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
Attachments
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
Attachments
Remember always work on theses big triodes with one hand tied firmly behind your back, so your not tempted to use both, this 833 WILL FULLY KILL YOU, where as the 805 WILL ONLY HALF KILL YOU.
Cheers George
Cheers George
- Status
- Not open for further replies.