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> Two cooling fans very low noise 19DB@7V audio grade diy
Two cooling fans very low noise 19DB@7V audio grade diy
Vacuum tubes need heat for the thermionic emissions to kick in, but, heat does shorten their life. That's why Pearl tube coolers exist (excellent info on this subject at their site http:// /06_Lit_Archive/01_Audio_Notes/PEARL_Tube_Coolers.pdf ).
So, all you DIY'rs... consider running one of these fans in your design at 7 volts with a little sound absorbing baffling built in. No noise (?) and happy long lived tube audio. Cool all the components and use Pearl tube coolers on the tubes! Electronics in general don't like the heat!
These are very high quality PC cooling fans, new, unused & first quality.
They are a brush-less 12VDC design with an operating voltage range of
6V ~ 13.8V. The design employees ball bearings to achieve a noise rating of 22dB at a flow rate of 24.7 cfm. Dimensions are 80mm x 80mm x 25mm.
The lower the voltage, i.e. 7 Volts = 19 dBA@1m & 14 cfm
This Link takes you to the PDF data sheet:
http:// /content/pdf/TMP00123/I/3110kl.pdf
On the net I found prices for NEW (not used) fans of this make and model ranging from `$11.55 to $135 ( http:// /3110KL-04W-B10.html what were they smoking!), delivery charges not included.
Digi Key sells an equivalent model at this link:
http://search.digikey.com/scripts/DkSearch/dksus.dll?lang=en&site=US&KeyWords=3110KL-04W-B10&x=25&y=16
The following is an excerpt from a test of several cooling fans I found published on line. It is good information in that it shows measured noise levels (non-anechoic and therefore higher than published spec) at different voltages / speeds / flow rates.
Samples 1 & 2 (rated for 0.10A)
NMB-MAT is a large OEM manufacturer that is the end result of a three-way merger between three well known manufacturers: NMB, Minebea, and Panasonic's Panaflo division. Because of this, the specifications for the company's fans can be found in a dizzying number of places, as all three companies still maintain independent web sites. Even worse, the specifications published in different places do not always agree with each other, making it difficult to know exactly which fan you're looking at.
Our samples bear NMB's mark, not the more recent NMB-MAT brand, so it seems likely that they were manufactured before the merger took place. For now, we will assume that the specifications on NMB's web site are the correct ones.
