joe3rp wrote:All the st35 I've heard were STOCK ...even the Jack Elliano (Electra-print transformer) owned in vegas was stock. I liked it very much. I guess it was like the old Bedini 2020 class a amp...it was really good...then when they made a bigger/higher powered version it sounded different. Event the original 20 watts class A Krells/ML or even NAD 3020(?) when they went higher power there was something lost? again IMHO lang po
Basically you are saying it is the
quality of watts not
quantity! The EL84 tube is probably the most linear of all pentodes, easy to drive therefore simpler input/driver circuit and the required transformer is small and easier to design for wide bandwidth. However we are limited to 10-15W in PP depending on operating points. For greater power, one needs a bigger pentode or tetrode/transformer and more complex circuitry. Thus quality can or may suffer. Back in college I used an NAD 3020 and I agree, it was the best amp that company ever produced. I'm not adept with solid state circuitry but surmise that in order to get more power the circuit also becomes more complex.
Prior to getting into DIY/SET/Hi-Eff, I built up a collection of PP EL84 amps - Acro 20/20, Dyna ST35, Leak 20 and Pilot SA232. They all sounded glorious driving LS35As or Quad ESL57s. I briefly owned a Citation II but it didn't sound as dynamic or musical as these tiny critters. Eventually I unloaded all of them to finance acquisition of Altec drivers/horns, DHTs and Tango/Tamura transformers. This time
the first watt counts! je