Coytee Posted September 8, 2007 Share Posted September 8, 2007 Been framing downstairs and trying to think ahead not only for "where might I want an outlet" but also, might I ever want to place an amp "here" and if I do, how am I going to run a cable to it. So, with that as the picture, SOME people swear by putting the amps as close to the speakers as possible (I think McIntosh does this?) My Jubes are going to be on the opposite side of the room as anything/everything else. I've already got 4 lines run to them for biamping BUT it has dawned on me that I might possibly someday like the idea of putting an amp next to them, possibly mounted on the wall, possibly simply hidden behind the honker horn. That got me wondering about getting the signal there. I just measured and although it's about 40 feet after all the turns are made let's bump up to 50 feet for some cushion. I don't think IC's are good for 50' runs?? If I run an XLR cable to this location can I have XLR on the active xover side and RCA on the amp side? will that setup allow me to run a distance or must it be XLR/XLR to run a longer distance like that? Remember my food chain will be RCA inputs to Peach RCA's, Peach RCA out to Dx38 XLR inputs. Dx38 XLR outputs into ??? (currently XLR on Crown and XLR on McIntosh) I'm contemplating some OTL's for the honker and they have RCA inputs. It's those that I'm wondering about placing near the speakers (reason?? "just because" if nothing else) so, what issues if any, might there be placing an amp 50' away from the Dx-38 and if there ARE issues, how might I best address them now while I still have stud walls? Quote Link to comment Share on other sites More sharing options...
gaspr Posted September 8, 2007 Share Posted September 8, 2007 If you have the opportunity to put in some runs of pvc conduit to places where you might want to run some wire in the future, now is the time. Cheap and easy to do now... Quote Link to comment Share on other sites More sharing options...
Coytee Posted September 8, 2007 Author Share Posted September 8, 2007 I agree on the conduit. What I want to do is hard wire all I THINK I'll need and then run the conduit (empty) so I can add anything else later if I need to. Quote Link to comment Share on other sites More sharing options...
bhendrix Posted September 8, 2007 Share Posted September 8, 2007 Coytee, it's not uncommon to see snakes (bundles of XLR's) running 100' to 150' or more at concerts from the mixer to the amps on stage. Don't know what the limit is, but it's a loooooooong way. Quote Link to comment Share on other sites More sharing options...
Coytee Posted September 8, 2007 Author Share Posted September 8, 2007 Yes Bill, though I was aware of that much, I was wondering if I had the same ability. (I AM speaking out of ignornace here sooooooooooooo) My understanding is the pro guys have an over all hotter signal than us lowely home guys. If that's right then I'm already starting out with a bit of a disadvantage on the voltage (as done by the cd player/Peach...) unless I use a XLR transformer (or so I understand) I HAVE a transformer but I'm not so sure it's dead quiet. So, if I don't use a transformer will my system still carry the signal that far? Does the fact that the DX38 hvae XLR outputs automatically put it into the same ballpark as the pro signals?? If no... will it do enough to push the signal 50'? If YES, will I have any other issues since the terminal end might be a RCA plug instead of another XLR?? (do I keep the same signal levels mixing/matching ends?) (MAS, I got your message, thanks!) [Y] Quote Link to comment Share on other sites More sharing options...
Marvel Posted September 8, 2007 Share Posted September 8, 2007 It has to be balanced on both ends. They can very easily go hundreds of feet at line level. Bruce Quote Link to comment Share on other sites More sharing options...
bhendrix Posted September 8, 2007 Share Posted September 8, 2007 Richard, I just connected 50' of RCA cable (2 x 25' with couplers) between my Audionics BT-2 preamp and my Auionics CC-1 amp and took the pre into another room. I had more than enough output from the pre to drive the amp. The Dx38 has more output than my pre. Quote Link to comment Share on other sites More sharing options...
DrWho Posted September 9, 2007 Share Posted September 9, 2007 They can go for miles as long as you're properly balanced on both ends of the line. You would have to double the length of the wire to notice a 6dB rise in the noise floor. When you're already talking a SNR of 90-100dB, you're talking a crap load of wire for it to become an issue. You could probably get up to -60dB before you start hearing it in a quiet room. Quote Link to comment Share on other sites More sharing options...
djk Posted September 9, 2007 Share Posted September 9, 2007 I've run unbalanced cables 135' with no noise at all. The cable was terminated with a 2.2K resistor at the far end (this reduced noise by over 10dB). Sheffield Labs made 'the King James version' with a stereo mic feeding balanced cables 3/4 of a mile long. Quote Link to comment Share on other sites More sharing options...
capo72 Posted September 9, 2007 Share Posted September 9, 2007 I've run unbalanced cables 135' with no noise at all. The cable was terminated with a 2.2K resistor at the far end (this reduced noise by over 10dB). Sheffield Labs made 'the King James version' with a stereo mic feeding balanced cables 3/4 of a mile long. I'm not trying to be a smart a$$. How do you terminate an unbalanced cable (RCA) with a resistor. I mean how is it physically done? Is a resistor paralled with the positive side, or is it in series? Is there some special type of resistor made for this? I'm just curious as someone who has attempted to make their own signal and speaker cables. Thanx for your time, Jeremy Quote Link to comment Share on other sites More sharing options...
djk Posted September 9, 2007 Share Posted September 9, 2007 "I mean how is it physically done? " In this case the input jack of my electronic crossover (in the rack on stage) had the 2.2K resistor soldered to it (parallel). This also helps negate the capacitance in the long cable as well (less HF roll-off). If you use an 1/8W resistor you can solder it inside the jack (as long as you're not using garden hose sized wire). I got the idea from the RCA audio amplifier manual. It showed that shorting the input of an amplifier with a 22K input impedance gave about a 15dB improvement in SN ratio. With the resistor on the end of a 20 foot cable the improvement was only 3dB less than the short, hence my claim of an over 10dB inprovement. A grid choke vs a resistor shows a similar improvement for a similar reason, an old accepted practice. Quote Link to comment Share on other sites More sharing options...
capo72 Posted September 10, 2007 Share Posted September 10, 2007 Thanx for the info. I always appreciate the good info in your posts. Jeremy Quote Link to comment Share on other sites More sharing options...
Coytee Posted September 11, 2007 Author Share Posted September 11, 2007 To put a twist to the question... As background, I'm currently stringing some 12g wire from the closet to where the rear speakers might be. I'm using 50' as a round number, the real distance in net lineal feet is less than that. I'm also now stringing some XLR cable so if I ever choose or need, I can put an XLR type amp near the speakers and bypass the speaker wires... then it hit me. As opposed to using the 12g wire connected to the amps, could I connect the amps to the XLR based wire and use IT as my 'speaker wire'? On one end I'd have ALL my electronics (including all amps). Connected to the amp outputs would be a wire plugging into the XLR input in the closet. On the speaker end, I'd have to get an XLR plug and on the opposite side of the plug I'd have the wires go directly to the drivers. (I'm putting in a double plug so each speaker will have two XLR wires/plugs available to it) I don't know the size of the XLR wire... I think he said 22g? It is certainly NOT 12g. Quote Link to comment Share on other sites More sharing options...
oldtimer Posted September 11, 2007 Share Posted September 11, 2007 I was thinking Richard that XLR cable can go all the way to your car, since that's where you keep your amps? Quote Link to comment Share on other sites More sharing options...
Coytee Posted September 12, 2007 Author Share Posted September 12, 2007 I was thinking Richard that XLR cable can go all the way to your car, since that's where you keep your amps? Ok........ I think I .... Just got spanked! (suddenly, I feel like I'm speaking like Duke) Quote Link to comment Share on other sites More sharing options...
ZAKO Posted September 12, 2007 Share Posted September 12, 2007 I,m running XLR 200ft with no ill effects,,,, Beldon wire XLR both ends. Quote Link to comment Share on other sites More sharing options...
ZAKO Posted September 12, 2007 Share Posted September 12, 2007 I,m running XLR 200ft with no ill effects,,,, Beldon 3 conductor shielded wire XLR both ends. Quote Link to comment Share on other sites More sharing options...
djk Posted September 12, 2007 Share Posted September 12, 2007 Maron must be running stereo. Quote Link to comment Share on other sites More sharing options...
ZAKO Posted September 13, 2007 Share Posted September 13, 2007 No i was trying to edit somehow it came out two posts. I like XLR and balanced circuits. Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted September 17, 2007 Share Posted September 17, 2007 a long, long, long, long, long, long, long, long, long, way- per Bill's point. Make certain that your wiring is correct. I always remember the old PA guy mnemonic device: 1=George = Green or Ground 2=Washington = White or hot 3=Bridge = Black or negative Quote Link to comment Share on other sites More sharing options...
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