seek a threashold power amplifier


in the 80s,threshold sold a mono block power amps.one class a and one class a/b.i seek the class a/b to buy.maybe not available because none sold.do not remember tag or model name.it was listed as 1 horsepower at 8 ohms.look up watts horsepower conversion table.the class a and class a/b were indentical cabinets.huge.the current mcintosh labs power amps mc2kw are 2000 watts at 2 4 8 ohms.about 3 horsepower and cost a fortune.threshold less by a mile if burn time a year or two classical music.HELP?anyone out there knows anything about this power amplifier.i am trying to buy the pair.
goingnuts
I think you are looking for a Threshold SA-12E

They pop up here sometimes and on Ebay too

Good luck

Peter
Threshold didn't make a 1 horsepower Class AB amplifier in the 80s. They did make one in the late 80s/early 90s. It was called the S/1600e. It used the same chassis as the top of the line Class A SA/12e but was biased to operate in AB.

From my book...
Rated output: 1 horsepower @ 8ohms @ <0.15% distortion
Bandwidth: flat @ DC to -3dB @ 100KHz
Slews rate: 100 volts/uS
Output current capability: 35 continuous/200 peak amperes
Power: Two 1.2KWatt transformers & 216,000uF capacitance
Input Impedance: 50K ohms RCA/600 ohms XLR
Output Impedance: 0.1 ohm
Gain: +32.6dB
Weight: 130 lbs each

Personally, I prefer the higher biased class A designs at lower wattages. YMMV.
You might have more luck finding a pair of SA 12e's and sending them to some one like Jon Soderberg of vintage amp repair to have them re-biased to the S 1600e's specs. The SA 12e's pop up from time to time, but the S 1600e's not so much.
Unsound - I don't know for sure about the Thresholds - but it may not be that easy as the higher wattage requires a higher rail voltage which would require a different transformer not to mention that the components (Capacitors/Transistors) in the circuit may not be rated for the higher voltage required. Just adjusting the bias current does not "make' more watts.

Its all a matter of how much heat one is willing to accept or how much heat the sinks can dissipate. Rail voltage x bias current = heat (W) so if you turn down the bias current you can "turn" up the voltage (not that easy, requires changing the transformer) and your amp would have more watts, but less of them in class A because of the reduced bias current,

I have found that most output devices have a "sweet spot" as far as voltage/bias current where they sound the best - running them at a higher voltage to my ears makes the sound "harsher"

Thanks

Peter