 
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
|
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
98.212.42.230
In Reply to: RE: Mercury-wetted relays posted by TimFox on September 12, 2014 at 12:02:31
Does anyone know the spec for ON resistance for these devices?
(I once saw a relay specified in a catalog by a non-speller as having ON resistance measured in MΩ and OFF resistance measured in mΩ--a useless device.)
Follow Ups:
nada aqui
--------------------------
Buy Chinese. Bury freedom.
Triode_Kingdom: How many relays do you need?
I can get back to you in about a week after a trip.
"How many relays do you need?"
Ha, ha, as many as I can get! My next pre will have nine or 10 selector positions, so I have to double that for stereo unless the relays are double pole. Seriously, mercury relays probably aren't affordable for this use unless you're practically giving them away. Incidentally, I'm surprised more people haven't raised this issue (grounding unused inputs). Few manufacturers have bothered, but it really cuts down on crosstalk between live inputs. Heathkit was one of the few that included this functionality on their selector switches.
--------------------------
Buy Chinese. Bury freedom.
Shorting live inputs to ground is not without issue. I've run into situations where the driving device really disliked being shorted to ground and ended up creating a super distorted/clipped signal that radiated to other inputs far worse than if left open...usually SS sources. It sounded a lot worse too! Easiest solution was to simply turn off un-used sources.
How can a source signal radiate to other inputs if it's shorted to ground? By definition, if it's shorted to ground, there's no signal.
--------------------------
Buy Chinese. Bury freedom.
What I suspect was occurring was that the signal was so thoroughly clipped from being shorted that what remained was essentially a square wave. Even though the input was theoretically grounded there is a low but non-zero impedance betw input jack and the selector switch/ground point. It seems that HF harmonics of the clipped signal were radiating from the non-shielded portions of the shorted input to the non-shielded portions of the active input. Obviously, this condition is layout and circuit dependent among other things and may not be an issue in all cases. Regardless, I feel it's not a great design practice to short a signal to ground to get rid of it. YMMV
Post a Followup:
| FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
||||||||||||||
This post is made possible by the generous support of people like you and our sponsors:
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2024, Audio Asylum, all rights reserved ]
