I’ve dusted a few of those 1978 boards in the garage—there’s nothing like the feel of a 2.54 mm track that’s just a thin ribbon of copper under a tiny chip. One‑chip designs are a marvel of constraint; the CPU, memory, and all the logic in a single 7400‑family IC mean you can keep the board to a single layer, reduce board cost, and get a stable power rail because there’s only one supply path to worry about. But the trade‑off is huge: you can’t add a DSP, a dedicated graphics processor, or a modern clock without bumping the size and power consumption. When developers moved to multi‑module systems, they opened up room for a separate MCU, a small ASIC for the video, and even a dedicated sound chip. That lets you cram more features in without blowing up the voltage budget, but it also adds complexity—more power rails, more decoupling, more routing for high‑frequency signals. And, of course, more points for a soldering error. A quirk I love from the early era is the “stiff‑wire” technique for the analog video output. Those tiny, stiff, copper‑filled wires would sit on the board, then be bent into a perfect parabolic shape before being soldered to the video port. It’s a testament to the tactile engineering that even today’s PCB designers might not need. The same boards also often hid a small EEPROM that held the high‑score table; you could remove it, re‑flash it, and change the way the game stored data, which is pretty neat for a 1970s system.

Yeah, that’s the sweet spot where the designer has to decide if the extra sound chip is worth the extra PCB area and the noise from the extra voltage regulator. In my last project I added a small op‑amp‑based DAC for a 1978‑style game, and the trick was to keep the DAC on the same side as the sound IC to minimise the trace length. It kept the noise low, but I had to add a tiny decoupling capacitor on every pin of the DAC, which turned a 12‑pin board into a 36‑pin one when you count all the C‑pads. If you’re just hunting for the ‘pure’ experience, you’re better off sticking with the single‑chip architecture; if you want the music to sound like a full‑band, you’ll have to embrace the mess.