Welcome To the Hoffman Amplifiers Forum

September 08, 2025, 03:09:50 am
guest image
Welcome, Guest. Please login or register.
-User Name
-Password



Hoffman Amps Forum image Author Topic: Help matching impedance  (Read 1856 times)

0 Members and 1 Guest are viewing this topic.

Offline 1blueheron

  • Level 3
  • ***
  • Posts: 524
  • More junk than I know what to do with...
Hoffman Amps Forum image
Help matching impedance
« on: April 09, 2020, 02:14:57 pm »
I am building a 2X12 cab for a little Silvertone SE amp.  The original speaker measured about 7.6 ohms.  I have 2- 8ohm speakers I would like to use in the cab.  I am not that familiar with tube amp to speaker impedance matching other than I know it is supposed to be more critical than with SS.

What are my options?

Offline sluckey

  • Level 5
  • *******
  • Posts: 5075
    • Sluckey Amps
Hoffman Amps Forum image
Re: Help matching impedance
« Reply #1 on: April 09, 2020, 03:10:12 pm »
Don't worry. Be happy.
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline PRR

  • Level 5
  • *******
  • Posts: 17082
  • Maine USA
Hoffman Amps Forum image
Re: Help matching impedance
« Reply #2 on: April 09, 2020, 09:45:30 pm »
Ohm meters read DC. Amp-"matching" you want an Audio impedance. "8 Ohms" audio will read 5 to 8 ohms on the ohm-meter.

Anyway an SE amp will work fine if impedance is even "close". It may be down on power. But a more efficient speaker may compensate. Anyway if you need BIG sound in big spaces you won't be using an SE amp.

Or what Sluckey says.

Offline Latole

  • Level 4
  • *****
  • Posts: 2522
Hoffman Amps Forum image
Re: Help matching impedance
« Reply #3 on: April 10, 2020, 04:22:42 am »
8 ohms speaker is impedance ( in ohms )
Meter can read only resistance, ( in ohms too ) but two different things. It is close from speaker impedance.

Meter resistance reading : Not good for transformer impedance, too far

Résistance and impedance :

https://circuitglobe.com/difference-between-resistance-and-impedance.html
« Last Edit: April 10, 2020, 04:24:56 am by Latole »

Offline 1blueheron

  • Level 3
  • ***
  • Posts: 524
  • More junk than I know what to do with...
Hoffman Amps Forum image
Re: Help matching impedance
« Reply #4 on: April 13, 2020, 12:13:26 pm »
Thanks for the help guys.  We wired the 2- 8 ohm speakers in parallel Fri. and tried it out.  Sounds good so proceeding with the new cabinet build and will leave them in parallel.   Will post some sound clips when finished.

 


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