A DCC Sound review of Hornby TTS Sounds of the GWR British Rail Class 47 of functions and sound. I installed the sound decoder in my Bachmann Class 47 no 47834 Fire Fly which is 21 pin model, I used the 21 pin to 8 pin adapter for the tts decoder. Also I replace the hornby speaker with much better, the Zimo Dumbo 26x20x8mm 1W 8ohm. The sound file is in good high quality and perfect improvement. Hope you enjoy this video and thanks for watching.