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Hi: need an opinion or help. Although my Buffalo 3 se /HD/BP/IVY with TPA's transformers is sounding mightily good, to this date I have not been able to set the shunt current. The CCS current is in the neighboorhood of 560ma and the output voltage is set at 5.2v when I read the shunt current and it is always .001-.002 range. BTW, if I turn vr2 the output voltage is not changed at all, only by turning vr1 is the output voltage changed. It seems vr2 is not making any difference.
The resistance measured across vr1 is +/- 960 o and in vr2 +/- 850 So, is this an issue, not having any shunt current?
Thanks!
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Yes that's an issue :-)
Are you absolutely sure you understand the nature of a shunt supply (sorry, I have to ask since this is essential)
Try do the following:
1. Disconnect the dac, and observe the output voltage. What's the reading ?
2. With the DAC disconnected, measure the shunt current. What's the reading?
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Hey thanx! no offence. No I don't really. I read about the theory in the manual here, but this is the first time I'm dealing with SS diy. I'll do what you are saying and report back.
Regards
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OK, I did the whole procedure again following the manuals as you stated -no difference to what I had been doing- final voltage 5.2v CCS current reading 562 ma, Shunt current reading -0.3ma - yes with a minus sign.
But I have a question that the answer might clarify this. What does "without load" really mean? What I have been doing, is to simply disconnect the dac from my preamp and cd transport. Or does it mean that The Placid HD has to be disconnected from the dac board itself?
Thanks.
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Placid without load = disconnect the DAC board (the buffalo).
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All set! Output v 5.2v CCS o.63 v Shunt current 64 ma
Thanks!
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And..... can I use the 5.25 v output from the HD to power the usb section of my i2soverusbd JLSounds board?
Thanx!
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Cool. Happy to help you. I don't know that board, but if it can handle 5.25v and you can provide the current necessary to drive it, then yes, why not? . Edited by user Tuesday, September 6, 2016 3:54:34 PM(UTC)
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a little to much
good catch
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Hi do you mean my CCS current might be a little high?
I know shunt current and voltage are the same value here because of the 1 ohm resistor.
I still remember my Ohms law.
Thanks.
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No not your ccs. Your shunt current.
Aim for 50mv = 50ma shunt current.
You wrote 0.63v. That would be 630ma shunt. Thats to much.
Remember shunt current is measured across r2 not r1.
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No, CCS current is 630ma and Shunt current is 64ma Do I have to lower it to 50 ma?
Hope this clarifies.
Thanks!
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No. Thats spot on. Enjoy.
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