Nice Stereophile article on Nelson and First Watt

[Nelson Pass]

After I left in 91, the company apparently did not do well under
Gary Hudson (with the technical assistance of Michael Bladelius).
After losing enough money, Dynatech decided to sell it, and it
is my understanding that Harmon came around and kicked the
tires. Interestingly, they were not interested in an offer from
me, and sold it to Ed Woodard for about half as much.....

 

[gl]

I just read the 5 P reference as well. The F1 owners manual clearly shows N channel parts for the gain transistors. The CCS's can be either way but it would seem likely from a prts counts point of view that the upper CCS's would be P and the lower one N. The article does claim the MOSFET's are of more than one type.

Graeme

 

[GRollins]

Hmmm...perhaps I should offer to buy the company. Wonder what would happen if I offered them the contents of my wallet?

Grey

 

[Nelson Pass]

I just read the 5 P reference as well. The F1 owners manual clearly shows N channel parts for the gain transistors. The CCS's can be either way but it would seem likely from a prts counts point of view that the upper CCS's would be P and the lower one N. The article does claim the MOSFET's are of more than one type.

The positive current sources are P channel types. N channel
types work as well, but require a more complex bias circuit.

 

[lumanauw]

Anyone can figure out how a configuration like F1 (a differential) can make F2 with 2nd harmonic domination? A differential in itself will cancel 2nd so makes 3rd dominant.