[krikor]

Anyone know if there is any difference between an Elpac WM220-1 and WM220-1950?  I've seen both for sale in various places, but I can't find any reference to how they differ and the datasheet from Elpac is of little help.

They look the same and both have a 5v 2a output, so I'm thinking it's just a labeling thing but I'd like to make certain before I buy the WM220-1950 (I found a great price on one).

Thanks.

[Wayne1]

I believe all of the internals of the WM220 series are the same. I have seen WM220 come in with different DC connectors, depending on what the supply was intended to be used for.

After the mods, they all work the same. The only parts that are left alone are the transformer, 5 volt regulator, the case, and the AC input cable. The DC cable has the connector changed to match the SqueezeBox.

Make sure the seller does check the stock supply for hum. Some of these surplus supplies do have a mechanical vibration or hum from the transformer. There is not really anything I can do to get rid of this.

[krikor]

Thanks for the info Wayne.  I ordered a WM220-1 on ebay but it was poorly packed and arrived with the connector crushed (no big deal since it gets changed anyway) and the transformer loose inside.  I'm sure UPS dropped the package.  It also had a fairly loud hum until I opened it up and reseated the transformer (this helped a lot and now I can no longer hear the hum more than a foot or two away).

Anyway, the seller sent me a WM220-1950 to compensate for the problems, so I opened both up and took a look inside.  While I don't think it will make a difference which one is used for modifications, there may be a difference for people using these in their stock form.  Though they share the same circuit layout, it looks like the WM220-1950 is a slightly beefier design:

- Thicker gauge wire for the 5v line (if you use the existing cable).
- 20,000ufd of capacitance (2x10k caps) vs. 13,600ufd (2x6.8k) in the WM220-1
- Slightly different looking transformer with a stick-on vibration pad on top
- Green circuit board vs. brown circuit board (I have no idea what difference this may be)

Also, the WM220-1950 I received is dead quiet compared to the WM220-1.

BTW, I'm going to use these for awhile in the stock form with the 12v section dissabled before I send one in for Bolder modifications.  I'll be curious to hear the differences between these.