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In the Forum: Melquiades Amplifier
In the Thread: Building Melquiades: Chronicle of full-range
Post Subject: .... and grounding of secondary.Posted by Romy the Cat on: 6/24/2006
 hagtech wrote: |
| Not sure I understand. You run the speakers floating from ground? Are you doing polarity swithing on the outputs? |
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Sure, all my secondaryes are no grounded and the speakers are floating. I do not see any technical problem with it.
| hagtech wrote: |
| First, it just doesn't seem right to me to phase switch the amplifier outputs. I'd rather do it to the inputs. Not sure I like the relay contacts on the larger currents. Of course it works. I just wonder what is being lost. |
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The super Melq has after each channels a set of two really that reverse the connection of the secondaryes to the binding posts. I do not see any problem with it as in not-balance design to flip the phase at inputs I would need one extra active stage. A good quality relay work very nice with higher current as higher current breaks thru the contacts. The relays are well-tested at line level and with speaker level and I have heard no sonic degradations.
| hagtech wrote: |
| Second, I don't know if it's bad to float the outputs. Seems like maybe there will be some common mode issues. Maybe noise injection or some HF instability. Possible feedback of external noise source reflected back into primary. My personal preference is to run balanced secondary. Or more specifically, a center tap to ground (or some earthly reference). I like the balanced transmission of signal. This too, reduces any common mode interactions. I think grounding one amplifier output is a mistake brought on by cost considerations. Unfortuantely, it is near impossible to find an output tranny with the right characteristics. But to float? I wonder if you can get charge buildup or some other wierdness. |
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Nope, I had it floated and grounded and practically have seen no difference. There is very very minor sonic differents but so minor that I would call it negligible. I left in the new Melq the secondary lifted. I might ground it eventually but I have no opinion about it so far… and so far I did not see any weirdnesses.
The Cat
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