Sound and DCC in a trio of P2K Geeps
#1
I thought I'd share a recent install job I just completed. It was a bit of a chore, but turned out well.

I was asked to install sound in 2 Proto2000 GP9s, and a speed decoder in another, and match them up so they would run well in consist.

They are a nice-looking trio of Northern Alberta GP9's:

   

My go-to decoder for sound these days is the Soundtraxx Tsunami. I had an AT1000 and GN1000 567 on hand, so that's what I used. As for the third, rather than try to match speeds by using another brand, I thought I'd give Soundtraxx's MC1H102P8 decoder a try, since it uses the same motor-drive protocol as the Tsunami's.

I don't generally like doing sound installs on the P2K units because the weight is a single piece, screwed to the chassis. There's always some milling and cutting required to get things to fit. Even with the little mobile decoder, I needed to notch the weight at the top so the plug and decoder would clear.

Here's how things looked after the dust settled:

   

Back-to-front are the mobile-decoder, the GN1000 and the AT1000 units.

The speakers are a relatively new product to me: Railflyer Model Prototypes SK-8701s. They're actually a laptop speaker, but they're a decent price, and sound pretty good. They come with a ported enclosure, and fit nicely inside a road-switcher hood.

For the sound units, I had to carve off a large chunk of the weight forward of the cab. I usually prefer putting the speaker in the rear of the units, but the way the Proto weight is made, it's simpler just to cut the top off the section over the front truck that to try and remove all that material in the back.

As anyone who's done a few of these installs knows, one of the big pains with a sound decoder is where to put the capacitor Curse . With the GN1000, the caps are small and mounted on the board, but where they hang over the end of the motor over the flywheel on an Athearn Genesis, here they needed to have some space carved out of the weight for them. With the AT1000, the cap is floating around on the ends of its leads. I could have carved some more space out of the weight, but I realized it would tuck into the top of the cab, next to the clear plastic light/numberboard insert.

As well, the Tsunami boards are longer than the circuit board originally in the unit, so I had to carve some more space on the top of the weight. For both of the sound units, I kept one of the screws that held the original circuit board so that I could tie a wire to the chassis for the right-hand pickup (left hand is off the top of the trucks).

I replaced the blow-out-if-you-sneeze stock bulbs with Digitrax warm-white LEDs. I used 680 ohm resistors for the mobile decoder and the AT1000, but the GN1000 has 1.5 V outputs all around. I scratched my head for awhile before discovering that this decoder has a 14V function common lead so you wire the outputs as usual, and instead of running the blue common to the paired terminals, you run it to the 14 V common. One wierd problem with this decoder was that when I tried using the head/backup light outputs, the LEDs were always on... no response to F0. So rather than fuss around I moved them over to the FX5 FX6 outputs, and remapped F5 and F6 to F0 - they worked fine. Space was a bit tight with the AT1000 at the rear, so I folded the resistor under the end of the board, hence the extra space cleared in the weight there.

After several minutes of trying to hold my mouth the right way, I got the shells back on, and ran them. They sound pretty darn good, but oh my are they stiff Eek The original grease in these units had turned into some sort of brown waxy gummy mess... I had to open the gear towers and swab it out, and I replaced it with white Teflon grease. Now they're a smooth trio.

I'm going to try to get some video of the 3 in operation, so we'll see if it does the sound any justice.
Reply
#2
Great thread, thanks for sharing. You did a mighty fine job on those installs. I've got a sound decoder to install in an Athearn CF7, but haven't gotten up the nerve or motivation to do it yet.
Reply
#3
Gary S Wrote:Great thread, thanks for sharing. You did a mighty fine job on those installs. I've got a sound decoder to install in an Athearn CF7, but haven't gotten up the nerve or motivation to do it yet.

Thanks Gary! I'm pretty pleased with how they turned out.

Actually, the hardest part of custom installs is building an enclosure for the speaker. Using a speaker like the Railflyer Prototypes one will make it very easy to put sound in your CF7. You can plug a Soundtraxx TSU-1000 (the original one) directly into the board (that takes care of motor and pickups and lights) and solder the speaker wires up, tuck everything inside and away you go!
Reply
#4
The real issue that is keeping me from doing the install is the lights. I haven't researched how to best handle those, whether they need to be changed to LEDs. Also, I dislike having to mess wires from the chassis to the shell. I like the way that my P2K GP30 uses clear plastic to transfer the light from the chassis to the lens, with the light mounted on the chassis.

The CF7 cab is quite large, and a 1" speaker will go in there. The speaker can be mounted facing down, and the upper part of the cab is the speaker box.
Reply
#5
Thanks for posting this, I'm always interested in how people solve decoder install problems/challenges. :-)
What you didn't write (yet) is how you went about speed matching these, and if they (the decoders) all performed more or less identical or was there a lot of fine tuning involved? I've also still got a few Tsunami installs to finish, and also have one or two loco's that will get a non-sound decoder first, to get them operational, so your experiences with matching these up would be great to read about. Cheers!

Koos
Be sure to visit my model railroad blog at <!-- m --><a class="postlink" href="http://www.namrr.blogspot.com">http://www.namrr.blogspot.com</a><!-- m -->
Reply
#6
Actually, since they're all identical mechanisms, they're pretty closely matched in speed as it is...

... well, now, anyways. They're about 10 years old or so, and the lube in them had turned waxy/gummy/gross. It was weird to watch them run, because you'd start them off, and you could hear the motor straining to get the lube liquid, then once it did become liquid it was like someone smacked them in the butt, and they'd take off.

So, after disassembling the drives, cleaning thoroughly and re-lubing with teflon grease, they all run close enough that I can put them 1-2-3 on the track and run them back and forth in consist without them bumping into each other. Unfortunately I don't have a layout per-se, just an 8' test track, so I can't let them do laps to see how they'll act. Also, I'd like to see them after an hour or so of breaking in.

As far as actually speed-matching with the decoders, I haven't played with speed-matching different drive locos yet. You can't do the quick-and-dirty speed match using the Min, Mid and Max CV's because Tsunami's don't use the CV5 (Mid) value. I've found, though, that if the speeds are very close, once they're in consist well-tuned BEMF evens out the slight differences and they seem to run well together.
Reply
#7
If you had to notch the weight on those style P2K Geeps just to fit a motor only decoder - I think you're using the wrong motor decoder!
FOr motor only I've been using a TCS T1 and hard wiring it in. The lights get repalced with a T3 (3mm) Yelo-glo LED and 1K resisotr for each one - the LEDs fit int he space where the bulbs were and shine through the same plastic light guides. Another motor only option is the Digitrax DH165L0, it simply repalces the board with the 6 diodes, and has resistors in palce to use the stock light bulbs with no other changes required. Both of these fit int he space in the shell were the DC light board was with no need to mill any extra space.

--Randy
Modeling the Reading Railroad of the 1950's in HO

Visit my web site to see layout progress and other information:
http://www.readingeastpenn.com
Reply
#8
Randy,

It probably didn't need it, but I'm paranoid. When I set the hood in, I could feel a little resistance, so I just filed the rails down a bit near the rear. I'd rather take a couple of minutes to make sure things are clear than to force it and have to fix it later.

There are lots of options for decoders that fit in these units, but I especially wanted to use the Soundtraxx decoder since the motor drive circuit is exactly the same as used in the Tsunami's. Since these are going to be run as a set, any speed matching that would be required is much easier if all 3 are on the same wavelength, so to speak.
Reply
#9
Gary S Wrote:The real issue that is keeping me from doing the install is the lights. I haven't researched how to best handle those, whether they need to be changed to LEDs. Also, I dislike having to mess wires from the chassis to the shell. I like the way that my P2K GP30 uses clear plastic to transfer the light from the chassis to the lens, with the light mounted on the chassis.

The CF7 cab is quite large, and a 1" speaker will go in there. The speaker can be mounted facing down, and the upper part of the cab is the speaker box.

Gary,

The 1.5 V bulbs in your unit should be fine. Unless you're planning on adding ditch lights, I wouldn't worry about changing them. Athearn leaves the leads long enough to make it easy to work on the unit without worrying about yanking the bulbs out. There's lots of room in there for a TSU-1000 (that'll plug directly into the board's 9-pin plug), its' capacitor and a good-sized speaker in the cab (as you said).
Reply


Forum Jump:


Users browsing this thread: 1 Guest(s)