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In the Forum: Melquiades Amplifier
In the Thread: 6 Channel Version of Super Melquiades
Post Subject: The mystery of Ansar capacitors in Melquiades.Posted by Romy the Cat on: 1/12/2008
 Romy the Cat wrote: |
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I really do not know what is going on and how to explain the phenomena; I just dump it to you “as is”. Because of multiple reasons I decided to drain the Milq’s power supply when the amp shits down. I have a set of four 6A double-poll relays that short the first cap of each power supply to a powerful 50R resistor. (For the people who what to thing here is a homework: why the sorting resistor must NOT be between the input chokes and rectifier but only beforethe chokes?)
So, when the amp is off then all caps begin to discharge backward, via the relays, to the 50R resistor. I presume that the higher capacitance of caps and higher voltage the more current flows back during discharge. I took very high quality 6A Japanese relay, bridged the 6A poles (12A), and figure out that it will be enough. It was perfectly enough, worked fine with the 6-ch Milq, that is in operation for a few months, but recently I got problems. With introduction to the recent revision the 200V power supply with non-electrolytic capacitors the new power supply begin to burn my relays. Thai is kind of funny. The 440V/8.000uF does not do it. The 220V/30.000uF does not hurt the relays as well. However, the 300uF of non-electrolytic capacitors (metalized polypropylene) weld the contacts off my relay. It is not happening immediately but this happen already 3 times and it forced me to order industrial 24A+24A relay to use with my polypropylene power supply.
So, I wonder what is going on. Do the non-electrolytic caps have MUCH faster discharge rate that make them to develop higher currant during the discharge? Very interesting…
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