It has always been a mystery to me about the cost of adding Sound to O Gauge locos, so I thought I would share my own experiences so far.

I recently joined the Warley Model Railway Club where DCC operation in O gauge is the norm. Gathering other peoples experience encouraged me to upgrade my 7mm locos into DCC Sound.

One important facter pointed out to me is that current sound decoders cater for N Gauge, 00 Gauge etc and for the very larger scales LGB, Guage 1, etc but there is little information on the inbetween scale of 7mm and I guess this has a lot to do with the mix of quality modern electric motor verses older heavy duty technology that exisits within the O Guage world to cater for hauling long rakes of variable quality stock.

I was always of the understanding that O gauge required High Ampage Decoders which come at a high price, but if you are installing modern motors in your kits , this aint exactly so.........

My stock are fitted with Buhler, Mashima, Maxon mechanisms all of which draw the same ampage as their 4mm equivalents. Armed with this knowledge I put all my motors to the test............

All motors drew less than 0.5amp in normal running and no more than 0.8amp at stall, which meant that I could use an appropriate (4mm) decoder as I had in my 4mm locos.

As already mentioned, I am very impressed with ZIMO decoders and I opted for ZIMO MX645 which is rated at 1.2 amps normal and 2.5amps max, and up to 3watts of sound, more than capable of handling my 7mm stock. I have been keen to avoid generic based steam sound and have chosen appropriate real GWR sounds from Youchoos supplied through Wickness Models.

I started with my GWR Diesel Railcar an ancient kit (1986) with an equally ancient motor set up. I was surprised it drew less than half an amp at full pelt.

Thanks to all those evenings long ago in the 1970`s determined to make those open framed K`s motor and gears to mesh quietly, this set up runs very smoothly.

For all those modellers out there that have got this far and are perhaps hesitant, there is no great difficulty in hard wiring decoders yourself. With Zimo decoders.......

Purple wires go to the speaker, red and black wires are left and right side pickups, orange and grey are right and left motor. The blue and white attached to the stay alive capacitor. The remaining wires in this project are seperated with black tubing to be used another time on fitting LED lighting. All exposed wires need to be sealed with heat shrink tubing. and everything insulated from the metal body/chassis parts. I used a Zimo LS 2040B bass reflex speaker which is housed in a plastic baffle box.

These sound decoders are very robust but will not tolerate electrical shorting between motor and pickups and metal loco bodies. As I did`nt anticipate DCC when I constructed my locos over the past 6 years some time was spent eliminating any problem areas within the metal chassis. To help me , especially when guzzling Coors Light ( wimps water ) or disturbed by phones and doorbells I label all wires as I go along.

First task....separate motor leads from pickup leads

Insulate as much as you can from metal chassis.......

Then tidy up making sure no wiring is able to be pulled or snagged on swinging bogies.

For any of you that have lasted this far this is the link to see how she sounds...........