I have several F and E A/B units (Athearn, Stewart, P2K) in which the A is powered and the B is not. Some have decoders and some do not. It seems the B units would be the perfect place to install sound since there should be ample room. I'd appreciate a little guidance as to the essential things that would need to be done to make this work. If it would not work or is a bad idea, I'd like to know that as well.
Many thanks,
Mike
There's a couple ways to do it:
1) Install a decoder with both motor control and sound in the A unit, and run two wires back to the B unit to the speaker and enclosure. I run the wires thru the open windows of the doors between the units. It's not noticeable, especially if you use diaphragms between the units. I usually use a drawbar between the A and B units.
2) Install a normal motor-control decoder in the B unit, and run two wires from the track power pick-up wires in the A unit back to the B unit, and install a sound-only decoder and speaker in the B unit.
In either case, you can get a very large speaker and enclosure in the B unit. I've used 1" round speakers, but larger oval ones (like 1"x1.5") should work too. Experiment a little to find the best spot for the speaker. I found on my Stewart FT set that putting the speaker right in the middle of the B unit facing towards the A unit rendered the best sound for example.
I guess a third alternative would be to get a powered chassis and power both units, and put a sound and power decoder in the B unit. Since most F unit chassis are the same whether used in an A or B unit, you have plenty of room to put in a speaker in the B unit where the chassis slopes down on one end to allow room for the low nose of the A unit and the crew cab.
Here's a short cut at Tony's Train Exchange.
Use the shortcut to down load the info you want.
http://tonystrains.com/download/dec-installation-hout.pdf
Modeloldtimer
Thanks for the ideas and help guys. The manual from Tony's is great! Looks like I've got some serious reading to do.
mreagant wrote:I have several F and E A/B units (Athearn, Stewart, P2K) in which the A is powered and the B is not. Some have decoders and some do not. It seems the B units would be the perfect place to install sound since there should be ample room.
Here is a unit (Athearn) with only the speaker. Note how big a speaker can be placed inside a dummy B. The bigger the speaker the better the sound can be. Also notice how the body shell of the locomotive IS the speaker enclosure. The white styrene inside is the edges. Had I spent more time on it, I would have found a way to make the whole thing an enclosure. In general the volume of the speaker enclosure should be at least twice the area of the speaker cone. What cannot be seen is that the bottom of the fuel tank has been cut out so it is not a hinderance to the thrust of the speaker. This produces really good sound.
This unit (Stewart) has the sound decoder on board (Soundtraxx DSX) and is self contained. The speaker enclosure (black tube) is very thick on this unit so it doesn't vibrate. A vibrating speaker enclosure will lessen the quality of the sound. The wires poking out each end of the loco is track power so it can be shared with any units attached to either end. This speaker was tuned specifically for the EMD first generation 567B prime mover sounds. I could have done a bit better had I been more willing to trim more of the metal from the frame away.