Adding sound to an HO Atlas SD35

[jon grant]

My latest project changes era again, back to the 1990s, after spending the last couple of months in 1930s Chicago and 1940s Pennsylvania.

I hope to fit a Quantum Revolution soundchip into an Atlas SD35 and then detail the loco to show three different owners at once - Atlantic Coast Line, Seaboard Coast Line and CSX, with lots of patchwork evident.

The first job is to make room for the speaker and soundboard, including the capacitor by cutting away parts of the loco weight. I also removed the dual-mode DCC decoder that came with the loco.

The next job is to make a seat for the speaker above the rear truck and fit the rear light.

Ps. You may have noticed that the hill in the background has been somewhat de-forested - the trees went to Sweethome Chicago last month

Jon

[jon grant]

I finally finished the install tonight after a few busy days at work.

I added some lead to the top of the motor to compensate for what had been cut away. More will be fitted beneath the long hood, when I start on the body.

I modified the 8ohm high-bass speaker to include the LED for the rear light. This was the only way I could get the LED at the correct height. I also had to cut away some of the clear plastic from the lens/numberboard casting so the speaker would fit.

The capacitor wires were shortened to suit and the capacitor sits loosely on a cradle made using the pickup wires and those for the front nose-mounted LED.

Here are the photos

Even without the body-shell in place, I am pretty pleased with the sound quality from the speaker.

Now to start on the detailling and weathering on the loco.

Jon

[HLShortLine]

Thanks for your detailed explanation and great photos, Jon.  I am part way towards adding DCC sound to my Atlas Alco S 4.  It is very helpful to see what you have done in your modification of the SD35.

Cheers,

Harold

[jon grant]

HLShortLine

Thanks for your detailed explanation and great photos, Jon.  I am part way towards adding DCC sound to my Atlas Alco S 4.  It is very helpful to see what you have done in your modification of the SD35.

Hi Harold

Although it's not an Atlas, I fitted decoders to a couple of my P2K Alco S1s and the method may give you some food for thought. I decided that the best speaker location was in the cab, face down, with the sealed inside of the cab itself as the speaker baffle 

 

Finally, heres some video of one of the S1s in action

http://www.youtube.com/watch?v=Ylk4oag6Pe8

Hope this helps with your installation

Jon

[rrinker]

 Which speaker is that, looks like a perfect fit. I might do that to my second S-1.  I'm sortra surprised the Rev-A board fits width-wise, although if it fits under an Atlas RS-3, then I suppose it shoudl fit under the S-1.

                            --Randy

[jon grant]

rrinker

 Which speaker is that, looks like a perfect fit.

Not sure Randy, but I did have to shorten it by a couple of mms to fit across the cab.

Jon