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Ichiban  
#1 Posted : Wednesday, September 19, 2007 8:37:16 PM(UTC)
Ichiban

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I can only touch one of the heatsinks on the LCPS
for two or three seconds.
That LM317 feeds the digital power supplies.
Both regs are set to 7.5 volts.
Is this normal? Also, I will be adding on
a second dac board for dual mono'ing the dacs.
That will probably make the sink white hot!
Would backing off on the voltage drop solve
this? Will the digital sections low drop out
regs handle the higher voltage? How high
is safe for the dac/reciever boards?
Cheers,
Russ White  
#2 Posted : Wednesday, September 19, 2007 8:40:00 PM(UTC)
Russ White

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Hmmm, something sounds not quite right..., what is your input voltage? You can safely increase the output of the LCPS to around 12V(even a bit higher).

Cheers!
Russ
Ichiban  
#3 Posted : Wednesday, September 19, 2007 8:51:13 PM(UTC)
Ichiban

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The AC voltage into the LCPS is 13v7.
I should add that I'm currently using
a xfmr which is center tapped, which
means that the two regs share the
common center tap.
By the way the OPUS sounds very tasty
compared to my five times more expensive
and highly reguarded, by some, dac.
Burning it in with a 40cycle tone.
Russ White  
#4 Posted : Wednesday, September 19, 2007 8:55:35 PM(UTC)
Russ White

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That may be the problem right there, try just using one half of the trafo (not both) just the center tap and one hot. Power both sides of the LCPS from that same tap and center tap, in parallel. See if this makes it behave better. :)

Edited by user Wednesday, September 19, 2007 8:56:09 PM(UTC)  | Reason: Not specified

Russ White  
#5 Posted : Wednesday, September 19, 2007 8:57:17 PM(UTC)
Russ White

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BTW, Very very, glad you like it. :)
Russ White  
#6 Posted : Wednesday, September 19, 2007 9:01:31 PM(UTC)
Russ White

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Further explanation, the circuit is not designed to be wired to a center tapped trafo like that. :) One secondary will work, but two is better.
Russ White  
#7 Posted : Wednesday, September 19, 2007 9:07:14 PM(UTC)
Russ White

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also, an apology, I should have the manual done by now. I will get cracking on them. :)
Russ White  
#8 Posted : Wednesday, September 19, 2007 9:11:14 PM(UTC)
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One other option, take any hot tap and the center tap and connect it to one side of the LCPS, you should be able to run all of the modules off that one side. :) You won't come close maxing the current with 5 or 6 modules.
Brian Donegan  
#9 Posted : Thursday, September 20, 2007 3:18:17 AM(UTC)
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Note the "EDIT REPLY" feature... ;)
Ichiban  
#10 Posted : Thursday, September 20, 2007 11:03:45 AM(UTC)
Ichiban

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Thank you, heatsink now much cooler.
Will run it this way while waiting for
the torroid from TPA.
Cheers,
OneyedK  
#11 Posted : Friday, October 5, 2007 2:53:57 AM(UTC)
OneyedK

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Ichiban wrote:
I can only touch one of the heatsinks on the LCPS
for two or three seconds.
That LM317 feeds the digital power supplies.
Both regs are set to 7.5 volts.


d'oh! Just noticed I have the same "problem", while using a 2x15V 80VA ILP
transformer (no center tap, two seperate windings).
2x16Vac measured with the LCPS connected to the DAC and receiver during operation.
It's the side that feeds VD that gets hot, the VA-side is cold.

I'll try changing the fase of one of the inputs to see if that matters...

/edit 1: doesn't matter

/edit 2: I also noticed that I mounted D9 and D11 upside down, guess correcting that will solve the problem -blush- Whistle

Edited by user Friday, October 5, 2007 3:19:48 AM(UTC)  | Reason: Not specified

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