Is my Pass amp overheating?
Hi Bryon, Elizabeth's answer strikes me as reasonable. For additional information see this paper. Note the section on "Material Homogeneity" in particular. Best, -- Al |
Hi Alan. Here's an except from the article that Al linked... In general, apertures should be smaller than L = l/50 [where L=length of slot (in meters) and L ³=w and L >> t and l = wavelength in meters]. To achieve acceptable attenuation values at a frequency of 1,000 MHz (not unusual for high-speed digital devices) apertures should not exceed 6 mm. Actually, it's quite remarkable that mesh with apertures up to 6mm provides effective RFI protection, since 6mm apertures look like this. That mesh is 77% open and would provide more than enough ventilation. In fact, I was thinking about taking Elizabeth and Al's advice and choosing something more like this, which has 1.3mm apertures and is 67% open. Thanks Al and Elizabeth for your help. Very appreciated! Bryon |
Update... I built a new lid for my amp out of aluminum and copper mesh. You can see a picture of the lid here. You can see it installed here. The copper mesh is electrically continuous both with the lid and the chassis of the amp, which improves the mesh's RFI rejection, according to the folks who sold it to me. With the new lid installed, the amp's bias needle is at 12 o'clock at idle. That is down from where it was when the lid was off, but up from where it was when the stock lid was on. So... -With stock lid: 11 o'clock. -No lid: 1 o'clock -My new lid: 12 o'clock This makes sense, since the copper mesh is only 70% open, and the lid's aluminum frame narrows the opening somewhat. So it's a little hotter inside than it was without the lid on. When I get a chance to sit down and listen, I will report back the results. Bryon |
