Welcome To the Hoffman Amplifiers Forum

September 06, 2025, 01:27:26 pm
guest image
Welcome, Guest. Please login or register.
-User Name
-Password



Hoffman Amps Forum image Author Topic: transformer ratings question  (Read 2587 times)

0 Members and 1 Guest are viewing this topic.

Offline worth

  • Level 2
  • **
  • Posts: 251
Hoffman Amps Forum image
transformer ratings question
« on: October 29, 2010, 02:01:20 pm »
If I use a Fender PT for 325-0-325@200ma. for a single channel fender build with tube recto and reverb , ( 4 preamp tubes instead of the usual six ) how much should I expect the voltage to rise with two less tubes ?

Offline jojokeo

  • Level 4
  • *****
  • Posts: 2985
  • Eddie and my zebrawood V in Dave's basement '77
Hoffman Amps Forum image
Re: transformer ratings question
« Reply #1 on: October 29, 2010, 02:12:03 pm »
For B+ - very little if any since preamp tubes use so little current. Budget 3mA for a 12ax or ay, and more like 10mA for a 12au. Practical or actual use is less. Same for 6.3 heaters, you're only talking .6amp on a tranny like that won't any noticeable difference.
To steal ideas from one person is plagiarism. To steal from many is research.

Offline HotBluePlates

  • Global Moderator
  • Level 5
  • ******
  • Posts: 13127
Hoffman Amps Forum image
Re: transformer ratings question
« Reply #2 on: October 29, 2010, 07:07:36 pm »
Will you use a similar number and size of output tube? That would alter the B+ much more than the preamp tube current draw.

 


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