Well, i got the chance to go to dvse's house today (a fellow Sydney Head-Fi'er) who, ridiculously enough, owns two pairs of O2's, a KGSS, Stax 717, and two outboard DACs 0_o

Comparing the 717 to the KGSS with some of my reference material, IMHO there is far less of a difference than i've been made to believe between the Stax amp and the Gilmore. Listening to Loreena McKennitt's Marco Polo and Highwayman, the differences were subtle at best.

Imaging on the 717 was just as accurate, and to me the amp actually sounded slightly more forward or sharper on the attack than the Gilmore. dvse remarked that he had found the 717 to be very slightly 'diffused' as opposed to the KGSS in the imaging department, but as close as i listened i couldnt really detect it. The 717 did seem to emphasise the decay of notes slightly more than the KGSS, giving it a tad more 'body' at the cost of maintaining the very last word on resolution, but it was very minor at best.

The KGSS in comparison, came off as slightly smoother, slightly more refined, and, dare i say it, perhaps a bit more polite? dvse disagreed with me on this one, but to me there was a hint of oomph to the 717 that the KGSS seemed to lack. But it made up for this with slightly clearer imaging (the placement was the same, but instruments seemed perhaps a tad more seperated and with less decay on notes, contributing more to a sense of individual identities in the soundstage) and a slightly smoother presentation.

If i had to pick one to use, i would probably go the KGSS. But the difference i found to be so small as to be more or less irrelevant to me. Of much more significant impact was the source used. Switching between the two DACs was instantly and immediately obvious. The more expensive model (i forget what their names were, although the cheaper i believe was a Lavry) sounded refined, smooth, and clear. Wheras the cheaper was more forward and agressive, but also noticably grainier. The source swaps made a much bigger difference than the amp swaps, IMO.

So i think Elphas is on the right track about source-first with the O2. The 717 unit does the job well enough and is transparent enough that a highly refined source cascades through clearly.

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I expected this outcome, good however for those of us that cannot justify all that extra expenditure(BHSE) for perhaps less than 10% better SQ.
Have I got my percentage right?

BTW thanks for your mini review Covenant.

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If you sell a few of your pens...

Did you have a listen to the WooGES?

Anyone have any info on Blue Hawaii home/pro builts? Has there been a group buy or public offering of boards &/or transformers? Or are the few examples posted built totally from scratch ?

I'm extremely curious about the difference between the Blue Hawaii & SRM007tII, but I'm a little conflicted about the price and availability of this run of HeadAmp BHSE. I have no doubt Justin is going to deliver something exceptional, but it's a chunk of change to plop down unheard. I'm also not on the list (yet) and it seems like it's too late for this round anyway. I'd love to get a board set and transformer without too much hassle and take it from there myself.

Anyone have any experience listening to O2's through both the HeadAmp prototype and a one-off rendition of the Blue Hawaii ? Any big differences sound wise ?

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Did anyone listen to both the KGSE and the GES and perhaps give a quick comparison?

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Try and get in touch with pabbi1. I'm pretty sure he built his Blue Hawaii.

Covenant, thanks for those impressions.

I'm also interested in a DIY blue hawaii, it'd be nice if there were members that did this, kinda like the beta22

A year ago, [AK] Zip did build electrostatic amps amongst DACs and CDPs. At that time he was building himself a KGSS (iirc!). I guess so much work goes into building one of these it would be an unsustainable business venture given the rather limited market. I doubt Justin would manage if he only sold electrostatic amps either. They simply don't sell enough to turn enough profit.

"Originally Posted by me
[The SRD-7] can drive them, just not to the max. This was definitely confirmed by my experience with the BHSE prototype at Canjam. But I am listening to my O2s as we speak with an SRD-7/Mk2, and it sounds lovely. But the BHSE adds more bass, much more midrange (my god that midrange!!), more coherent soundstage, and even sharpens the treble without making it bright or fatiguing."

Those differences almost sound like tube vs. SS differences. Have you tried your SRD7/mk2 with a good tube amp?

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The Beta22 is a whole lot simpler to build then the BH and is not something you should consider unless you have a whole lot of experience. There is also a scarce supply of parts to worry about so the design on Headwize is mostly obsolete.

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No worries I wouldnt even call it 10% though, 5% would be closer to the difference I heard. But then I only got to spend 2 hours with the units in side-by-side comparisons, perhaps extended listening would yield more differences.

It certainly made me alot less hesitant about using a Stax amp in the interim while i wait for the oddball used Hawaii or ES-1 to go up on the FS forums

Covenant, your impressions of the KGSS vs 717 were analagous to my own comparison between the 717 and 006t, just that I found the 717 to be more forward than the 006t. If the KGSS is a further refinement upon the 717 (clearer imaging, better separation, slightly more resolution), then I would be very satisfied indeed. It costs a lot to get those last few percent, doesn't it...

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Yeah, but I understand there is an underground movement to make a simpler version... still waiting on Linear Devices? C'mon, you can't hide _that_ BH++ design forever...

The only path to the old design is through KG, but it really is not the way to go today, though Naamanf did last year. Both Spritzer and Luvdunhill might comment more, but Marc's UBER KGSS (bigger, badder dedicated PSU) kicks almost every electrostat amp I have ever heard (HEV90, ES-1, etc), but, were it not for a bad tube that blew one channel of my ('stock') BH, we could have shot this out with several very knowlegeable members in Dallas..

For the poster who brought up McAlister - only if you hear the individual unit you are buying first, and can take physical possession of it then. Caveat emptor.

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If i was to give one word to my overall impression of the KGSS as opposed to 717, it would be 'refined'. As mentioned, the differences were subtle, and on some music like rock/dance/metal the slight forwardness of the 717 might even better the KGSS. But overall the Gilmore seemed to possess just that last iota of clarity and smoothness over the 717.

And yes it definitely does. The first thing i did when i got home was listen to the same reference tracks on my home system (Eastsound > M3 > HD600). I realised that the differences werent night and day - everything i could hear on the O2, i could hear on the HD600 - but in comparison the imaging of the HD600 just wasnt as clear, images were diffused and interfered with each other, instruments didnt have the same sense of definite placement in the soundstage, and the whole thing became somewhat more 2-dimensional.

Now if only I hadnt heard the O2 I might've been happy

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I sent an email to Jack asking about the availability of NOS tubes from his own stock that he could ship with the GES. Here's the update:

"I can ship the GES with 12BZ7 NOS (GE or Sylvanias). The upgraded tubes cost $64 for a matched quad."

Now to me that seems like a very reasonable price for a matched quad of NOS Sylvanias, but i'm unfamiliar with the type 12BZ7, which i assume is a drop in replacement for the 12AX7 driver tubes.

Anyone with some tube-savvy can chime in as to how such a tube would perform?

Edit: Trying to read info about tubes from a straight google search feels sort of like trying to learn chinese 0_o