Grounding Question with a HF81

tube-a-lou

Addicted Member
Hi all,
I been upgrading a few of the sockets and see that a few resistor's and caps are grounded to
the one of the socket's tabs for a ground. Should I on the other side of the socket add a grounded
wire for a better ground?

Thanks
 
Interesting thought...Sometimes, a "better" ground can be helpful. I have restored some tube gear which literally required better grounding connections. Often, manufacturers relied on rivets to mechanically "ground" the socket. Then, the socket's surrounding tabs continued the grounding. If the unit showed oxidation and/or signs of hot-running, the mechanical ground connection, often accomplished with dissimilar metals, could oxidize over time and build up a resistive connection. With multiple grounding points as well as using the chassis as the ground buss, quality connections are a must.

You can check the various ground points using your VOM Ohmmeter with its' lowest resistance setting, measuring from each ground point to a clean chassis ground. You should read very low ohms, under .7 Ohm with a digital VOM. If you do measure over an Ohm, chances are that particular ground connection point could cause some hum or buzz later. Augmenting any resistive ground connection could be helpful. If you do not have any hum/buzz issues, I would leave things as they are. Now that these early stereo vintage units are over 55 years old, it makes many of us wonder why a strong ground buss, mechanically grounded at only one, lowest hum point, was not standard practice...
 
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