seek a threashold power amplifier

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

I've been told that the two different amps are based upon the same chasis etc.. Threshold was very conservative about their use of transistors, with only about 20% of total capability actually used. As was mentioned above, each unit had two very large trannies. Nelson Pass has written a paper which would agree with the "sweet spot" concern. Either asking Nelson Pass on his section of the DIYaudio.com site or speaking with ex Threshold tech Jon Soderberg at vintageamprepair.net would probably give the most difintive answers.

You could call Threshold Audio and see if they can help you. please see

http://www.threshold-audio.com/

Have the manual right here. Same # of per channel output transistors 64, same uF size power supply = huge .25 Fahrad (key is cap voltage rating), bias current almost identical 1.1-1.2 amps with the lower the 12e, same peak current output 200 amps (35 for the 1600e versus 70 for the 12e class A). This suggests to me that you can tap the transformer to change the voltage & I believe NP told me once it was possible for my S/550e. Ask him at diyaudio or ask Jon. If I saw one I'd buy a 12e but I think they're very rare and I've never seen a S1600e here.

Component wise, the SA12e and the S1600e are identical.