[n3rdling]

The speaker amp has way less of an impact on the sound than the fact the phones are being driven by a transformer.  I have never heard an O2 powered by a transformer sound better than by a proper electrostatic amp, no matter how good the speaker amp used was.  

 

[DaveBSC]

Quote:

If the WEE doesn't work out what are my other options? The SRD-7 Pro or some of the others that are pro bias?

The Stax transformers are likely to be too limiting compared to the 717. They were never designed with phones like the O2 in mind. The best transformer would be a DIY design, like Spritzer's Lundahl LL1627 boxes - probably not that hard to make I'm guessing.
 

 

[YOONG 2112]

There is a big price jump between 507 and 407... is there a big jump in sound difference? Is the 323s better than the old SRM1 mk2 pro amp?Please advise as I am choosing to buy STAX gears and in my town, Perth, we have no way to audition any higher end gears. Thanks

 

[YOONG 2112]

Is the 507 that much better to te 407 since it costs much more? also, is the 323s equal or better than the older SRM1 MK2 pro in terms of sound n built quality? Thanks

 

[Tilpo]

The Stax transformers are likely to be too limiting compared to the 717. They were never designed with phones like the O2 in mind. The best transformer would be a DIY design, like Spritzer's Lundahl LL1627 boxes - probably not that hard to make I'm guessing.

Do these DIY designs have bias? I can imagine it's easy just to built a step up transformer, but don't all the Pro-bias headphones also need a very DC bias voltage?

It does seem like a reasonable plan to me to go DIY. I have already ordered a pair of SR-202's, but I don't know if I'm patient enough to wait until a good deal (<$200) comes around for an energizer/amp with pro-bias.

 

[catscratch]

I like the coloration imparted by certain tube amps and going the transformer box route lets you get that coloration in your system - but when it comes to transparency, no transformer box rig will get even remotely close to the 717, much less something like a Blue Hawaii. A better idea is to get a source that sounds exactly the way you want - and has enough resolution to support the 007/009 - and then get the most transparent amp possible, which would be the BH/BHSE or a T2, or something similar.

 

[spritzer]

Quote:

Quote:

Since the issue of the WEE was brought up, it has a couple of major design issues which people should be vary of.  First off is the speaker input switch and how it is implemented.  Stax have always used a switch which would switch both the positive and negative inputs independently for both channels but in the WEE the negative's are all connected together and not switched.  Not really a problem in some cases but if you connect a bridged amp to this setup then it will blow up. 
 
Second issue is with the bias supply.  Looks like they are using an off the shelf solution which is wholly unsuitable for this role, designed for high frequency use in TV's. 
 

 
Is it a CCFL inverter for LCD backlighting? I've wondered about the viability of using them for the output stage of a DIY electrostatic headphone amp. I'm not sure what the typical switching frequency is for those. IIRC, the output waveform is far from resembling a sinewave.

I use a EMCO high voltage DC-DC converter for the bias supply in a DIY transformer box setup. It works well, although it's more expensive and probably better suited for the task than an inverter. What do the step-up transformers in the WEE look like? Off-the-shelf or custom made?

It's a voltage tripler for CRT tubes.  Designed to run at 15kHz or so it isn't suitable for this role. 
 
I've tried the EMCO's and they are great.  Excellent spec and very linear with super low ripple.  Crazy expensive though but I have a pile of them waiting for some amp project. 
 
Never seen the transformers in the WEE since they are all fitted in aluminum cans inside the main chassis.  These aluminum extrusions are firmly glued shut which is never a good sign though.  They claim these are for shielding but then they would have to be made out of steel... 
 
Quote:

Quote:

The Stax transformers are likely to be too limiting compared to the 717. They were never designed with phones like the O2 in mind. The best transformer would be a DIY design, like Spritzer's Lundahl LL1627 boxes - probably not that hard to make I'm guessing.

Do these DIY designs have bias? I can imagine it's easy just to built a step up transformer, but don't all the Pro-bias headphones also need a very DC bias voltage?

It does seem like a reasonable plan to me to go DIY. I have already ordered a pair of SR-202's, but I don't know if I'm patient enough to wait until a good deal (<$200) comes around for an energizer/amp with pro-bias.

All the boxes need some way of generating a bias voltage.  There are a number of ways of doing this including self bias and mains powered bias.  All the boxes I've built feature my own bias supply which is pretty much a modernized version of the Stax SRD-7Mk2 supply.  At it's core is an input voltage limited multiplier which is very high impedance. 
 
 

 

[EddieE]

Quote:

There is a big price jump between 507 and 407... is there a big jump in sound difference? Is the 323s better than the old SRM1 mk2 pro amp?Please advise as I am choosing to buy STAX gears and in my town, Perth, we have no way to audition any higher end gears. Thanks

AFAIK the 407 and 507 share a driver, but feature a different set of pads (which IMO are way superior and can easily be bought separately but aren't cheap), headband assembly and cable. The pads make a big difference to sound, the headband makes none. I don't know what difference cables make with electrostatic headphones, I believe from blind testing they make none with dynamics.
 

 

[Magick Man]

That's the way I understand it, some people have bought the 407s and grabbed 507 pads off ebay. That's still a very good savings.

 

[EddieE]

Quote:

That's the way I understand it, some people have bought the 407s and grabbed 507 pads off ebay. That's still a very good savings.

I have 507 pads on my 303s - one of the best money-to-SQ investments I've ever made.
 

 

[Headdie]

Would these 507 pads fit any Lambda ?

 

[EddieE]

Quote:

Would these 507 pads fit any Lambda ?

Yep. Pretty low-tech fitting mechanism - they come with double sided tape cut-outs.
 
I didn't even need mine as the glue left over from the old pads was strong enough to hold them on.
 

 

[ri_toast]

Just got a Stax srm-1 mk2; you know, one normal and one pro (its the A model with the larger voltage swing). I don't have any pro bias phones but recall reading some where that electret phones could be used in either socket; I have an SR 80 that I could test the socket with.
I just can't seem to find that info that I could use the electret type in the pro bias socket. Was I dreaming?
 
edit: found on the third page of the manual: non biasing (electret) can be used in either socket.

 

[sridhar3]

J-Pak posted up a Spritzer-modded SRD-7 on the FS forums, if anybody's interested in picking one up.  Tilpo?

 

[di_andrei]

I'm in Tokyo for a couple of days this week and would like to pick up a pair of 407's. Can anyone recommend a shop? I am also considering used. I believe Yodobashi has them in stock but they are just about the most expensive option in town - let me know if you know of a better price. Thanks.