wjm@whuxj.UUCP (MITCHELL) (02/21/84)
I'd agree with the comment made that oxide shouldn't affect the performance of speaker wire itself to any great extent, given the relatively low frequencies involved in audio work. Where oxide could be a significant problem is at the connections, and several companies make compounds to reduce contact resistance. Not only is this a problem on speaker leads, but contacts on low-level signal cables are prone to oxidation. Actually, the worst problem caused by oxidation isn't the resistance but the increased vunerability to RFI since oxide can act as a semiconductor and rectify the RF and put the resulting audio into your audio system. There are several remedies for contact oxidation. The first is to periodically rotate the pin plugs to clean off their contacts (some people use gold plated plugs to reduce vunerability to oxidation). The second is to use one of these cleaning compounds, although I don't know how well they work. I agree with the note about the need for LOW contact resistance switches in speaker A/B selector boxes for cable, amp, or speaker tests. I'd suggest a power relay for the actual switching - you might be able to cannabalize one out of a motor starter - if you don't mind a CLUNK when switching from one side to the other (of course, you could put the relay in another room). Bill Mitchell Bell Communications Research (formerly known as CSO) Whippany, NJ (whuxj!wjm)