Great Video, no audio
This will be more of a pictoral post, since it’s all pretty mundane stuff. This need for this project was borne from the fact the CoCoDV doesn’t transfer audio thru the hdmI cable. And apparently, it’d cost a lot more money for the hardware to inject audio into the cable. So, I went the onboardamp/speaker route.
To get sound from the RF box, we’re going to need an amplifier and a speaker. This is the amp I chose from Amazon:
it’s own power/volume knob and terminals, and tiny size it’s really perfect for a project like this. Really, though, it’s probably overkill since it’s also a stereo amp, and as we all know, the CoCo doesn’t put out stereo audio.
For power, the little amp runs on 5vdc. I weighed the options, including external power or sucking 5vdc from the coco main board, and i chose external power using USB type C. This seemed to be the easiest way to get power without potentially harming the power supply on the coco main board.
In the left image, you can see the speaker off in the distance a little. In both images, you can also see where I opted to solder the speaker wires to the amp instead of using the terminal blocks. The right image shows, if you look close enough, where I had to use a grinding tool to remove some plastic to make things fit properly. The nut the holds the amp potentiometer to the case, for example, even with a good bit of material removed, only has a couple of threads engaged.
above you have a slightly better view of the wiring. and of course the obligatory Gorilla hot glue used to help hold things in place. the board to the left of the audio amplifier is a buck convertor. since the USB C standard cals for voltages from 5 to 52 vdc, i decided to use a little caution and use a buck convertor to limit voltage to 5 vdc, in the event I forget my usualy USB block. This way I can remove the top, and turn down voltage if needed.
The image to the right shows a mount for the speaker. This was designed to snap in place on the front of the speaker, with tabs that extend to the right an left for mounting to the floor of the CoCo case. Holes & mounting screw could have been used, but I chose to use, again, Gorilla hot glue.
That’s pretty much it. I think in total, I’ve got about $25 wrapped up in this endeavor, and really the audio quality is great. There are options to improve this, and I may do so later on. For example, it could be made to have switchable audio inputs. This would give the option of connecting a speech & sound pak or an orchestra 90 – maybe even one of the sound feature of the newer MPI’s Ed made. Below, I’ll add in two quick video demos of the audio quality. There’s more id like to try, but the Muscia disks on the SDC are giving me a massive headache…