Wow, excellent information. I was mistaken, I had 105’s installed. Could you clarify your last sentence? Thanks!Installing 105°C caps is usually only a cost issue unless one takes the time to evaluate all parameters.
Old electrolytic caps increase ESR and decrease in capacitance. Loss of bass indicates capacitor coupled [boohoo] stages.A high pass filter is a cap in series with a resistor. Typical design would place the corner one or two magnitudes below the minimum frequency of interest. For 20Hz, corner range would be 2 to 0.2Hz. It also blocks DC [A/C coupled]. As caps age, capacitance decreases, raising the corner frequency. The caps were shot long before a loss of bass would be perceived. The ’boohoo’ is because everything is audible and electrolytic capacitors tend to smear the sound. All other things being equal, which they seldom are, direct coupled can sound better. Bottom line, NAD weighed the trade offs and made fine sounding equipment for reasonable prices.
I run a fan on an amp at such a low rpm and airflow rate, that if it’s power supply is unplugged, it stalls out. It’s a small 12V fan running at approx 4.1V DC. When I plug it in, I have to touch one of the vanes to start it by hand. That is what you call the ’just above stalling’ voltage for the 12VDC fan. Each will be different.IMO, this is a bad idea. Line voltage varies all the time and unless one is using a well regulated supply, the fans will stall when the line voltage drops. Additionally, a fan may run when cool, but stall when it warms up.
You can also buy a 12V fan speed controller from a computer shop. One that is all passive, just resistors and a few switches. That would have the least level of interference in your audio equipment.Not so. If running multiple fans, resistors and switches are a PITA. The adjustable supply is a small transformer and an adjustable voltage regulator. The transformer is several feet away and injects ZERO noise. I know, I measured. Most 12v fans will run within about 0.5v of one another. If one fan is overly fast, add a diode [1N914 or 1N4001] in series to drop the voltage slightly.
For added flexibility, a small control panel http://ielogical.com/assets/Audio/FanCtrl.jpg