Not exactly what you asked for but close. 805 is similar, a step down in power. But gets driven by 300b. (input tube (13d3) b+ is 200v not 388v. typo) and pre driver is now 12bh7. The way this is set up i get 10mv peak to peak of noise/hum at the spearker terminals, very good low noise for a SET.
Cheers George
Cheers George
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300B - 833
Hello Wasibi,
as "Garbage" correctly noted: these triodes do get warm. Last winter when i listened....the central heating was not switched on. The amplifiers did that job as well..... And i live in chilly-and-wet Netherlands.
Nevertheless these 833's do give a wonderfull sound. Never overpowering or dominant, but just everything perfectly in order. And the bass is that authorative; never heared that even with the real transistor beasts from Krell or Mark Levinson.
Your question regarding the 300B-833 connection. I use a 4:1 stepdown interstage to get a lowish impendance (833 wants that) and enough feeding power (the 833 needs that).
It's the same reason why Wavac uses a triode connected penthode: to get low impendance !
It works great and there are variations to this theme like using a 6C33C (already a low impendance) for a hgher quality interstage (lower ratio).
And how you use the 300b (what voltage) and how you drive that tube is completely up to you !
The essence is that 300B to 833 is possible using a stepdown interstage.
Lots of building pleasure.
Reinout
Hello Wasibi,
as "Garbage" correctly noted: these triodes do get warm. Last winter when i listened....the central heating was not switched on. The amplifiers did that job as well..... And i live in chilly-and-wet Netherlands.
Nevertheless these 833's do give a wonderfull sound. Never overpowering or dominant, but just everything perfectly in order. And the bass is that authorative; never heared that even with the real transistor beasts from Krell or Mark Levinson.
Your question regarding the 300B-833 connection. I use a 4:1 stepdown interstage to get a lowish impendance (833 wants that) and enough feeding power (the 833 needs that).
It's the same reason why Wavac uses a triode connected penthode: to get low impendance !
It works great and there are variations to this theme like using a 6C33C (already a low impendance) for a hgher quality interstage (lower ratio).
And how you use the 300b (what voltage) and how you drive that tube is completely up to you !
The essence is that 300B to 833 is possible using a stepdown interstage.
Lots of building pleasure.
Reinout
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