JRDG Coherence One Series I & II powersupply - diyAudio
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Old 19th January 2013, 04:25 PM   #1
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Default JRDG Coherence One Series I & II powersupply

Dear Pro's

What causes the brown (heat) coloring on the PCB's of the powersupply's of this beautifull preamp?
I'm biased so I won't suggest my amature opinion..

Thanks.
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File Type: jpg JRDG Coherence One Series II powersupply.jpg (216.6 KB, 224 views)
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Old 19th January 2013, 04:28 PM   #2
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It's Heat.

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Old 19th January 2013, 04:32 PM   #3
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Quote:
Originally Posted by Nelson Pass View Post
It's Heat.

Wrong it's molten caramel for to induce the mellow sound of Rowland equipment.
You should try it out on your brainchilds..
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Old 19th January 2013, 04:48 PM   #4
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Let's rephrase the question.
What's causing the brown heatstains on the PCB of the powersupply and how can I avoid the generating heat in the future?
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Old 19th January 2013, 05:22 PM   #5
hm4nine is online now hm4nine  Europe
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I suggest to increase distance between parts and board and substitute coloured resistors with those of higher wattage.
Of course this will cause some solder and mechanical work
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Old 19th January 2013, 05:56 PM   #6
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Originally Posted by hm4nine View Post
I suggest to increase distance between parts and board and substitute coloured resistors with those of higher wattage.
Of course this will cause some solder and mechanical work
I already installed six new higher wattage (2 Watts) resistors at some greater distance and ordered two Microsemi VJ247m bridges with a metal topsurface that can be heatsinked for the plus/minus 20 volts rails (the other bridge is only used for the 12 Volts necessary for operating the relays in the main unit) in my series II.
But I'm curious what causes this (surplus) heat in your opinion. Not in the sense that the components radiate heat and that decolours the epoxy layer on the fiberglass, but why do they generate so much heat.
At the first 1 Ohm resistor that's directly connected to one of the bridges I measured more then 55 degrees Celcius. The second one which is much further away but also connected to the other bridge stays just under the 50 degrees.
It's not a quiz but a real interest why these parts radiate so much heat. i suppose Jeff Rowland did not intend or forsee this behaviour/decoloring when he designed thos powersupply.
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Old 19th January 2013, 06:40 PM   #7
hm4nine is online now hm4nine  Europe
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Sent you a PM
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Old 26th November 2013, 05:06 PM   #8
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check out also this thread:
Jeff Rowland Coherence 1 - Schematic for the Modules wanted
here I have an interesting question.

Last edited by tiefbassuebertr; 26th November 2013 at 05:16 PM.
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