On Mon, 2021-04-05 at 22:30 +0200, Attila Kinali wrote: > On Sat, 03 Apr 2021 08:36:28 -0700 > Shawn <[email protected]> wrote: > > > Tried putting an LM317 regulator in the line to drop the 30V supply > > to > > 10-12V and the power dissapation is beyond the heatsinking I have > > that'll fit, also seems wasteful. I have a switcher thatll fit the > > bill but amd concerned about the noise inside the chassis that it > > might > > make. I can bypass the input/output but concerned for radiated > > hash > > noise. > > This depends. The MRT/FRK types are not that well shielded, > but still better than modern telecom grade types. If you > have a well designed switcher, then that should not be a > problem. If you bought one of the many switcher on ebay/aliexpress, > then I would not trust those... They are horribly designed, > violating the layout rules in the datasheet (and those are > already not up to time-nuts/noise-nuts standards). There are > some 78xx replacments from reputable manufacturers (Murata, etc). > Those should be good enough for that need. Still I would not place > them close to the MRT, if possible. > > > Attila Kinali >
Thanks Attila, I have ordered a 24V low speed and a PWM 24V fan to try out. Still want to keep the loise down where I can so may still use a regulator (the LM317 perhaps) to drop the 27V down to 20-23V and place the regulator in the airway, prior to the FRK. Hopefully there is a bit more room so a larger heatsing will fit and allow the regulator to get the necessary cooling. The PWM fan idea Poul suggested is intriguing and I may give that a try as well when the fans arrive. I am assuming the PWM unit is quieter, electrically, than some units I have found in the past, otherwise the linear approach will have to do, assuming the thermal issues are addressed. Shawn _______________________________________________ time-nuts mailing list -- [email protected] -- To unsubscribe send an email to [email protected] To unsubscribe, go to and follow the instructions there.
