Brian did an awesome job repairing my GR07's and converting them to use detachable cables. He was also very understanding of a travel commitment, and even expedited the work so the IEM's would come back in time!

Any updates here? Also, is there any information available on the length of the cable? 

Quote: I regularly run my GR07 straight out of the UD100 and have had no problems yet. The same goes for a few other headphones I have. This DAC is USB-powered; it should not have the capability of blowing out a pair of headphones.

For a 4-pin XLR? One ground-signal pair should be going to each RCA. The inner section is signal, the outer ring is ground.

The UD100 sounds great, but is balanced across the board in terms of sound. Bass is tighter, and the highs are clearer with possibly a tad of emphasis. I'd expect the Hifimediy to sound roughly the same. 

And if the plethora of links above do not have what you are looking for, take a meander around Lunashops.com. They have plenty of nice plugs for reasonable prices.

If you look at the second plug you posted, you'll notice that there is a short cylinder of a smaller diameter near the base. That is designed to be used with music players in cases. I believe most Neutrik plugs have them. Also, there's nothing wrong with recabling headphones for use with...

The portable aspect will be very difficult to achieve. Speaker drivers are relatively easy to procure, but not ones that sound decent and are high-enough efficiency to perform off a battery-powered amplifier. Your best bet may be just to buy the Logitech Bluetooth speaker off Amazon.

I typically do not use EQ, but thank you for the tip!

There was some others who reported damping the back, although I believe they used felt. Either way, if I get the time, I may try this.  

Could you post a few impressions on the effects of the damping? I'm considering doing the same to mine.

The HD25 is much livelier than either of those. The R50 or CKN50 may be more suitable.

A really fantastic set of impressions and comparisons! I'm sure many will find your post a great asset! 

The MH1C is great from experience. I've been hearing great things about the VC02 as well. Both are pretty close to your budget.

By pricing (Approximately), not necessarily quality. GR99, GR02, VC02 (New), GR04 (Flagship, Professional), GR06, GR07 (MKI, MKII, Bass edition), GR01, V7007 (Upcoming)   The GR07 (MKI and MKII) is the most highly regarded. The Bass edition is relatively new, and hasn't quite caught on...