So I pulled the TRS-80 apart for a minor tweak this afternoon, as I wanted the ROM selector switch work in the opposite direction, a simple matter of flipping over the plug to the switch.
While I was in there, I though I'd check on my sound mod, because the volume was super low, and found the plug for the audio input partially unplugged. I'd obviously not noticed when I was reassembling after fitting the amp and speakers, so to make sure it didn't happen again, I extended the lead.
What a difference!!!
Audio is now loud and clear and during tested I found Robot attack, a version of Berzerk:
PXL_20231209_141008366.jpg
And it's only got digitised speech. In 48K, Just brilliant and it plays like Berzerk too. 'Game Over Player 1' :)
I'm now on a hunt to find out what games do have sound. It's funny, Tandy told you to connect an amp to one of the cassette leads for sound, shame they couldn't have just added a small amp in the base, there's so much space.
I have had to turn the volume down a fair bit as it really is quite punchy with the volume up.