I want to replace the noisy fans in my Audio Research D150 with (much) more silent fans. I don't know which to choose, as I don't know how many cubic feet pr. minute the old, noisy fans deliver each. I wrote to Audio Research Corp. but they didn't know it either.
Does anyone have experince with this?
Does anyone have experince with this?
Looks like fan supply is 120VAC and with series resistor 400R 5W.
You might manage with cleaning the fan in case it's dusty and maybe increasing resistance of series resistor.
Typically "silent" fans move less air so cooling capacity might be compromised.
http://www.audioresearch.com/ContentsFiles/D150%20Schem%20%20PL.pdf
You might manage with cleaning the fan in case it's dusty and maybe increasing resistance of series resistor.
Typically "silent" fans move less air so cooling capacity might be compromised.
http://www.audioresearch.com/ContentsFiles/D150%20Schem%20%20PL.pdf
Then you have a choice of computer fans that are quieter, plentiful and cheaper overall, but reqiure a 12 Dc source. Notebook PW supplies work well, but would require an external PW switching arangement.
The mentioned oiling will make a difference as well as rubber mounting or some kind of decoupling from the chassis. Ball bearings will be noiser than oiled bushings and (bb) will transmit more vibrations to your chassis. They are made for long hours of operation
An "L" bracket mounting and some velcro makes a huge difference that works well at decoupling noise if looks are not a concern , or at least being able to convert back to the original when selling.
The AC fans are limited in noise / cfm combinations and seem geared towards longevity concerns in comparison to the avalabilty of computer fan options.
Reducing speed should be your goal and I wouldn,t worry about capacity overall.
Regards
David
The mentioned oiling will make a difference as well as rubber mounting or some kind of decoupling from the chassis. Ball bearings will be noiser than oiled bushings and (bb) will transmit more vibrations to your chassis. They are made for long hours of operation
An "L" bracket mounting and some velcro makes a huge difference that works well at decoupling noise if looks are not a concern , or at least being able to convert back to the original when selling.
The AC fans are limited in noise / cfm combinations and seem geared towards longevity concerns in comparison to the avalabilty of computer fan options.
Reducing speed should be your goal and I wouldn,t worry about capacity overall.
Regards
David
Modern fans have way better blade design so they can move the same amount of air as your old ones at a much lower sound level.
But the silent ones are mostly 12V DC fans as already mentioned.
It's the blade design of the fan and the chimmney effects that creates the noise in the D-150. The fans are already isolated within a wire steel "cradle". Better to pull 2 of the 6550's out and use the 16ohm tap with a couple of smaller CFM sparkle fans for better sound and 75 wpc instead. The heater windings in the transformer can deliver the current required.
Although modern DC fans may have quieter fan blade designs, they tend to make an annoying HF buzz from the commutative switching. Ball bearings are noisy unless greased, so forget them. Either sleeve bearings or magnetic bearings for quiet. If the old fans were AC, then I would look for something like Rotron "Whisper" fans, or similar, which have serrated trailing edges on the blades for quiet running. Check the noise dB spec for lowish. AC types don't make the buzz sound. Look for a model with similar AC V and Watts as the old one. Use the same or similar series resistors. Since they already had series resistors, they likely weren't pushing much air through to begin with, so most any similar size fan is going to work as well.
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ARC customer service is good, but their service department is not as up to speed on really old gear since Leonard retired. You would be looking at $200 minimum for a replacement and there are three of them. Low noise was not a design requirement - the manual says so, so its not really fair to assume more of the original design than was first intended.
I would recommend the Noctua fans already mentioned. They don't have the nasty commutation noise of other fans as they seem to use a slower rise time on the leading edge of the squarewaves driving the motor windings.
Technologies
Not the prettiest things in brown and cream but they really are very quiet.
Cheers
Matt
Technologies
Not the prettiest things in brown and cream but they really are very quiet.
Cheers
Matt
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