Toppobrillo Mini-Bus
Power Supply

I always use a linear supply on my bench for repairs. Most of my Buchla cabinets have the 211 Power Supply. I am not a fan of this power supply for two reasons - the individual supplies are quite noisy and there are no specifications that I can find for the individual outputs.




I bought this Toppobrillo Mini-Bus power supply to try out. It is also documented on the Muffwiggler thread DIY Buchla low noise power supply boards are in stock! With the two DC-DC regulators I know what the supply specifications are and what I need to use for an external supply. It is also compact when mounted with the components toward the bottom. But most of all, the +/-15V supplies are quiet.

The outside hole patterns match the 211 so I can install it without drilling new holes (the PCB outline doesn't match but there is typically clearance).


There are a wide variety of components listed for both DC-DC converters. I chose the TDK-Lambda CCG302415D +/-15V for its low profile. Likewise I chose the Murata OKI-78SR-5/1.5-W36HE-C +5V converter to lay flat. It is also fully insulated. I don't use the I2C communications so I didn't install R1 and R2.


The TDK-Lambda CCG302415D +/-15V converter needs the Remote Start pin wired low to operate. There are two pads on the rear that need to be jumpered with solder with this converter.


The edge fingers are lead-free HASL (hot air solder leveled). My preference would be for hard gold fingers but that adds significant expense and this supply is targeted as a low cost solution. I plan to replace all of my 211 power supplies as this supply provides ample power for my cabinets.



Bus Xtdr

I don't have the production version of the Bus Xtndr but have an earlier version. This can be used with a connector to extend the Mini-bus or as a passive bus in a separate small cabinet. In that case you have to hard wire to the vias.