percy said:
300B, 2A3, 6B4G, 211, 845 some 3CX/4CX radio tubes and lots of other tetrodes/pentodes that work well triode strapped. The 6C45 would probably count too, in some systems.
Add also all Chinese 805, 833C, 811-A, 572-B. The 811A and 572-B are available from Svetlana also. There is another triode, may be the 572 that comes in three flavors with low med and hi Mu signified by a dash and 10, 20 or 30 following the tube number. This may be the Svetlana 572, example 572-10. Memory is full. 🙁
And those strange triodes by Alesa Vaic, KR and Emission labs.
Has anyone tried any of these tubes?
Especially, those with the mesh plate. KR says that mesh plate is a myth.
I haven’t heard any amp with any of these tubes so….
🙁
Has anyone tried any of these tubes?
Especially, those with the mesh plate. KR says that mesh plate is a myth.
I haven’t heard any amp with any of these tubes so….
🙁
805, 833C, 811-A, 300B, 2A3, 6B4G, 211, 845 and some 3CX/4CX.
So only these tubes are in production ? Not even their equivalents or substitutes ? I was expecting to see 6AS7.
Anyway, looks like the only ones in sane operating voltage levels(IMO) are the 300B, 2A3 and 6beforeG. Others are in the 1KV+ region!
Now it explains why 300B followed by 2A3 are the most sought after power triodes.
So basically for someone wanting to play in the sub 1KV area, in the tube world as it stands today, you have the choice of only three power triodes ??!!
.
So only these tubes are in production ? Not even their equivalents or substitutes ? I was expecting to see 6AS7.
Anyway, looks like the only ones in sane operating voltage levels(IMO) are the 300B, 2A3 and 6beforeG. Others are in the 1KV+ region!
Now it explains why 300B followed by 2A3 are the most sought after power triodes.So basically for someone wanting to play in the sub 1KV area, in the tube world as it stands today, you have the choice of only three power triodes ??!!
.
There are also 845, 211, 205D and 45 in production in China. I am not sure whether the 572-XX is discontinued or not , but last time I checked they were readily available from New Sensor.
There are also NOS types like the 6CK4 which is cheap and will produce about 2Wrms into 4K. The EL34 will provide very good performance triode connected as well. 😀
Personally I prefer either the 45 or 300B..🙂
There are also NOS types like the 6CK4 which is cheap and will produce about 2Wrms into 4K. The EL34 will provide very good performance triode connected as well. 😀
Personally I prefer either the 45 or 300B..🙂
300B's and 2A3's keep me nicely out of mischief..........or should that be keep me in mischief..............
percy said:
For some reason we didn't think of the lowly little 6AS7. Yes these are in current manufacture in Russia and are a good sounding option in the right circuit. Don't forget that the 6S4 is also considered a 'power' triode, at least by writers of the RCA technical manuals, but these are not in current production anywhere AFAIK.
Interesting. Given that its a twin triode, in current production, and has a plate disp of 13W at a modest 250V, I am curious to know why is 2A3(or 6B4 FTMOF) more popular and expensive then the 6AS7 ?
Hi,
Actually it's a DUAL triode not a TWIN triode.
This certainly has implications when you need matched triode halves.
Another aspect one should not lose sight of is the low mu of the 6AS7G.
Given the fact that there are literally hundreds of thousands of these tubes sitting on shelves, I doubt they're actually currently still produced.
There really isn't that much demand for it and the asking price reflects this clearly.
Still one my fav IDHT, excellent sound quality.
The 2A3 is a DHT, fashionable now and, as many will concur, one of the best of it's kind: it's hard to build a bad sounding 2A3 amp.
To my ears and wallet to be prefered over the much more pricey 300B.
If you have high effeciency speakers, say 92dB+, the 2A3 is all you'll ever need powerwise.
Given that production runs start at a minimum of 10K pieces/type I very much doubt Ulyanov has sufficient demand to justify yearly runs but AFAIK they can still respond to demand should such occur.
Same family : 6C41-C, 6C19-P.
Cheers, 😉
Actually it's a DUAL triode not a TWIN triode.
This certainly has implications when you need matched triode halves.
Another aspect one should not lose sight of is the low mu of the 6AS7G.
Given the fact that there are literally hundreds of thousands of these tubes sitting on shelves, I doubt they're actually currently still produced.
There really isn't that much demand for it and the asking price reflects this clearly.
Still one my fav IDHT, excellent sound quality.
The 2A3 is a DHT, fashionable now and, as many will concur, one of the best of it's kind: it's hard to build a bad sounding 2A3 amp.
To my ears and wallet to be prefered over the much more pricey 300B.
If you have high effeciency speakers, say 92dB+, the 2A3 is all you'll ever need powerwise.
Given that production runs start at a minimum of 10K pieces/type I very much doubt Ulyanov has sufficient demand to justify yearly runs but AFAIK they can still respond to demand should such occur.
Same family : 6C41-C, 6C19-P.
Cheers, 😉
^^ Also the 6AS7 is hard to drive, you need to drive it with a pretty grunty circuit (no 12AX7s here!) You need a cathode follower or power tube to drive it...
Hi,
Not really: it has a very low mu (2) so Miller effect is almost non-existant.
If you choose the OPs wisely a single half of a 6DJ8 is all it takes to drive half a 6AS7G nicely with enough gain left to be useful.
Cheers, 😉
Not really: it has a very low mu (2) so Miller effect is almost non-existant.
If you choose the OPs wisely a single half of a 6DJ8 is all it takes to drive half a 6AS7G nicely with enough gain left to be useful.
Cheers, 😉
fdegrove said:
Well maybe for half a bottle but my 6080 P SET design parallells eight triodes (four bottles) in a slick common plate choke ultrapath-parafeed configuration. Miller was a real obstacle at the higher end of the audio band. I haven't finalized the driver yet but am planning to try a 6AG7 for this task. If I wanted a small tube a 6CL6 could be used here instead. I have stock of both. My artistic design for this retro looking piece wants the older octal look. I wish the 6AG7 were glass and not metal though. 🙁
6AS7 as audio tube
The 6AS7 is a good sounding tube, but section to section match is problematic in most samples which requires special precautions in PSE applications to assure current sharing. In pushpull applications the same situation appears in the form of an additional balancing circuit. The mu of this triode is about as low as it gets. (Around 2) Voltage drive requirements are significant, as much as 250Vpp-300Vpp so this seems like this might be a good place to try transformer coupling. (Step up) Fixed bias is sometimes used but is not really recommended. There are a number of examples of both pushpull and PSE amplifiers using this tube. Note that the 2A3 has a mu of around 4 which makes it a lot easier to drive in the voltage domain. IMHO I am not sure why the 6AS7 does not garner more respect, but I suspect it is due to the fact that it is indirectly heated and hence does not have the cachet of the 2A3. 🙄
Personally I prefer the 45, the additional 3dB of power is not that significant, and I think the single plate construction does sound better.
😀
The 6AS7 is a good sounding tube, but section to section match is problematic in most samples which requires special precautions in PSE applications to assure current sharing.
In pushpull applications the same situation appears in the form of an additional balancing circuit. The mu of this triode is about as low as it gets. (Around 2) Voltage drive requirements are significant, as much as 250Vpp-300Vpp so this seems like this might be a good place to try transformer coupling. (Step up) Fixed bias is sometimes used but is not really recommended. There are a number of examples of both pushpull and PSE amplifiers using this tube. Note that the 2A3 has a mu of around 4 which makes it a lot easier to drive in the voltage domain. IMHO I am not sure why the 6AS7 does not garner more respect, but I suspect it is due to the fact that it is indirectly heated and hence does not have the cachet of the 2A3. 🙄 Personally I prefer the 45, the additional 3dB of power is not that significant, and I think the single plate construction does sound better.
😀
Hi,
Isn't that what I said?
Naturally you'll need to adapt the driver for the task at hand which still isn't such a big deal all else considered:
Choke loaded so mu is optimized, let's assume mu max. = 2
C_in = [Cgk + Cgp*(A+1)]*8
C_in = [(5.5 + 8.6)*3]*8
C_in = 46*8 = 368pF + 32pF = ~ 400pF C_tot.
Now take a similar powertriode, look up the figures and put those in the formula.
You'll soon notice that 6AS7G isn't as awkward to drive as it first looked, you could do a lot worse.
Chances are it does have a glass bulb underneath its metal battle dress so maybe it could be stripped nekkid....
Haven't checked this though.
Cheers,😉
Isn't that what I said?
Naturally you'll need to adapt the driver for the task at hand which still isn't such a big deal all else considered:
Choke loaded so mu is optimized, let's assume mu max. = 2
C_in = [Cgk + Cgp*(A+1)]*8
C_in = [(5.5 + 8.6)*3]*8
C_in = 46*8 = 368pF + 32pF = ~ 400pF C_tot.
Now take a similar powertriode, look up the figures and put those in the formula.
You'll soon notice that 6AS7G isn't as awkward to drive as it first looked, you could do a lot worse.
Chances are it does have a glass bulb underneath its metal battle dress so maybe it could be stripped nekkid....
Haven't checked this though.
Cheers,😉
SHiFTY said:
Funny you should mention that. I made just last night, a 12AX7 mu-follower that drives them just fine 🙂
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