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Post by Jim on Jul 5, 2013 9:01:14 GMT -5
Hello, - A little help for you... If you want to make a perfect cooling system, you must know that, hot air is lighter than cold air. - The hot air rises and cold air (heavy) descends. This means you have to push the hot air to the top, and it will stay there, keeping the cold air below. This is the natural dynamic between hot and cold air! In the case of XPA-1L should be placed on top of the RACK for best dissipation possible. I don't see any problem with cross-flow ventilation... Placement and thermal currents matters more when you have a real rack, not a shelf with a couple items.. |
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Post by Chuck Elliot on Jul 5, 2013 9:48:22 GMT -5
ET-3
Each fan draws 40mA for a total of 160mA. I would bet that it could do the job, but it only has 3 outputs. And, I've already purchased the other parts, so a relay will be a better solution for me.
USB Power
I think I would run into current issues using a single USB port to power the fans. These units must convert 5V to 12V so I expect the 160mA 12V draw might exceed the 200 mA USB spec after voltage conversion.
Convection vs Cross-flow
Just because I've set up a cross-flow air current doesn't mean that the convection currents generated by the heatsinks will stop. I just need air exchange in the tight spaces so the convection isn't blocked. The top shelf isn't an option as it is occupied by a LCD, keyboard and mouse. Plus, it would make the rack top heavy.
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DYohn
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Post by DYohn on Jul 5, 2013 9:50:18 GMT -5
So the fans are preventative. Cool if that's what you want, and it looks like a good job. Me, I'll rely on the thermal management built into an amplifier's design and if it shuts itself down from getting overheated then I'll either move it or add cooling, but I wouldn't add fans to a system unless they absolutely need it. I say why add the potential for noise (both mechanical and electrical) to a system unless you have to?
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Post by monkumonku on Jul 5, 2013 9:59:44 GMT -5
So the fans are preventative. Cool if that's what you want, and it looks like a good job. Me, I'll rely on the thermal management built into an amplifier's design and if it shuts itself down from getting overheated then I'll either move it or add cooling, but I wouldn't add fans to a system unless they absolutely need it. I say why add the potential for noise (both mechanical and electrical) to a system unless you have to? I saw the XPA-1L's at the Newport Beach show last month. Because I'd heard about how Class A runs hot, I put my hand on top of one of them and immediately took it away - it was too hot to keep there for more than a second. They make an Onkyo AVR seem like a cold frying pan. That said, I'm sure Emo must know what they are doing. There were 4 amps in the rack, two stacks of two, so there was very little space between each amp in each set of two. If I had them in a rack with low ventilation I'd be thinking about using fans, too. |
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Post by Deleted on Jul 5, 2013 10:04:11 GMT -5
>> I say why add the potential for noise (both mechanical and electrical) to a system unless you have to? <<
Because that heat is gonna rise and affect all of the components above. And every EE worth his degree knows that heat is death to electronic circuits...
-RW-
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Post by Chuck Elliot on Jul 5, 2013 10:14:16 GMT -5
So the fans are preventative. Cool if that's what you want, and it looks like a good job. Me, I'll rely on the thermal management built into an amplifier's design and if it shuts itself down from getting overheated then I'll either move it or add cooling, but I wouldn't add fans to a system unless they absolutely need it. I say why add the potential for noise (both mechanical and electrical) to a system unless you have to? Although you can looks at it as preventative, IMO heat is the enemy of all electronics. The units may not fail immediately, but the MTBF will decrease dramatically for the unit that is run at the top of its temp specification. |
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DYohn
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Post by DYohn on Jul 5, 2013 10:47:51 GMT -5
Of course, like I said, preventative. Since my business these days is thermal management, I understand this very well. And like I said, if you feel like it's warranted more power to you. But I stand by my statement that it is likely unnecessary and I would avoid unless it proved to be necessary.  |
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Post by GreenKiwi on Jul 5, 2013 11:06:06 GMT -5
Actually I think that it might make sense if it can keep the heat down and let the amp work in class A longer.
I guess if you really wanted to help it, you could have ducts that funneled the air in the bottom and helped suck it out the top.
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Post by Chuck Elliot on Jul 5, 2013 11:11:37 GMT -5
Actually I think that it might make sense if it can keep the heat down and let the amp work in class A longer. I guess if you really wanted to help it, you could have ducts that funneled the air in the bottom and helped suck it out the top. If I had a bit more room, I'd put a Sherbourn C-12 Cooling between the 2 units with the flow in from the bottom and up to the top unit! |
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Post by Dark Ranger on Jul 5, 2013 12:09:25 GMT -5
^ The Sherbourn C-12 works very well for me. The amp itself stays much cooler and the power conditioner/voltage regulator on the shelf above the amp doesn't heat up unnecessarily. If When I can buy two more of these amps, I'm getting two more C-12s.  Thanks for sharing your cooling solution with us, Chuck. That should work well with minimal noise. I like your engineering skills.  |
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Post by Deleted on Jul 6, 2013 8:28:03 GMT -5
Is that push-pull arrangement similar to the blow-suck arrangement? " Thanks for sharing your cooling solution with us, Chuck. That should work well with minimal noise. I like your engineering skills." Oh thanks Dark Ranger, although sometimes the moaning gets a little audible.  |
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Post by Chuck Elliot on Jul 6, 2013 9:29:59 GMT -5
Is that push-pull arrangement similar to the blow-suck arrangement? " Thanks for sharing your cooling solution with us, Chuck. That should work well with minimal noise. I like your engineering skills." Oh thanks Dark Ranger, although sometimes the moaning gets a little audible. Teslacle's Deviant to Fudd's Law: "It goes in, it must come out." Fudd's Law: "If you push something hard enough, it will fall over." |
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Post by Deleted on Jul 6, 2013 13:19:00 GMT -5
Teslacle's Deviant to Fudd's Law: "It goes in, it must come out."
Fudd's Law: "If you push something hard enough, it will fall over."
Chuckie's Teslacle Law: "One hangs lower than the other."
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Post by Gary Cook on Jul 7, 2013 23:19:46 GMT -5
Back in my Class A days (25 watts per channel) I had a recycled computer fan located behind the amp. Using a cheap thermometer I found that the fan outlet temperature was hardly more than the ambient temperature, 2 to 3 degrees. But it still took all of the excess heat out of the amp. So my guess is 4 fans will be somewhat of an overkill, 2 fans should be more than enough. One mounted low as the air source and one mounted high as the air extraction to take advantage of any thermal current.
I'd also be tempted to at the very least equalise the gaps between the 2 x XPA-1L's and the bottom and the top shelf. The gap between the lower XPA-1L and the upper XPA-1L is arguably the most important, so I wouldn't want it to be any less than the other gaps above and below.
Cheers
Gary
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Post by Chuck Elliot on Jul 14, 2013 14:39:47 GMT -5
I have a friend with a CNC machine so I gave him the 3/16 black lexan panels to cut for me.
I moved the fans up to get better flow over the top unit.
I should have pictures of the final units this week.
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Post by Chuck Elliot on Jul 19, 2013 21:48:11 GMT -5
Here's a picture of the final unit. The CNC cut of the panels came out perfect. The Lexan material is high gloss black. You can see part of me in a backwards chair taking the picture! Changes from prototype: Fans moved up. Used dual strips of 3/4" Velcro instead of 2" piece to remove a bit of overlap that was showing. Stripped the excess on the rack posts with razor.  |
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Post by geebo on Jul 19, 2013 22:30:30 GMT -5
Here's a picture of the final unit. The CNC cut of the panels came out perfect. The Lexan material is high gloss black. You can see part of me in a backwards chair taking the picture! Changes from prototype: Fans moved up. Used dual strips of 3/4" Velcro instead of 2" piece to remove a bit of overlap that was showing. Stripped the excess on the rack posts with razor. Those look great, Chuck. Did you decide on a triggering system yet? |
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Post by Chuck Elliot on Jul 19, 2013 23:16:34 GMT -5
Those look great, Chuck. Did you decide on a triggering system yet? Yes, I found a 12V SS Relay that will do the job. My trigger path will be XSP-1 -> XDA-2 -> XPA-1L -> XPA->1L -> fans This is part of a bigger job with a goal of making this the cleanest equipment rack that I can. I have 3 bigger lexan panels being cut to cover the rear of the rack. These are 25" x 8 3/8" x 1/4" with a 17.5" x 7 5/8" cutout for each of the 3 rack shelves. I'm going to put a AC junction box on the right side of each new lexan panel daisy chained. Then I'll cut some old computer power cords to needed length and wire them inside the junction box. Every unit has its power connector on the right side. The signal path cables will be routed on the left. I'm also going to route as 12V source through the junction boxes for the fans and the supply voltage for my external USB Disk and Blu-Ray. Wall-Wart supplies suck as they seem to always cover 2 wall plugs! I use the single 4A supply I got for the fans to power them all. |
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Post by geebo on Jul 19, 2013 23:29:26 GMT -5
Those look great, Chuck. Did you decide on a triggering system yet? Yes, I found a 12V SS Relay that will do the job. My trigger path will be XSP-1 -> XDA-2 -> XPA-1L -> XPA->1L -> fans This is part of a bigger job with a goal of making this the cleanest equipment rack that I can. I have 3 bigger lexan panels being cut to cover the rear of the rack. These are 25" x 8 3/8" x 1/4" with a 17.5" x 7 5/8" cutout for each of the 3 rack shelves. I'm going to put a AC junction box on the right side of each new lexan panel daisy chained. Then I'll cut some old computer power cords to needed length and wire them inside the junction box. Every unit has its power connector on the right side. The signal path cables will be routed on the left. I'm also going to route as 12V source through the junction boxes for the fans and the supply voltage for my external USB Disk and Blu-Ray. Wall-Wart supplies suck as they seem to always cover 2 wall plugs! I use the single 4A supply I got for the fans to power them all. Sounds nice. I trust you'll post some pics for us. |
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Post by LCSeminole on Jul 20, 2013 18:19:35 GMT -5
Looks great Chuck! I have to actually thank you as I had not heard of fans by Noctua. My new Panasonic plasma seems to get warmer in back on different sides where there are perforated vents, so I bought a couple of 80mm fan that I thought would be quiet attached them to those vents to draw out any heat. Well they weren't near as quiet I had hoped so I tried out Noctua fans, anyhow my plasma is now cool as a cucumber. Definitely quiet and I barely hear them while my home theater is idle.
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