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The following photos are from Goran Blazic's cellphone. They demonstrate how he and Milorad assembled the Vilobhas. The chassis are constructed of high-grade Plywood. This was CNC'd into the desired final contours and wall thickness, stacked, bonded and sanded down for the primer coats. The outsides eventually received multiple coats of white lacquer—black for the separate plinths—while the insides were lined with copper to comply with international safety standards for electronic appliances housed in wood.
Here are the lateral heat sink assemblies for all the tube heater stabilizing circuits.
Prior to painting, the integral stanchions still show off their 7-layer Ply construction. A white Aries chassis can be seen in the background.
The custom metal bases for the seven valves on deck sport thru-holes for the stacked aluminum/acrylic tube covers. The longer shafts of the covers insert into their frontal receivers to create proper grounding with an internal contact.
The circuit construction exhibits a combination of PCBs and flying leads with sturdy bolt rather than solder connections for critical junctions.
Here we see the LED bypass for the inductively biased C3m input tube and various chokes. The direct-heated 45 triode driver is conservatively biased. The amps can thus take anything from the stock Emission Labs solid plate to vintage globe types. Thanks to Dan's surprising inventory of over 5000 bottles, our informal gathering would learn that rolling this valve offers significant voicing options.
Here we see one of the heater circuits coupled to a lateral heat sink. "The Vilobha architecture is basically very simple. The advances are hidden in the execution particularly of the transformers. It's not about unusual circuit cleverness or exotic cores."
"One of my later OPT prototypes exhibited beautifully extended frequency response to beyond 100kHz save for a very narrow 10dB suckout centered at 40kHz and spread from 38K to 42K. There was no rational explanation for this behavior. Assuming a minor imprecision in its assembly, I wound a second transformer to exactly the same configuration. It too exhibited the same head-scratching anomaly. Rather than a minor revision, I had to completely rethink the transformer's makeup from scratch. The next day I approached it from a different direction and finally achieved the desired results. It's these and related R&D items which take up a lot of time to get just so."
Milorad: "During this 3-month project we would work our regular 8:00-16:00 shift in the Trafomatic Audio shop. Then Sasa would take a half-hour to one-hour nap and have a quick meal before working non-stop again from about 18:00 to well past midnight. It was the only way to fulfil our commitments for the regular models and develop what to date is our most ambitious custom amp. This took quite a physical toll particularly on Sasa. He really is due for an extended vacation."
