Replace DCC Decoder for Bachmann 4-8-4.

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#1
Hello - what's a recommended or the best DCC decoder (and speaker) replacement for a Bachmann 4-8-4 Northern? Looking for optimal performance and realistic sound.
 

beiland

Well-Known Member
#3
I just may need to do this myself as I think I burned one of them up on my latest experiment with a Shinohara double crossover :eek:

I had plans on perhaps a WOW decoder with sound.
 

tootnkumin

Well-Known Member
Staff member
#5
Came across this article on Bachmann's releases of this loco. Interesting as far as the improvements that were made since inception. A note near the bottom advise that N&W's 4-8-4's are not the same.
http://www.spookshow.net/loco/bach484.html
I have been using iPhone 6s plus speakers rather than the 4s because, although wider, the fit up into the shell of an e.g. Athearn diesel, are slimmer in depth and fire out of the end instead of the side. All that needs to be trimmed off is that mounting bracket. There is also the 7

The 7 plus is similar, but requires more trimming of the bits on the side. In a wide tender, may not need trimming at all or only slightly. Doesn't seem to affect the sound volume or quality. The 7 seems a tad better in both departments than the 6, the exit being fractionally larger.

Picture sizes aren't relevant, they are both about the same dimensions.
 
#8
I plan to do this myself. How difficult is it to swap the Bachmann decoder for a SoundTraxx Tsunami? Does SoundTraxx provide good wiring instructions - or will I have to research on the net?
 

trailrider

Well-Known Member
#9
I plan to do this myself. How difficult is it to swap the Bachmann decoder for a SoundTraxx Tsunami? Does SoundTraxx provide good wiring instructions - or will I have to research on the net?
I have NOT attempted to do this on a Bachman 4-8-4, but have converted four (4) Mantua-based steam locomotives to DCC/sound using Soundtraxx Tsunami2 TSU-2200 digital sound decoders (P/N 884007) with their Current Keeper that plugs into the decoder. I use their P/N 810131 28mm Mega Base Speaker (square base) that measures 1.10" on each side, and is 0.44" high. Although there are four small holes in the speaker's base, I just glue them in with silicone calk. The TSU-2200 decoder is good for motors with stall currents plus lighting outputs up to 2.0 amps total. Their wiring diagrams are very clear, with the wire colors described in parenthesis right along side of each wire in the diagram. For headlights you can either use incandescents or LED's (with the proper resistor in series. (I have been using 12-14v Grain-o-wheat bulbs. You can download a great manual to determine all sorts of stuff, including selection of whistles, chuff sounds and bells. I don't do a bunch of stuff that is available, but even the default CV's are great. The only thing about the sound as it comes is that it is pretty loud, and you might want to adjust the master volume CV. If you happen to use an NCE Power Cab, there is a neat feature: In addition to blowing the whistle by pressing that button, if you press F9, it will automatically blow the - - o - grade crossing sound. Don't know about other controllers. Best of luck with it.
 

autocoach

Active Member
#10
Would the Bachmann 4-8-4 be the ATSF 3700, NW J or the SP GS4. Sounds would be different as the ATSF and SP locomotives were oil fired rather than coal as in the NW J. And I believe the J had a mechanical stoker so no shoveling coal by the fireman. They had different distictive whistles and in the case of the GS4 an air horn as well.
 
#11
This is a Bachmann 4-8-4 Northern, Union Pacific with an oil tender. This model train is from the 90's. I rebuilt it and added a new drive train that was bundled with a decoder, as a project I took on. I think this decoder is Bachmann's brand, or a low standard SoundTraxx, as you will see in my prior post,
http://www.modelrailroadforums.com/...s/ho-bachmann-4-8-4-northern-greyhound.25028/

I was planning to get the SoundTraxx Heavy Steam (826103) https://www.soundtraxx.com/dsd/tsunami/1000.php
 
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trailrider

Well-Known Member
#13
This is a Bachmann 4-8-4 Northern, Union Pacific with an oil tender. This model train is from the 90's. I rebuilt it and added a new drive train that was bundled with a decoder, as a project I took on. I think this decoder is Bachmann's brand, or a low standard SoundTraxx, as you will see in my prior post,
http://www.modelrailroadforums.com/...s/ho-bachmann-4-8-4-northern-greyhound.25028/

I was planning to get the SoundTraxx Heavy Steam (826103) https://www.soundtraxx.com/dsd/tsunami/1000.php
The TSU-1000 is only a 1 amp decoder. Are you sure that is a high enough rating for the stall current of the motor plus whatever lights you have? While waiting for repair of my TCU-2200, I temporarily installed a -1100. While it handled the motor and the headlight, as well as the whistle and bell, you could hardly hear the chuff sound. I called Soundtraxx was was told that was because of the 1 amp rating. Might want to check it.
 
#14
I guess it shows my ignorance with DCC decoders. I have the locomotive's main headlight and the tender's rear headlight. I may plan to place a light in the cab. Which SoundTraxx heavy steam decoder is adequate for what I have?
 

trailrider

Well-Known Member
#15
I guess it shows my ignorance with DCC decoders. I have the locomotive's main headlight and the tender's rear headlight. I may plan to place a light in the cab. Which SoundTraxx heavy steam decoder is adequate for what I have?
Again it depends on the stall current of the motor, plus the combined current draw of the lights (bulbs or LED's). You need an ammeter that can be hooked up in series with the motor and a DC power pack. Run it at full throttle (or about 12 volts DC), and then stop the drivers from turning either by pressing the locomotive down on the track or upside down, with you fingers. Note the current draw, and that should tell you what you need. If the total draw is 1 amp or less, then a TCU-1100 will work. If current draw is over 1 amp, but 2 or less then the -2200 is what you need. I doubt you'd need anything of a higher rating in HO, unless you are using a large open-frame motor, like a Pittman.
 

MikeM

New Member
#20
This is a Bachmann 4-8-4 Northern, Union Pacific with an oil tender. This model train is from the 90's. I rebuilt it and added a new drive train that was bundled with a decoder, as a project I took on. I think this decoder is Bachmann's brand, or a low standard SoundTraxx, as you will see in my prior post,
http://www.modelrailroadforums.com/...s/ho-bachmann-4-8-4-northern-greyhound.25028/

I was planning to get the SoundTraxx Heavy Steam (826103) https://www.soundtraxx.com/dsd/tsunami/1000.php

All the newer Bachmann 4-8-4s are the same underneath the shells (in fact you can buy shells from Backmann and swap them out, for example if you wanted a Daylight just order the Daylight shells (loco and tender). What I did was leave the PCB board in place on the locomotive and just trace the wires in the harness to the proper pin out on the new decoder that you will install in the tender. I utilized the Bachmann wiring harness and soldered the leads from the Sountraxx to it. Its actually pretty simple. Here is a pic of the testing stage before I added the second speaker and tidied up the wires a bit.

Great job on your 4-8-4 rebuild by the way. Looks really good.
 

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