The Clearest Line Stage of All

[korneluk]

I assume it's the topology rather than the valves themselves that make it so clear?

On the contrary - please read the article:
"In my previous tests of small-signal tubes, some experiments with UX-201A and 01A radio triodes showed me something interesting. The original UX-201A had a thoriated tungsten filament, while the later 01A had an oxide-coated filament. Otherwise, these tubes are supposed to be exact plug-in replacements for each other. And although my distortion tests showed comparable levels of THD for both types, and both types had similar "tubey" distortion, the older version seemed to have much clearer treble and greater detail than the 01A. Subsequent listening comparisons of the SV811 and SV572 triodes versus oxide-filament triodes (such as the 300B) seemed to support the impression that a thoriated filament is more detailed in apparent sound than an oxided filament".

THE CLEAREST LINE STAGE OF ALL

 

[tubesguy]

In both of the articles I have read the tube Barbour used was an SV572-10, a large 150 watt DHT. It hasn't been made for quite some time, so might be hard to get today.

Not to mention all of the custom EP iron.

Great fun looking through an old issue of Doc's magazine, though.

 

[Lingwendil]

6N16B is a lovely, very linear tube. I'm not a fan of SRPP but I bet it will do very nice in this design with a direct coupled cathode follower.

 

[indra1]

In both of the articles I have read the tube Barbour used was an SV572-10, a large 150 watt DHT. It hasn't been made for quite some time, so might be hard to get today.

I think Viva Tubes still got plenty of them tubes. 🙂

 

[craigtone]

Hmmm ... Maybe a pair of Salas HV regs and a pair of Coleman regs to resurrect this beast! Does Lundahl offer a 10K 1:1 interstage capable of 20mA? Sowter has a 1491 at 15mA but hate to run it at 100% rating!