Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Sine_wave_surfer on May 20, 2020, 02:29:30 pm

Title: Quick Grounding Question
Post by: Sine_wave_surfer on May 20, 2020, 02:29:30 pm
So this is kind of a goofy question, but I want to make sure I'm understanding this right.  On the 6v6 plexi layout/schematic there's a ground point for the speaker jack.  The jack should already be grounded to the chassis, I don't need to solder another wire from the ground tab to my other grounds right?
Title: Re: Quick Grounding Question
Post by: tubeswell on May 20, 2020, 03:02:48 pm
Depends on the type of jack. Some are sleeve-grounding (switchcraft type), others have insulated sleeves (which is normally what you see on a Plexi).
Title: Re: Quick Grounding Question
Post by: nandrewjackson on May 20, 2020, 03:10:41 pm
A couple minutes to run a ground wire to your main ground (buss) in addition to the Jack's contact with the chassis, just-in-case, ya' know?
Title: Re: Quick Grounding Question
Post by: Sine_wave_surfer on May 20, 2020, 03:25:57 pm
Yeah, it is a switch craft jack.  Running another wire won't cause a loop will it?
Title: Re: Quick Grounding Question
Post by: tubeswell on May 20, 2020, 03:43:33 pm
Yeah, it is a switch craft jack.  Running another wire won't cause a loop will it?


The ground end of the OT secondary winding goes to the switchcraft jack’s sleeve terminal. That is the chassis  ground attachment point. No other ground attachment is necessary. The other (extension speaker) jack doesn’t even really need a separate ground wire, because the ground connection to that jack is made through the chassis. (Note: both jack sleeves need to be firmly attached to the chassis (ideally with locking spring washers) to make a good ground connection. If your chassis is coated with paint/powder coating etc, the coating around the jack hole will need to be scrapped/ground off).
Title: Re: Quick Grounding Question
Post by: shooter on May 20, 2020, 04:45:20 pm
a multi-meter is a handy tool;
clip the black lead to main chassis ground, set for ohms, use red lead to probe the jack, if it's <2, you can move on, >2, make it less than 2 with wires  :icon_biggrin: