Welcome To the Hoffman Amplifiers Forum

September 08, 2025, 12:49:49 am
guest image
Welcome, Guest. Please login or register.
-User Name
-Password



Hoffman Amps Forum image Author Topic: Power transformer mystery winding/possible short  (Read 1765 times)

0 Members and 1 Guest are viewing this topic.

Offline Masterwaiter

  • Level 1
  • *
  • Posts: 9
  • I love Tube amps
Hoffman Amps Forum image
Power transformer mystery winding/possible short
« on: January 24, 2019, 10:00:01 am »
So my 5e3 build saga continues.  Trying a different power transformer, so new post.  I have all the windings id’d and wired in, but I have these two brown wires that are confusing me.  This winding is not the high voltage centertapped winding and when I power the transformer out of the circuit, just one brown lead to ground is giving me a voltage reading so high that my multimeter won’t even register it.  My suspicion is that the transformer is shorted, but I just wanted to run it past wiser men than myself in case I’m looking at something beyond my knowledge.  I promise that this is my last attempt to make this amp work with junk I have on hand before I order a new classic tone with proper specs.

Offline sluckey

  • Level 5
  • *******
  • Posts: 5075
    • Sluckey Amps
Hoffman Amps Forum image
Re: Power transformer mystery winding/possible short
« Reply #1 on: January 24, 2019, 11:28:41 am »
Measure resistance between the two brown wires. Then measure resistance between one brown wire and all the other wires. Probably infinity ohms. Measure resistance between one brown wire and the bolts on the transformer. Probably infinity ohms. Report your resistance readings.

Now measure voltage between the brown wires. Several PTs have a separate bias winding and the wires are brown. Show us the data sheet for that transformer. Or at least tell us which PT you have.
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