Alco PA1 sound decoder

[canadaandsouthern]

I have a proto 2000 pa1 with a Mars light and I would like to know what the best sound decoder for it would be and where would I put the speaker for the best output.

[lyled1117]

Before recommending a sound decoder for this locomotive, there is something you need to be aware of. The motors of these locos without too much effort can exceed a one amp draw. They stall at well beyond two amps. There was a story going around when these were new releases that Lifelike had an improved motor and supplied it as an upgrade. That is apparently not true. They did supply a 'new' motor but the prevailing opinion is that is what hoped that the new motor drew a little less than the original. I learned this when I contacted Walthers a few months ago when I did an install into one of these locos for a customer, hoping they might have one of the 'improved' motors buried in their parts after buying Lifelike. You could gamble and let the sound decoder power the motor. It will probably hold up, but I wouldn't count on it.

I installed a Digitrax DH465 four amp decoder, letting it power the motor and lighting. It's nice and slender so not a lot of milling was required. I used a Soundtrax Mini-Tsunami as a sound only decoder. I milled a cavity across the top of the weight into which I placed the DGTX decoder and placed a speaker and the Tsunami in the rear area. Component wise this is not cheap, but it makes for as bullet proof of an install as one might get. If you use my method, you can not use a Loksound decoder for sound. Those require being attached to a motor to read load changes for the exhaust rate to change. A cam input is possible with some versions of their decoders, but I don't know how workable that is on a diesel. A Digitrax sound decoder riding shotgun would work as well. They don't require motor attachment. Early MRC decoders needed motor attachment as well, but I don't know about their newer products. I have rarely used them. If you want sound quality, Tsunami is the way to go. However, there is a sizable price tag to go that way. Digitrax for sound will keep the price lower, but the sound quality is not nearly as good. My opinion, and many agree with me, is that Digitrax sound is pretty weak.

Hope this information helps,
Lyle


eta: the owner of the locomotive had 'daylighted' the radiator fan screen which made for an easy escape for the sound. I used a 1" round speaker and enclosure below it.

[Mark R.]

It was only the first run of the Proto PAs that had the high current motors in them. The first run roadnames and numbers are listed here ....

web.archive.org/web/20050421064422/http://www.lifelikeproducts.com/proto/holocoarchive/previouslyreleased/papb.htm

If your engine(s) are not on this list, the motors in them will be fine with whatever decoder you install in them. I ran my first generation PAs with TCS A4X decoders in them for a couple of years before I was made aware of the high current motor issue. I got the replacement motors and continued to run them with no problems to this day.

Adding open grills to a car body to "let the sound out" isn't really good accoustic design. You aren't taking advantage of the cavity within the shell to improve the accoustics. Having done more than a hundred installs for clients, sealing up all the fans and open grills makes a marked improvement in sound quality - especially with brass engines.

Mark.