amp Motorola output transistors in the output stage. Twenty in the positive channel and twenty in the negative channel.
The story behind these amplifiers is that I purchased them from the original owner in 1998 and use them very sparingly in one of my rooms.
Since I have a large collection of audio equipment at home and limited space to use it all, I've decided to abandon these wonderful SA/1s.
The all-black finish looks very elegant with the VU meter.
These monoblocks are 100% original, require no maintenance, and work perfectly.

Just so you know, the Threshold design is so good that they don't fail or break, and it's a proven, reliable design.
The heat sinks are still perfectly black, with no fading. No fading means low hours of use. If you're looking for the perfect pair of SA/1s that you'd want to keep for a lifetime, given the conditions and low hours of use, this is it!
Threshold amplifiers are designed to amplify music signals and analog modulation, and Nelson Pass, with his "Stasis" output stage, created the perfect analog amplifier, unmatched by any other amplifier to this day.
Specs mean nothing to the sound, but the Stasis output stage is so linear, down to almost zero short circuit on an inductive load!
Do you believe in balanced amplifiers? I was, back when everyone believed balanced amplification was the best. But this is just a matter of specifications, and it actually translates into a loss of live music sound quality, a sucked-out midrange, a loss of room presence. Yes, a lower noise floor, but by gaining this, you lose the natural sound.

Balanced amplification eliminates noise and distortion. But music is a type of distortion, a natural distortion of acoustic instruments.
Balanced amplification refines a signal, reducing distortion while simultaneously altering the music's natural distortion.
Single-ended signals don't alter distortion. What goes in is what comes out. RCA-based single-ended signals represent the purest method of amplifying analog signals.
Audio purists, myself included, believe that, of all amplifiers, the single-ended input and driver stage, which drives a pure Class A push-pull output stage, in a Stasis design, is the best solution for analog amplification in a power amplifier.
If you're unfamiliar with the Stasis design, you can read about it online and in the user manuals for these amplifiers.
Stasis is the way the output transistors and driver transistors are configured, to create an ultra-linear output stage, unmatched by other manufacturers' amplifiers.

Stasis is the way the output transistors and driver transistors are configured to create an ultra-linear output stage unmatched by other manufacturers' amplifiers.
The Stasis output stage is so musical, yet fast, dynamic, and powerful, that it doesn't require complex circuitry, stabilized power supplies, or
complex bias regulators.
Furthermore, the Stasis output stage is so stable that these SA/1s easily drive a 0.65 ohm load.