My Buchla-Format Cabinet

I started with just a small Buchla-format system consisting of 12U of modules I built. Similar to my 5U experience, I continued to add more modules and needed a larger cabinet. While the folding cabinets are nice, I dislike the depth and the noisy switching power supplies. I chose to build a 36U slant cabinet with linear power supplies. I kept my Easel in a 8U flat cabinet that sits to the side since both the 208 and 218 are more usable in a horizontal format. The blank panel on the left is now my 275 Dual Equalizer/Reverb


Here is a photo of the cabinet shot in the dark with the 275 installed with the Digitech MPS4 on top.


Here's a photo with all the modules installed and the 218 and Easel. Behind the Buchla is my Hammond B3, Leslie 142, and to the right out of the photo the Hammond PR-20 Tone Cabinet setup. Behind the Hammond and not visible is my Casio Privia PX-320 and Kurzweil MicroPiano setup. Just visible is my vintage Dynaco stereo. To the right is my Yamaha Tenori-On, my Farfisa Combo Compact from my band days, and a Roland MT-32. On the right is my Moog Etherwave, and my Hammond M-2, Leslie 45 and Alesis MidiVerb-II setup.


I've reconfigured the cabinet several times and this is the current configuration with a vocorder patch.



The 8U side cabinet houses my 212s, Benjolin, and a 285r.


The complete setup also consists of an Arturia Keystep keyboard to my MIDI interface. The Roland amplifier is for my keyboard synth behind this system. My power amplifier is standing vertically on the right.




I chose the HCC15-3-A+G for 3 amps of +/-15V and the HBB512-A+G for 1.25 amps of +12V and 3 amps of +5V. I initially planned an all-wood cabinet but the module mounting holes are too close to the edge of a wood mounting rail to have any structure. Metal rails got expensive with the amount of machining required.  I chose to build a wood slant cabinet using six 6U boats. I selected boat with Tinnerman nuts since they provide some minor adjustability.

Note that Buchla used a Tinnerman C991-440 which better fits the narrow mounting rails. The C991-440 are 0.252" wide while many other U clips are 0.315" wide.


 Here is a comparison of a standard U clip on the left and the Tinnerman on the right.



I bought my boats from Jason Butcher who makes them 3.2" deep in order to fit modules like the 296M. I chose Poplar for the wood similar to my 5U cabinets and added 1/2" filler strips between the boats to eliminate any interference from adjacent panels. This also provided nice solid structure  that I simply built the cabinet around.


On each front corner I added a banana jack for signal ground. Since the wood is 3/4" thick I had to recess the nuts.


I made a 1U power panel to mount on the rear with the AC switch, IEC mains in and thru, fuses, signal ground jack, and a 6 pin power plug to be able to power external modules if needed. This is a FrontPanelExpress printed panel over natural aluminum.



I insulate all mains wiring with heat shrink and cover any exposed terminal with silicone. The two cables terminate in 3 pin Molex connectors for the power supplies.



I drilled 7/8" holes behind the power distribution boards and connected them with 18 gauge wire to barrier strips on the rear so the power to each boat is direct and not daisy chained. I made a bus bar for the Q and N grounds.


Here is a close-up of the side of the power panel.


Here is a close-up of the power supplies and wiring.


The cabinet does have a back. All of my cabinets are totally enclosed. The B3 is in the foreground and the M2 is in the background. That is my Sony/Tek 323 oscilloscope on top.



Even though I mounted my 212 far away from the transformers it still picked up a bit of 60 Hz hum from the transformers. It was only audible in the headphones at high volume but I decided to make a steel shield for the tank which eliminated it completely. It also protects the reverb when out of the cabinet. It mounts nicely on two standoffs and has notches cut for the wires and springs.



Power consumption for the cabinet (1U blank) is quite conservative.

+15V -15V +12V +5V
mA Draw 1,971 1,602 173 468
mA Supply 3,000 3,000 1,200 3,000
% Capacity 65.7% 53.4% 14.4% 15.6%