Sound Decoder Options (May 07)

Introduction.

The manufacturers of locos for our NSW and other Australian states prototype are making models that are coming in different stages of “optional sound”.

• Eureka Models provides a RTR sound option
• The next couple of releases from Austrains, no speaker or sound decoder, but hopefully room inside to fit speaker/decoder. The NSW 35 Class steam loco is advertised as coming with DCC sound. 
• Trainorama is offering “Sound Ready” that has one or two speakers installed in the loco, ready for the user top provide a sound decoder, but no RTR sound in the near future. Hopefully that will change.

One of the great things, that have happened, in the last few non sound RTRs, is that there is room for a speaker or in the case of Trainorama 44, two 8 ohm speakers. The Trainorama 47 had one 16 Ohm speaker. Fitting an after market sound decoder into a loco is hard enough to find room for just the decoder, but generally to fit the speaker required a bit of metal removal, that required total dismantling of the loco. At leat the 44 and 47 did not need this. So we have to be happy with this. The smaller the loco as in the case of the Austrains T Class, locating the speaker was easy – in the plastic tank, but required total dismantling to drill a hole through the footplate, for the two wires to the speaker.

The fitted speakers in the 44 and 47 were different values, only Trainorama can tell you why, but in their defence, it doesn’t really matter, as the user will fit his “chosen” sound decoder with the appropriate correct speaker. These are the present sound decoder manufacturers with their speaker impedance requirement:

• Soundtraxx - 8 ohms.
• MRC - 8 ohms.
• QSI - 8/16 ohms.
• Digitrax - 32 ohms.
• C-T - 32 ohms.
• ESU Loksound - 100 ohms.

Options.

Options are numerous, but generally price dictates what feature are available in each decoder.

I have fitted many sound decoders in my own fleet and in other modeller’s locos ranging from:

• Soundtraxx DSD-100LCs (diesel and steam)
• Soundtraxx DSD101LCs (Alco in the Trainorama 44).
• Soundtraxx DSXs that are “sound only” decoders in a 53 and AD60 DJH kits.
• Soundtraxx Tsunami in 30T, 32, 35, 36, 50 and 53 DJH kits and Austrains 36.
• Loksound 3.0 and 3.5 in 36s, NRs, 44, 47, 80, 81, C Class & T Class.

Prices of decoders are in Australian Dollars and from Australian dealers, with their features.

Soundtraxx:

• DSD-100LC were $65 BUT no longer available, superseded by the DSD-101LC below.
• DSD-101LC - $92 and come in 3 diesel versions – Alco, EMD 1^st Generation & EMD 2^nd Generation and 1 Steam, I think.
• DSD-090LC – were $110 (there has been a price rise) and come in more versions, please check availability of these at the dealer.

The features and drawbacks of these above decoders are:

· Combination Motor and Sound decoder.

· Motor Current Capacity – 1.0 Amp.

· Low frequency (up to 2,000 Hz) PWM motor drive that causes a hum/buzz in some mechanisms hence the term “noisy” decoder. This is the same as early pre 2003 motor decoders.

· 2 function

· 8 Ohm speaker requirement that is NOT included.

· Does not operate LED headlights correctly. The rear flashes on/off when selected OFF.

· The diesel versions of the DSDs have “idle” sounds when the loco stops, where as the steam versions, the sounds just stop.

Soundtraxx has released the Steam Tsunami at $165 (speaker extra) but NOT a diesel version yet, that comes in 6 versions. The main difference between the versions are the types of whistles included (about 7 in each decoder). The main improvement in the Tsunami over the previous DSDs are:

• “Quiet” 25 KHz PWM motor drive that eliminates the buzz/hum from the mechanisms.
• Basic Back EMF that is used in sound control to modify effects according to the loco “load”.
• A take off at Speed Step 1, every time, no need to play around with CV 2 and does not vary according to load. This provides the best possible slow speed performance. This is one of the great features of Back EMF.
• 14 functions
• Many sound and light effects.
• Size - 42.7 x 17.3 x 6.4 mms. Plus an external capacitor on “fly leads” that is used for DC operation – not a DCC Stay Alive.

The Tsunami, as all Soundtraxx decoders do, DON’T support CV 5 (Volts Max) and CV 6 (Volts Mid) that makes fine tuning and speed matching that just bit more difficult without Decoder Pro. Soundtraxx decoders do have 15 Internal Speed Tables (many decoders have this), but I find only one “nearly suitable”.

As for all Soundtraxx decoders, the speaker is EXTRA. A suitable speaker for the Austrains 36 costs $19. I have used the Trainorama 44 speaker in one of my Austrains 36s and the sound is great. Thanks for that Trainorama.

Loksound V3.5.

At $195, these decoders from Germany from ESU are the ultimate, in that they offer all of above major features, being:

• Quiet >25kHz PWM motor drive – no hum or buzz.
• Back EMF that provides “sounds” varied for load.
• Take off at Speed Step 1 every time that provides the best slow speed performance.
• 4 functions.
• Two sizes available – Normal - 34.5 x 15.5 x 6.5 mms and Loksound Micro - 28 x 10 x 5 mms.

PLUS

• Many different sound files for all types of Steam and Diesels that can be ordered from the dealer at the time of purchase.
• Using the optional $250 Lokprogrammer, the user can download any combination of sounds from the ESU website and load them into the decoder. This allows a user to have a “tailor made” sound. Also with the Lokprogrammer, you can “upgrade” your decoder or fix a bug. I have been able to do both of these items to my Loksounds.
• This feature allowed the installation of a 2005 recording of a real 44 horn at Penrith Station to be installed into a basic Alco decoder for my Trainorama 44s.
• A 100 Ohm speaker is included in the price of $195.
• There are optional different size 100 ohm speakers available.

Downloading and making your own sound files for your locos is not for everyone (I don’t have a Lokprogrammer, but have a few mates who do. They enjoy playing around with sound, where I play around with everything else), so this feature may not appeal to you, BUT where it shines, is that you can change the sounds. Take your Loksound Alco decoder out of your 44 for whatever reason, fit it to an Austrains 36 and take it to the dealer and he can add a new sound file. Even change the version of firmware. Anyway, enough said about programmable decoders. You get my drift on the advantages.

Which decoder to fit?

What do I recommend as of May 2007 (this may change when the Tsunami Diesel Decoder arrives) but at the moment, are:

• Steam: - The Soundtraxx Tsunami (“Light Steam” version for NSW locos) at $160 plus speaker ($19). Total of $179.
• Diesel: ESU Loksound $195 complete with 24 mm speaker with enclosure.

There is not much in it when comparing the “complete” price.

The DSD-101LC and the 090 DSDs at $94 plus $15 – $20 for speaker and the DSD-090LCs etc at $120 plus speaker are a suitable alternative.

Since I have fitted all of my fleet with sound decoders, my preference is for decoders that offer “QUIET” Back EMF motor drive, similar to what is provided in the Eureka Garratts and other QSI locos.

To get the same performance from a DSD as the Tsunamis and Loksounds, you could add a “second” Back EMF decoder that is harder to fit in the available space and have the extra hassle of dual decoder installations, and use the DSD for sound only. The $50 or so, or a Back EMF decoder from Lenz or Loksound etc, would make this nearly the same price as the S=Tsunami or Loksound.

So for the cheap option of about $110, you may have the annoying buzz/hum, poorer speed control and less features, but this is your choice. To see if your loco mechanism buzzes prior to installing a DSD, see my Buzz article

Something to think about when fitting decoders. In the case of steam locos that cost $450 – $650 depending on type, a few extra dollars spent on the better DCC decoders is not much in the big picture of modelling with DCC and having sound. A “noisy” $560 to $760 (that includes the cheap sound option) with less than the best motor control, is bad value when spending a further 10 – 15% more, would give you the “best”. Diesel locos are considerably cheaper due to their simpler manufacturing process, but the same analogy can be applied. 

Speakers.

Speakers come in all different shapes, sizes and impedance (resistance). Soundtraxx uses 8 Ohm speakers whereas Loksound uses 100 Ohm speakers. Do not fit any other that that what is required. The decoder may be damaged.

Speaker Enclosures.

To get the best sound and reasonable volume, most speakers should be fitted into the loco with some sort of enclosure. The purpose of this is to stop the sound waves from the back of the speaker “mixing” with the sound waves from the front and cancelling out each other. Only with higher output power decoders and larger speakers, can we get away without using enclosures. Also a speaker in an enclosure makes a “bassier” sound.

With the speaker and enclosure mounted in the loco, the sound volume is lower with the body off. Put the body on before you become disappointed with your sound installation.

Soundtraxx decoders prior to the Tsunami are generally quieter than the Loksounds.

The volume you operate your sound decoders is up to you, but I operate my Loksound on about “10” out of 63 and my Soundtraxx on about “100” out of 255.

See Also the “Sound” articles at  Marcus’ DCC for Novices and Ogden Lamont’s Installing Sound in HO Locos.