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Ok, my fault I paid £16 for a 600watt power supply, so I got what a paid for.
Problem is I have three of these and the noise is just stupid when they are all on. So, what can I do - I took a peek inside and the fan uses a 2pin connector (not your standard 3 pin or molex).
So choices are: New PSU - decent quiet ones are about £35-£40 NOT an option
New fans: £7+pp for a decent sub 20dB fan. BUT they'll have a molex or 3pin connector, not the 2pin, so I'll either have to hack about and solder the old fan connector on, or plug it into the motherboard or spare powerlead - how the PSU will like this not having a fan connected to its own dedicated socket is qustionable.
Fan speed controller (my M/board doesn't support variable speed chassic/pwr fans ), no not one of those ugly manually controlled things you stick in a 5.25" bay. I mean a proper AUTOMATIC one that sits inside the case with a thermistor to vary the fan speed depending on temperature (like the CPU fan). Do they even exist? as all I can find are manual ones.
Final one is a DIY version of the above. Should be able to cobble one together for about £6, like this one: Thermal Control (PWM version ). With the thermistor glued to the PSU's heatsink. Anyone made/use one or have a better design?
No doubt like most of my posts in here, it will fly over the top of the heads of most folk and they'll suggest to buy manual controller or new PSU, neither of which are an option
Well, after some indepth googling, it appears no such cost effective domestic solution exists. Yes there are controllers, but they are all manual or need a 5.25" bay or cost far far too much money.
Its also dawned on me that my degree in electronic and mechanical control systems might be handy for this....
So, I'm dusting off my old microprocessor instruction sets and seeing if I can come up with a Microcontroller using the PIC 16C or 16F series chip.
The advantage is I will have full speed power up (to get the fans up and spinning), and also apply my own ramp up/down rates to the temperture feedback loops. With the possibilty of using rpm sensing wires to maintain minimum speeds. Not as complex as you may think If I get it wrong, I just re-flash the chip with some new parameters Plus I think I still have the code for a PWM based electric heater in my old notes somewhere which I might adapt. Although there is probably some open source code on Microchip's site (no point re-inventing the wheel ).
Alternative is this I spotted: http://ww.microchip.com/downloads/en...Doc/21447c.pdf Does the job, but I probably could do the solid state op-amp based system in my first post more cheapy, with a logic gate and R/C circuit acting as a delay circuit to hold 100%PWM for one second during power on, ok no fault sensing, but I won't need that - I can hook up the RPM wires to the m/board fan outputs and it'll flag it up on the PC.
Yes this is boring stuff But I wonder why nobody seems to have covered it before without resorting to junk thats already on the market?
Last edited by Shark Man; 20 November 2006 at 11:29 PM.
Well, I finally sorted it (they had been runing on fixed 7volts before hand).
Two of the systems have these, which is a slightly modified version of the one in the link on my first post, and works very nicely indeed, the motors can buzz a little with teh PWM, but its not that loud.
I chopped the connectors off some old hard drives I had (IBM Deathstar ). It has a minimum idle speed pot, and another pot to adjust the sensitivity.
Annoying thing I'd like to comment on: Does Maplin stock anything these days? I must have gone through 10 different transistor options before I found one they had in stock. Same with the thermistors (no 100K; had to use 150k of which they only had two), and no 10K pots except 18turn jobbies...useless Wish I had ordered it online now. Think I'll have to send them an e-mail, as not stocking any suitable power transistors is getting stupid.
My third system is having this; as its a HTPC with 5 fans and needs to be ultra quiet, which currently it ain't (although quieter than my mates PVR ) . So I'm investing in this: mCubed Home as it has 4 fan ouputs and loads of temp sensing options. Plus it inferfaces with my iMON VFD
Last edited by Shark Man; 14 February 2007 at 10:38 PM.
Oh boy you have it bad. You sound like I did a few years ago, desperate for quiet machines. The good news is that modern machine are generally very quiet, and there are now lots of components to help you out.
With the dedication and knowledge that you are showing, you will be really welcomed over at silentpcreview.com | Everything about Silent / Quiet Computers . This place is an amazing resource of info. The recommended and reviewed section is a great place to start when it comes to what to buy. But the best resource on the site are the forums...these ppl are more into silence than ppl here are into scoobies.
Be careful with those PSU mods of yours. There will be a lot less airflow through your PSU now. Couple that with the fact that those PSU were dirt cheap, then you will have am inefficient PSU and also poor heatsinks. The max sustained power outputs of those units will now be a lot lower than they were before you fiddled.
If they go bang, they may take out various components, maybe not. It can be false economy to fiddle around with a cheap PSU. I speak from experience. Some of the PSU I modded lived, others went bang.
Last edited by Luminous; 14 February 2007 at 11:51 PM.
Modern machines are quiet? These are new! lol I should have sent the PSUs back as it says "fan control" in the listing and on the box, when they have none of the sort (lost in translation probably).
I should add (incase anyone else tries it), I did inspect the PSU's internals before doing this work (and to clarify they had no fan control circuitry), and found the circuitry and quality seems to be as good as any others I have seen. Being 600watts PSUs with 12cm fans they are running little load for their rating on the two systems. The exhaust temp and die temps tested were slightly above room temp when the fans were at 12v; that should give the idea of the headroom they have. The thermistor of the fan controller is attached to the heatsink of the PSU and calibrated as such, not left hanging mid air like many people seem to do.
On the subject of PSUs: I previously bought more pricey PSUs (£30-50) and found they were not anymore stable or any better made than the cheap ones, and thus I have become disillusioned with them. So the choice was either stupid money PSUs (i.e one that costs more than the processor; I could make an even better one for less ) or the cheap ones, and I've alreadyspent enough money as it is. Its that old lottery of branded vs non-branded, where the branded stuff sometimes uses the same internals as the unbranded, but without buying and taking it apart and looking there is no way of knowing; so thats the risk, sometimes it works, sometimes it doesn't.
I'm pretty new to this quiet PC lark (not to electronics though; if that didn't seem obvious ) As the predacessors to these PCs were three HP vectras...totally silent. Superb lock and load case design, well made thick metal chassis that didn't vibrate or resonate ,and RF supression too (so it didn't interfere with radios etc); Makes the expensive Silverstone case I have and its multitude of fans seem like cheap junk in comparison (barring the fancy front).
So switching from the HP Vectras to these self-builds came as an accoustical shock to say the least.
Last edited by Shark Man; 15 February 2007 at 12:42 AM.
I find reading independant reviews on PSU is a good starting point towards a silent machine.
Hiper silent 530w are only £48 and have multiple SATA and SLi conectors and can run a conroe cpu and two 7950's without any disruption. 5/5 in over 49 reviews by buyers.
After ten years, the PCs that these PWM controllers were finally retired (bar one as it still has the post franking software on which is playing funny beggers on win 10 ).
So these fan controllers are going spare; Just as well as my multi-room audio system...a bank of three Technics SU-X series amps all run extremely hot when idle or working at low volumes. These gave them a poor reputation as the heat caused solder joints to fracture....
Hence the auxiliary cooling....just an extra fan on the cover over the heatsink.
The thermistor based controller keeps the fan speed down and therefore quieter. Just added a Isolated 240v to 12v mini PSU separate to the main amp PSU as that has 40volt rails and could be prone to noise affecting the audio circuits.
I had to dig up this old thread to remind me what I did as I've long lost the circuit diagrams and forgot which variable resistor did what (one is idle speed and the other is sensitivity). I feel old
Last edited by ALi-B; 23 December 2017 at 11:07 AM.
17 November 2006, 06:48 PM
PSU fan sounds like a hover mower...what to do...
), no not one of those ugly manually controlled things you stick in a 5.25" bay. I mean a proper AUTOMATIC one that sits inside the case with a thermistor to vary the fan speed depending on temperature (like the CPU fan). Do they even exist? as all I can find are manual ones. 
So maybe the solution is a pair of earplugs 
But I wonder why nobody seems to have covered it before without resorting to junk thats already on the market? 
I must have gone through 10 different transistor options before I found one they had in stock. Same with the thermistors (no 100K; had to use 150k of which they only had two), and no 10K pots except 18turn jobbies...useless 
) . So I'm investing in this: mCubed Home as it has 4 fan ouputs and loads of temp sensing options. Plus it inferfaces with my iMON VFD 
