Digitrax Sound Decoder for Kato E8 - how good is it?

[Maletrain]

When I asked about the MRC version of the drop-in decoder for my Kato E-8s, the replies were not "glowing".

So,  now I am asking about "Digitrax SDN144K0A N Sound Decoder, Kato P42/E8/PA1/F40 4-Function 1A" that seems to have a substantial speaker and a keep-alive. 

How does it sound?  How is the motor control?

[reinhardtjh]

Also not glowing.  The Digitrax SDN144 series has a design defect that causes the audio amp to draw too much power.  You have to be very careful with the sound output levels or else when you do things like blow the horn and sometimes ring the bell, the loco will slow noticeably or stop.  There are also issues with the BEMF settings which can cause problems.  Google "digitrax sdn144ps slows" for other reports.

If you join the Yahoo group for Digitrax sound, you might be able to contact John McMasters who has done an excellent job of creating sound projects for Digitrax decoders which limit this problem.

Or you can spend a few bucks more and get an ESU LokSound Select Micro, have sound file 73883 - Dual EMD 12cyl 567C for Select Direct/Micro loaded and have something that really sounds terrific.  Of course, it's not a drop in so it will take some filing/machine work which may be more than you want to do.

[peteski]

The lack of responses also seems to indicate that not many people even use Digitrax sound decoders.  So that should also be telling you something.  I tried one of their smaller sound decoders and wasn't very impressed.

Also the last digit in SDN144 indicates that it is a 4th generation decoder firmware and hardware. Currently they are up to the 6th generation (the last digit is a "6"). So it is old technology.

[Mike C]

Never used a Dgitraxx  sound decoder . But ....I am really happy with Soundtraxx tsunami  2 decoders ..... OK different company named ...but ... look at the manuels for the decoders . They read virtually the same !   OK so this is a rant ...... Digitrax non sound decoders work just fine , it's what my LHS sells and I have no problems with them . But I stay away from Digitrax sound decoders . Poor sound , and their speakers suck !

[OldEastRR]

Be advised you need to bore a big hole down thru the rear of the E8 frame to install the speaker as instructed. Plus the capacitor for the "keep alive" is inadequate.

[peteski]

Be advised you need to bore a big hole down thru the rear of the E8 frame to install the speaker as instructed. Plus the capacitor for the "keep alive" is inadequate.

Yes, that will improve sound quality (of any decoder/speaker installed in that loco).  I did that on a Digitrax sound decoder install for a fellow NTRAK member.  After the speaker was installed I covered the top of the opening with sheet styrene to seal the sound enclosure.

[jdcolombo]

Yes, that will improve sound quality (of any decoder/speaker installed in that loco).  I did that on a Digitrax sound decoder install for a fellow NTRAK member.  After the speaker was installed I covered the top of the opening with sheet styrene to seal the sound enclosure.

Honestly, folks, if you're going to go to that kind of trouble to use a Digitrax sound decoder, you'd be a lot better off just finishing the job with a LokSound Select Micro and be done with it. 

I understand the appeal of drop-ins, and realize some folks may not be comfortable with the milling and hard-wiring necessary to do an after-market sound install in a typical diesel.  But we are where we are in the hobby - from here on, I suspect that Atlas, IM, Fox Valley, Kato, etc. will all offer sound options in their diesels (in the case of Bachmann, you may not have an option - it will just come with sound installed).  But getting good sound (notice the "good") as a retrofit is just going to take work, and if one isn't comfortable with doing that work, there are lots of custom installers out there.  There's a reason Atlas, et. al. aren't using MRC or Digitrax drop-ins for their new sound-equipped locos, and it isn't because LokSound is cheaper . . .

BTW, Pete, superb milling job!

John C.

[robert3985]

I use 'em in both my Kato E-9's for my COLA, and I'm not very impressed with their sound as compared to ESU.

Also, they're not really "drop-in" as considerable machining must be done to the frames for the big cap and the speaker.

But, they ARE cheap!...and the sound is acceptable except the horn's sound file can be heard "stitching" itself on long whistles as it loops.

Although I've got both a mill and a big, commercial drill press, drilling out the hole for the speaker wasn't easy because the alloy Kato uses on their chassis is difficult to drill.  However, with a good, sturdy drill press vice, then a good, sturdy milling vice,  both the boring of the speaker hole and milling the cap cavity were fairly easily done.

I wouldn't have wanted to do this without proper machine tools.

I don't remember the exact size of the drills I bought and my shop is still all packed up in boxes from my recent move to a new residence, but there is enough metal in the big rear chunk on the Kato chassis to drill a "stepped" hole that a circular speaker can be friction fit into it, with the smaller hole forming a shallow "shoulder" to keep it from dropping out and keep it from buzzing with a nice, close clearance fit.

Ideally, if you have a lathe, you can easily machine a friction-fit "lid" for this hole and it forms a very nice and dense airtight speaker enclosure, with excellent volume.

If you don't have a lathe, this setup will operate just fine and with plenty of volume with the close-fitting shell attached.  There is a very noticeable increase in sound level from test running your E's without shells, and when you put the shells on....from barely perceptible, to LOUD.

Photo (1) - Kato E's on my workbench being equipped with Digitrax "drop-in" sound decoders:


Photo (2) - Kato E chassis with one being finished, and the other bare.  Notice the "stepped" hole in the bare chassis which keeps the speaker captured:


When I get ready to DCC-ize any more Kato E's or PA's, I'll change the hole-drilling procedure to a single, non-stepped hole drilled from the bottom of the chassis upward, and stop before I get all the way through, which will form an airtight enclosure without having to machine a brass "lid".  Drill a small hole for the speaker wires to come out and attach to the decoder, sealing the wire-hole with a dab of caulk or gasket maker.  The drill I used (which I can't remember the size of) was a perfect "friction-fit" for the round speakers that came with the Digitrax Sound Decoders and they won't fall out because of that tight fit, so the shoulder was superfluous.

When I get ready to DCC-ize any more Kato E's and/or PA's, I'll do it the way John ( @jdcolombo  ) does it, and I won't be using Digitrax sound decoders.

When installing any Digitrax "drop-in" decoder, make sure you solder the power tabs to the board by first tinning the tabs, bending them down to touch their respective contact points, holding them down with a pointy metal object and just touching your iron to their top, backing off and continue holding until the solder freezes.  Reinsert the Kato attachment clip to hold the decoder in place.

I have never had a problem with speed changing during application of sounds. 

These certainly are not the best sound decoders, but their speed controls are okay and they're easy to speed match with each other, including the non-sound drop-in decoders (which really ARE "drop-in" ) which I run in my B's.

They are okay for their price, which is about half of what an ESU decoder will cost you.

In my mind, even not-so-great-sound is better than no sound at all, so if Digitrax sound decoders are all you want to afford, they are better than no sound.

My use of them was a temporary solution, and they'll be getting replaced with Loksound decoders and better speakers when I get around to superdetailing my passenger diesel prime movers.

[peteski]

Honestly, folks, if you're going to go to that kind of trouble to use a Digitrax sound decoder, you'd be a lot better off just finishing the job with a LokSound Select Micro and be done with it. 
. . .
BTW, Pete, superb milling job!

Thanks John - Sherline mill makes this easy (but it still took some time to remove all that metal).
I was given the model and the decoder and asked to install it.   I went the extra step by milling the chassis for the included speaker.  It was basically a favor for a friend and a fellow NTRAK member.  He is in high-school with limited funds. While the enclosed speaker makes a big difference I was still not very impressed with the Digitrax sound.

[jdcolombo]

@robert3985

Bob, when you decide to DDC-ize your PA's and E's, don't use the 15mm round speaker.  Part of the problem with the Digitrax sound decoders (not all of the problem, but a significant part of it) is that the 15mm round speaker packaged with it is terrible. 

Instead, use an 8x12mm Soberton (available from Digikey) in John LeMerise's 3D printed enclosure, like this:

[ Guests cannot view attachments ]

This will sound a ton better, and takes less milling too, since you just have to mill a bit at the front.  This is a Kato PA, for the E's, you might have to put the speaker in the back and mill the frame (Rick Brodzinsky has done E's, and now I can't remember if he put the speaker up front or in the rear).

There's plenty of room for speaker, LokSound, and keeper caps.  I did mill a small space in the rear for the caps, like this - though I actually milled way too much):

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This PA sounds terrific, and at the end of the day, really isn't much more work than using a Digitrax "drop in".

John C.

[jdcolombo]

Thanks John - Sherline mill makes this easy (but it still took some time to remove all that metal).
I was given the model and the decoder and asked to install it.   I went the extra step by milling the chassis for the included speaker.  It was basically a favor for a friend and a fellow NTRAK member.  He is in high-school with limited funds. While the enclosed speaker makes a big difference I was still not very impressed with the Digitrax sound.

Hi Peteski.

Didn't mean to imply that you chose to use the Digitrax; I know you wouldn't! 

I was only trying to point out to others reading this thread that if it takes that much work to do the Digitrax "drop in", there's not much MORE work involved to install and wire a LokSound, which will produce a much happier ending for all.

John

[RBrodzinsky]

For the E units, I put the speaker in the rear. There is a huge amount of space (after milling) back there, and it is easy to make the milled pocket the "right" size to hold the speaker/enclosure snugly.

[Jbub]

  I did mill a small space in the rear for the caps, like this - though I actually milled way too much):

(Attachment Link)



John C.

John, I've seen those caps elsewhere but I'm not sure what type and rating they are. I'm doing an install on a pair of 'LL gp60's and realized I need a keeper cap for the lok sound decoders. Also I'm having a hard time finding where to solder the cap to.  Sorry for the hijack
Jason

[jdcolombo]

John, I've seen those caps elsewhere but I'm not sure what type and rating they are. I'm doing an install on a pair of 'LL gp60's and realized I need a keeper cap for the lok sound decoders. Also I'm having a hard time finding where to solder the cap to.  Sorry for the hijack
Jason

The caps I use right now are 16v, 220uf tantalum chip caps, made by AVX.  These are black, not yellow.  They are available from Digikey here:

https://www.digikey.com/product-detail/en/avx-corporation/F931C227KNC/478-8257-1-ND/4005713

Kemet makes a similar cap, which is probably the ones I used in the Kato PA, since they are yellow.  The Kemet is about 40 cents cheaper, and I've used Kemet caps in the past:

https://www.digikey.com/product-detail/en/kemet/T491D227K016AT/399-10429-1-ND/3907798

I see no reason to spend an extra 40 cents per cap, so buy the Kemet. 

You do want to be careful with your track voltage when using these caps.  I keep my track voltage at 11.5v; the "HO" setting on Digitrax is about 14v, give or take.  These caps should be OK with track voltage up to about 14v.  But go over that, and you risk a cap blowing up (and I literally mean "blowing up" - these things go with a loud POP and much fury, so don't try to push the envelope unless you want a melted shell or worse).

As for connecting, the caps must be wired in parallel if you use more than one.  I suggest using at least two.  If you use more than two, then you probably should wire a 100-ohm 1/2w resistor and a 1N4007 diode along with the caps to keep the charge current from causing your command station to think there is a short when you first put the loco on the track or power up the layout.  A resistor/diode circuit is shown here:

[ Guests cannot view attachments ]

 The positive end of the cap (usually the end with the band, but you should check the manufacturer's data sheet to be sure) is wired to the blue wire (function common positive supply).  The negative end of the cap gets wired to a bare pad on the "back" side of the LokSound, immediately opposite the blue wire pad on the front.  You will have to cut away some of the plastic wrap to get to this pad.  Here's a photo:

[ Guests cannot view attachments ]

John C.

[Jbub]

The caps I use right now are 16v, 220uf tantalum chip caps, made by AVX.  These are black, not yellow.  They are available from Digikey here:

https://www.digikey.com/product-detail/en/avx-corporation/F931C227KNC/478-8257-1-ND/4005713

Kemet makes a similar cap, which is probably the ones I used in the Kato PA, since they are yellow.  The Kemet is about 40 cents cheaper, and I've used Kemet caps in the past:

https://www.digikey.com/product-detail/en/kemet/T491D227K016AT/399-10429-1-ND/3907798

I see no reason to spend an extra 40 cents per cap, so buy the Kemet. 

You do want to be careful with your track voltage when using these caps.  I keep my track voltage at 11.5v; the "HO" setting on Digitrax is about 14v, give or take.  These caps should be OK with track voltage up to about 14v.  But go over that, and you risk a cap blowing up (and I literally mean "blowing up" - these things go with a loud POP and much fury, so don't try to push the envelope unless you want a melted shell or worse).

As for connecting, the caps must be wired in parallel if you use more than one.  I suggest using at least two.  If you use more than two, then you probably should wire a 100-ohm 1/2w resistor and a 1N4007 diode along with the caps to keep the charge current from causing your command station to think there is a short when you first put the loco on the track or power up the layout.  A resistor/diode circuit is shown here:

(Attachment Link)

 The positive end of the cap (usually the end with the band, but you should check the manufacturer's data sheet to be sure) is wired to the blue wire (function common positive supply).  The negative end of the cap gets wired to a bare pad on the "back" side of the LokSound, immediately opposite the blue wire pad on the front.  You will have to cut away some of the plastic wrap to get to this pad.  Here's a photo:

(Attachment Link)

John C.

Thanks John! I appreciate the help

Jason