So I commented on a thread about Adrian's Digital Basement Cube and the lack of internal audio. There I mentioned the DAC that is on the production board. DAC 3550. I also posted about that on reddit and on a Facebook group and was led to Hap at http://www.alittlebytedifferent.com who has a prototype Cube with an internal speaker. I contacted him and got some nice high res photos of the top of his Cube motherboard with the same DAC on it. Closer inspection didn't reveal any real changes from my board to his. Different colour caps and resistors, but no real changes in values that I could see. He also told me that the speaker was connected to the 2 prong connector by the ram labelled J2. So I got to continuity testing from J2 and it lead me to a chip at a spot called U18, this chip had 04BK LM 4861M written on it, which told me that it was an LM4861 audio amplifier. So the production board still has the amp on it as well. J2 was connected directly to the output pins (8 and 5). More investigation ensues. Knowing what each pin did, I was able to confirm that GND is still connected to ground, VCC is connected to a capacitor, but I haven't tested with it powered on, so I don't know if the cap is smoothing out 5v power, but I suspect it is. Pin 4 is -IN and is connected through a resistor to -analog out on the DAC. +IN is connected to pin 2 labelled bypass, but in the sample circuits on the datasheet it was as well. Which leaves pin 1 labelled shutdown. I'm still a beginner at electronic circuitry so I'm still wrapping my head around how the shutdown works, so it's possible they either added or removed resistors to shutdown the amp. I asked Hap for photos of the the amp on his board, but as it's on the underside he may not want to go that far in disassembling his rare cube.
Anyway to me it's looking more and more that the internal audio is there, but disabled through firmware rather than actually physically disabled. Or if it is physically disabled it's only though the addition or removal of very simple components.
If anyone else has insigts, ideas, or whatever let's discuss. My photos of the chips are attached, here are the datasheets:



Anyway to me it's looking more and more that the internal audio is there, but disabled through firmware rather than actually physically disabled. Or if it is physically disabled it's only though the addition or removal of very simple components.
If anyone else has insigts, ideas, or whatever let's discuss. My photos of the chips are attached, here are the datasheets:


