Like many others I've been looking for a replacement for the stock 9V DC
Power Supply Adapter as many of mine keep breaking (3 so far).  I'm
going to compile a lot of information here so this will be a long post,
I'll do my best to compartmentalize.

_GOAL_
Getting a replacement 9V Power Supply Adapter to work with the
Squeezebox Duet Receiver (and possibly other models)

_CHALLENGES_
  
- *Barrel Plug Size is Non-Standard*: As many have noted, this can be
  a tricky thing to accomplish as the DC Barrel plug size Logitech
  decided to use for the Duet Receiver is NON-STANDARD.  The exact
  measurements are 3.5mm Outer Diameter x 1.05mm Inner Diameter, Center
  Positive.  Many have opted for the "Universal" DC Power Supply
  Adapters that come with multiple plug sizes but unfortunately none of
  those are perfect fits despite what some online users may claim.  Yes,
  that's right, I'm all-knowing, all-powerful, and infallible so I know
  without even looking at their particular adapter that the sizing is
  not perfect.  How?  This is because all of those adapters come with
  standard sized plugs that do not match the aforementioned dimensions
  on BOTH the inner AND outer diameter.  So you may get a snug fit on
  the outside but not on in the inner diameter or vice versa.  They're
  still "doable", but also sub-optimal.  The standard sizes those
  universal power supplies come with include; 4.0mm x 1.7mm, 3.5mm x
  1.35mm, and 3.0mm x 1.1mm.  Notice that none of them match the 3.5mm x
  1.05mm size of the original.
- *The PSA05R-090-R Spec Sheet is Incorrect*: Despite the official
  power supply adapter model # being PSA05R-090-R, the spec sheet from
  Phihong states the DC barrel plug as standard @ 5.5mm x 2.1mm, except
  you'll notice that doesn't match the aforementioned plug.  This is why
  you'll find a lot of Amazon/eBay/etc listings claiming they have a
  replacement power supply specifically for the Logitech Squeezebox
  Duet, yet the reviews will often show someone saying the plug didn't
  fit.
  

_POTENTIAL_SOLUTIONS_
  
- *Settling for suboptimal universal power supplies*: This is the most
  common solution you find throughout the forums.  These DC Power Supply
  Adapters have dials so that you can select 9V (amongst others) and
  then also swap in a plug that happens to fit your device.  As noted,
  none of these DC barrel plugs are exact matches (refer above) despite
  anecdotes you will hear online of people claiming they fit perfectly. 
  Some users are simply unaware that it's not an exact match and that
  the other sizes CAN work, despite being different sizes.  The 3.5mm x
  1.35mm size is the one I found to be the least problematic despite
  being a little loose (and no surprise since it's the closest to 3.5mm
  x 1.05mm), but the 4.0mm x 1.7mm and 3.0mm x 1.1mm sizes also work
  albeit are finickier on connection.  The 4.0mm x 1.7mm is the most
  misleading as the outer diameter feels like a perfect fit when you
  slot it in, but you may notice as you place the device around, that
  the connection can be lost by slight movements since the inner
  diameter has >0.5mm of play.
- *Using USB Power Delivery to replace the power supply*: This is
  something I haven't found as much dialogue in the forums for and what
  inspired this post.  The basic gist of it is that you can use most
  standard USB Power Adapters that have come with phones ever since the
  original iPhone 3G to replace the official Logitech Power supply. 
  Most of these adapters you will note are 5V 1A adapters but it's not
  hard to get them to 9V 0.56A (the spec of the Logitech power supply)
  since that still fits with the overall power demand (e.g. 5V @ 1A  =
  5.00W while 9V @ 0.56A = 5.04W, almost identical, and recall that the
  the device doesn't use the max output so that 0.04W of headroom is not
  very consequential), but it will require a special USB cable.  For
  added bonus, the official Apple USB Adapters have similar ripple
  requirements as the Logitech Power Supply so one less thing to worry
  about.  I would not recommend knock-off adapters as those tend to have
  looser ripple requirements and are more of a gamble.  I would explain
  more but this video does a better job without me having to type it all
  out (ignore the USB C-type requirement, as that's optional and you can
  use a standard USB Type A plug)
  




https://youtu.be/kZOe7aaiqqE

So in conclusion, search for a "9V USB cable" and you'll see a bunch of
results come up.  You want to match the barrel plug size for the device
you need but I'll defer that challenge to the details below as it's
complicated for the Squeezebox Duet Receiver.  On the plus size, if you
need this for the Squeezebox Touch, that barrel plug is the standard
5.5mm x 2.1mm so it's easy to find.  The catch on that one is that it
requires 5V @ 3A, and that means a more modern USB charger that goes up
to 3A or more (typical was 1A or later 2.1A, which would both fall
short).

_ADDITIONAL_DETAILS_ON_SOLUTION_#2:_
    
- *USB Type A or C Cables Work Fine*: You don't have to force yourself
  to use a USB Type C Power Supply Adapter (since those are more recent
  and less common).  If you do go that route, the good news is that most
  USB Type C power supplies are greater than 5V @ 1A so you easily
  exceed the Logitech Power Supply requirements.  Again, would not
  recommend you use knock-off power supplies as those tend to have
  looser ripple requirements.  A USB Type A cable works fine provided it
  has the added chip to convert 5V to 9V.
- *Where to buy the cable*: As mentioned, USB Type A cables are
  available with barrel plug ends at Amazon, eBay, etc.  What you need
  to look out for is that it's 9V (as there's also 5V, 12V, etc.
  variants) and that the barrel plug matches the size we need (3.5mm x
  1.05mm).
- *Finding the right barrel size (3.5mm x 1.05mm)*: And here dear
  reader, we come full circle to trying to solve the same problem.  The
  3.5mm x 1.05mm barrel plug size is non-standard and a PITA to find
  online.  As far as I can tell, it's non-existent.  There's apparently
  a standard size that is 3.8mm x 1.05mm according to 'this website'
  
(https://www.cui.com/blog/selecting-appropriate-input-and-output-plugs-for-your-power-adapter)
  (pic below), however, I have been unable to locate such a size
  online.
  
  

[image:
  https://www.cui.com/image/getimage/139667?typecode=m]
  
  One solution that is handy, is that most 9V USB--> DC Barrel plug
  cables are 5.5mm x 2.1mm for the barrel plug, and the barrel plug
  "size converters" all seem to originate at that 5.5mm x 2.1mm size, so
  once you locate a 9V USB Type A cable at that size, it's just a matter
  of also getting a barrel size converter to your desired size (e.g.
  3.5mm x 1.35mm) and voila, you've essentially got the same solution as
  the Universal DC Power Supply Adapter except for far less money.  That
  latter piece is the challenging part and you will likely have to
  settle for 3.5mm x 1.35mm via an adapter (from 5.5mm x 2.1mm) and that
  is sub-optimal but will get you into the same territory as the
  universal power supplies.
  

_POTENTIAL_IMPROVEMENTS_
    
- The last piece of the puzzle here is trying to find an adapter that
  matches this darn barrel plug size that would be an EXACT match to the
  original power supply.  If anyone finds a source online, please feel
  free to share although I suspect because it's non-standard, that it
  would likely either be far more expensive or simply impractical.
- A good alternative would be the 3.8mm x 1.05mm size which is
  supposed to be standard.  Why?  Well, remember how I said that the
  4.0mm x 1.7mm barrel plug fits the Squeezebox Duet Receiver quite
  snuggly?  Well, that's because there's some margin there to fit a
  larger plug.  Since the inner diameter would be an exact match at
  1.05mm, oversizing the exterior barrel diameter would be
  inconsequential since you'd simply have a snugger fit on the outside
  with an exact fit on the inside.  Win-win.  The catch is that I have
  been unable to find any barrel size converter that goes to the 3.8mm x
  1.05mm size.  If anyone does, please feel free to share as this would
  solve the last piece for an even better solution.
  
  _POTENTIAL_FEEDBACK_
            
  - *This seems like a lot of work when the universal power supply is
    an easier solution overall*: No argument there.  The plus of using
    USB Power Delivery is that it's cheaper since most of us already
    have the actual power supply end of a bunch of chargers lying
    around.  All you need is a cable that can convert the 5V to 9V and
    you're pretty much done.  This is also a more scalable solution
    where each universal power supply is ~$15 where as each cable is ~$2
    (at least where I am in Canada), different markets may differ.  Of
    course, if you don't have spare old power supplies from old phones
    lying around, this argument goes out the window.
  - *My plug fits perfect from the universal power supply so this is a
    waste*: RTFM, or in this case, OP
  - *So you're saving $10 maybe?  Is that worth it*: In my case, yes,
    but that's because I have 6 Squeezebox Duets throughout my house
    plus another 2 Squeezebox Touches.  3 of my Duet power supplies have
    gone over the years, so now I'm short 3 power supplies and suspect
    I'll have more dying over time.  I've tried placing them behind
    power surge protectors as I've noticed they often fail after a power
    outage was experienced, but even those behind power surge protectors
    have gone as well, so it seems random and with age. As I keep
    replacing more, it's getting more and more expensive.
        
  
  Phew, I think that's about it.  If anyone has questions, I'll try to
  update the OP.  Hope this info helps someone, particularly into the
  future as this may become an even more common challenge.


------------------------------------------------------------------------
-Axle-'s Profile: http://forums.slimdevices.com/member.php?userid=40475
View this thread: http://forums.slimdevices.com/showthread.php?t=117298

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