betamax Unlike a certain subset of audiophiles that will pay stupid amounts of money for things that have no proof of even working.
Unlike a certain subset of audiophiles that will pay stupid amounts of money for things that have no proof of even working.
An addage in this part of the world is: 'The secret to financial success is NOT building the better mousetrap, but finding ways to separate the financially successful from their money.'
While we may have rivet counters, at least they can usually prove their point. While it may not make a difference in operations, it can make a good model even better.
Unlike a certain subset of audiophiles that will pay stupid amounts of money for things that have no proof of even working. (All copper wire is oxygen free, as it would otherwise be too brittle to pull throught the dies.) Like green markers which will improve the sound of your CDs. Or questionable magical wires which are directionally matched and treated with a secret cryogenic process., to improve an invented quantity.
While there seems to be some voodoo surrounding DCC, most of it is rooted in a lack of understanding about it, or how digital signals work. Some claim you need terminators on the bus or else, while others dismiss the idea. But without specialized equipment and a knowledgeable user, how to you really know if it makes a difference?
Digital really is all or nothing: It works or it doesn't. Too much corruption in the signal means it won't work properly. If the decoder is set for analog mode operation, it can just switch over and take off if it believes it isn't running on DCC trackage.
I'm not kidding about the wire suspension, either. They actually make thise little shock resistent towers to run your speaker wire through. There's even reviews on thsi device which say how much better things sound - these people are such a joke it isn't funny. There's also a parallel noise filter - I can see connecting a surge strip and noise filter between the equipment and the wall outlet, but these you plug in to another outlet, nothing conencts to them. Review for this device ALSO says how much clearer they made the audio.
Best ever was a particular DVD player, there was a consumbe rmodel for $399, and an 'audiophile' brand for somewhere north of $1200. One of the legitimate electronic review sites purchased both adn took them apart - outside of the wood used int eh fancy one for the cabinet, vs the metal of the cheaper one, the circuit boards and all components on them were EXACTLY IDENTICAL.
Thankfully this ridiculousness has pretty much stayed away from model railroading and DCC. So far.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Let us not forget the absolute requirement of the $700 1metre USB cable needed to connect a computer to your DCC system. This audiophile quality cable with insure true prototypical nature of the DCC packets being sent to the throttle bus. Anything else risks losing that protypical feel you want.
(I'm not kidding about the cable, it exists, made by an audio outfit (California, where else) claiming it will enhance digital signals. Somebody in that chain really doesn't understand how digital signals work and how the cable has little to no impact, regardless of cost...)
Not that it has any effect on the quality of the DCC signal on the track either.
betamaxOnly if the Marrettes are the cryogenically treated audiophile quality ones. The others don't exhibit that behaviour.
That's because the audiophile quality ones, $100 each, are gold plated, not tin lated like the common electrical wiring ones. That's in addition to the special treatment of the plastic. This assures that up to 10x the electrons stay within the wire for richer, fuller sound. Because of this, you should not use less than #6 wire else it will not be able to hold all of these electrons, and you really should suspend all wires via specially designed anti-vibration suspension brackets, since the slightest vibration in the wires will carry over as unwanted harmonics in your audio.
Yeah, I'd heard of those new-fangled thingies. Personally, they take all the thrill out of operating in DCC.
mfm37 Tape over the ends will keep the little electrons from leaking out.
Tape over the ends will keep the little electrons from leaking out.
Yes, they can't get past the plastic. However, I have heard of electrons being cyclotronned around the threads inside the metal liner of the Marrettes. That means some X-Rays, so be sure to wear a lead apron if you use them for snubbers.
the one thing that might make a difference is to twist the pair of wires. The phone company does this with the lines to your house (up to 2 miles) and i believe most cat cable uses twisted pairs (i know cat-5 does).
the idea behind twisted pair is that a magnetic field inside a loop of wire induces a current in the loop. So if you twist the wire, the same magnetic field goes thru multiple loops, every adjacent loop inducing a current in the opposite direction. When you twist the wire, you not only create multiple loops that cancel one another out, but also creates smaller loops because the wires are drawn closer together. (bear in mind that the locomotive(s) closes the loop).
This might not normally be an issue, but locomotive motors and other power components produce stronger magnetic fields which can be picked up by a pair of wires.
So while bus terminations and reflections may not be an issue at DCC frequencies, low-frequency noise can be, and twisting the DCC wire pairs, even loosely, may be a big help to avoid noise problems.
greg - Philadelphia & Reading / Reading
zstripe Bruce, Put a Electrical wire nut on each end of the wire and forget about it. Frank
Bruce,
Put a Electrical wire nut on each end of the wire and forget about it.
Frank
Will that keep the little electrons from leaking out?
Rich
Alton Junction
betamaxIn the old days of SCSI devices and coaxial cables used for networks on computers, termination was very important, as an unterminated bus, while appearing to work correctly, could have errors and erratic behavour if the buses were not terminated.
looks like the slowest scsi can run from 5-160 Mhz. Not sure a 10 kHz DCC bus is likely to have the same issues as 5 MHz SCSI.
I agree that if there are issues, you need to find the problem, such as by using an o-scope, and not rely on voodoo and mysticism
AS to terminating the ends of the bus, depends. Some manufacturers recommend it, others don't. For short runs, not really an issue.
For longer runs, it may become an issue. If trains suddenly take off with no control at one end of the bus run, the signal may be so distorted the decoder switches to analog mode. (If you have no reason to run your motive power in analog mode, set them to DCC Only during programming, that solves that problem.)
The only real way to see what is going on is to get an oscilloscope and see what is happening on the track at various places. If the signal is still strong and clean, you don't need one. If the signal is very distorted, there is either a wiring error or reflections are taking place. The idea of a terminator is to absorb that energy to minimize the reflections.
In the old days of SCSI devices and coaxial cables used for networks on computers, termination was very important, as an unterminated bus, while appearing to work correctly, could have errors and erratic behavour if the buses were not terminated.
Same advice here. NCE Power Pro, no issues, bus is about 40' long max out of two boosters.
The need for snubbers, terminations, whatever you want to call it has to do with the way the DCC pulsed wave-form is reflected in the wiring. If the reflections get strong enough, they interfere with the source signal, causing errors. The less convoluted your bus is and the shorter it is reduce the chance that the bus will require some type of termination. For the typical home layout, the chance of running into this is low anyway, so if you don't notice any issues with commands going astray, ignored, etc, you likely never need to worry about this.
And if you do end up noticing it, the fix is relatively easy to retrofit and cheap.
Mike Lehman
Urbana, IL
I also have the NCE Power Pro (Radio). I just connect my last set of feeders to the end of the Bus (about 40' away). That solves the problem of what to do with the ends of the Bus. Never had an issue. I never understood why people run bus lines past the last set of feeders and then worry about what to do with the end of the bus. But then the electrical part of this hobby is my weekest part. Maybe someone can explain why we need to run Bus lines past our last set of feeders (other than for future expansion)
Brent
"All of the world's problems are the result of the difference between how we think and how the world works."
Bruce, are you having an issue with the buss wires or the PH-Pro?
I agree with cacole that there shouldn't be a problem on a layout of that size and dimension.
I see no need for terminations on a layout of that size. At our large (20 x 40 foot) HO scale layout we have bus wire runs of close to 40 feet in some cases, no terminations, and absolutely no problems with NCE PowerPro Radio throttles.
I have a 30 foot shelf layout fed at the center from my NCE power pro. Since the waveforms are essentially square waves, the edges of them can round off if the bandwidth is insufficient or the lines are mismatched.
Would terminating the ends of the busses help the square wave response? Whaty is the impedance of the various boosters? Does it really matter?
73
Bruce in the Peg