spritzer

That would work but 20W is a bit too much for that use. What about two of these stacked (+260/+520V) driving a fully balanced GES. The tubes are run off the 12Vdc supply so the amp could be tiny, 10" by 10" and 1U tall.

Now here is something really different I got in the post today, a 12V-260V DC-DC switcher. Very small and no problem going bipolar or even stacked for super small electrostatic amps. There is one I've already drawn up that will be rather cool..

Some impressions of the 43ohm mod with fresh ears, unspoiled by electrostatic glory. It does dull the sound quite a bit so the top end appears to be smoother but it does also remove the natural bite that should be there with some instruments/mixes. The midrange is also affected as they have a bit of that "lost in the clouds" presentation the HE90 is famous for so the sharp focus is gone. The bass is not as clean as it should be, everything is a bit smeared and out of control. It is a big improvement over the 120R adapter I made back in the day though so perhaps there is value that makes them just right? For the record, this set is stock everything except I used the old speaker trick and coated the inside of the cups with a thin layer of faux suede. I'd just be proud as it is the equivalent of being kicked off the Head-Fi short bus...

Sennheiser just uses what ever they have around. The Eternal Arts amps are made by ex-Senn staff (i.e. the HEV90 team) so they have used those plus ever so mediocre Lehmann stuff. I just whipped up an adapter and the effect is less severe than my old 120ohm version. I'm throwing all the crappiest stuff I have in my playlist at them and the top end is more subdued but still a bit too hot. The biggest annoyance is in the bass though, a bit too lumpy and thick. This is driven from a Dynalo with 42.9ohm resistors. What could be messing with my findings is coming straight off my highly modified HE60-BHSE combo.

They might have or it is just normal unit to unit variation. Sennheiser would never publicize any design changes though, even when they are quite severe. Has Tyll done any tests on this? So the output impedance of the new Sennheiser amps has been measured... 43ohm. Not really surprised but I guess it is time to knock up some adapters and try this value out.

No real performance benefit for using either the 450V or 500V option. The bias is the same so there is more power at 500V but that's about it. Same thing for the CCS's, the A1968 is more stable when warming up so less drift but that's about it.

I've bought from them and they were excellent to deal with.

Happy Birthday!!

They are a bloody curse...

EC has his own set of shills but the amps are ok. Build issues and cheap parts are a problem though.

...and on this one they are already matched.

Happy Birthday!!!

No really, the LSJ74's are in production. Seriously... they are finally seeing daylight.

To be fair, the B22 is more than just a bit bright. There is already a supercharged offboard version... it's the Dynahi. We might do an on board version of that though given that the LSJ109 will finally be available soon. Matching isn't all that critical, the amp will function just fine without any matching and 1% resistors. The servo should have no problem taking care of any extra offset.

Sorry about that, I had the thought of modifying the board so the same one could be setup for L+R instead of just balanced while writing the post. Stock it can't be done but I'll see about changing it. Might just change the board and offer a single ended one as well as I'm not really a fan of cryptic jumpers etc. It should just have all the parts on the PCB, stuff it and it works.

This one has been brewing for a while now but since I wanted to build a nice balanced amp it moved up in line. Basic setup is the same as the old Dynalo but now with Super Symmetry input, higher rail voltages and naturally a bit more power. Input stage changed to THAT340 which is a quad bipolar transistor array with matched NPN and PNP pairs. It is cheap and easy to source so no jfet drama. The other transistors are new as well and the pinout is different to reflect that. Here is a look at the new PCB design which is pretty much ready: It is 138*86mm. Another thing from the same vein is a fully discrete unbalanced to balanced circuit that we have been working on so no DRV134 garbage. I'll start with this one though and order some proto boards this week.

A new ECC83/12AX7 is less than 15$ so that would be my first step.

It's airing now in Canada. Ep 2.03 was yesterday....

I can't spare any room there... The end result is a truly lovely headphone though. Closer to the HD6x0's in balance but with that super quick response and lean bass of the HE60. Doesn't hurt that it was practically free, only paid for the cable and new earpads. Rest were either pulled parts from repairs that I reconditioned or parts given to me.

Yes but I went the other way and recessed the drivers inside the cups. It helped that I used HD600 parts for this...

Well they had to angle the drivers somehow. I do wonder if they would achieved a better balance by pushing the drivers further away from the ears. I just did this with a set of HE60's and the effect is far from subtle. A lot less bright...

Ok. I'll give him that.

Why would anybody do business with Headphile?

RTFM!!!!

Purrfect!! You are not the first one to make that mistake though.