Sharing power supply nodes from 124 with built in D'Lator

[Joost]

I am trying to figure out my layout for a Dumbleator in my 124 build. I've been reading and researching all old post for the past few days... I'm seeing blue from all the posts I've read.

However, there is very little info on the power supply on a built-in dumbleator. Heisthl wrote somewhere you can share a supply node and others say you need one specifically for the dumbleator. I see other parts of the 124 sharing power nodes.

So what is the answer. I've done a lot of research but can't find the definitive answer. All help and guidance would be greatly appreciated (on all things relating to a built-in dumbleator)! thanks

[markusw]

I'd go for a separated dropping string connected to the screen supply node.

Peace,

Markus

[glasman]

I'd go for a separated dropping string connected to the screen supply node.

Peace,

Markus

I agree that is the best place to tap off for the loop.


Gary

[Joost]

I'd go for a separated dropping string connected to the screen supply node.

Peace,

Markus

I agree that is the best place to tap off for the loop.


Gary

Ok, thanks so using B+2 right after the choke. How would I go about calculating the right value for the dropping resistor? And would I need to use another one of those large 20uF Sprague Atom TVA1906 caps? I don't think I have the room!

thanks!

[glasman]

I'd go for a separated dropping string connected to the screen supply node.

Peace,

Markus

I agree that is the best place to tap off for the loop.


Gary

Ok, thanks so using B+2 right after the choke. How would I go about calculating the right value for the dropping resistor? And would I need to use another one of those large 20uF Sprague Atom TVA1906 caps? I don't think I have the room!

thanks!

Start with the standard 47K -> 100K string. if you have 440 to 460 at the screen node, this will get you very very close.

Figure about 1.5ma total current flow between the cathode follower and recovery stage. The 47K will drop about 75V for the cathode follower and the 100K will drop another 75V to the recovery stage.

Gary

[Joost]

Start with the standard 47K -> 100K string. if you have 440 to 460 at the screen node, this will get you very very close.

Figure about 1.5ma total current flow between the cathode follower and recovery stage. The 47K will drop about 75V for the cathode follower and the 100K will drop another 75V to the recovery stage.

Gary

Wow thank you so much! Do you (or anyone) know the smallest physical size filter caps I could use for this purpose?

[ToneMerc]

Start with the standard 47K -> 100K string. if you have 440 to 460 at the screen node, this will get you very very close.

Figure about 1.5ma total current flow between the cathode follower and recovery stage. The 47K will drop about 75V for the cathode follower and the 100K will drop another 75V to the recovery stage.

Gary

Wow thank you so much! Do you (or anyone) know the smallest physical size filter caps I could use for this purpose?

If you want a small footprint radial style cap try this 22UF 450v one. Mouser #, 647-UVY2W220MHD

[Joost]

If you want a small footprint radial style cap try this 22UF 450v one. Mouser #, 647-UVY2W220MHD

Thanks! Will these have an adverse effect on tone versus the full size ones?