Welcome To the Hoffman Amplifiers Forum

September 06, 2025, 05:22:00 pm
guest image
Welcome, Guest. Please login or register.
-User Name
-Password



Hoffman Amps Forum image Author Topic: Very Specific Grounding Question (I Swear)  (Read 1823 times)

0 Members and 1 Guest are viewing this topic.

Offline AHeck

  • Level 2
  • **
  • Posts: 114
Hoffman Amps Forum image
Very Specific Grounding Question (I Swear)
« on: October 14, 2019, 08:26:33 am »
I just brought up my first guitar amp build, it's a 5E3, and I'm very happy with it except for the one last ground demon I can't get out.  It lives in the tone pot.  First things first, I had wanted to use an Alpha amp pot with SPST switch in one of the volume positions for a power switch, but ended up with a SPST toggle as power, and I ended up using it for the tone pot, I don't really know why.  Anyway, I have the tone pot ground connected by a Mallory .0047uf cap to a ground chain to both volume pots and then to a four input conglomeration.  I don't even need to touch the pot, just hold my hand over it and the hum is gone, but when I do try to  touch it, there are crackling and poping noises.   I'm not an expert, but it sounds like 60cycle.  I've  tried taking the pot ground to chassis, but it makes it a signal attenuator. No grounding point I could find reduces the noise, but a bunch of them made it worse.  So what do I need to do, besides change out that pot when it arrives tomorrow?  At this time I'm also trying to straighten resistor values out to zero in on voltage points.

Offline Williamblake

  • Level 2
  • **
  • Posts: 483
  • I just picked values that I've seen in other circu
Hoffman Amps Forum image
Re: Very Specific Grounding Question (I Swear)
« Reply #1 on: October 15, 2019, 08:25:22 pm »
When i soldered pots to smithereens they did the same.

 


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