Passive Cooling vs Silent Cooling for my purposes

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batou069
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Passive Cooling vs Silent Cooling for my purposes

Post by batou069 » Sat Aug 01, 2015 3:39 pm

Hello there,

I found out about silent PCs/passive cooling from another community called computeraudiophile (CA). I love music and audio gear, and got inspired from the CA CAPS Server

I wanted to build a PC more or less like this one, just with better hardware:

I bought so far:
CPU: i7 4790k
MOTHERBOARD: Asus Z97-A
SSD: Samsung 850 EVO 500GB
RAM: Crucial 4x8GB

My purpose is music listening trough an external USB DAC (Digital to Analog Converter, a more fancy or correct way of saying soundcard), watching movies (onboard video) and a download center.

I am aware of the fact that my hardware is total overkill for my purpose, but that's what I have for the moment. Maybe I will get less good components in the near future and switch my HTPC internals with those, but in the meantime this will have to do the job.

My question is: what would be the advantage of passive cooling only (fan-less CPU cooling and PSU) over a silent fan and silent PSU?

Even if I had all passive, I still would need to turn A/C on (hot country) or a fan that will surely make more noise then the fans.

Is there another reason for passive cooling besides the absence of noise?

Thanks

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Re: Passive Cooling vs Silent Cooling for my purposes

Post by CA_Steve » Sat Aug 01, 2015 8:33 pm

Welcome to SPCR.

The only advantage to passive cooling is you don't want fans. :)

Ok, there are other side benefits - the potential for a smaller form factor. Instead of the full ATX board, you could move to a much smaller (even NUC sized) case that uses a passive wall wart rather than an ATX PSU. More efficient at these low loads and less heat inside the case.

Also, it really depends on your environment. You can build a fanned PC that is very very quiet. But, if you live in a very very quiet area, it may still be possible to hear the fans...however, if the PC is 10' away like most HTPCs, then even a quiet fanned PC will be for all purposes silent.

Yes, an i7 is utter overkill for your needs unless you are doing a lot of video transcoding as part of the downloading. Otherwise, an i3 would suffice and possibly a Pentium (again depending on the video file format/compression). In any case, an efficent build with an i7 will draw about the same amount of power as an i3 with your audio playback as they'll both dynamically adjust the clocks for the load.

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Re: Passive Cooling vs Silent Cooling for my purposes

Post by xan_user » Sat Aug 01, 2015 9:32 pm

If you can't actually hear a noctua (or comparable) at 500-600 rpm, with your ambient noise floor, then fanless is pointless.

Can you just locate the pc in another room? thats usually the best way to eliminate any noise.

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Re: Passive Cooling vs Silent Cooling for my purposes

Post by QUIET! » Sat Aug 01, 2015 10:01 pm

I would take anything from CA with several grains of salt.

Their idea of a music server is a $2,000+ PC with a Xeon CPU and ECC ram. Gross overkill to put it mildly.

In my opinion, passive cooling mainly leads to excessive operating temperatures. You can get away with it if the parts are low power and you have big heat sinks.

With high power parts I wouldn't try passive. A few big low rpm fans can keep it running cool fairly quietly.

CA also suggests using linear regulated power supplies in some of their CAPS systems. I seem to recall that the best efficiency possible for a linear supply is around 50% compared to 80+ in a decent switcher. That's just more heat in the case which makes cooling even more difficult.

I think there might be some merit in a clean power supply for the USB to power the DAC but that is about as far as I would mimic CAPS hardware.

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Re: Passive Cooling vs Silent Cooling for my purposes

Post by xan_user » Sat Aug 01, 2015 10:59 pm

QUIET! wrote:I would take anything from CA with several grains of salt.
Oh & my. :shock: (now there's something i've never seen posted on the internetz...)

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Re: Passive Cooling vs Silent Cooling for my purposes

Post by quest_for_silence » Sat Aug 01, 2015 11:51 pm

xan_user wrote:
QUIET! wrote:I would take anything from CA with several grains of salt.
Oh & my. :shock: (now there's something i've never seen posted on the internetz...)
Hu? :?:

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Re: Passive Cooling vs Silent Cooling for my purposes

Post by sschnee » Sun Aug 02, 2015 4:24 am

xan_user wrote:
QUIET! wrote:I would take anything from CA with several grains of salt.
Oh & my. :shock: (now there's something i've never seen posted on the internetz...)
I'm sure he meant CA to mean computer audiophile, not CA-Steve, just to be clear.

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Re: Passive Cooling vs Silent Cooling for my purposes

Post by CA_Steve » Sun Aug 02, 2015 6:57 am

Acronyms can be evil.

batou069
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Re: Passive Cooling vs Silent Cooling for my purposes

Post by batou069 » Sun Aug 02, 2015 7:13 am

Hello everybody and thanks for the replies.

The reason for the CA community not to use fans:

Code: Select all

Fans create RF noise feedback back into the mobo and other components. That degrades sound quality. For Mac Mini there are special packages that fix this (UpTone audio sells them). For PCs you can get fan filters from SOtM. But the best and cheapest way is to avoid fans altogether.
I'm not sure if it really is the cheapest way, since passive cooling cases are not cheap, and they are heavy - expensive shipping.
I intend to undervolt the CPU, should I go the passive cooling way

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Re: Passive Cooling vs Silent Cooling for my purposes

Post by QUIET! » Sun Aug 02, 2015 9:02 am

Yes, CA because I don't trust myself to spell audiophile reliably.

CA_Steve seems downright rational by comparison.

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Re: Passive Cooling vs Silent Cooling for my purposes

Post by CA_Steve » Sun Aug 02, 2015 10:00 am

How do (few watt) DC voltage fans create RF noise?

Audiophile stuff is a combination of best practices and snake oil salesmen. Unfortunately, it's hard for laypersons to distinguish between the two.

Here's the big picture: The inside of a PC is a swamp of RFI/EMI caused by large switched mode regulators for the PSU (hundreds of watts), the VRM circuitry on the mobo (hundred watts), and the CPU and associated circuitry clocking in the gigahertz range. The best way to avoid this in an audio build is to have an external DAC. Go with the motherboard's optical out, or if you run at a higher bitrate, look for an aftermarket PCIe card that can provide it. Or, use USB. Use the mobo rear connector rather than any front panel connection - because case mfgrs tend not to provide well shielded cables..and while USB is a digital signal, some RFI/EMI may couple it's way to your DAC plus it's less likely to have ground return (60Hz hum) issues. There are also audiophile USB add-in cards...but, I think this is down into diminishing returns.

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Re: Passive Cooling vs Silent Cooling for my purposes

Post by QUIET! » Sun Aug 02, 2015 12:22 pm

Yes, there are much worse things in a PC creating PSU ripple, RF, etc.

There is no solution so the only workable strategy is to get clean data out of the USB port and make sure your USB DAC has a separate, clean power supply.

Reading up on the subject, I think most USB DACs are lacking in low noise PCB layout technique. That stuff seems like black magic to me but there is a science to it.

People do notice differences in DAC sound and DACs are notoriously difficult to design with better than 13 bits of resolution (don't ask how I know) so doing everything you can in the DAC will pay off if you can maintain the full resolution of the silicon.

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Re: Passive Cooling vs Silent Cooling for my purposes

Post by Pappnaas » Sun Aug 02, 2015 12:59 pm

If you just want to listen to music, stick with what people say about DACs.

If you want to make music, have a look at http://xi-machines.com/en/systems-audio.php

Those are sold to high level music studios and recording companies (mainly to work with Steinberg-Software and the likes).

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Re: Passive Cooling vs Silent Cooling for my purposes

Post by xan_user » Sun Aug 02, 2015 1:16 pm

sschnee wrote:
xan_user wrote:
QUIET! wrote:I would take anything from CA with several grains of salt.
Oh & my. :shock: (now there's something i've never seen posted on the internetz...)
I'm sure he meant CA to mean computer audiophile, not CA-Steve, just to be clear.
Whoops! :oops:

batou069
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Re: Passive Cooling vs Silent Cooling for my purposes

Post by batou069 » Sun Aug 02, 2015 2:20 pm

Hello people, thanks for all the replies, really helpful. I was also wondering about the RF from the fan, but CA is certainly no community to start convincing people that they might be wrong, especially if you're not a specialist.

The computer will be used for music listening, but also more. After having read some build articles on this site (especially the Fractal Design Define R5 build), I think that I'll go for a silent design over a passively cooled design. It will also give me the possibility to buy less "high-end" components in the future to take over as my HTPC, and to use my current components for my future desktop PC.

I use a USB DAC that came from an Indiegogo crowdfunding capaign, the LHLabs (Light Harmonic) Pulse Sfi DAC. I will certainly buy a linear power supply for it one day, but for now the wall will have to do the job.

I would be interested to hear about your opinion (or experience) of SOTM Products
The Fan Filter (although discussed earlier), the SATA Filter, the ISO-CAT6 Filter and especially the SOTM Usb card that can be externally powered by a linear power supply. if this goes too much offtopic, pardon me and simply don't answer.

I will open a new thread regarding my build in the System Advice Forum. Thanks for all the help, great Site I've found there :)

QUIET!
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Re: Passive Cooling vs Silent Cooling for my purposes

Post by QUIET! » Sun Aug 02, 2015 3:21 pm

SOTM seems expensive.

Those SATA filters might be good for a HDD but I have doubts about its usefulness with a low power SSD (like a Samsung 840 that barely sips power).

The USB 2.0 external hub seems more portable than a PCIe USB card and a bit cheaper but I think the CA forums have DIY instructions for externally powering USB so you can decide which way makes more sense.

If you take care of the USB, do the fans matter? I have doubt's.

Noise on the network cable will be stripped out by packet correction before it gets to the audio signal so I have doubts on that one too.

On the other hand, if they were cheap, I would buy.

batou069
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Re: Passive Cooling vs Silent Cooling for my purposes

Post by batou069 » Mon Aug 03, 2015 1:17 am

QUIET! wrote:SOTM seems expensive.
On the other hand, if they were cheap, I would buy.
No brainer ;)

Thanks for your opinion

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Re: Passive Cooling vs Silent Cooling for my purposes

Post by Mr Evil » Mon Aug 03, 2015 8:26 am

batou069 wrote:...I would be interested to hear about your opinion (or experience) of SOTM Products
The Fan Filter (although discussed earlier), the SATA Filter, the ISO-CAT6 Filter and especially the SOTM Usb card that can be externally powered by a linear power supply. if this goes too much offtopic, pardon me and simply don't answer...
On the plus side, the few pennies-worth of components on those products actually do something, unlike many audiophile products. On the minus side, what they do is completely useless - PCs are electrically noisy inside and there's nothing you can do about it.

USB DACs are available with 120dB SNR, which is well beyond the limits of human hearing (although some will claim otherwise without being able to prove it), and they don't need any esoteric filters or linear power supplies to acheive that.

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Re: Passive Cooling vs Silent Cooling for my purposes

Post by QUIET! » Mon Aug 03, 2015 11:18 am

Some people have "golden ears".

Mine are OK, I can hear some of the differences that the "golden ears" talk about. On the other hand, I seem fairly able to tolerate sonic defects up to and including turntable rumble and a little bit of tape hiss. I am perfectly happy with good enough but I can appreciate better and will spend a little money or time to get it.

When people throw around SNR numbers, the questions I have are: how is that measured and what else is in the playback system. Glitching can make bad sound but generally isn't included in the published numbers. Speakers are a difficult load with varying impedance and not very linear output so how they interact with the amplifier is another variable.

I also have very good eyes, (20-15 vision) and I find it far more objectionable to watch low resolution video. When I go in the store and look at a 4k set, I am mildly disapointed with my very nice 1080p set for a little while...

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Re: Passive Cooling vs Silent Cooling for my purposes

Post by RIchardF » Sun Dec 06, 2015 12:25 am

batou069 wrote:My purpose is music listening trough an external USB DAC (Digital to Analog Converter, a more fancy or correct way of saying soundcard), watching movies (onboard video) and a download center.
Skylake G4400T Pentium for H.265 decoding:
Skylake also expands hardware-accelerated encoding and decoding support. It can encode and decode 8-bit H.265/HEVC content, which its predecessors couldn’t do, and it adds hardware encoding support for the JPEG and MJPEG formats. Some of this work is performed by the GPU itself, while some can be handled by the lower-power multi-format codec in the GPU’s unslice. Notably, H.265/HEVC decode is supported by the unslice, which should be good for power usage if you’re just streaming video (encoding requires firing up the GPU).

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Re: Passive Cooling vs Silent Cooling for my purposes

Post by LostHighway » Sun Dec 06, 2015 3:33 am

Given the parts the OP has/wants to work with a "silent" PC with fans seems like the obvious answer to his/her question.

When we depart from the OP's basic question I think the waters quickly become far murkier.

Putting the fan electrical noise question aside, the following post from CA Steve I generally agree with although I would argue that the question of whether to use a toslink/optical output or USB output often comes down to decisions make by the DAC's designer(s).
CA_Steve wrote:How do (few watt) DC voltage fans create RF noise?

Audiophile stuff is a combination of best practices and snake oil salesmen. Unfortunately, it's hard for laypersons to distinguish between the two.

Here's the big picture: The inside of a PC is a swamp of RFI/EMI caused by large switched mode regulators for the PSU (hundreds of watts), the VRM circuitry on the mobo (hundred watts), and the CPU and associated circuitry clocking in the gigahertz range. The best way to avoid this in an audio build is to have an external DAC. Go with the motherboard's optical out, or if you run at a higher bitrate, look for an aftermarket PCIe card that can provide it. Or, use USB. Use the mobo rear connector rather than any front panel connection - because case mfgrs tend not to provide well shielded cables..and while USB is a digital signal, some RFI/EMI may couple it's way to your DAC plus it's less likely to have ground return (60Hz hum) issues. There are also audiophile USB add-in cards...but, I think this is down into diminishing returns.
This post below mischaracterizes or misunderstands some digital audiophile thinking, it is not alone in that respect.
QUIET! wrote: Their idea of a music server is a $2,000+ PC with a Xeon CPU and ECC ram. Gross overkill to put it mildly.
CA also recommends NUC server designs.
CA also suggests using linear regulated power supplies in some of their CAPS systems. I seem to recall that the best efficiency possible for a linear supply is around 50% compared to 80+ in a decent switcher. That's just more heat in the case which makes cooling even more difficult.
Generally, the accepted practice if choosing to use a highly regulated linear PSU for an audio server is to place it outboard of the case. In that context it has no bearing on temperatures inside the case beyond the fact that the primary PSU is now outside the case.


If people in the SPCR community want to believe that Thorsten Loesch (AMR/iFi) and his team, Charles Hansen and the crew at Ayre, the late Don Moses (founder of Wadia, I know nothing about their current staff), Mike Moffat (Theta/Schiit), John Stronczer (Bel Canto), etc. really don't know their craft and are just blowing smoke I can't and won't attempt to persuade you otherwise but I do reserve the right to raise an eyebrow.

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Re: Passive Cooling vs Silent Cooling for my purposes

Post by RIchardF » Wed Dec 09, 2015 3:25 am

What's interesting about audio today is how:

1) Young people are generally content to damage their hearing more than before by constantly using earbuds in noisy environments and having music going even during the school day.

2) Young people are generally content to listen to lossy compression which, despite all the claims I have seen, does sound worse (even at 320).

3) Music has been clipping/squashing audio since 1989 (depending on the CD) which can dramatically reduce the quality of the sound (see "loudness war"). Music for radio and singles (as opposed to full-length CDs and LPs) has typically been mastered to have a low dynamic range for a long time but lossy compression, noisy environments with earbuds, and highly clipped audio does not make for a great recipe.

4) Young people are generally content to say things like "Who cares that much about fan noise because I'll wear headphones when gaming?" The idea is that noise can be defeated by cranking up the volume of the music and sound effects.

5) Many computer users listen to music through very low-grade monitor, laptop, or external computer speakers because of portability and cost.

Despite all these things, sound engineering forums are full of people claiming that they can truly hear a big difference between a Grace preamp and a cheaper one. Is that going to matter to the people who listen to the finished music, especially if it has been mastered poorly like most things are today?

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Re: Passive Cooling vs Silent Cooling for my purposes

Post by CA_Steve » Wed Dec 09, 2015 11:25 am

LostHighway - I think the biggest factor is how much is the user willing to spend for the solution. I'd break it into three groups of people: Those that want to spend an extra $100 or less, those willing to spend hundreds of $'s, those willing to spend thousands of $'s. Obviously, the optimum solution varies by the category. :)

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Re: Passive Cooling vs Silent Cooling for my purposes

Post by MikeC » Wed Dec 09, 2015 1:55 pm

LostHighway wrote:Generally, the accepted practice if choosing to use a highly regulated linear PSU for an audio server is to place it outboard of the case.
The question is why choose a linear PSU? Switching PSUs have been used in many high end components for years -- nay, decades. The famous Hypex guys offers SMPS for all their amp modules, and a handful of well known audio brands have used SMPs in preamps and amps since the early 90s. iirc, Linn was an early adopter & they've never looked back.

Aside for the low efficiency, in a typical PC suitable for use as an audio playback machine, the power demand is very low, so you could probably get away with a linear PSU as low as 100W, but it would still be way pricier than a switching PSU. I'm certainly not convinced there's any difference, measurable or audible, when the output is via SPDIF, especially optical... or via ethernet. Perhaps USB could be affected by the higher noise from a typical switcher, but as others have pointed out, switching power is right on the motherboard itself.

PS -- Of course not all ATX PSUs are the same, some have much higher noise than others. But most of the better brands I've tested in recent years are hard to differentiate by ripple noise alone.

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Re: Passive Cooling vs Silent Cooling for my purposes

Post by Mr Evil » Wed Dec 09, 2015 2:07 pm

MikeC wrote:...The question is why choose a linear PSU?...
There are some reasons why it might be a good idea, for instance they are easier to design. However the audio world is full of snake oil, cargo-cultism and self-delusion, which are the usual reasons.

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Re: Passive Cooling vs Silent Cooling for my purposes

Post by quest_for_silence » Wed Dec 09, 2015 3:35 pm

MikeC wrote:The question is why choose a linear PSU?

The question is why choose digital distribution music (at home, where a PSU can be plugged into a wall socket)?

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