MRC 4-6-2 and 2-8-2 Sound Decoder Selection and RS-11 Install

[narrowminded]

Recently picked up 2 each of these units, latest version with wired headlight, and will be doing my first decoder and sound install.  I couldn't find a specific recommendation for these but figured to go with Loksound and a speaker with enclosure.  I suspect it will be a Loksound select mini but see them with (I think) wires, six pin, and eight pin variations.  I also have to select a sound file and/ or purchase their programming tool.  I will probably want to do that someday but might want to wait until I've gained a little experience.  Also need to select "the biggest speaker that will fit" and fabricate or purchase a sealed enclosure.  Does a "sugar cube" speaker accomplish this as a contained package (and which one) or do I need to do some mixing and matching to get a decent package?

These are the basic things I've gathered from reading up in the DCC threads but to aid in getting my feet wet would appreciate any specific advice on component selections for these two applications and/ or links to others experience with installs in these models. 

Thanks in advance.

[jdcolombo]

For my MRC 2-8-2, I used a LokSound Select Micro.  Just buy the 8-pin version (which is the most popular one, and the one most often stocked by dealers) and cut off the plug.  That leaves you with a couple of extra function wires (the green wire and the purple wire) that you won't use.  There will also be two brown wires for the speaker connection that aren't part of the plug.  The rest of the wiring is pretty straightforward because there are six wires that go from the boiler to the tender on the updated MRC version of the 2-8-2, and my recollection is that they are already mostly color coded.  The black decoder wire goes to the left-side track pickup wire; the red decoder wire goes to the right-side pickup; gray and orange go to the motor, and blue and white go to the headlight (I don't recall a backup light in the tender on this model, but you could add one if you wanted by drilling a hole in the rear of the tender and using an LED).

The speaker I used was an 11x15mm "sugar cube"-type in a custom enclosure made of .040 styrene.  The speaker/enclosure then will fit snugly in the tender shell mounted transversely.  Here's a photo of that:

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The decoder then mounts behind the speaker.  You will also need some kind of keep-alive, because the MRC 2-8-2's electrical pickup isn't great.  I made my own from 8 220uf, 16v tantalum caps, but I think there is room for a commercial TCS KA-3 keep alive if you mount the decoder and keep alive on their sides next to each other on the tender floor.  I'd have to measure to be sure, though.  Here's a photo of the interior of the tender in my install, which does not use a commercial keep-alive:

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For a sound file, I used the SOO Line Mikado sound file.  It's SOO-specific, in the sense that it was recorded from a specific SOO 2-8-2 and only has that one whistle and bell, but unless you have particular memories of a specific whistle you want to re-create, the SOO file sounds great.

John C.

[narrowminded]

Thank you, John.  That sounds great. 

So, is it correct thinking that the decoders are the same in all respects (for knowledge) but one has the additional function wires already installed? 

And for the speaker enclosure, when you mention .040" styrene, is that for convenience or is it important that the box be robust/ rigid for sound quality?  For example, would .020" or .010" wall do the job or is the rigidity important?  I recall your posts about a specific volume (500cc?) and also wondered if any attempt was made to subtract the volume of the speaker or just go with the straight cube calculation to the back of the speaker flange. 

And is there a reason not to use a standard "sugar cube" as made or is it just the flexibility or cost of making your own?

And the speaker is best when rated at 8 ohms? 

In addition to this specific requirement, these are the kinds of things I am trying to get up to speed on.

And finally, any thoughts on the 4-6-2 selections?  The hardware should be the same but maybe the sound file should change?

[jdcolombo]

Thank you, John.  That sounds great. 

So, is it correct thinking that the decoders are the same in all respects (for knowledge) but one has the additional function wires already installed? 

And for the speaker enclosure, when you mention .040" styrene, is that for convenience or is it important that the box be robust/ rigid for sound quality?  For example, would .020" or .010" wall do the job or is the rigidity important?  I recall your posts about a specific volume (500cc?) and also wondered if any attempt was made to subtract the volume of the speaker or just go with the straight cube calculation to the back of the speaker flange. 

And is there a reason not to use a standard "sugar cube" as made or is it just the flexibility or cost of making your own?

And the speaker is best when rated at 8 ohms? 

In addition to this specific requirement, these are the kinds of things I am trying to get up to speed on.

And finally, any thoughts on the 4-6-2 selections?  The hardware should be the same but maybe the sound file should change?

1.  Yes the decoders are all the same.  The 8-pin version already has wires attached to the Aux1 and Aux2 function pads (green and violet), whereas the six-pin version doesn't.  But the decoders are identical, and the pads are there for attaching wires if you need them even on the 6-pin version. 

2.  Rigidity of the enclosure is important.  I use the most rigid (or perhaps I should say the "most inert") material I can.  I used to make speaker enclosures out of lead sheet, but many sugar cube speakers have their electrical leads exposed along the long sides of the speaker, and using lead sheet would cause a short.  So I use the thickest styrene I can get away with, and sometimes use lead sheet for the bottom to add weight to the overall installation.  On my 2-8-2, the speaker enclosure is .040 styrene sides and 1.5mm lead sheet on the bottom. 

3.  For an 11x15mm speaker, I have found that an internal enclosure volume of about 750 cubic mm is the minimum (the 500 cubic mm was for an 8x12).  I don't bother subtracting the speaker itself from the internal volume, because the back of the speaker is open, and really all you "lose" in internal air volume is the space taken up by the physical parts of the speaker superstructure and diaphragm.  That's not enough to worry about if the enclosure is big enough to begin with.  My recollection is that the enclosure I built for this had sides that were 6mm wide, with a 1.5mm lead sheet bottom.  The 6mm sides produce internal volume of 6x11x15, or about 990 cubic mm, and that seemed to work fine even with the speaker mounted flush with the sides.  A commercial "sugar cube" with similar internal volume would be fine; I just roll my own for the flexibility and convenience.

4.  A Loksound can use any speaker (or array of speakers) rated between 4-16 ohms.  8 ohms is just the common value for the rectangular cell-phone-type speakers (e.g., the "sugar cube" speakers).   I've actually never seen a 4-ohm flat rectangular; I have seen 32 ohm ones, and those would not be appropriate.  Just stick with 8 and you'll be fine.

5.  I've never done a 4-6-2.  The basic hardware should be identical; it's all just a matter of space in the tender to mount everything.  If the tender is smaller, an 8x12 speaker might be a better choice to free up some space.

John C.

[narrowminded]

Thanks again, John.  I knew I could count on your replies and they are always helpful.

In your installation it looks like you removed the factory weight.  I would guess if true, it was a room problem?

[jdcolombo]

Thanks again, John.  I knew I could count on your replies and they are always helpful.

In your installation it looks like you removed the factory weight.  I would guess if true, it was a room problem?

I generally strip everything out of a tender when I do an install just as a routine matter.  I think in this case I also wanted to hard-wire the tender trucks for electrical pickup and was worried about potential shorts.  But I honestly don't remember. 

John

[narrowminded]

I'm getting there.   Thanks for folks patience.

When I see this description, "ESU N 73814 LokSound Select Micro Sound Decoder Programmed with Steam Locomotives, 4 Driven Axles",  is this just the 73800 with some pre-programmed standard sound files?  And would those files include one of the ones I would want for the 2-8-2?  And with a Lok Programmer this could be changed and in fact, is zero difference in hardware than a simple 73800. 

And taking it one more step, it seems that the 738xx model is always a 73800 with different pre-programmed sound files specifically identified by the last two digits.  Is this a correct understanding?  And does this hold true with other Loksound models like the "direct" series?

[Lemosteam]

@jdcolombo, is there a market for 11x15 printed enclosures for the dimensions you specified?

[RBrodzinsky]

I'm getting there.   Thanks for folks patience.

When I see this description, "ESU N 73814 LokSound Select Micro Sound Decoder Programmed with Steam Locomotives, 4 Driven Axles",  is this just the 73800 with some pre-programmed standard sound files?  And would those files include one of the ones I would want for the 2-8-2?  And with a Lok Programmer this could be changed and in fact, is zero difference in hardware than a simple 73800. 

And taking it one more step, it seems that the 738xx model is always a 73800 with different pre-programmed sound files specifically identified by the last two digits.  Is this a correct understanding?  And does this hold true with other Loksound models like the "direct" series?

Yes, that is correct.  Always the same hardware; just either the sound pre-installed or wiring harness differences (8 pin vs 6 pin).  The Micro Select Direct boards (73100 and 73199) are different hardware. I don't know of any "preloaded" versions of these, other than from a dealer with a LokProgrammer

The 2-8-2 in the Heavy Steam collection is ok, but there is a newer file, project 73474, that is a recent recording of SOO #1003 which is an existing 2-8-2. It is more distinct than the generic file.  You just need a LokProgrammer.   Only downside of the that file is limited whistle selection.

[narrowminded]

The 2-8-2 in the Heavy Steam collection is ok, but there is a newer file, project 73474, that is a recent recording of SOO #1003 which is an existing 2-8-2. It is more distinct than the generic file.  You just need a LokProgrammer.   Only downside of the that file is limited whistle selection.

Thanks, RBrodzinsky.   That steam file is the one mentioned/ recommended by jdcolumbo.  I'm narrowing down my understanding of this and it leads to another question.  With the programmer would it be possible to easily select a different whistle or other specific sounds and edit them in to the Soo line recording? 

I'm inclined to get one of those programmers based on reading and also some searches that were answered by jdcolumbo.  It seems like it would be a valuable tool if you're going to play with these in any more than a few installations.

[RBrodzinsky]

If you want to edit in sounds, you need to move to the V4 line of decoders, not the Select line. About $15 to $20 more, depending on vendor, but then you can edit to your heart’s content with the LokProgrammer. With the exception of the Micro Select Direct decoders (73100 & 73199) the hardware and installation is the same, just different firmware in the decoder.

If you are planning on any significant number of ESU installs, then the LokProgrammer is a necessity, even if just loading Selects.

[Paradise275]

I was told by the ESU LokSound rep that their decoders work best with 4 Ohm speakers.

Rick

[peteski]

I was told by the ESU LokSound rep that their decoders work best with 4 Ohm speakers.

Rick

That is also what the ESU decoder manual states, but the usable impedance range is 4-16 ohms. Lower then 4 ohms impedance would overload the amplifier, and higher impedance simply won't be able to utilize the amplifier's full power (but no damage will occur to either speaker or the decoder).

The lowest impedance utilizes the maximum power available from the amplifier, however this might cause distortion at the higher volumes. This might not be desirable. To me, 8 ohms seems like a good compromise.  Plus, 8 ohm speakers seem to be the most popular in the small sugar-cube-type speaker range.

[jdcolombo]

@jdcolombo, is there a market for 11x15 printed enclosures for the dimensions you specified?

Hi John.

Well, I don't know.  It's a good size to use in smaller tenders.  In larger tenders, I tend to go with a 13x18mm speaker and use an enclosure that is 10mm deep overall.  Steam installations are a bit different from diesels.  On the diesel front, it was an easy call to use a 6mm-deep enclosure for an 8x12mm speaker.  That's a perfect size for almost any hood diesel.  But steam tenders vary so much that I'm not sure there is one good "standard" size that would work for everything.  So, I guess I'd probably say "no."

John C.

[narrowminded]

The 12 x 8mm had a specific number recommended, the SP-1208, but for the 11 x 15mm, from this list I was considering the second line item.  The specs seemed similar enough but the thickness was the least.  Does that look OK or would you choose a different one?

https://www.digikey.com/products/en/audio-products/speakers/156?k=&pkeyword=11+x+15+soberton&pv589=3&FV=ffe0009c%2Cfffc01b1%2Cb8a819%2C1f140000&quantity=0&ColumnSort=0&page=1&pageSize=25