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james.evans@frost.com  
#1 Posted : Wednesday, November 25, 2009 3:30:24 AM(UTC)
james.evans@frost.com

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Hi all

Just got my placid boards installed last night. Initial listening impressions are very favourable indeed. A question though - my heatsinks are getting pretty damn hot, especially on the BP. I have the R17/18 voltage set to 0.25 on all 3 boards as described in the manual. Should this be adjusted at all for VA/VD/Ivy? BP transformer is 18-0-18 with BP output set at +-15v. VA is set to 6.6v, VD 6v.

A quick snap:

UserPostedImage

Cheers

James
Beefy  
#2 Posted : Wednesday, November 25, 2009 5:34:37 AM(UTC)
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250mA is WAY too high. Measure the actual current flow and add, say, 25%. Set the CCS to that current.
james.evans@frost.com  
#3 Posted : Wednesday, November 25, 2009 6:40:02 AM(UTC)
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Beefy, thanks for the reply. I assume you're refering to the Ivy supply? I suppose I might as well measure consumption of the buffalo supplies while I'm at it.

Cheers

James
Brian Donegan  
#4 Posted : Wednesday, November 25, 2009 7:41:25 AM(UTC)
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250mA combined with the 10V drop (18 * 1.4 = 25Vinput - 15Voutput = 10Vdrop) is what's creating your heat. The supply should be fine with this, but dropping the current to something closer to what you actually need will reduce the heat.
james.evans@frost.com  
#5 Posted : Wednesday, November 25, 2009 8:03:04 AM(UTC)
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Thanks Brian. I'll do some fiddling when I get some time. I assume I just whack my dvm in the +ve supply line, measure, and then adjust +ve & -ve accordingly. Worth doing this on the buffalo VD & VA lines as well, or is 250mA ok there?

Cheers

James
Beefy  
#6 Posted : Wednesday, November 25, 2009 8:21:07 AM(UTC)
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james.evans@frost.com wrote:
Thanks Brian. I'll do some fiddling when I get some time. I assume I just whack my dvm in the +ve supply line, measure, and then adjust +ve & -ve accordingly. Worth doing this on the buffalo VD & VA lines as well, or is 250mA ok there?


Instead of getting us to guess, measure it! :)
james.evans@frost.com  
#7 Posted : Wednesday, November 25, 2009 8:48:12 AM(UTC)
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Beefy wrote:
james.evans@frost.com wrote:
Thanks Brian. I'll do some fiddling when I get some time. I assume I just whack my dvm in the +ve supply line, measure, and then adjust +ve & -ve accordingly. Worth doing this on the buffalo VD & VA lines as well, or is 250mA ok there?


Instead of getting us to guess, measure it! :)


:-)

Fair enough, just thought Brian might know off the top of his head if that was there or thereabouts for buffalo. I'll unsheath the probes!
james.evans@frost.com  
#8 Posted : Saturday, November 28, 2009 3:29:17 PM(UTC)
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ok, these are mA measurements and new placid settings in brackets:

Ivy: 41mA (80mA on both -ve & +ve)
Buf VD: 101mA (150mA)
Buf VA: 131mA (180mA)

Things are much cooler in there now. Will keep an eye on it after being run for a while.

Cheers
Beefy  
#9 Posted : Sunday, November 29, 2009 8:50:08 AM(UTC)
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Excellent :)

VA is drawing more than I expected, but that is based on my highly scientific recollection of how hot the heatsink on the LM317 supplying VA was about a year ago......
james.evans@frost.com  
#10 Posted : Monday, November 30, 2009 2:07:18 AM(UTC)
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Yeah, VA is also supplying the mux, 2 toslink boards, the volumite and power on LED. I may look at a separate supply for those at some point. For the moment, just enjoying the music :-)
avr300  
#11 Posted : Monday, November 30, 2009 1:00:27 PM(UTC)
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Hi James.

Why are you supplying those digital bugs with the VA supply ? You're better off using the VD.

Keep the VA as clean as possible.
james.evans@frost.com  
#12 Posted : Tuesday, December 1, 2009 2:12:14 AM(UTC)
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Hmm, thanks, have I got myself confused along the buffalo path? I'm sure I read somewhere it was VD that was meant to be clean? It would of course make sense for VA to be as clean as possible...

Edited by user Tuesday, December 1, 2009 5:06:34 AM(UTC)  | Reason: Not specified

Beefy  
#13 Posted : Tuesday, December 1, 2009 6:24:47 AM(UTC)
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Brian and Russ have always said that putting MUX, Toslink etc. on VD is a good idea.
james.evans@frost.com  
#14 Posted : Tuesday, December 1, 2009 7:52:03 AM(UTC)
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Thanks Beefy. Mind must have crossed me on this one over time. Easy enough change to implement. Cheers.

James
james.evans@frost.com  
#15 Posted : Thursday, December 3, 2009 8:55:46 AM(UTC)
james.evans@frost.com

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Right then, I've gone psu crazy now. VA and VD have their own placids and the mux/volumite/toslink boards have a separate bridge/cap/teddyreg (already setup to 6.6v from a previous experiment) running off the VD placid AC secondary. This thing is now super clean. Really really impressive. Best I've heard it sounding yet. Well chuffed :d/
avr300  
#16 Posted : Thursday, December 3, 2009 9:13:38 AM(UTC)
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Great.

And you're feeding the Vref board from the VA, right ?
james.evans@frost.com  
#17 Posted : Thursday, December 3, 2009 9:17:13 AM(UTC)
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yup, from VA.

One thing I can't get my head around is, I always felt like the left channel was a bit quieter than the right. That appears to have gone away with this psu meddling. I may be imagining it, as it doesn't seem logical at all.

I should add, the move to using the placids really has turned the buffalo into a completely different beast. Big thanks to Brian and Russ for all the development! I wouldn't be enjoying the music half as much if it wasn't for you two (and my neverending desire for solder burns/fumes ;-) )

Edited by user Thursday, December 3, 2009 9:46:05 AM(UTC)  | Reason: Not specified

Russ White  
#18 Posted : Thursday, December 3, 2009 5:04:15 PM(UTC)
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Sounds like your having fun. :) Enjoy!
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