Welcome To the Hoffman Amplifiers Forum

September 07, 2025, 03:55:04 pm
guest image
Welcome, Guest. Please login or register.
-User Name
-Password



Hoffman Amps Forum image Author Topic: Thordarson 13S41 instructions  (Read 3216 times)

0 Members and 1 Guest are viewing this topic.

Offline eetechTom

  • Level 1
  • *
  • Posts: 5
  • I love Tube amps
Hoffman Amps Forum image
Thordarson 13S41 instructions
« on: December 13, 2020, 01:01:38 pm »
Hello, I am looking for a instruction sheet/wiring diagram for a Thordarson 13S41 output transformer. It’s a P-P type, universal replacement type. I recently bought a Peerless cathedral speaker, and am hoping to use the transformer to do a sound check. The Peerless has a high impedance, and sounds like crap connected to my little AA5 radio speaker terminals.

Offline eetechTom

  • Level 1
  • *
  • Posts: 5
  • I love Tube amps
Hoffman Amps Forum image
Re: Thordarson 13S41 instructions
« Reply #1 on: December 13, 2020, 01:18:13 pm »
I checked a few of their catalogs, but the didn’t supply PIN number data in any of them. It has pins labeled 1-6 on the secondary, and P, P B on the primary side.

Offline silverfox

  • Level 3
  • ***
  • Posts: 531
Hoffman Amps Forum image
Re: Thordarson 13S41 instructions
« Reply #2 on: December 13, 2020, 07:42:15 pm »
Let's see if I can get pg. 24 of the cat to attach. Can't too much wacky loading.


If you have the number: 400-FX 1942 catalog, reference pg. 24 and notice the wiring diagram on the upper left corner of the page. If you don't have the catalog, it should be out there on the net.


silverfox.
« Last Edit: December 13, 2020, 07:50:31 pm by silverfox »

Offline mresistor

  • Global Moderator
  • Level 4
  • ******
  • Posts: 3209
  • resistance is futile
Hoffman Amps Forum image
Re: Thordarson 13S41 instructions
« Reply #3 on: December 13, 2020, 08:30:04 pm »
PG 24

Offline PRR

  • Level 5
  • *******
  • Posts: 17082
  • Maine USA
Hoffman Amps Forum image
Re: Thordarson 13S41 instructions
« Reply #4 on: December 13, 2020, 09:33:24 pm »
.... I recently bought a Peerless cathedral speaker, and am hoping to use the transformer to do a sound check. The Peerless has a high impedance, and sounds like crap connected to my little AA5 radio speaker terminals.

Let's skip the details. What IS the Peerless speaker impedance? I assume the AA5 is 3 or 4 Ohms.

If the speaker is anything like 400 Ohms, try a 120VAC:12VAC 1A power transformer *backward*. If closer to 1,500 Ohms, try 120:6.

It is of course entirely possible the Peerless is sick or needs some odd bias. Particularly a magnet.

https://www.antiqueradios.com/forums/viewtopic.php?f=1&t=230307
« Last Edit: December 13, 2020, 09:36:39 pm by PRR »

Offline eetechTom

  • Level 1
  • *
  • Posts: 5
  • I love Tube amps
Hoffman Amps Forum image
Re: Thordarson 13S41 instructions
« Reply #5 on: December 13, 2020, 10:54:00 pm »
Thanks silver fox and resistor, I was able to guesstimate the speaker taps with my DMM. Also wanted data for future reference. Didn’t seem to work well with the speaker.

Offline eetechTom

  • Level 1
  • *
  • Posts: 5
  • I love Tube amps
Hoffman Amps Forum image
Re: Thordarson 13S41 instructions
« Reply #6 on: December 13, 2020, 11:04:25 pm »
PRR, I measure 2 Henry’s, and 1,800 ohms with my DM27XT DMM. The speaker was manufactured in the late 1920’s. As a side note, I want to brag about my trusty Wavetek DMM for a sec. It has enough output to drive that speaker with a decent tone when testing inductance. Used that feature to test a few speakers when buying vintage gear. Anyway, I will try the power transformer trick tomorrow. Thanks for the tip!

Offline eetechTom

  • Level 1
  • *
  • Posts: 5
  • I love Tube amps
Hoffman Amps Forum image
Re: Thordarson 13S41 instructions
« Reply #7 on: December 13, 2020, 11:13:34 pm »
Here is a photo, better late than never.

 


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