Sunday, 12 January 2014

Setting the volume to 11...

So, yesterday my replacement amp turned up, pretty decent delivery time from China, so I set about putting into the system without destroying it... or my PC... or my house.

This, you may remember, is the amp in question:


First up I should thank a guy called +Paul Huinink whose Youtube video helped me to figure out how to wire my head phone jack to the three pin connector.

Having figured the sound input bit out (with Paul's help) and fiddled around with getting the three wires wrapped around the pins whilst simultaneously watching Match of the Day - after that, everything else was pretty simple.

Here's a video (Yeah, video, I'm stepping up my game with this blogging shenanigans!) of the test rig I set up. (You'll need sound, obviously.)


Not sure what's with the the PC needing two attempts to fire up - think it might be a safety feature as it's only done it when the case is open.
You can see that I used the PC for power only and took the sound from my Asus Transformer tablet, it was just more convenient for this test and as the amp is wired to a standard 3.5 headphone jack the sound can come from anywhere.

Having proven the concept to myself and managed to not burn the house down I set about installing the thing inside the PC cabinet.

I had a rummage around in my tub-of-random-stuff that lives in the garage and came up with these.



I then pulled the front off the PC which revealed a honeycomb plate, ideal for my purposes.

First thing I did was insulate the back of the pcb in typically lo-tech fashion (gaffer tape) and I also used the cable ties as plastic washers by wrapping one tight around each screw between the PC cabinet and the PCB.
The bolts turned out to be superfluous - the screws I found may have been varying lengths, but they were exactly the right diameter to hold fast to the board without fixing from the other side - which was a bit of result really as it was enough of a fiddly bastard already.

Eventually it looked like this:



You can see the cut cables from my test power source in the foreground. There was a small connector block in my tub-of-random-stuff so I decided to put it to good use.
I also found some sticky back tabs with holes for cable ties so, after a bit of tidying up, it looked like this:


Both the headphone plug and the speaker wires run out through an open pcb slot in the back of the machine.

Unfortunately, I'm getting a bit of interference with this set up. Seems to be when the HDD is getting a bit of a workout. I tried putting the PCB in different locations but it made no difference.
The problem  mainly manifests at start up and shut down, so it's not a biggy - just an annoyance. 

Because of this I may remove the component from the case and reposition elsewhere in the cabinet when it comes to the final build, but for now...

I should add that the noise on that video is some idiot rubbing his finger against the microphone, not the interference I mentioned above!
I'm really happy to have all this together and especially to have implemented the sound without the need for an additional power source.

So as far as components are concerned I'm all ready to go, I just need to find the time to get started on the woodwork - and the inclination to get out in the freezing garage to do so.


#mame #arcade #Retrogaming