Welcome To the Hoffman Amplifiers Forum

September 06, 2025, 04:42:04 pm
guest image
Welcome, Guest. Please login or register.
-User Name
-Password



Hoffman Amps Forum image Author Topic: Best method for 150v screen supply.  (Read 1538 times)

0 Members and 1 Guest are viewing this topic.

Offline Stuff4bikes

  • Level 2
  • **
  • Posts: 138
  • I love Tube amps
Hoffman Amps Forum image
Best method for 150v screen supply.
« on: January 02, 2022, 11:45:10 am »
Like the title states.....
I need 150v for the screens of two output tubes.

0A2 or dedicated seperate transformer?
Or if even possible another node on the PT dropping it down to the needed voltage.

Offline PRR

  • Level 5
  • *******
  • Posts: 17082
  • Maine USA
Hoffman Amps Forum image
Re: Best method for 150v screen supply.
« Reply #1 on: January 02, 2022, 11:51:40 am »
What is any available B+? How much current *and current swing* available/needed on main B+ and screen supply? Does your religion forbid Silicon?

What is "best"? Fastest? Cheapest? Coolest? Most stable? Best sound? Uses parts already in your shed?

Historically the answer was to use high-Mu(g2) tubes so that G2 could eat very nearly plates supply voltage, with maybe a slight filter between.

Offline Stuff4bikes

  • Level 2
  • **
  • Posts: 138
  • I love Tube amps
Hoffman Amps Forum image
Re: Best method for 150v screen supply.
« Reply #2 on: January 02, 2022, 12:07:07 pm »
Sorry I am a novice hobbyist.

I have several nos 0A2 tubes and half a dozen 6BQ6gtb's just wanted to see if I can do something with them
Even if it was a ipod/CD/record player amp...


Offline sluckey

  • Level 5
  • *******
  • Posts: 5075
    • Sluckey Amps
Hoffman Amps Forum image
Re: Best method for 150v screen supply.
« Reply #3 on: January 02, 2022, 12:19:41 pm »
Connect a series resistor and 0A2 between B+ and ground. Take the 150V from the tube. Here's an example...

     https://el34world.com/charts/Schematics/files/Gibson/Gibson_mercury_i_ii.pdf
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

 


Choose a link from the
Hoffman Amplifiers parts catalog
Mobile Device
Catalog Link
Yard Sale
Discontinued
Misc. Hardware
What's New Board Building
 Parts
Amp trim
Handles
Lamps
Diodes
Hoffman Turret
 Boards
Channel
Switching
Resistors Fender Eyelet
 Boards
Screws/Nuts
Washers
Jacks/Plugs
Connectors
Misc Eyelet
Boards
Tools
Capacitors Custom Boards
Tubes
Valves
Pots
Knobs
Fuses/Cords Chassis
Tube
Sockets
Switches Wire
Cable


Handy Links
Tube Amp Library
Tube Amp
Schematics library
Design a custom Eyelet or
Turret Board
DIY Layout Creator
File analyzer program
DIY Layout Creator
File library
Transformer Wiring
Diagrams
Hoffmanamps
Facebook page
Hoffman Amplifiers
Discount Program