spritzer

I'll see about having them side by side over the weekend and do some direct comparisons.

Twice the voltage would help as it offsets the natural cable loss. Mics also follow the same basic line as cartridges so more voltage means more problems. Nothing that can't be over come though but most are also balanced as in there are just two conductors for the signal. I do agree with Tyll that some balanced amps make no sense at all and could never surpass a properly done SE unit. People want tube amps for the "tube" sound and running a quad of single amps will not give you that. Working on the Stax side also spoils as those are true balanced amps where the channels are linked internally and there is no individual drift between the two outputs. I really like the idea to use Susy on these newer SS amps as it just improves their performance so perhaps it is time to do something similar to a tube amp... As for going off topic, isn't that what we always do?

They certainly have some comfort issues for me. The pads are indeed too thin and the material is a bit clammy. My head is gigantic though with them at max extension...

Well the common mode rejection applies with no ground as well. It's the difference between the two conductors that matters so any interference will be applied in equal amounts to both conductors and thus cancelled out.

Inductors would certainly be possible and one could pot them all in one piece.

Stax did change the earpads when they moved over to the cloth dust cover so they are thinner now, too thin IMO. Still the leather pads are the worst of the bunch so the normal black pads are a bit better. I just asked my friend to borrow my old 507's so I can do a comparison off the same amp. I do know that the 207 trumps the 507 to these ears but it's nice to know just how much of a difference there is.

For balanced signal transmission you don't need ground, it's just the difference between the "+" and the "-" (remember this is AC so not actually + and -) that matters. The ground is there as a shield but that's it. For balanced transducers this is more complicated or rather, the signal transmission is mixed in so that pretty much anything with a XLR socket is balanced. Take something like a spud amp for instance. It has one triode per channel so only one phase could be amplified but with input and output transformers that are center tapped it can have balanced input and output. Now the question, is it really balanced and do you get the same benefits as with something like the SuSy Dynahi? I'd like to see some better separation of this but I doubt it could be done and I doubt the noobs would understand even a tiny bit of it. This is also why I want to make an electrostatic spud amp as they have to be balanced to function...

It will always be a huge compromise, no matter how one tries to spin it. No magic to it really though, just switchable secondaries on the output transformers. Use relays to leave the secondary open and take the ESP signal directly off the tube plates through caps and for dynamics you just engage the secondary.

So one way to get rid of the heat is not to produce any in the first place. Run the tubes far from the levels you see in the Blue Hawaii would make heatr far less of an issue. Then we have the switching PSU which is very efficient. I mean, just look at the output transformers, they are quite small.

The circuit is certainly as good as it can be for something this cheap. Far better than some of the aftermarket crap...

We are working on it....

Kevin sent me the board files so I'll see about reducing them. Size is now about 230*160mm so difficult to fit sideways in a 19" chassis.

I can take a stab at reducing the size a bit since those boards look to be gigantic. Local film PSU bypass caps as I used on the Dynalo Mk2. They are on the amp boards to help make the PSU "faster".

Well you want to shoot anything that even might be a zombie... There is a giant leap there in performance though but for the price the 323S really isn't bad and the SRM-300 is far worse. I just jumped from the 252S to the BHSE and yeah... a tiny bit of difference.

There is something truly special about them Blue Hawaii's...

323S by a nice margin.

We could make that one quite smaller... Also needs moar film caps!!!!

They will work but not optimally which kinda defeats the point. I used OPA2604's which is very good and drop in compatible with most circuits. All the SRM-300's can be rewired but the 117V wires have been cut short so you'll probably have to extend them. No big deal really but when I do this I run the wires to the correct spots on the PCB and then jumper there for the correct voltage. Makes it easier to change later on.

It's been too long since I've had an ESP950 here for any meaningful comparisons but as a system it never impressed me all that much. That is mostly the amps fault though, same as if you'd try a Sennheiser HE60/HEV70 setup which isn't very impressive at all. The Stax setup is also cheaper and there are huge variables with the ESP950 based on how the damping is configured.

There is always the option to mess with the electrical damping. I could always appreciate the HD800's ability but it was never a headphone I'd use unless I was too lazy to fire up any of the electrostatic amps. Just too bright and edgy with less than stellar material. Add some resistors and they loose almost all of the weak points yet retain the positive aspects.

They do matter but not as much as you'd get with a more basic amp. I always run XF2's but use SED's for testing. Good news on the tubes Todd.

I'd certainly try it. It is a single ended triode amp so it is not balanced but it will accept a balanced input. Been looking at the interior shots...

That's a cue for Kevin to show his Single Power rig...

Should take a set amount of time based on the 555 timer. Could be a bad chip?

That hum has to be a ground issue as at the extreme left there is max resistance between the input, viper and ground.