Solow Watt 12a_7 power supply question

[pullshocks]

Time to do something with the 6F4P's I got.  Looks like the Solo Watt 12a_7 is it.  I will be using a Hammond 125E for the output transformer, and the Hammond 269EX power transformer as shown in the schematic.


Studying the schematic and layout, I notice V1 gets B+ from the same node as the screens.  I am guessing this was done for reasons of wanting to keep B+ on V1 as high as possible in a power supply that is only 255 V to begin with.


But that way the V1 B+ has only been through 2 stages of filtration.  Is this a noise issue?  I have plenty of room to do a more elaborate power supply if that would be any benefit.


Thanks in advance


Pullshocks / Mark

[pullshocks]

Should have included the link to the schematic and layout.


http://el34world.com/Forum/index.php?topic=13438.msg126186#msg126186

[sluckey]

I notice V1 gets B+ from the same node as the screens... But that way the V1 B+ has only been through 2 stages of filtration.  Is this a noise issue?

Would be for me. I'd rather tap off from node B, Go through a 10K (or more more appropriate) dropping resistor to a 22µF or even 47µF cap. Feed that to V1 only. Experiment with the dropper to get the desired voltage.

[pullshocks]

Thanks Sluckey.


Tubenit has a post on Ampgarage indicating VI is connected to Node D, after all.



https://ampgarage.com/forum/download/file.php?id=26323&mode=view


https://ampgarage.com/forum/viewtopic.php?f=6&t=20234&p=236316&hilit=solow+watt#p236316

[tubenit]

I do like Sluckey's idea to have another resistor and filter cap coming off node B for the V1 tube to have the voltage higher.

I sold this amp to a guy that opened for Derek Trucks and also Dave Matthews so I no longer have it. Years later, he said it was still his main practice amp.

Another forum builder built one called the BumbleWatt using the 5879 pentode.  He used node D also.  His workmanship was excellent (&much better than mine) so you might one to take a look at it. He also commented on what good bass response it had for small tubes.

http://el34world.com/Forum/index.php?topic=13151.msg122821#msg122821

With respect, Tubenit

[pullshocks]

Thank you.


I transposed your layout from left to right, and re-drew in DIYLC with all power supply components showing.  I need to recheck a few more times, but I should be just about ready to drill the chassis and make the boards.