my plan to limit top speed), they would need more than a sim-
ple HO scale decoder. Josh at QSI suggested that one of the
Titan Magnum decoders [8] would fill the bill and he was, jus-
tifiably, proud of the sounds that they put into the decoder.
Next came the speaker selection. There was a 50 mm diam-
eter boss molded into the fuel tank. I had a 50 mm speaker
with a tall magnet structure in my stock, but it was rated for
¼ watt. With the decoder able to supply 2 watts of power, I
wanted a more robust speaker. Chatting with Jack at Litch-
field Station, I found exactly what I needed, a thin‐profile 50
mm speaker with a 1½ watt rating.
The next stumbling block was fitting the decoder into the
loco. The Magnum is designed with garden scale in mind and
the RS3 is a very narrow and low hood loco. Well, I was all
set to install the decoder on the floor pan of the loco when I
realized that the hood opening is narrower than the decoder.
9. Decoder installed in the loco floor. Bruce Petrarca photo.
9
DCC Impulses Column - 11
OK, I had to design a verti-
cal mount and even then,
the decoder reaches almost
all the way from the floor to
the roof.
Once all of these issues
were addressed, the instal-
lation was straightforward.
I did adjust rail wires to the
NMRA color code of red and
black, away from orange and
black. I’m still experimenting
with series vs. parallel for the
motor connection. But the
decoder is capable of han-
dling either connection.
MRH-Nov 2014
