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Old 21st January 2012, 08:49 PM   #461
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I just use a big dumb generic 30A 400V from Digikey.
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Old 21st January 2012, 08:55 PM   #462
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Michael, have you compared the sound using the switchers vs. a simple CRC passive supply?

I don't know if Vicors sound better, but you often can pick up an appropriate model from eBay without too much waiting or searching.
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Old 21st January 2012, 10:35 PM   #463
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Juanitox! Excuse me not asking for the heat problems, but.....

For the sound, did you here the same big jump forward in precision and clarity I meant to here after changing to thick film resistors.....?
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Old 21st January 2012, 10:43 PM   #464
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Originally Posted by generg View Post
Juanitox! Excuse me not asking for the heat problems, but.....

For the sound, did you here the same big jump forward in precision and clarity I meant to here after changing to thick film resistors.....?
What I have found with the resistors as light bulbs ( incandescent or halogen ) that they are slightly sensitive to vibrations . In other words they can "sound" better dependin where and how they are mounted .

Regarding the dissipation , I am approaching 2 Amps with 2 little fans , the heat sinks and then the Sit transistors cool down to a comfortable temperature with little effort . The fans are not noisy at all .

Last edited by stefanobilliani; 21st January 2012 at 10:45 PM.
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Old 21st January 2012, 11:15 PM   #465
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Originally Posted by serengetiplains View Post
Michael, have you compared the sound using the switchers vs. a simple CRC passive supply?
I don't know about that particular supply, but I have an adjustable heavy duty switching power supply in my lab and it's terrible for audio work.
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Old 22nd January 2012, 12:24 PM   #466
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michael , you are the man!! i put the heatsink of the 10ohm resistor outside the case, it is very hot but the case , transfo and Caps stay warm for the sound no change for me with the wirewound resistor , but i have lost my hexfred bridge for a 3 cents one .. this afternoon if my wife set me free i will put a old good motorola bridge and tell you..

Click the image to open in full size.
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Old 22nd January 2012, 02:28 PM   #467
generg is offline generg  Germany
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finally it looks like a heavy machine......driving something very dangerous.....


glad you fixed the problem.....

and I am astonished that you do not have the sound difference with the thick film resistors I found astonishing..................................that´ s life!
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Last edited by generg; 22nd January 2012 at 02:30 PM.
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Old 22nd January 2012, 03:01 PM   #468
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That's great! And, it looks great too.

Now you can focus on dialing-in the sweet spot for your speakers/taste. It may take a little time, but you'll have fun.

Well done
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Old 22nd January 2012, 04:46 PM   #469
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Originally Posted by generg View Post
finally it looks like a heavy machine......driving something very dangerous.....


glad you fixed the problem.....

and I am astonished that you do not have the sound difference with the thick film resistors I found astonishing..................................that´ s life!
bow with the motorola bridge it sounds superb! , even better than before with the hexfred and the wirewound resistor , so it think the upgrade came from the Thick film res ..

this week / Rcore transfo test and CLC with Rifa PeH200 and hammond 10mh choke ...

this amp 's got so few part , very funny to tweak
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Old 23rd January 2012, 12:16 AM   #470
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well the lamps are beautiful but not simple here in EU , the alogen stick have hi price and not so clear resistence ...plus the philips mbtf only 200hr ,the GE 2000hr but I see only 500w .....

with 39v bias 2A ,speakers 5,5ohm I'm near of Stefano working amp ie 16 to 20ohm needed resistence...

Suggestion?
What's the voltage/current rating of the Philips pieces? If you're running them at significantly less than rated power, MTBF will increase dramatically...

Roscoe
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