Wireless Sennheiser Wall Worts: Linear or Switching?

RetiredBum

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Jul 11, 2011
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Santa Rosa, CA
Sennheiser used to ship their EW xxx G2 & G3 receivers with a linear (transformer) wall wort. Now they are shipping them with a switching-supply version of their wall wort.

Switching supplies, unless carefully designed, can radiate RFI. Anybody have experience with the Sennheiser switching supplies & is there any reason to perfer one over the other?

Thanks, Alan
 

FMEng

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Both types have their issues. A transformer wall wart runs hot. Some equipment relies on the wall wart for adequate DC smoothing. That DC filtering is done by an electrolytic capacitor whose life span is severely limited by heat. A better approach for equipment design is to use an AC output wall wart, which puts all of the rectification and filtering, the parts that fail, where they belong, inside the equipment. Or, at least put enough filtering in the equipment that it'll still work OK when the capacitor in the wall wart dies. I have replaced piles of bad transformer type wall warts.

As for switching supplies, a well designed one runs cool which means it might last longer. I like it when the power supply is cool to the touch. They can sometimes radiate some RF, typically up into the low VHF range. For wireless systems operating in the UHF range, probably not a problem. Boston Acoustics famously made an HD Radio whose own "line lump" power supply interfered badly with reception. It certainly doesn't hurt to keep switching supplies away from antennas. I suspect that switchers are cheaper now, which the manufacturers love.

Often times, the choice of which type to use is determined by the power needs of the load. Transformers are seldom used for high current loads (over a few hundred milliamps) because they get bigger, heavier, and more expensive very quickly as the current goes up. Most digital wonder boxes need lots of current.

Radio Shack makes some pretty good, regulated, switchable voltage, and high current wall warts. They are handy to have as a quick emergency replacement. I don't bother with their adapter plugs. I just cut the cord off the failed wart and splice old cord to the new supply. That way I know the plug really fits, the polarity is correct and cannot be changed.
 

PolishGuy

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Mar 1, 2012
Location
South Carolina
We ran 20 ew100 G3's with the power supplies all patched into power distro in the same rack before switching to NT/ASA1's. If you ever have a problem with the power adapters, you can always switch to Sennheiser NT/ASA1 power supplies/antenna distro. The ASA's are 1/2 racks and can supply power to 4 G3's, allowing you to free up some space on the power distro.

Edit: I understand the NT/ASA1's can be a bit out of budget for low end systems, but the antenna distro you gain with it can be priceless ;)
 

Clarkwg3

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Mar 15, 2012
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BELOIT, WI
I understand the NT/ASA1's can be a bit out of budget for low end systems, but the antenna distro you gain with it can be priceless ;)
My7 theater runs 14 G2 receivers; 8 on antenna/power distribution w/ no problems. the other 6 each have their owns wall warts with 4 of them mounted in a rack, the other 2 of them 'free range' the only issue I've experienced is RF interference when renting additional units.
 

TimmyP1955

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Oct 29, 2006
Location
Indianapolis
Note that the supply that comes with the wireless unit cannot be used with the antenna splitter - it does not have sufficient current capability. You must use the supply that's meant for the splitter.
 

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