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Joined: 4/28/2007(UTC)
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Location: Ireland
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Off to bed now zzzzzzz
but..... I swapped in my dac board with the "new" counterpoints and the hiss is there just as before. So it ain't the DAC thats causing this.
So this brings this back to the counterpoint rather than the DAC I think.
Hiss - grounding - oscillation?
Fran
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Rank: Administration
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Hi Fran,
It very hard to say. Could be a bad Q, or maybe the opamp. If you have an opamp to swap that might be worth trying.
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Rank: Member
Groups: Member
Joined: 4/28/2007(UTC)
Posts: 18
Location: Ireland
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I think I might have this sorted. It struck me that the side that had most hiss was nearest the LCBPS. So I reoriented the 2 boards. While this didn;t make any difference, I found out when doing it that by touching one of the wires the his dropped. So it must be some kind of RF pickup. I managed to reduce the hiss a huge amount by routing of wires. Its not all gone but its a lot better.
Before discovering this, I also tried things like bringing all the analog grounds to a star at the LCBPS - but that made no change.
I need to go back and do some more cleaning up and will report back.
Fran
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