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Old 10th September 2007, 11:55 AM   #31
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IIRC, the last buy was .090 thick, 2 oz. copper. Advanced Circuits got ~$11.50 per at 125 pieces. The price of copper has gone up though.

I'm fine with standard green/white/silver plating. I think a thicker board should be considered given the size, though.
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Old 10th September 2007, 12:45 PM   #32
hags is offline hags  United States
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Quote:
I'm fine with standard green/white/silver plating. I think a thicker board should be considered given the size, though.
I agree, .090 sounds good and I like the 2.5 traces on this current quote.
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Old 10th September 2007, 12:54 PM   #33
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Quote:
Originally posted by hags


I agree, .090 sounds good and I like the 2.5 traces on this current quote.

Ditto.
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Old 10th September 2007, 02:10 PM   #34
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Yeah I have some of those Ebay heatsinks for an Aleph project. I just didn't think these would be generating as much heat as the aleph because they are Class A/B. 20x20x10 is huge I'd rather do like 2 chassis I probably don't need 7 channels could do 5 or 6. Would it be bad if the fins were going horizontal? I know its not ideal but these heatsinks are quite large.
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Old 10th September 2007, 02:41 PM   #35
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You shouldn't have a problem with horizontal fins in normal home use. Pass uses horizontal sinks on the XA60.5 and others- Click the image to open in full size.

I have a 4 channel Leach on the Apex jr tunnels horizontally running without a fan. They stay reasonably cool at sane listening levels, although one amp on each side is just powering the tweeters. You sinks have more surface area.

Click the image to open in full size.
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Old 10th September 2007, 02:53 PM   #36
AndrewT is offline AndrewT  Scotland
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Hi,
while testing my bare uncased Leach, running 3pair @ 210mA total bias from +-58Vdc, I laid the sink flat with fins pointing down.
The 200mm by 130mm by 40mm sink became far too hot to touch within about twenty minutes. During this overheating the multiplier had reduced the bias significantly below the 210mA but fully recovered within thirty minutes of standing it back up properly.
In the upright position the sink runs at about 10C above ambient. I guess it ran @ >30C above ambient laid flat and with much reduced bias.
If these quesses are about right, then Rth s-a went from 0.5C/W to 2C/W due to orientation.
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Old 10th September 2007, 02:56 PM   #37
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My Leach amps are only at 125 mA bias, which could explain some of the difference.
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Old 10th September 2007, 03:01 PM   #38
AndrewT is offline AndrewT  Scotland
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Hi Bob,
2pair or 3pair?
Re=0r33 or higher?
Vre=?

I run Vre=24mV and Re~=0r35.
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Old 10th September 2007, 03:03 PM   #39
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If the output devices were detatchable I could make the amp much smaller quite easily. So I'd say I'm interested in the seperate output model. And 6 amp boards.
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Old 10th September 2007, 04:25 PM   #40
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i wonder if advanced circuits still has the original information for the last group buy. where are they located. i will give them a call and see if they can do the same deal. the like the thick board idea myself. i will order the heaviest copper, within reason, that they offer. thanks for the input tad
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