Well that's one supplier I wouldn't recommend. Then I added a week. Then today notice a youtube where 4 ohms is an issue for him. I'm yet to try but the spec suggests it's fine.
First the volume knob comes off.
Then the 4 Allen Key fastenings come out, and the front lifts away
Then the fastenings at the rear, including the 5th that holds the input sockets firmly to the rear. This 5th screw may also retain a ground wire inside that could need relocating during reassembly. I'm using a bit of tissue to protect the finish on the screws, although chewed up already during manufacture.
Now the lid can slide away, and the board slid from the bottom casing so we can have a look at it.
The heatsink can now be taken off, and a resistor on the board located and removed to reduce the amps gain. As standard full volume is reached very early on the dial, and this excessive gain causes a slight hiss we don't want.
This resistor between a couple of the audio input caps is a little hard to get at, but will likely stick to your iron and lift away very easily. I used a tinned chisel tip to cover the entire component. Try not to disturb it's neighbour though. You might need some £1 shop reading glasses just to see it. Putting one back can be a mare if your not used to surface mount work.
Now lets have a look at the decoupling caps and filter stage. To fit the caps we will be drilling the board and scraping away some of the coating. The tiny filter resistors and associated capacitors just solder on. Here is the board before work starts.
The next few pictures will hopefully need no introduction. Finding where to drill is best done by looking through the board at a bright light. Or copy closely.
Somewhere along the way I swapped the led and straightened a smoothing cap, loosing another to make way for the more useful low impedance one right at the chips power input position. This so called decoupling cap. One of which exists for each half of the chip. The positive side being the long bus bar looking part, and the negative the larger mass as usual.
Got there in the end. Now watch me loose my post lol