Sapphire Sound

[thirdline]

This is probably a daft question but as I don’t know the answer I’m going to ask it anyway. I have two tender drive Hornby A3’s which I have converted to DCC with a Sapphire decoder to cope with the current draw of the ring field motor, both models are in excellent condition and I don’t intend to replace them, though I’d like to fit sound, so, if I was to hard wire a TTS decoder to receive current from the track but leave the grey and orange wires isolated, then set the TTS decoders accel/decel etc the same as the Sapphires and the create a consist using the two decoders would that work?

I’ve thought about it for some time and in my simplistic way of thinking it would work, but I stand to be corrected.

[Chrissaf]

A3 is a steam loco. The TTS experts on here will or will not concur, but my understanding is that the TTS decoder reads the 'back EMF' voltages generated by the electric motor to speed up, slow down and coast the TTS steam engine 'chuff' sounds. So if you piggy back the TTS with another decoder that is providing the motor control and use the TTS decoder just for the sound element, then the sounds the TTS decoder plays will be compromised and not play correctly.

[96RAF]

Correct Chris

Piggy backing TTS works with diesels but not steam for the reasons you have given.

[thirdline]

Thanks chaps,

I thought there might be a tech reason why it wouldn’t work.

thanks again.