Bottlehead Forum

Bottlehead Kits => Legacy Kit Products => Stereomour => Topic started by: howardnair on August 27, 2011, 02:15:03 AM

Title: selector switch question
Post by: howardnair on August 27, 2011, 02:15:03 AM
i see some selector switches that the ground from the input is not present at the switch it is  grounded in several different ways but not through the selector -- the bottlehead inputs  ground through the selector switch and then volume control and then to ground-i just wired a goldpoint 2pole 3 throw 1 deck-with the grounds tied together- separate channels- then to volume control-then to ground-am i making a mistake
Title: Re: selector switch question
Post by: Jim R. on August 27, 2011, 03:09:30 AM
Howie,

The equivalent gold point switcyh to thye one that comes with the kit would be a 4-pole, 3 position switch.

What you have will work but will not switch the grounds, so there is a chance it may pick up some extra noise.

Not sure how best to run the grounds as you'll also have to consider the shields as well, though my inclination would be to wrap the common ground wire around the other hot wires, and connect to signal ground, then connect the shields together and to chassis ground near the rca jacks.  Though, not having tried this I have no idea if that would be optimum or not.
-- Jim
Title: Re: selector switch question
Post by: howardnair on August 27, 2011, 05:43:41 AM
jim-- i am using shielded belden wire-rca to selector-so at selector sw-drains tied together to ground
-grounds tied together for each channel on separate terminals-then sheilded wire to volume  control for hot and grounds-  drains clipped- volume control to terminals 7 and 9 with drains and grounds to ground-this all is on a wooden chassis-ground plane to a star ground-i have not received the stereomour yet-but have built chassis-installed switch and controls-rca inputs -tube sockets etc -per your suggestion on another post i am using 47 uf cathode bypass caps wired direct to the cathode resistors-i used mundorf tube caps-and the cree diode's--i also just did this on my first stereomour-back to the selector switch- - don't know what i was thinking when i ordered it--i am certain it was the thinking part that caused the difficulties--howie
Title: Re: selector switch question
Post by: Paul Joppa on August 27, 2011, 07:29:22 AM
When there is hum, a fairly frequent cause is current in the ground lines. This is most often capacitive coupling inside a power transformer, from some high AC voltage such as the primary, to the power supply ground. Since the Stereomour (like all Bottlehead line-powered products) uses the safety ground from the wall socket, any such current within the stereomour is carefully routed to cause minimal hum, but an external source component may also generate such a current. By switching the grounds, that source of hum is disconnected when you are listening to another source. Sometimes you can use that to identify a source of hum.

But if you don't have a source-related hum problem, then switching the grounds does nothing for you. It won't hurt anything, and it is normal in most gear.
Title: Re: selector switch question
Post by: howardnair on August 27, 2011, 05:48:32 PM
thanks paul-makes perfect sense-i think i will order the proper one-and alleviate any future issues--howie