Hey Ron, Happy Anniversary!! 
The output transformers you have are not optimal for parallel 2A3's, first they are designed for 60mA of current and also the load impedance would be too high, unless you have 4 ohm speakers you plan to use which would reflect a lower load. But still you would only be able to bias each 2A3 @ 30mA.
I use turret boards and I really like them a lot. My latest amp I used tag boards but most of the time I use turret boards.
I would just go ahead and use the Hammond transformer, it should work great for your application. The only thing I would think of doing is getting a separate filament transformer to power some DC regulator boards for the 2A3 filaments, this will help the Hammond 302AX run cooler too. Maybe an option is to run the two 2.5v windings on the Hammond in series and full wave rectify it, I believe the DC current would be equal to the rated AC current rating, A bridge rectifier would stress the windings too much.
Edit: I think for Rod's board the minimum voltage is 6.9v for one 2A3 which is 2.5A. For two you would need 5A which requires 13.5v min.
https://www.dropbox.com/s/ujaoh4mrnpourtl/ANdht01v7.pdf?dl=0
The output transformers you have are not optimal for parallel 2A3's, first they are designed for 60mA of current and also the load impedance would be too high, unless you have 4 ohm speakers you plan to use which would reflect a lower load. But still you would only be able to bias each 2A3 @ 30mA.
I use turret boards and I really like them a lot. My latest amp I used tag boards but most of the time I use turret boards.
I would just go ahead and use the Hammond transformer, it should work great for your application. The only thing I would think of doing is getting a separate filament transformer to power some DC regulator boards for the 2A3 filaments, this will help the Hammond 302AX run cooler too. Maybe an option is to run the two 2.5v windings on the Hammond in series and full wave rectify it, I believe the DC current would be equal to the rated AC current rating, A bridge rectifier would stress the windings too much.
Edit: I think for Rod's board the minimum voltage is 6.9v for one 2A3 which is 2.5A. For two you would need 5A which requires 13.5v min.
https://www.dropbox.com/s/ujaoh4mrnpourtl/ANdht01v7.pdf?dl=0
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i haven't built a 300b, but 2A3's at this point, and i can say that the 2A3 is very quiet wrt to humming, unlike what i heard about the 300b, and extra efforts are needed to combat the hum...not so with 2a3...
lately the 12hl7 drives my 2a3 with gusto....
future plans is to challenge the JJ 2A3-40 outside of the 250 volt 60mA operating point to something like 400v 60mA....
lately the 12hl7 drives my 2a3 with gusto....
future plans is to challenge the JJ 2A3-40 outside of the 250 volt 60mA operating point to something like 400v 60mA....
Verbiage
Hi,
I have seen such things as "the OP" and "wrt", what do these things mean in english?
Thanks,
Rob
Hi,
I have seen such things as "the OP" and "wrt", what do these things mean in english?
Thanks,
Rob
Ron,
wrt, with respect to, or sometimes re:
OP here means original poster, with tubes OP is operating point....
wrt, with respect to, or sometimes re:
OP here means original poster, with tubes OP is operating point....
Old guy
Hi,
Thanks AJT, I don't Twitter, SpaceFace, Facebook, Myplace, Instagram or any of those things, my kids 27,and 24, think me and my wife are old fashion. Born in th early 60's, the best I can do with the letter representations of words is WTF.
Not meaning to offend but if you don't communicate that way, you can't know.
I saw ROFLMAO and for the life of me couldn't figure out what it meant. My kids were amused.
Sorry for the sidetrack.
Ron
Hi,
Thanks AJT, I don't Twitter, SpaceFace, Facebook, Myplace, Instagram or any of those things, my kids 27,and 24, think me and my wife are old fashion. Born in th early 60's, the best I can do with the letter representations of words is WTF.
Not meaning to offend but if you don't communicate that way, you can't know.
I saw ROFLMAO and for the life of me couldn't figure out what it meant. My kids were amused.
Sorry for the sidetrack.
Ron
i am 63 myself.....😀
in my case, whenever is see those, i highlight it and then do a google search, works for me all the time, in fact when any word i do not yet know the meaning of, i google it...
you can say, i am google educated...😉
in my case, whenever is see those, i highlight it and then do a google search, works for me all the time, in fact when any word i do not yet know the meaning of, i google it...
you can say, i am google educated...😉
Thoughts
Hi,
So FMB (famousmockingbird) , easier to type. I want to build the PSE posted. The 302ax is is not capable of supporting the build. What power transformer do you recommend to achieve what I would like to do? I could save the 302ax for another build.
Thanks,
Ron
Hi,
So FMB (famousmockingbird) , easier to type. I want to build the PSE posted. The 302ax is is not capable of supporting the build. What power transformer do you recommend to achieve what I would like to do? I could save the 302ax for another build.
Thanks,
Ron
Hey Ron, Happy Anniversary!!
The output transformers you have are not optimal for parallel 2A3's, first they are designed for 60mA of current and also the load impedance would be too high, unless you have 4 ohm speakers you plan to use which would reflect a lower load. But still you would only be able to bias each 2A3 @ 30mA.
this is iffy to me,
in the world of steady state sine waves i would agree....but we listen to music...and of course, desiderata for OPT is lowest dc resistance you can build into it..
using the 8ohms tap to feed the 4 ohm speakers is the way to go paralleling 2A3's...
you should see how tubelab.com tortures tubes and the OPT's with it, extracting more power out of a given tube and OPT...
Agree
Hi,
Yes AJT, there seems to be an entire new way in life. Having Google is a good thing,...until it's gone. Funny this New world we have here now...
Regards,
Ron
Hi,
Yes AJT, there seems to be an entire new way in life. Having Google is a good thing,...until it's gone. Funny this New world we have here now...
Regards,
Ron
Tubelab
I got discouraged last week, so I explored the whole Tubelab thing. Nice that someone is furthering the exploration of this hobby. But the site has not much good to say about the tubes I have, so I decided to return to the point to point thing. I just want to build this right and leave some options open. I need advice on everything, like wire-whats the best wire to use, there are people selling cloth covered, silver stranded, oxygen free copper, etc. All kind of crazy as electrons travel on the outside of the wire strands, so I would thing a fine (small diameter strands) multi-stranded wire would be the best. But you all would know. I'm sure someone will tell me. Getting down to not many questions left, and then we will build this thing, and you all can have fun picking on me!
Regards,
Ron
I got discouraged last week, so I explored the whole Tubelab thing. Nice that someone is furthering the exploration of this hobby. But the site has not much good to say about the tubes I have, so I decided to return to the point to point thing. I just want to build this right and leave some options open. I need advice on everything, like wire-whats the best wire to use, there are people selling cloth covered, silver stranded, oxygen free copper, etc. All kind of crazy as electrons travel on the outside of the wire strands, so I would thing a fine (small diameter strands) multi-stranded wire would be the best. But you all would know. I'm sure someone will tell me. Getting down to not many questions left, and then we will build this thing, and you all can have fun picking on me!
Regards,
Ron
tubelab says it like it is, no nonsense type of guy, his posts here are gold....you can take him or leave him...
the 2A3 and the 300b are hyped tubes so they sell high in cost....there are other options out there for those looking to build cheaper alternatives...
the 2A3 and the 300b are hyped tubes so they sell high in cost....there are other options out there for those looking to build cheaper alternatives...
Tublab2
Hi,
Oh, I certainly meant no criticism of his efforts. i think what he has done to further this hobby is excellent. I just meant for my application at this point in time a build for me around his platform did not seem to be my best option. I will if time permits attempt to construct around his platform. Looks like fun and everyone should try working on PCBs at least once.
Thanks,
Ron
Hi,
Oh, I certainly meant no criticism of his efforts. i think what he has done to further this hobby is excellent. I just meant for my application at this point in time a build for me around his platform did not seem to be my best option. I will if time permits attempt to construct around his platform. Looks like fun and everyone should try working on PCBs at least once.
Thanks,
Ron
Remember mix/match and pick/choose. A 5U4 is directly heated, while the 5AR4 has a cathode sleeve that slows B+ rise down. Also, forward drop in a 5U4 is greater than that in a 5AR4. Earlier in this thread, a 5AR4 B+ PSU was shown.
PSU
Hi Eli,
How you been? Do you mean this one?
http://www.hagtech.com/pdf/clarionarticle.pdf
Thanks!
Ron
Hi Eli,
How you been? Do you mean this one?
http://www.hagtech.com/pdf/clarionarticle.pdf
Thanks!
Ron
Hey Ron, Happy Anniversary!!
The output transformers you have are not optimal for parallel 2A3's, first they are designed for 60mA of current and also the load impedance would be too high, unless you have 4 ohm speakers you plan to use which would reflect a lower load. But still you would only be able to bias each 2A3 @ 30mA.
I use turret boards and I really like them a lot. My latest amp I used tag boards but most of the time I use turret boards.
I would just go ahead and use the Hammond transformer, it should work great for your application. The only thing I would think of doing is getting a separate filament transformer to power some DC regulator boards for the 2A3 filaments, this will help the Hammond 302AX run cooler too. Maybe an option is to run the two 2.5v windings on the Hammond in series and full wave rectify it, I believe the DC current would be equal to the rated AC current rating, A bridge rectifier would stress the windings too much.
Edit: I think for Rod's board the minimum voltage is 6.9v for one 2A3 which is 2.5A. For two you would need 5A which requires 13.5v min.
https://www.dropbox.com/s/ujaoh4mrnpourtl/ANdht01v7.pdf?dl=0
Hello
Between two OPTs 3K/46H/25W and 3K/29H/10W for application in 2A3 SE How prefer
Τhank you
Hey Ron, Happy Anniversary!!
The output transformers you have are not optimal for parallel 2A3's, first they are designed for 60mA of current and also the load impedance would be too high, unless you have 4 ohm speakers you plan to use which would reflect a lower load. But still you would only be able to bias each 2A3 @ 30mA.
I use turret boards and I really like them a lot. My latest amp I used tag boards but most of the time I use turret boards.
I would just go ahead and use the Hammond transformer, it should work great for your application. The only thing I would think of doing is getting a separate filament transformer to power some DC regulator boards for the 2A3 filaments, Hello
Between two OPTs 3K/46H/25W and 3K/29H/10W for application in 2A3 SE How prefer
Τhank you this will help the Hammond 302AX run cooler too. Maybe an option is to run the two 2.5v windings on the Hammond in series and full wave rectify it, I believe the DC current would be equal to the rated AC current rating, A bridge rectifier would stress the windings too much.
Edit: I think for Rod's board the minimum voltage is 6.9v for one 2A3 which is 2.5A. For two you would need 5A which requires 13.5v min.
https://www.dropbox.com/s/ujaoh4mrnpourtl/ANdht01v7.pdf?dl=0
Hello
Between two OPTs 3K/46H/25W and 3K/29H/10W AM for application in 2A3 SE Both 60mA How prefer
Τhank you
Well, this is a tough question without knowing the exact transformers and testing them myself. The 29H/10W will be good and may have better high frequency bandwidth than the 46H. 46H only gets you from 4Hz to 2Hz, sometimes with high primary inductance there is a tradeoff of high frequency due to the increased C, so I myself would go with the 3k/29H/10W.
Hello
The transformers for are talking about are LL 1623 and LL 1664 AM
Thank you
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