ESU LokSound Micro Select Direct install in Atlas GP40-2

[conrad]

In Colombo's Best of LokSound Installs I found Brodzinsky's  73100 install into an Atlas GP38-2.  I discovered that both my GP40-2 and his GP38-2 have the same 1997 frames, p/n 486101 and 486102.  Looks like the perfect match. 

My plan is to use (no laughing) a Digitrax SP10188, 8 ohm, 10x18 oval speaker.  It's only 4mm thick (0.157").  It has a peel off adhesive strip around the perimeter so I can stick on a thin piece of styrene to seal the "enclosure".   Two years ago, after reading all the threads on speaker enclosures, I did this to the same speaker in my Atlas SD7 (Digi SDN144A0 decoder).  The result was a vast improvement in volume.

Now I'm stepping up to LokSound.  I know the old hifi adage:"put your money in the speakers" but i'll give this a try.

Hope to provide some photos of the build.

Conrad

[RBrodzinsky]

Conrad, yes, the install should be identical. 

[jdcolombo]

I really hate to see someone install an ESU sound decoder and skimp on the speaker.  Really.  Really, really.

If you keep reading that master installation list, you'll come to a section on speaker enclosures.  The L-shaped enclosure that Rick used for the GP38 installation is now available as a 3D print, here:

https://www.shapeways.com/product/47AN33V3Y/gp-38-40-9x16-speaker-enclosure-2pk?optionId=85016610

You would need to get a couple of 9x16mm speakers for it, but they are available from Digikey and Mouser.  Here's a link for a Soberton 9x16mm from Digikey:

https://www.digikey.com/product-detail/en/soberton-inc/SP-1609S-2/433-1134-ND/6099108

And here's a link to a CUI speaker, also from Digikey:

https://www.digikey.com/product-detail/en/cui-devices/CMS-16098A-SP/102-4338-ND/7404546

The CUI has better specs than the Soberton, but I'm not sure it matters much in these applications.  I use both.

If you're going to go to the trouble of installing the ESU board, why not pony up another $15 to do the speaker right?

John C.

[conrad]

John, you are correct. 

The cost is not an issue.  Modifying the frame is the problem.

I am hoping to get away without "milling".  I know modelers have hand filed the frame but this worries me.  My only modified frame was done by Aztec.  They did a great job.  I've also thought about using a dremel.  It might be to crude though.  AND, I only have those small modelers files, couple mm wide.  Advice on files would be appreciated.

I did go to a technical high school 60 years ago.  Sort of remembering filing v blocks and a parallel clamp that we made.

Conrad

[RBrodzinsky]

I’m not certain you will be able to get even that speaker in without the modification.

[Steveruger45]

Conrad, I only use metal files for milling my frames and occasionally a dremel when files wont cut it (see what i did there😃)
I support the frame halves against a block of wood that i have shaped with indentations to accept the frame ins and outs, so to speak, screw it to the work bench and wedge the frame half against this wood block with clamp on the work bench resting up against the frame half.
Then i use a junior hacksaw and cut the frame in several side by side cuts on the section i want to remove and then use a 8” x 3/4” smooth single cut metal file and/or a 2nd cut file.
I finish off and smooth out with a flat jewelers file.
You dont want to use a coarse file, the frame metal is too soft for that.
Cleaning the file with a file brush or file card helps to keep the files clean of metal that will get stuck in the file teeth.
A good trick to limit that is to rub some school chalk on the file first and reapply as needed as you work.
Here is a link to a set of files cheap that might be worth a look at.  I haven't tried these and cant attest to the quality.
https://www.harborfreight.com/12-in-file-set-5-pc-60368.html

Some think im crazy filing frames but i find it very therapeutic.

[jdcolombo]

I do understand the reluctance to mess with frames (I recently destroyed an FM H16-44 frame trying to modify it for a decoder install; thankfully, Atlas sells parts!).

But I don't think Rick modified the frame very much, and a file probably would work fine for what he did.  If I understand his install correctly, what he did was "file down" the side of the frame opposite the phosphor-bronze clip that holds the worm gear bearing blocks in place so that it was even with the clip, and took just a tiny bit off the frame on both sides behind that clip.  I suspect this isn't more than a 30-minute job with a good file; maybe less depending on how soft the frame material is.  If there was ever an install that was suitable for a first-timer, it would be something like this.

I really think you can do this . . .

John C.

[peteski]

Yes, the speaker (and its enclosure) makes or breaks the sound quality.  To me it is a waste to use the ESU decoder with such a inferior sound transducer.

Conrad, since you are familiar with old-school HiFi, this would be like listening to a record playing on a Garrard 301 turntable, with a Marantz Model 7 stereo tube preamplifier, and a Bryston 4B stereo power amplifier, playing through a 2" transistor radio speaker without an enclosure. 

[RBrodzinsky]

But I don't think Rick modified the frame very much, and a file probably would work fine for what he did.  If I understand his install correctly, what he did was "file down" the side of the frame opposite the phosphor-bronze clip that holds the worm gear bearing blocks in place so that it was even with the clip, and took just a tiny bit off the frame on both sides behind that clip.  I suspect this isn't more than a 30-minute job with a good file; maybe less depending on how soft the frame material is.  If there was ever an install that was suitable for a first-timer, it would be something like this.

Yep, didn’t need much of anything.

[bdennis]

Has anyone done a Atlas U23B with the ESU decoder?
Looking for pictures of the install.
I have installed one, but have not used a speaker enclosure and the sound could be better.
I am happy to mill the frame where needed and have ordered a few speaker enclosures from shapeways.

[RBrodzinsky]

Haven’t done one, but should be relatively similar to the discussion above.  The key will be the amount of room at the rear. On many of the Atlas models, there are minor differences in frame dimensions which can cause major headaches for a sound install.

[conrad]

I think the key for many Atlas locos is to get the rear of the frame milled/filed down, level with the bearing retainer.  My Atlas SD7 is that way factory OEM.  Thus the drop in Digitrax  SDN1440A0 decoder with oval speaker. 

For my GP40-2 I'll order the Harbor Freight file set as a starter and see how it goes.  I have other Atlas loco that required frame mods for the 73100 decoder.

Conrad

PS Peteski, don't forget McIntosh.  Also, I had a audiophile friend who had a Klipsch horn.  A monster, sitting in the corner of his room.

[jdcolombo]

Conrad, another thing you can do to speed things up without much risk is to take a Dremel with a cutoff wheel installed and set the Dremel (use a heavy-duty wheel, not one of the thin ones we all use to cut rail) to the slowest speed you can.  Then LIGHTLY make a cut to the depth you want at the front and rear of the frame.  Now with the Dremel still at its slowest speed, "drag" the cutoff wheel across the cut area - again LIGHTLY.  The cutoff wheel will "scrap" away metal as you drag it across the frame.  When you get close to the correct depth, finish with a file to clean up the cut.

I used to do this all the time before I got my milling machine.  As long as you maintain a light touch with the Dremel, you'll be fine.

John C.

[peteski]

PS Peteski, don't forget McIntosh.  Also, I had a audiophile friend who had a Klipsch horn.  A monster, sitting in the corner of his room.

I did contemplate mentioning McIntosh. 

[conrad]

This is a project update.  While waiting for delivery of the decoder, CUI speaker and Shapeway enclosure I worked on the loco.

I found an 8 by 3/4 file in my home workshop and "made" a file card (it really works).



Next step was to secure the frame halves for filing.  One of my Ntrak C clamps and two wood blocks did the trick.  I did both halves at the same time for a strong hold in the vise and to maintain symmetry.



Vaguely remembering my high school machine shop filing technique (2 hands, nice level strokes) filing commenced



Intermediate result was a slight rearward down slope.  Need a little more file pressure on the uphill side.



After many, many strokes I'm done!  Just a fingernail thickness above the bearing retainer slot.



And a top view; a little sloppy front and rear but flat and true where it counts.