[Currawong]

It seems that the eXStata DIY electrostat amp is already exceeding expectations, using only $350 or so of parts, including the case. HeadphoneAddict has provided us with a short review mid-thread thus:

Quote:

Originally Posted by HeadphoneAddict /img/forum/go_quote.gif The eXStata is a great amp, but it was so highly detailed that we could hear jitter (grainy griity in the highs) with the Apple TV on Saturday, which at first was more difficult to pick up with the GES until 3 hours into the meet, making us have to change the transport to a Macbook Pro instead (big improvement). I posted about this in the CanJam @ RMAF impressions thread Saturday. Although much better with a new transport, it was still a bit bright with my PS Audio Digital Link III, and more suited to the O2 Mk1. Also we think the PSA was overdriving the XLR inputs which we measured on Sunday at 5v @ 60Hz. So on Sunday (today) Bill started the day with a DIY Opus DAC, and that fixed the sound completely. At that point the amp was very good to my ears with O2 Mk1, Jade, SR-404 LE, HE60, Smegma Pros (woody Gamma pro), SR-404 LE, and SR-Lambda normal bias. Being in a separate rig than the GES on Sunday made it more difficult to compare the amps like we did on Saturday. But on Saturday (with the same source and side by side) we felt the Woo's timbre and tone/Frequency balance was better, but the soundstage and separation was much better with the balanced eXStata (with a little more power too). With the Opus DAC the brightness/thinner sound became more balanced and punchier in the bottom end, and with even more power - enough to tickle your ear drums and make the skin on your face vibrate with O2's. I thought that wiatrob had modded the amp overnight, the improvement was so dramatic! Today, at the end of the meet, we tried the CullenCircuits modded PS Audio which was better with the eXStata than the stock PSA, but the Opus DAC seemed to have the best synergy with it to me. I picked my PS Audio DLIII initially because it was what I needed to brighten up the dark sounding O2 Mk1 with the GES (after rolling brighter tubes). What works for the GES isn't always the best for the eXStata. I was very impressed with the eXStata by the time we had sorted out all the jitter/synergy issues with the transport and DAC. Even if nothing gets changed in the design, this amp will still be a big hit, and my understanding is there are still a few things that can be done to make it even better. The listener just needs to remember that with this amp whatever you feed it is VERY important, because it will be so resolving that you will hear any issues - for example it was fairly bad with 192k MP3 files on the Cullen modded DAC owner's PC, and we had to switch to a CD transport to evaluate the amp with the Cullen modded PSA DAC. It's caused a dilemma for me because I was thinking I would have to sell my GES, WA6, K1000 and RS-1 for a Woo WES, and now maybe all I really need is to add an eXStata (and EHHA for K1000) to what I already own, and just sell the APS V3 RS-1 to cover the cost.

I'll be building one as soon as I can, as I'm currently sans amp for my two Stax.

 

[GardianEnjel]

Okay, now I believe I won't regret taking this amp

 

[stang]

I heard one of these yesterday with the Stax O2. Now I really want to go high end like K1000 or Stax O2. I do not know if it is an O2 trait or amping issue, but the mids were a tad recessed and the highs rolled off. I loved the silky smooth presentation, especially the highs, but the mids could be a tad more upfront IMO.

 

[GardianEnjel]

Could it be the source issue? Many of my friends were also saying the same thing, O2's mid too recessed, but it was due to the not-synergy source issue (he was using neko audio). When he changed it to cambridge dacmagic it was a lot better he said. Despite maybe O2's mid itself was designed not forward.

 

[stang]

I will try and look up the source used. But I know it was iBook G4 (playing my CD), Source>eXStata>Stax O2. I am pretty sure it was an expensive source, too.
edit: it is this http://www.mhlabs.com/metric_halo/products/mio/uln2/
 
They are the Stax O2 MK1. Here is the man himself who owns them: http://www.head-fi.org/forum/thread/482962/t1-and-o2mk1-some-impressions

 

[n3rdling]

The exstata I had seemed to give a bit of midbass bloat on the O2's and couldn't drive them as good as the 717 and not close to the Blue Hawaii.  I don't think the O2 has a recessed midrange at all, but it could have been the midbass bloat of the exstata that made the mids sound recessed in comparison.

 

[stang]

Well right now, the O2 are my dream headphones to own and I would definitely settle with the eXStata amp with them. Sure, maybe later down the road I would upgrade it, but it sounded wonderful to me. Sure, there were some issued, but the O2 were just too good to criticise 

 Damn I wish I could at least have them loaned to me for a week, but that's not going to happen 

 I guess I will have to wait until the next meet. But yeah, regarding this amp. I would definately say it is a decent amp, maybe a little underpowered for the Stax O2, but hey, for $300 in parts (approx), you really can't go wrong 

 

[sachu]

Quote:

The exstata I had seemed to give a bit of midbass bloat on the O2's and couldn't drive them as good as the 717 and not close to the Blue Hawaii.  I don't think the O2 has a recessed midrange at all, but it could have been the midbass bloat of the exstata that made the mids sound recessed in comparison.

Milos..again you do need to remember that yours was the prototype version without the output CCS. The current version with the output CCS is easily better all around over the proto version.