Krell KSA 50 PCB

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NUTTTR

Member
Joined 2004
Fans...

So my current fan is a panaflo FBA08A12U....
47cfm
38.2dBa
3450rpm
47Pa...

I want a fan that is quieter.... I run them at 8 or 10v depending on the airflow I need.... So obviously they drop in noise levels... What should I look at for this? Any ideas? I would like something UNDER 30dBa!! :)

Thanks
Aaron
 
Zen Mod

Zen Mod

Official Court Jester
Joined 2003
zenmod.in.rs/
Paid Member
Re: Fans...

NUTTTR said:
So my current fan is a panaflo FBA08A12U....
47cfm
38.2dBa
3450rpm
47Pa...

I want a fan that is quieter.... I run them at 8 or 10v depending on the airflow I need.... So obviously they drop in noise levels... What should I look at for this? Any ideas? I would like something UNDER 30dBa!! :)

Thanks
Aaron
Click to expand...


Noctua NF-S12

tip somewhere from KSA threads........
 
troystg

troystg

Member
Joined 2004
Search made easier.. Well sorta

Hi all-

I just recently found this out so it may be news to others also. If not just ignore...

To seach for an item in any long thread there is a "Search this thread" area at the bottom right side of the page.. It really come in handy when your refering back for information you read 20 pages ago.. :D




As for projects..

I will FINALLY be starting my KSA-50 this year... I have everything to make 2 stereo pairs and hope the first turns out well enough that I don't need the second.

Right now I'm modding my Twisted Pair Rev_C from the incredible Mr. Mauro and Kook pre-amp. On deck are the VSPS phono stage, the Pass Labs A30 clone, my 5th BrianGT LM3886 GC (I give them away like candy) and then my Servo controlled active 3 way main speakers.

Happy New Year!!! Now back to it... :smash:
 
N

NUTTTR

Member
Joined 2004
AndrewT said:
Thanks Lgreen.
It's a pity such a comprehensive report missed the opportunity to compare different sizes.

I think that bigger fans running at slower speed to produce the same airflow will develop less noise.

If this is true, then adopting 120mm fans may be significantly quieter.
Click to expand...


This is true, however if you are running heatsinks that form an 80mm tunnel, then you will need a reducer, which will generate noise and take up space. I have 4 80mm fans running and it can be noisy, however, running the fans metioned before (Noctua) at 12v should be under 20dBa, which should produce a very similar result to the panaflo @ 10v. Hopefully.... I'm looking into them as they are only ~$20 AUD for the 8cm quiet version :). If it suits it would be so so perfect! (No need for voltage regulator for fan control!)

Aaron
 
jacco vermeulen

jacco vermeulen

Member
Joined 2004
The noise level of fans is generated by the blades of the prop and the bearing.
The mechanical noise level can be reduced by flexible mounting of the fan to the heatsink, and damping it with rubber.

The bigger the diameter of the fan prop the higher its efficiency can be. That is why ships have the biggest screws that are still submerged, usually there's only a few feet of water above the screws of modern ships.
Fan noise increases linearly with airflow, as does airflow with increasing rpm.
But the tangent is not the same for both correlations, hence the advantage of reducing the fan speed.
Most noise is generated at the tip of the fan blade.
A 80mm fan at twice the rotational speed as a 120mm fan can have the same airflow but will have a higher noise level.
There are a couple of hightech ways of increasing fan efficiency, but that requires surgery and a pro workshop. (me thinks i'm the fan and prop expert of this forum, kT and kQ propellor theory on request)

Seen my post at the KSA100 thread ?
Assembled heatsink tunnels with a Papst fan included, predrilled for 12 output devices. Brandnew for $50/pc.
Tomorrow, tomorrow, i'm going to have myself a ball tomorrow. (when the shops open) :clown:

Al de miKrello,
Happy New Year, seen the fireworks show in London ?
 
lgreen

lgreen

Member
Joined 2003
AndrewT said:

I think that bigger fans running at slower speed to produce the same airflow will develop less noise.

If this is true, then adopting 120mm fans may be significantly quieter.
Click to expand...

From personal experience, a smaller fan is definatley noiser than a larger fan. My KC has a an "aspire" 120mm fan on one end of the heat sinks. Originally I was going to just use this fan but as my fan controller can control up to 4 fans, I put another fan (80mm) on the other end of the heat sinks. It needed to be an ultra thin small fan to fit in the case (vertical sinks) but I got a fan that was reviewed favorably in the "low noise" category. The smaller one is definately louder than the big one and it moves less air (of course). I had no clue when making the amp how fast I would run the fans but they work out just fine. The aspire is very very quiet even at high speeds.
 
jacco vermeulen

jacco vermeulen

Member
Joined 2004
KMJ,

you could consider adding a slab of rubber on both sides of the fan + adding 2 extra TO3s per channel.

I recall that your tunnel has the space and pre-drilled holes for that.
The rubber damping will allow for a bit higher rev at the same noise level.
Splitting the heat across 6 devices instead of 4 allows the heatsink tunnel to have a higher temperature.
Adding 50% of those output devices allows the heatsinks to have a temperature rise that is 25% higher.
You have plenty of space around the tunnel, the higher temperature of the heatsinks will hardly influence the temperature inside the case if the case has ample ventilation.
The heatsink elements in your tunnel are not placed very tight together, thereby reducing the efficiency of the fan.=> Means: lots of airflow(noise) or accepting a higher temperature

(PS: the metal grill you are using raises the fan noise level)
 
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