STAX or HD800?

I would get a HD800 first and use it single-ended with your WooAudio2. IMO, the HD 800 is better than all the stax Lambdas; you'd have to go all the way to the OmegaII to better the HD800 and even then it's a matter of taste.

Who knows, you might not find the need to go balanced at all.

If you have the cake, I'd go for both-- simultaneously. Order the HD800s from Music Direct, and you've 30 days to make the decision.

NK

In my opinion, I think the HD800's are better than the Omegas. The Mk2s are dark, and I think the Mk1's are a bit boring, although some would disagree. HD800 can be a bit analytical to some. HD800 bass is more visceral, although it's not that substantial (less than your HF2's).

Definitely go to a meet or buy used or do a 30 day return policy purchase (headroom, for example).

I've both the O2 Mk1 with 717 and HD800 with Phonitor. Source is Monrio Top Loader cdp. Cables from Acrolink Mexcel and Oyaide. All components output from CSE RK100 Isolation Transformer. Stax is better in most aspects while HD800 is slightly better in dynamic and speed. If I've to choose one, I'll go for Stax as it sound so real and realistic. Non of my dynamic cans (including PS1000 and Edition 8) can produce that kind of imaging and soundstage.

Both 02 and HD800 are source and amp dependent so you'll need a good component to make them sing.

I found overall that a good lambda system was better overall and cheaper than getting the right combo to make the HD-800s enjoyable. Especially now with the eXStata DIY amp coming soon this will be even more true.

For a cheap thrill, you might want to look for a used Beyerdynamic DT48. With jazz, I enjoy them almost as much as the HD-800. Bang for buck, the DT48 is a much greater value. I only paid about $80 for the pair I use the most. A couple more incredible values for jazz are the AKG K-501 and K-240DF.

If you're in the HD-800 price range, give some thought to a used K-1000 as well. The few hundred you save over a HD-800 will pay for a decent power amp (as the K-1000 requires) to power them. An older NAD, Naim, Rotel, Bryston, etc. amp can be affordable and can also give you access to speakers.

Speaking of which, you can get superb performance for jazz if you buy used ones. I picked up the Quad ESL-63s for $600, but they need a little surgery. Good ones will run $1,000-$1,500. And they obliterate headphones. So will several Magnepan models, including the $600 MMG. You can find the wonderful 1.6 used for around $1,000, as well.

Of course, the HD-800 and Omega 2 are terrific and I recommend them. However, you don't have to limit yourself to those. Run speakers if you have the room - a pair of dipolar planars do things no headphone ever will.

Do not get hung up on the balanced thing. Not all balanced amps and sources are created equal. Manufacturers know people will pay a premium for "balanced" gear and it only costs an extra $20 to throw some XLR jacks on something. Unless you take the time to really learn what balanced operation is (and no, that's not reading a bunch of "OMGBALANCED!!!1!!1!" posts) you're likely to end up with something that is pretty much the same as a single-ended amp. And don't think single-ended gear is somehow a compromise - a lot of it is truly excellent and will knock you out. I chose not to go balanced because doing it right is wildly expensive and eliminates many fine sources and amps. I don't think it is worth it.

I was on the same boat, considering getting a pair of Omega II or HD800.

I've heard both and they both are in a league above the HD600 and 701.

I decided to go with the HD800 because if you want to go with the Omega II, then you have to get a separate electrostatic amp and headphones. It's a big price difference if you have to buy both.

Also, the Stax amplifiers aren't set in the standard 120v that is used in the US. You have to buy either a Headamp or Woo to drive them. Or you have to get a converter.

Lastly, the electrostatics may have the detail, but they don't have the punch you will get with a pair of dynamics. It's a matter of preference.

I'm pretty happy with the HD800.

You can change the voltage on most Stax amps to whatever standard you want.

I'm under the impression that you haven't heard the O2 arnesto as the O2 sure as hell out slam the HD800.

My vot foes for the Koss ESP950.

Simply the best bargain out there and in every which way better than the HD800. IMO of course

The HD800 being better than the Omega 2 must be a joke!!

When I intensively auditioned the HD800, I found that it is a respectable attempt by Sennheiser, but in the end can't touch the speed, detail, bass definition and 'effortlessness' of electrostatics. It does come close though.
This was compared to my HE60 and Lambda Signature. I didn't have the SR-202 back then, but that one is also very good and I like it better than the Signature, possibly even the HE60.
Therefore my vote goes to Stax.

@OP - from your post it sounds like you haven't auditioned the staxes. I suggest you do. I myself have been blown away with the electrostatic sound signature. You can always try the vintage models first to see if you like them.

Btw, if you go for one of the staxen, its automatically a "balanced" setup.

Stax. Nothing is better.

This is not necessarily true. I have a Stax SRM-727II that was manufactured to run at US voltage. However, the price for a US Stax amp is about twice that of a Japanese Stax amp, so most people just buy the Japanese amp and a converter, or reconfigure the input voltage on the amp.