build dynamic – As DRAM prices climb, one builder went the other direction: he built his own dynamic RAM from discrete components—then used it to run a drum sequencer with eight beats and eight samples per beat.
Before the past year. computer memory could feel like a background utility—cheap. available. and something you didn’t think about until a build needed it. Then prices surged. For a growing number of PC builders and other users. memory started to look less like a plug-and-play part and more like a question: how much do you truly need. and what does it even do beyond being “there”?.
[Igor] answered that question in the most hands-on way possible. He’s working on a drum sequencer project that needs a small amount of memory, and he built dynamic RAM from discrete components rather than buying a module off the shelf.
In his first video, he walks through the construction of the memory array and how it’s addressed. The array is only eight bytes total. The scale is eye-opening: because large electrolytic capacitors are used to store data. a single gigabyte of memory would require well over a thousand acres. Even so, it’s enough for his needs, and the point isn’t capacity—it’s control.
Each bit is built around capacitors and switching logic. Beyond the capacitor, each bit uses a pair of diodes to determine whether a read or write is occurring. On top of that, transistors sit on the read and write busses to perform those actions.
Dynamic RAM, though, comes with its own reality. Since the information is stored as a charge on capacitors, it needs to be refreshed as the charge decays over time. [Igor] also tested what the big capacitors can do in practice, confirming experimentally that they can hold charge sometimes overnight.
A follow-up video shows what happens when the module leaves the breadboard stage. [Igor] demonstrates several ways the memory can be used, starting with controlling LED arrays and 7-segment displays. Then he installs it into his drum machine.
With 64 bits available, the sequencer can create up to eight beats, with eight samples available per beat. There are plenty of complete machines already on the market for doing exactly this. What’s driving [Igor] is different: a goal of not buying any pre-manufactured hardware and instead constructing it all from the ground up. Analog drum machine options exist in a similar spirit, too.
The videos are embedded below, showing both the memory build and the drum machine applications—an unusually literal reminder that when tech costs change, some people don’t just tighten budgets. They get curious, and then they start soldering.
dynamic RAM discrete components drum sequencer DIY electronics memory refresh electrolytic capacitors LED arrays 7-segment display
So basically he made RAM out of capacitors?? Wild.
DRAM prices up and he’s like “nah I’ll solder it myself.” Honestly respect but also who has time for this. Wait though, dynamic RAM needs refresh right? So does the drum beat refresh too lol?
I don’t get it, if it’s only eight bytes, that’s like… less than a photo? Feels pointless. But people saying it’s about control like that matters for a drum sequencer. Also I swear this is just like capacitor storage not really RAM.
The part about needing to refresh the charge overnight is kinda scary? Like if you don’t keep it going it loses the data, and then your drum machine just forgets the whole pattern. Still though, the image of “a gigabyte would take a thousand acres” is hilarious and also makes me want to never buy computer parts again.