Look damn nice. Lot of filtering there too - very quiet by the look. I can see the convenience of a drop in solution. My build came in under $3KAU for two independent rack drawer modules with 6 separate voltage supplies per drawer including phantom, 5 of them being heavy duty. The lucky part of all that is the extensive filtering contained in the 5106 itself as they used 3rd party Kingshill supplies and built the desk around those - filter caps on the power bus rails plus on-card filtering for every rail at each chip stage. Hence so many boiled caps in these things - I did a complete re-cap of the whole desk - all DC filters and all electrolytics on all 36 channel, Aux, monitor and master modules plus bus compressors.
Maybe you could build an options power pack for the ancillary hardware in a 1RU tray module - a dual rail 15 and a 5 - convection cooled - the automation can’t draw too much current so the low profile supplies would be a possibility. Couple of caps and filter chokes inline in the tray but as it’s not in the audio path you may not even need that.
Took me less than 12 hours for design to finish including cabling. Took another couple to run and connect cabling to the Neve. Fair bit of time needed to plot and drill the mounting holes as I stood the supplies on their sides. I had to use a clamp meter to find current drain from existing supplies to determine which I would use and also gauge of cable to source DC multicore - I used 2 cores each for the hot and commons for the -15V and +16V, -16V runs - common not connected to earth here.
On any DC-300 C4, 10/150V, is a weak link. C4 is the input capacitor for the voltage doubler and I almost always found them open, vented or otherwise degraded.
Yeah that positive clip that comes good looks like a sagging cap somewhere. Might be worth metering the output of the doubler at turn-on to see what it does.
They went through so many changes in transistors for the outputs - the first run were unreliable Solitron, then RCA - slow, STC - faster unreliable, back to RCA, Westinghouse - curved bases causing failure internally when bolted hard to heatsink, back to RCA, finally Westinghouse with a flat base - if I got all that correct. There was a raft of so many other production changes it was hard to keep track.I was never a fan of the DC300 topology. Quasi-complementary output stages forgo some speed for stability to make NPNs behave like bigger PNPs. That said Crown had so much success with the DC300 series that they repackaged the amp design to make their later CE1000/CE2000 amps. They just swapped SMD for thru hole parts, plastic for metal power transistors. They made some spectacular mistakes in the repackage like undersized emitter degeneration resistors, that tended to burn holes in the PCB when output devices fail shorted. But they made a healthy profit without redesigning a power amp. At the time they made the bigger CE4000 model class D. I feel sorry for the amp product manager trying to explain that amp series to customers.
JR
Every chip on the older Neves was socketed not soldered - saves a lot of time and board damage to replace them when (not if) they fail. I think from a service point of view that a lot of designs don’t incorporate ease of service into the product - bad component placement, non socketed IC’s requiring removal of boards to replace, use of hard to obtain parts, components on the threshold of tolerance either voltage or temperature wise (eg capacitors), resistors that run too hot close to PCB’s, voltage regulators without heatsinks, interconnect cables too short to be able to remove and run boards out of place, poor case ventilation and inaccessible service documentation.
I was working at Peavey when we decided to stop putting all ICs in sockets. Indeed sockets save time and money performing repairs but analysis revealed that ICs got better so failed less frequently, and most failures occurred in input or output sockets where failure stresses likely came from the outside world.
At Peavey we had to honor many loudspeaker warranty claims for speaker failures that were caused by other manufacturer's amps. I do not recall any (many?) that were related to DC300 specifically, but being DC coupled the DC300s were notorious for that. The biggest warranty suck hole that I recall was caused by the current limiting in an early series of inexpensive QSC power amps that had the bad habit of clipping asymmetrically putting DC across the loudspeakers. The popular street wisdom was that the QSC amps were too powerful for the Peavey speakers but that was not the case. QSC eventually figured it out and corrected their rogue current limiting, but since QSC was not making and selling loudspeakers back then, they were not as focussed as we were on such things.
