[sdiy] buchla 200e power supply

Derek Holzer derek at umatic.nl
Wed Nov 19 22:36:01 CET 2008

Hi again, Mark,

I don't suppose you could post a closeup photo of this, could you?


ps.. is that Buchla tech blog out there yours?

mark verbos wrote:
> Hi guys, sorry I'm late on this one....
> The 2 unit case that Buchla is selling has a PCB with a PT6202A and a 
> PT5062A on it. These are a 5volt and +/-15 volt respectively DC-DC 
> converters. Also on that board is a simple passive circuit. The signal 
> from the 12 volt DC wallwart has a small electrolytic to ground before 
> it goes, before each converter, to a ceramic cap to ground, then through 
> a ferrite bead then another ceramic to ground, then into the DC-DC 
> converter. Each of the 3 outputs then goes through a ceramic to ground, 
> an electrolytic to ground then through a ferrite bead, then a ceramic to 
> ground before the power connector. Sadly, I don't know what the values 
> or part numbers of these parts are. These are about $20 each.
> The big 200e cases use Cincon DC-DC converters. I don't know the model 
> of them,but I can tell you that they are the big square ones and it's 3 
> of 'em in there. I'm guessing CHB75 series, since they're the biggest 12 
> volt input ones Mouser has. Those give out 15A at 5volts and 5A at 15 
> volts. I would guess they are similarly treated as in the other cabinet, 
> but I don't know. These are $83.85 each in the latest Mouser catalog.
> I have worked on a 259 module that was mounted in the smaller case and 
> it worked fine. No hi frequency bleed through, but the switching 
> frequency on these things is 300kHz or more, but I suppose there could 
> be some subharmonics that leak through. They have Thermal shutdown, 
> short circuit protection and over voltage protection built in. They're 
> likely much more GREEN and weigh much less than a linear supply, plus 
> easier to use in other countries. With a switching 12 volt wallwart, it 
> could probably work with any voltage from 100-250.
> Mark

derek holzer ::: http://www.umatic.nl ::: http://blog.myspace.com/macumbista
---Oblique Strategy # 96:
"Is the intonation correct?"

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