romeo@argus.Tymnet.COM (Michael Stimac) (12/13/90)
I received several informative replies in answer to my question regarding `long' interconects. Although I did not promise to do so, I'll summarize the responses I got (!) in case others are interested. Thank you all who replied. from Seth J. Bradley ---- Warning! Commercial message follows! The problems with long runs are high capacitance (loads down the preamp output stage, rolls off the highs) and noise pickup. In a few weeks I'll be marketing an interconnect with extremely low capacitance (about 1/3 of average cables) and with very high noise immunity due to using a balanced, double shielded configuration. Its rather expensive, though. Another alternative is to use a line driver/receiver conected with twisted pair. This can also be expensive if you don't build it yourself. The cheapest solution would be to run a low capacitance RF coax (such as RG-59, used for CATV). It has fairly low capacitance, fairly good shielding, and can be had for $0.20/foot at Radio Shack, less if you buy a spool at an electronics supply house. Try to stay away from AC lines and you'll probably be OK. Good luck! -- Seth J. Bradley Address: sjb@dalek.iwarp.intel.com Or: dalek.UUCP!sjb >From John Sellens - I have about 60 feet of Belden Belfoil cable running from my downstairs tape outs through the cold air return to my upstairs receiver's tape ins. The cables are little tiny ones, shield plus 2 conductors, 18 gauge perhaps, and I don't even think the shield is connected. They work ok, no real signal loss, and the fidelity doesn't suffer much if at all, and if you're going to a work room, you perhaps don't need extreme audiophile cable. If you're worried, you could get line balancing transformers, and balance the lines to cut down on noise (e.g. if you have to run past your refrigerator motor or something), but it's probably not necessary - for me anyway. Cheers John Sellens >From Jim Kuehn - No problem for line level. The result should be indistinguishable from a 3' interconnect, especially if the termination is a mid-fi amp. You would begin to notice degradation at several hundred feet. >The interconnects I've seen for sale are nowhere near this >long. Is this because longer ones won't work well, or because >there's just little demand? Would special (shielded and/or >low-capacitance) cable have to be used? Little demand, I suspect. My catalog lists ready-made RCA plug-to-plug and plug-to-jack cables up to 25' for about $5 (single channel) and 1/4" phone plug-to-plug up to 100' for about $15 (single channel). Or you can make your own -- just get some SHIELDED 2-conductor cable, preferably not coax. Figure $0.15-.20/foot plus connectors. Premium-grade microphone cable would be overkill. Happy soldering. Jim Kuehn kuehn@super.org >From Ross Werner - I have 42 feet of Monster Interlink 4 (or whatever, I forget exactly) between my preamp (PS Audio 4.5) and my power amp (Aragon 4004). The only drawback to the arrangement is that the highs can get rolled off a bit if using the preamp in the "straightwire" mode due to the higher output impedance driving the cable capacitance vs. using the line amp (class A, low output impedance) mode. I haven't done any comparisons to see if there is an audible difference, but I have been quite pleased with the sonic results. It makes it possible to keep the power amp close to the speakers while still keeping the rest of the system where I want it. Low capacitance cable is a plus. It sounds like in your situation the last bit of fidelity is not important, I agree that your best bet would be to ship the line level signals from preamp to the power amp in the other room. Most high end stores will sell cable by the foot, you could even go cheap and get some basic stuff from any old electrical supply place. Go for it! Happy listening, Ross Again, thank you all Michael Stimac