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I have an Altec Lansing 1270b with a fan in the case.  It is 115V fan and 120mm.  I have no trouble finding a 120mm fan to replace it but all of the super quiet ones are 12V.  The best fan I saw that ran at 120V was on ebay and the noise level was 33 decibels.  I thought about a AD/DC converter but that would take some rigging and I want to wire it in nice and clean.  Any ideas?
 

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Quote:
Originally Posted by murl  /t/1520725/making-an-older-amplifier-with-a-fan-quiet#post_24432387


I have an Altec Lansing 1270b with a fan in the case.  It is 115V fan and 120mm.  I have no trouble finding a 120mm fan to replace it but all of the super quiet ones are 12V.  The best fan I saw that ran at 120V was on ebay and the noise level was 33 decibels.  I thought about a AD/DC converter but that would take some rigging and I want to wire it in nice and clean.  Any ideas?

Bite the bullet and use the 12 v fan. There may be a place you can tap off 5 or 12 or 15 volts inside the amp, or you may use a power resistor to cut the voltage down from the main power supplies.


There are 12 v fans type that put out less than 10 dBA SPL. They are quiet!
 

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Is it a fan that runs constantly or does it cycle on when needed like a computer fan? If it runs constantly you could consider cutting it out of the circuit entirely. Then see if the amp overheats. Probably it will not because th amp really needs the fan only when driven to high volume levels. If it cycles on when needed then, alas, it is needed.
 

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Discussion Starter #4

The fan runs constantly.  How would you use a power resistor to cut the voltage?  Also wouldn't you need to convert AC to DC for a 12V fan?
 

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The "use a resistor" idea won't work as you know you need to convert ac to dc ... a little more complicated than a resistor. You could try cleaning the old fan.... dust on the fan lobs can cause a lot of air noise. Depending on the space, you might be able "lay in" a 12v "wall wort" supply that could then power a 12v dc fan.
 

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Quote:
Originally Posted by budwich  /t/1520725/making-an-older-amplifier-with-a-fan-quiet#post_24432799


The "use a resistor" idea won't work as you know you need to convert ac to dc ...

I'm talking taking power from the existing DC lines that provide the main source of power for the output stage.


In a 100 wpc power amp they run +/- 65 volts more or less, and are well enough filtered DC to be good for fans. The best way to knock down that voltage to DC would be chip voltage regulator. A TL783 http://www.ti.com/lit/ds/symlink/tl783.pdf looks pretty good.
Quote:
a little more complicated than a resistor. You could try cleaning the old fan.... dust on the fan lobs can cause a lot of air noise. Depending on the space, you might be able "lay in" a 12v "wall wort" supply that could then power a 12v dc fan.

+1 The 12v wall wart is good working solution - bulky and ugly but entirely functional.


here's a relevant DIY project:

http://www.instructables.com/id/Make-a-simple-12-volt-power-supply/


Here's an example of one all set up on a board with heatsink, etc.

http://www.ebay.com/itm/2-to-120V-DC-High-Voltage-Adjustable-Regulator-Module-Based-on-TL783-/200939896100

 

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back on the "wall wort", depending on what "pre-amp" you are using with the amp, you might be lucky with a "switched AC" outlet on the backside. Plug the wall wort into there, when you turn on the pre-amp, it will power up the fan. The overall "look" will just be another "wire" likely easy to "hide" with most of the rest.
 

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Discussion Starter #9

Quote:
Originally Posted by budwich  /t/1520725/making-an-older-amplifier-with-a-fan-quiet#post_24433495


back on the "wall wort", depending on what "pre-amp" you are using with the amp, you might be lucky with a "switched AC" outlet on the backside. Plug the wall wort into there, when you turn on the pre-amp, it will power up the fan. The overall "look" will just be another "wire" likely easy to "hide" with most of the rest.
I have a marantz and it doesn't have a switched AC outlet, this would have been an excellent solution.  I think i'm going with the nocturne fan and a wall wart.  I have an old AC/DC 12V adapter from an old portable CD player.  I think the days of jogging with the esp on are over.
 

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Quote:
Originally Posted by murl  /t/1520725/making-an-older-amplifier-with-a-fan-quiet#post_24434035


I have a marantz and it doesn't have a switched AC outlet, this would have been an excellent solution.  I think i'm going with the nocturne fan and a wall wart.  I have an old AC/DC 12V adapter from an old portable CD player.  I think the days of jogging with the esp on are over.

Hate to keep spending your money but I use one of these for my equipment to turn what I want on and shut off when not in use. This will work since your Marantz doesn't have the switched outlet in it. You can use this with the wall wort also to turn those fan/s on whenever your AVR or amp is on. There are smaller ones that cost less if you don't need a 10 outlet one. Google search "Smart Strip" energy saving surge protector.


http://www.amazon.com/Smart-Strip-Protector-Autoswitching-Technology/dp/B0006PUDQK/ref=sr_1_3?s=electronics&ie=UTF8&qid=1393883432&sr=1-3&keywords=green+power+strip
 

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Most of the so-called "muffin" or "whisper" fans are very quiet, and they are most often for 120 volt AC operation.


I have taken them out of cheap surplus desktop computer power supplies and used them and most of them are very quiet, especially if they are properly mounted using rubber bushings.


Also, there is no need for the fan to always be on.


You should connect it to a thermal switch mounted on the amplifier heat sink, so that it only goes on when the heat sink gets to a certain temperature.


In many cases, this will only happen when the sound is loud and the fan noise will be masked.


The fan will usually not operate when the sound level is lower, because the heat sinks will not be very hot.





Quote:
Originally Posted by murl  /t/1520725/making-an-older-amplifier-with-a-fan-quiet#post_24432387


I have an Altec Lansing 1270b with a fan in the case.  It is 115V fan and 120mm.  I have no trouble finding a 120mm fan to replace it but all of the super quiet ones are 12V.  The best fan I saw that ran at 120V was on ebay and the noise level was 33 decibels.  I thought about a AD/DC converter but that would take some rigging and I want to wire it in nice and clean.  Any ideas?
 

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Quote:
Originally Posted by commsysman  /t/1520725/making-an-older-amplifier-with-a-fan-quiet#post_24434659


Most of the so-called "muffin" or "whisper" fans are very quiet, and they are most often for 120 volt AC operation.

"Muffin" and "Whisper" are trademarks of the Rotron company that is still in business as Ametek Rotron..


Here is their full catalog of those fans:

http://www.rotron.com/download.asbx?AttributeFileId=d541ecb8-05aa-4d90-b6d8-ac7f5f6eeded


if you download that catalog you will find that the quietest of them is speced to have noise of and I quote: "Acoustic levels as low as 36 dBA"


Modern 120 mm fans have noise levels below 10 dBA.
 

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Quote:
Originally Posted by arnyk  /t/1520725/making-an-older-amplifier-with-a-fan-quiet#post_24435407


"Muffin" and "Whisper" are trademarks of the Rotron company that is still in business as Ametek Rotron..


Here is their full catalog of those fans:

http://www.rotron.com/download.asbx?AttributeFileId=d541ecb8-05aa-4d90-b6d8-ac7f5f6eeded


if you download that catalog you will find that the quietest of them is speced to have noise of and I quote: "Acoustic levels as low as 36 dBA"


Modern 120 mm fans have noise levels below 10 dBA.

No kidding on those Muffin and Whisper fans. Compared to the one below they must sound like room fans. The one below is only 15.5 dba and is a 120mm fan with a cost $11.95.

http://www.coolerguys.com/840556083054.html
 
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