|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
24.22.235.48
In Reply to: RE: BB Proof 2A3 DC posted by Garg0yle on December 05, 2014 at 20:22:08
Here is the first draft circuit.
Follow Ups:
The schematic is for the cat. I believe it is the basis for at least 2 commercially available DC 2A3 amps I guess you could pot in place of R-2. With a few minor modifications this circuit could be made to play either a 45 or a 2A3.The schematic comes from Robin & Lipman 1947 Practical Amplifier Diagrams. See the URL.
Observe, before you think. Think before you open your yap. Act on the basis of experience.
Edits: 12/10/14
The same schematic (omitting R3 and R6) is also used in a Glass Audio article "Hybrid Tube Radio by David Wang" mentioned for example in Ejam's post.
http://www.audioasylum.com/cgi/vt.mpl?f=tubediy&m=25401
I just wonder, what are the 2A3 and 6SF5 voltages in that "Hybrid Tube Radio"?
For the 2A3, plate voltage is around 275V and 40mA, or a bit lower. I don't know about the driver.
Observe, before you think. Think before you open your yap. Act on the basis of experience.
It is probably worth reading Jeremy's take at the link below.
dave
Thanks Dave - that takes me back! Very similar design.
It's nice to see the 125ese getting used in a design by an acknowledged first rate designer. I think it is really one of the best bargains out there for SE opts at this time.
Nice work Paul, I may have to bread board it myself. Thanks for offering it here on the forum!
Paul
I tried this design with zeners and VR gas tubes to bias the upper tube (replacing the 3k/20W resistor and no bypass caps clearly) ... any experience with this variant?
g
The problem with that is, the direct coupled design is excessively sensitive to power-line voltage variations. Not an unsurmountable problem of course! but I'm trying to keep this one simple.
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: