Hi,
I have see some Russian bulders use two half wave rectifiers tubes as 6D20P/6Д20П, instead one full wave rectifier as 5C4M, 5C8S or 3C8S.
There is any benefit in using two half wave tubes?
I have see some Russian bulders use two half wave rectifiers tubes as 6D20P/6Д20П, instead one full wave rectifier as 5C4M, 5C8S or 3C8S.
There is any benefit in using two half wave tubes?
The only advantage is if the rectifiers are gassy or pushed beyond their limits. In this case separate ones may be less liable to maintaining an arc.
If they are cheap to buy, that is the benefit.
Two sets of heaters to power is a drawback though.
Two sets of heaters to power is a drawback though.
They're no good! Don't use them! 😀
My personal favourite is the 6au4. I have a huge box of super ugly coin-base sylvanias that I got increadibly CHEAP a few years ago. They are phenominally reliable and have such a lovely slow start-up. My 2a3 heaters have time to get nice and warm while the B+ gradually rises.
Those russians look excellent contenders - top plate, 9pin base, unique look too. Zero chance of me reading the specs sheet though.
My personal favourite is the 6au4. I have a huge box of super ugly coin-base sylvanias that I got increadibly CHEAP a few years ago. They are phenominally reliable and have such a lovely slow start-up. My 2a3 heaters have time to get nice and warm while the B+ gradually rises.
Those russians look excellent contenders - top plate, 9pin base, unique look too. Zero chance of me reading the specs sheet though.
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i have the japanese versions of the 9 pin top plate dampers, nice to look at...
for octal dampers i have the 6G-k17's....
but my favorite of them all....the 6DE3/6CE3's, got them for a dollar each at Rogalskie's...many years ago...
for octal dampers i have the 6G-k17's....
but my favorite of them all....the 6DE3/6CE3's, got them for a dollar each at Rogalskie's...many years ago...
Hi Tony
The 6CG3 is indeed a little beast! A pair of them can handle up to 700mA (350mA each).
However its not so clear to me about the 6D20P/6Д20П.... it looks like a pair could handle only 180mA (90mA each). Or maybe I am mis-reading the sheet.
ian
The 6CG3 is indeed a little beast! A pair of them can handle up to 700mA (350mA each).
However its not so clear to me about the 6D20P/6Д20П.... it looks like a pair could handle only 180mA (90mA each). Or maybe I am mis-reading the sheet.
ian
Ian,
i made a table for easy and quick comparison...
i have around 200 pcs of these tubes in my stash...
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Hi Tony
I also have many of those. I pulled a bit more than 400mA through a pair of coin base 6AU4's without problem (choke input) for many years and they still test NEW. The GE specs sheet lists the continuous DC output currrent at 190mA. I think this is a low-ball estimate.
6AX4's are also very good, but they have a higher internal resistance than the 6AU4. These can be useful to drop the B+ a bit vs. 6AU4, or if your heater winding is not up to 6AU4. I actually find that some 6AX4's (especially some RCA) can't handle quite as much current as 6AU4's. The best performing of all these damper diodes tend to be coin base ones în my experience, and I have wondered if that helps in heat dissipation.
6DE4's and 6DW4's are somewhere inbetween 6AX4's and 6AU4's in terms of internal resistance. Much of the ones I have are labled with both designations. They can indeed handle 250mA but I did not test them for long periods of time.
Ian
I also have many of those. I pulled a bit more than 400mA through a pair of coin base 6AU4's without problem (choke input) for many years and they still test NEW. The GE specs sheet lists the continuous DC output currrent at 190mA. I think this is a low-ball estimate.
6AX4's are also very good, but they have a higher internal resistance than the 6AU4. These can be useful to drop the B+ a bit vs. 6AU4, or if your heater winding is not up to 6AU4. I actually find that some 6AX4's (especially some RCA) can't handle quite as much current as 6AU4's. The best performing of all these damper diodes tend to be coin base ones în my experience, and I have wondered if that helps in heat dissipation.
6DE4's and 6DW4's are somewhere inbetween 6AX4's and 6AU4's in terms of internal resistance. Much of the ones I have are labled with both designations. They can indeed handle 250mA but I did not test them for long periods of time.
Ian
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Hi Ian, i am making a Tabor clone this year,
contemplating using the japanese 6gk17 and the 6ax5's....
looking at the plate sizes, then maybe underrated....
i am reserving the bigger guys for heavy lifting...
6gk17, 19au4, 6da4.6dm4, 12BR3, http://tubedata.milbert.com/sheets/201/6/6BR3.pdf
contemplating using the japanese 6gk17 and the 6ax5's....
looking at the plate sizes, then maybe underrated....
i am reserving the bigger guys for heavy lifting...
6gk17, 19au4, 6da4.6dm4, 12BR3, http://tubedata.milbert.com/sheets/201/6/6BR3.pdf
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