Just acquired some vintage Stax cans SRX Mk. III

I've had & loved my Mark III's since they came out.
1) If you look inside the SRD7 adapter the "ear speaker/loud speaker" switch is just a big rotary mechanical switch, so it introduces no degradation to your loudspeakers in that position.
2) As mentioned elsewhere, these Stax will benefit from the best electronics you can throw at them so I wouldn't recommend any kind of hokey "headphone amp." Except maybe Stax's...
3) See above
4) There isn't any danger from EMF in the headphones (the MF is contained within the earspeakers -- and there's no research to show heads are susceptible to EMF anyway...) but I will pass along one related piece of advice I learned the hard way -- don't wear the Stax phones with wet hair. It can result in a most-unpleasant electrical shock!

Here's a warning! Those ear phones are so so good that you can easily be inclined to turn up the volume just to get more. Be careful, don't listen under the influence, that can really be harmful. You don't have to worry about a magnetic field so far as I know - and I've been using Stax for over 20 years.

Hi Jeff,

Even the Stax older models can sound fantastic if they are functioning properly. I have a pair of SR3s that sound wonderful as well as a pair of their more recent 404 Signatures (which are amazing!)

Don't use a receiver. While it would probably work, and sound okay, the Stax deserve the highest quality source and amplification you can feed them. They don't require high power/current, like speakers. A well-built amp capable of delivering 20 Wpc or more should work fine. I'd bet a decent tube integrated amp would be a great match. You cannot use a standard headphone output on your setup. It just is not designed to work that way.

I don't know if the small electrostatic fields that the Stax generate could cause any medical problems with long-term use but suspect the risk is minimal. It's certainly one I'm willing to take considering how great the phones sound. I don't think any long-term clinical studies have been conducted.

Another way to go would be to eschew the SRD 7 energizer, and look for a used Stax amp/driver unit. The solid-state models use class-A topology and can be found at good prices on the used market. The tube-amp models usually cost more, but sound amazing.

Check out the Stax website at: http://www.stax.co.jp/
If you go to the History page, you can see all the Stax phones, amps, and energizers, in chronologic order.

Happy Listening!

I used to have the same situation as you do.

After a short while I figured that SRD7 that hooks up to the amp's binding posts and than hooks up speakers might not do the right trick since the gauge for speaker binding posts is very limited.
Moreover it's not a perfect way to drive your electrostats either...
My solution:
1. Replace SRD7 binding posts on the ones that will accept higher gauge speaker wire. You can go with Canare or Dayton from Parts Express that are very inexpencive and trivial to install or you can go RadioSnack way.
2. I finally replaced SRD7 with active STAX SRM1 MK2 driver unit that hooks up to the preamp tape or any line-output. The combo that I have SRM1/SR5 is a killer headphone combo under $1500 that I bought at a small fraction of price overall.