Welcome To the Hoffman Amplifiers Forum

September 08, 2025, 04:32:58 am
guest image
Welcome, Guest. Please login or register.
-User Name
-Password



Hoffman Amps Forum image Author Topic: Help Confirm OT wiring on Classictone JTM45 OT  (Read 2231 times)

0 Members and 1 Guest are viewing this topic.

Offline Tsquared

  • Level 1
  • *
  • Posts: 54
  • Harnessing wild electrons
Hoffman Amps Forum image
Help Confirm OT wiring on Classictone JTM45 OT
« on: March 24, 2012, 04:13:34 pm »
I think I may have wired my OT wrong... SO

Which is the center tap on the primary? I'm not sure what the black dot next to the black primary lead means in the wiring spec sheet from Magnetic Components, but I assumed the center tap was the brown wire for some reason.
 Here is a link to the diagram: http://www.classictone.net/40-18039.pdf
Can anybody confirm the correct wiring, PLEASE??? I'm starting to go nuts!

Thanks,

Tod

Offline TIMBO

  • Level 4
  • *****
  • Posts: 2878
  • Blues Forever
Hoffman Amps Forum image
Re: Help Confirm OT wiring on Classictone JTM45 OT
« Reply #1 on: March 24, 2012, 05:04:49 pm »
Hi T2, Black wire, black dot to me is the more - side(i connect this to the power tube that is connected to the second side of the PI triode) Brown is CT (usually connected to A node) and Red more + side ( connected to the power tube that is connected to the first side of the PI triode) and Yellow is your -,ground for the speaker.

I don't know if the two PI triodes are split into + and - but this is how i see it. Thanks

Offline sluckey

  • Level 5
  • *******
  • Posts: 5075
    • Sluckey Amps
Hoffman Amps Forum image
Re: Help Confirm OT wiring on Classictone JTM45 OT
« Reply #2 on: March 24, 2012, 07:17:56 pm »
Quote
I assumed the center tap
It is. for that OT.

The black dots (notice one by the yel secondary wire too) are phase indicators. IE, when the AC signal on the black primary is swinging positive, the AC signal on the yellow secondary will be swinging positive also. IOW the signal on the yellow wire is in phase with the signal on the black wire.
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


password