Welcome To the Hoffman Amplifiers Forum

September 05, 2025, 11:43:49 pm
guest image
Welcome, Guest. Please login or register.
-User Name
-Password



Hoffman Amps Forum image Author Topic: Loud hum from boombox  (Read 6310 times)

0 Members and 1 Guest are viewing this topic.

Offline punkykatt

  • Level 3
  • ***
  • Posts: 1145
  • I love tube amps
Hoffman Amps Forum image
Loud hum from boombox
« on: July 26, 2012, 09:09:58 pm »
Hey Guys, I have a Optiomus boombox CD/ radio/ cassette player on the bench.  Everything works fine except when you push the cassette tape play, rewind or fast forward buttons there is a loud hum in the speakers. I`m guessing its coming from the motor when its running and getting into the audio circuit some how.  Does anyone know what I can do to get rid of the hum? Thanks in advance for any input.

Offline PRR

  • Level 5
  • *******
  • Posts: 17082
  • Maine USA
Hoffman Amps Forum image
Re: Loud hum from boombox
« Reply #1 on: July 28, 2012, 09:55:48 pm »
> push the cassette tape play, rewind or fast forward buttons there is a loud hum

Typically the switching shorts-out the tape head except in Play, and perhaps in FF/RW (so you can hear where you are).

So I say you have a hum in the head wires. Very likely the grounding.

You forgot to say if it also plays. One channel or both.

Offline punkykatt

  • Level 3
  • ***
  • Posts: 1145
  • I love tube amps
Hoffman Amps Forum image
Re: Loud hum from boombox
« Reply #2 on: July 29, 2012, 12:18:20 pm »
Thank you for the reply PRR.  Yes the tape plays, you can hear the hum behind the music.   Both channels do work.  I will have to hunt for a broken ground connection.   Thanks again.

Offline punkykatt

  • Level 3
  • ***
  • Posts: 1145
  • I love tube amps
Hoffman Amps Forum image
Re: Loud hum from boombox FIXED
« Reply #3 on: July 30, 2012, 11:07:27 am »
Pulled the cassette tape assembly, checked all wires for continuity and micro switch operation. All fine, plugged the mini connectors back on the board sockets, checked grounds, all fine. Put a tape in and  played it. No hum!!!! must have been a bad socket connection or crap in the micro switch?  Thanks again PRR  for having me hunt for a bad ground.

 


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