Horio

You can cross me off the list. I don't think I will have time to get down to SJ to pick up the headphones in the next couple of weeks. I'll just have to wait till the next big meet.

Sounds like a plan Al! We'll have to make sure to do some serious and careful comparisons, and then post a minimally helpful 3 sentence review for everyone.

Al, I'm going to have to invite myself over to your place in the near future... Glad to hear you and Kerry got that bad boy up and running again.

Thanks guys. I don't think any of my gear is going to have issues with the lower impedance, so I'll throw in the Khozmo and see how she works.

Khozmo decided to send me a 10Kohm attenuator instead of a 50Kohm unit for some reason. Is there any penalty with using the 10K attenuator with this amp?

I wouldn't mind taking a listen to them...

Mine is the all aluminum panel version (3U x 400mm deep). I also prefer the thicker aluminum panels, as they are a little stiffer than the much thinner steel panels.

There is a bit of a cost premium, but Modushop does offer the Dissipante cases with 10mm thick front and 3mm thick aluminum top/bot/rear panels. Its well worth the little bit of added cost in my book.

Thanks for all the compliments guys. The biggest thanks goes to Kevin for the great design!

Thanks guys. I just got the amp running last night, so I've only been able to listen to it for a few hours. I don't know if its just me being biased because I built this thing, but this amp sure kicks the crap out of my little SRM-1 mk2. The bass on my O2's seem to have better control and extension, and I think I'm hearing more detail too. Needless to say, I'm very very happy so far.

She lives, and boy does she sound fantastic!

That's good to hear. Just for fun I powered up my amp this morning (was cold in our place), and the offset V (O+/gnd) started off around -40V. The balance offset was only around -10V initially. These numbers came way down as the big sinks started to warm up (took a good 5-10 min I'd say). The initial offset really seems to be dictated by the temp of the big sinks at startup.

Yea, my offset seems to be starting off around 10V at initial power up, then it falls within a +/-1V range after about 5-10min. I don't recall what a safe offset "limit" is for stat phones, but I seem to remember 10V not being a big deal (unlike the dynamic world).

Andy, how much does the balance/offset float around after initial power up? A few volts? How long does it take to stabilize?

Congrats sir! Thanks for doing the "hard work" for the rest of us. Looking forward to your impressions of the sound. Hopefully I'll have mine playing music this weekend.

How important is it to nail the 2mA across the source resistors on the IXTP parts?

I'm kind of nervous about firing mine up, until we get a better idea of what is going on with your build. I've been working on some of my wiring in the mean time. I'm guessing he wants to make sure they are real?

Andy just out of curiosity, what were your measured output voltages (+/-) for your HV rails?

I was going to trying powering up my amp boards tonight, but now you have me nervous Andy. I am also using the IXYS CCS on my build. I am guessing you tested your PS prior to hooking up your amp boards? Could you post some close up photos of your amp boards?

Thanks Marc, So I'll tie the ground from the attenuator (and hence the input ground) to the chassis ground, instead of the GND point on the amp boards. The PS ground and L/R amp board grounds will all be tied to the star ground. I'll also try placing a pair of anti-parallel diodes between the star ground and the chassis ground. Would something like this work for the diodes?

I'm getting very close to finishing up my amp, and I'm working on the wiring. Here is a quick sketch of what I am thinking of doing. Do you guys see any potential problems or have any suggestions with this setup?

The pins on the Stax Jacks I got from Kevin are set back by about a 1.0mm too.

The standoffs just make it easier to attach/dismount the assembly from the front panel after the pins have been soldered to the board.

Here are a few photos of the Stax Jack PCB that Ujamerstand was nice enough to make. It solders right onto the Jack pins, mates perfectly with KG's teflon jack, and allows you to use a Phoenix Contact style screw header for convenience. All you need are (4) 6mm long standoffs to place between the teflon jack and PCB. BatchPCB was nice enough to send us a number of extra boards. For those interested in the PCB's, Ujamerstand will be posting more details about that soon.

Great to hear you've had some time to work on this project again Kevin. I'm really looking forward to this one, and I could definitely use a excellent preamp. Are you still considering incorporating a phono stage into the preamp as well? Either way, the more balanced inputs the better!