life ... what else
doing regular daily things for living
it is electronic (and PCs) also , but this here is still hobby side .....
doing regular daily things for living
it is electronic (and PCs) also , but this here is still hobby side .....
To step back a minute.....
It's been established that IR = Vishay = Siliconix
But how does Infineon fit in? It looks like Infineon bought IR, and that Vishay bought IR.... but it looks like Vishay bought only the Infrared part of infineon.
Does Infineon = IR = Vishay = Siliconix = ? Are all four of these the same?
Two quick questions:
Steef
- I have 3mV DC on the EDCOR of both channels. Is it
- a nice idea
- don't bother, or
- a stupid idea (how can you ask)
- On the bench this amp gets HOT. Should I go for a 4U chassis (Modushop 400mm deep dissipate) or is 3U sufficient?
Steef
1. 3mV is practically nothing but , if that makes you happy , put 20R trimpot there
2.4U/400 ; don't be cheapskate 🙂
2.4U/400 ; don't be cheapskate 🙂
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Ballpark rule-of-thumb for heat: You want 10 sq in of "good" heatsink for every watt of heat your need to dissipate. M2 produces about 80w per channel - you need about 800 sq in of sink per channel.
That results in 129mm x 400mm heatsink per channel. The 3U is 126mm.
So following this rule of thumb 3U is ok
Will follow ZM advice anyway🙂
Steef
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I am not sure you are thinking about this in the manner that I intended. Here is an example using the 3U 200mm sink:
A single 3U 200mm sink has 20 fins and measures ~7.75" wide, ~4.75" tall, and has fins that are 1.25" deep.
Total dissipation area for all fins combined = 20 fins * 1.25" deep * 2 sides per fin * 4.75 fin height = 237 sq in
Total dissipation area of one side (the outer side) of the heat sink base plate (the inner side is trapped inside the chassis) = 4.75 * 7.75 = 37 sq in
Total radiating area per 3U sink = 237 + 37 = 275 sq in.
With 275 sq in per sink, you want to limit power dissipation to somewhere between 25 and 30 watts per sink for a 25c temp rise.
This exactly matches my F4 that dissipates 100w for two channels and uses four 3U sinks (total of ~1000 sq inches). 1000 sq inches / 100w dissipation = 10 sq in/watt 😀
A single 3U 200mm sink has 20 fins and measures ~7.75" wide, ~4.75" tall, and has fins that are 1.25" deep.
Total dissipation area for all fins combined = 20 fins * 1.25" deep * 2 sides per fin * 4.75 fin height = 237 sq in
Total dissipation area of one side (the outer side) of the heat sink base plate (the inner side is trapped inside the chassis) = 4.75 * 7.75 = 37 sq in
Total radiating area per 3U sink = 237 + 37 = 275 sq in.
With 275 sq in per sink, you want to limit power dissipation to somewhere between 25 and 30 watts per sink for a 25c temp rise.
This exactly matches my F4 that dissipates 100w for two channels and uses four 3U sinks (total of ~1000 sq inches). 1000 sq inches / 100w dissipation = 10 sq in/watt 😀
I am sure I did not read you correctly 😀
Whoops that was a massive error of me 😱
Thanks for the clarification!
Steef
Whoops that was a massive error of me 😱
Thanks for the clarification!
Steef
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Thanks for the clarification - I had recorded ~75-80wpc dissipation in my notes. Thank you for catching my error. I have a pair of sinks that I previously thought were too small, but now I'm thinking they are a better match 😀
Still want somewhere near 10sq in of sink per dissipated watt. I'd bet a 9:1 ratio would work as well, it would just be hotter...
I have the 300 version, more than adequate. Gets warm, nothing like Aleph J. If you want dual mono, go with 400
Whoops, big misstatement. I am using the Deluxe 4, I thought we were discussing Deluxe 4, 300mm deep vs 400mm deep, sorry!
Russellc
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Ah, this makes more sense to me! The 4U x 300mm deep = 565sq in per sink. Divide 565 by 65w = 8.6 sq in per dissipated watt. This works. But put an Aleph-J in this same chassis (565 sq in/ 100w) = 5.6 sq in per watt - things will be much hotter!
Actually, my Aleph j is in the same case. It is a little hotter, but still not bad at all. I can keep my hands on the sinks as long as I want...but it is hotter. The M2 isn't really much hotter than the F6 was when it was in that case.
Russellc
3U (120mm)x200mm long heat sink in the diystore is rated at 0.5C/W so a 50W load would give a temperature rise of 25C above ambient.
what am I missing here?
Are the specifications defined at some unrealistic temperature differential and only accurate when the sink is way above ambient?
what am I missing here?
Are the specifications defined at some unrealistic temperature differential and only accurate when the sink is way above ambient?