Any Experience with Stax headphone?

Has anyone there have experience with Stax SR30 and its driver SRD40? I know Stax Lambda is a great headphone. Thanks in advance
I bought a used pair of Stax 30's on ebay...paid a little too much but they were advertised and were in extremely nice shape. I had no previous experience with electrostatics. I do however have a couple pairs of Sennheiser 600's. When I got the Stax I hooked them up to a Cary 2A3 tube power amp and WOW. They rival the Sennheisers in almost every department except comfort. The upper mid range and highs are a little better on the Stax....not brighter, just more detail. Almost equal in the low bass, with the Sennheisers just able to "illusion" the low bass slightly better. The Stax have a bit more "presence" and the illusion of being there is almost scary. I also have a Cary 300B SET integrated that really makes the mid-range come alive on the Stax. I also have a Krell 300i and have tried the Stax with it and found that it is a little brite and some matierial can sound "strident" especially horns. The Krell has no earphone jack so I have never listened to the Sennheisers with that amp. As previously stated, the Sennheisers are more comfortable to wear, especially for extended sessions, but the Stax are worth the discomfort. I have recently purchased another pair of Stax, but do not have them in the house yet. Larry
The SR-30 was the entry level electrostatic phone from Stax. Believe they are about 12 years old. The SRD-40 & 84's are electret - not electrostatic and do not sound as good. The Lambda's are great phones and IMHO are much better than the models you mentioned. Another good vintage Stax phone is the SRX-MKIII but you don't see many of them used.
I have the SR-30, SR-40, (electrets) and SRX Mk3 (electrostatics). The SRX MK3 is probably the most balanced and realistic; but the SR-40s sometimes do earn my favor.