Please Help!! 12-18 VDC Adapter Question

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Karen_2242

Joined Oct 21, 2018
2
Hi. I have a Shure UT4 Wireless microphone system ( https://pubs.shure.com/view/guide/UT4-Wireless/en-US.pdf )and the power adapter is missing. On the back of the unit itself says, 12-18 VDC. I can't seem to find anything like this to buy. I want to know what does 12-18 mean? Does it mean I can use any adapter from 12 to 18 volts or It has to be a special adapter that automatically varies the outputs from 12 to 18 volts when it needs to. In general what adapter should I buy for my device. Thank You.
 

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MrChips

Joined Oct 2, 2009
24,618
You can find a low cost AC to DC power adapter at most computer, hardware, or second hand stores.
Get one that is labeled 230VAC 50Hz input, 12VDC output, with + on the center pin.



 

ebp

Joined Feb 8, 2018
2,332
Adapters with ordinary iron core transformers (fairly heavy for the physical size and as opposed to switch mode types that are light; most phone chargers and similar things are switch mode) are usually unregulated and the output voltage can vary quite a lot. The voltage rating marked is usually at full load, so an adapter that is rated at 12 volts will deliver about 12 V at is full rated current and will be a few volts higher with no load or a light load.

I would recommend an adapter with an iron core transformer for this use because they are less likely to produce electrical noise that could interfere with either the radio frequency or audio frequency portions of the circuit. The current requirement is only 200 mA, so the adapter won't need to be very big. The second photo Mr. Chips posted is probably pretty close to what you are looking for. The manual says 2.1 mm female plug - this is a very common size - the hole in the centre of the plug is for a 2.1 mm pin in the jack on the receiver. The outside diameter of the plug will almost certainly be 5.5 mm.
 

MrChips

Joined Oct 2, 2009
24,618
Also note that the center pin sizes can be 2.5mm, 2.1mm, 1.7mm, and 1.3mm; and possibly others. Get the correct size.
Good point. The center pin is 2.1mm.
The replacement adapter is Shure PS20E. Power requirements are 12VDC @200mA. Any adapter rated for 200mA or higher will do.
 
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