Threshold 800A and 800S

[R-K Rønningstad]

I thought I would share a picture of the Threshold 800A with you. The picture is from a 1983 (cirka) Threshold Corporation brochure.
The text accompanying the picture was: "This is the original, fully operational evaluation model of the Threshld 800A as it was assembled in 1975 for analysis of its operation and appearance. Representing the first, ever, dynamically biased class A amplifier, the release of production 800A models in 1976 immediately gained the attention of the industry. The trendsetting impact of the 800A can be judged by the many "class A" amplifiers that followed it and the heightened awareness that it brought to audio enthusiasts concerning an amplifier's operating state."

Rolv-Karsten

[R-K Rønningstad]

And from the same page in the same 1983 Threshold broschure the Threshold 800S:
"This is the Threshold 800S. Originally manufactured in 1976 as an 800A, this amplifier was updated by Threshold in 1981 and now incorporates STASIS technology. Whenever the elements of a more sophisticated Threshold design can be practically applied, in whole or in part, to previously manufactured Threshold products these modifications are made available to owners of the earlier Threshold equipment at modest cost and minimum downtime. Modifications are available for all Threshold models manufactured prior to the current series. This is just one of the ways Threshold strives to assure that the purchase of a Threshold component is truly a lasting investment."

I posted these pictures with text for "historical reasons". I assume many of you like to see these pictures. I have larger, more detailed files as well....

RK

[steenoe]

Fantastic pictures, great amps. Thanks for sharing R-V. Great that you kept those papers for so many years

Steen

[Nelson Pass]

There was never an 800S during my tenure, which is up to '92.
The black faceplate was the standard 800A, and in addition to
the single silver prototype, there were 10 gold faceplates in
1975. All were the same circuit.

[R-K Rønningstad]

Nelson, seems some old 800A might have been updated with a Stasis circuit board for some customer, and pictured in the 1983 brochure? From the picture I cannot see the text "800S" anywhere on the faceplate. And I had never heard about an 800S either, untill I digged out that old brochure yesterday and saw the pictures from eons ago. I cannot explain this any better, but of course, give me some time, and I shall scan the complete 1983 brochure and send over via email to you.

Regds
Rolv-Karsten

[Mark A. Gulbrandsen]

The speaker company I workled for back in Chicago in the mid 70's had an 800A. It was THE single most impressive power amp I had ever listened to for many years after that time. I wish I could find a nice clean one to buy and restore.

Thanks for posting those pictures... brings back lots of memories.

Mark

[R-K Rønningstad]

For a limited amount of time the 1983 Threshold brochure will be downloadable from
http://home.no.net/rolvronn/Threshol...983_narrow.pdf
Sorry for the quality, but my flatbed scanner is not quite wide enough for the document.

RK

[Nelson Pass]

Since I have a full collection of Threshold literature and such
scanned, I can post them on at www.passlabs.com/np if
you are interested. Any particular requests?

[Netlist]

Originally posted by Nelson Pass
Any particular requests?

A talent for equal thoughtfulness.

/Hugo

[R-K Rønningstad]

Yes, please. Seems I have scanned most of my papers now. What I have not done is to scan the old folders discussing Class-A and cascode respectively. It's not that fun to sit and scan even if I can listen to music simultaneously