Stax SR-007 Mk 1 arc ringing with head movement

[plaurids]

Hi all,

I have a pair of Stax SR-007 e-stats - a 007 Mk 1 (s/n 71169) for which I made a new pair of diaphragms last year (long story, will make another post just about that here on HC soon) and a 007A (s/n SZ2-1636). In the last few days I've been noticing that the pair of metal arcs on the head assembly of my 007 Mk 1 makes a slight ringing sound transmitted to the drivers when I move my head, especially when these arcs are touching the headband. I don't recall them doing that before, but maybe I just wasn't paying attention. This ringing sound disappears if I either touch the arcs with my hand or reposition the unit so that the arcs no longer touch the headband. However, the latter doesn't last long and not allowing the arcs to touch the headband sometimes brings about problems of its own, like e.g. loud ringing whenever the arcs are accidentally tapped. This Head-Fi thread briefly discusses the arc tapping issue and also (mostly) the possibility of the arcs resonating with the driver sound itself (with potential ensuing problems like parasitic crosstalk and overall distortion), but I'm a bit distrustful about the latter hypothesis because it implies an unlikely design flaw by Stax.

Anyhow, I'd like to know if there is something I can do to prevent the arc ringing when my head moves besides keeping the arcs from touching the headband (e.g. adjusting the arc screws, etc.). It's important to point that my 007A doesn't have this problem. I don't know why, but what I do know is that my 007A has a tighter fit on my head than my 007 Mk 1, so I don't know if the different behavior is due to e.g. different tightness in the arc screws or just that the arcs are pressed harder against the headband due to the tighter fit and because of that the arc ringing just disappears.

Any hints on how to deal with this problem are welcome!

[spritzer]

You are supposed to bend the arcs on the 007 to get the perfect fit so perhaps that is the issue or they are a bit loose?  Please don't use anything but JIS screwdrivers on these or you will utterly destroy the screws.  

[plaurids]

Hi Birgir, thanks for the reply. 

20 minutes ago, spritzer said:

You are supposed to bend the arcs on the 007 to get the perfect fit so perhaps that is the issue or they are a bit loose?  Please don't use anything but JIS screwdrivers on these or you will utterly destroy the screws.  

Nowadays the only screwdriver I use to maintain my Stax cans is a Wera 1013 ESD precision screwdriver with a PH0 JIS bit (model 851/9C) which I bought to that very end.

I'll try to bend the arcs and tighten its screws a bit to see whether the ringing stops or not. I'll let you know soon enough about the results.

Thanks again!

Edited 1 hour ago by plaurids