The Stax thread (New) - Page 542

Maybe Stax has put aside some of the old products and then launched the new, bit worse, products. Then the employees sell the old stuff with enhanced prices after a while. I'd do this

Companies take a wrong turn every now and again when releasing a new product, just see HD650, K701 and GS-1000 for reference. My guess would be that the original engineers involved in the SR-007 were not doing the redesign or have lost their minds.

Guys, I am using the SR-001 MkII and I'm trying to figure out how the stax fart occurs. It seems to me that when I have a IEM-like seal the earpieces "fart", giving a suckout like sound, so I suppose that's not the way of proper insertion.

As best I know, any closed electrostatic can give a fart when the phones are placed on the ears (or in them for the SR001/2) because the diaphragm is being pushed by the increase in air pressure close to the stator and you are getting a voltage discharge between the diaphragm and the stator. The diaphragm will settle back in place after the pressure in the phone drops.

Even the old Koss ESP9 had warning about the fart, (although they didn't call it that.)

Most newer phones have some way of protecting the diaphragm from arcing and burning a hole, often just a simple plastic washer to prevent the diaphragm from getting too close to the stator.

I recall some years ago having a tech point out the holes in the diaphragm of the old B&W electrostatic hybrid speaker where they had burned through.

The 001 fart is much better if you ditch the headband and just insert them in your ears.

Two more earspeakers bought! Stax lambda Pro and a new pair of Stax SR-303. Though it will take a week or two before I receive them. Meanwhile I am enjoying my pair of Lambda Signature and the SRM-1/Mk2 P.P. Since they arrived, I have fallen asleep every night with the Signatures on my head!

A bottoming out of the diaphragm (a fart) in almost all cases will not hurt the driver. Arcing the driver is caused by a spark (an over voltage when playing to loud or other failure) that is between the stators burning a small hole in the diaphragm. Because the diaphragm also acts as an insulator the driver will arc at a lower voltage than before. As the arcing continues you make the holes bigger and more of them. At that point the driver is ruined.

When I owned a high end store in the seventies we were a Quad, Acoustat, Dayton-Wright and Stax dealer. I replaced many many drivers in stats. I remember some drivers out of the Quad ESL57 and Stax SR-XmkIII that the diaphragm looked like Swiss cheese. Some drivers have insulation around the stator and are hard to arc. Janszen, Acoustat and Audiostatic the stator was made of insulated wires. Martin-Logan uses a thick powder coating on perferated steel.

Stax tried to limit the arcing by installing a protective circuit inside the cups (two diodes) but the move over to amps instead of energizers and ultimately the Pro bias resolved the issue. The transformers can output a lot of voltage in an instant and the protection only goes so far.

In case anyone is interested, here are a couple of naked pics of my SRD-5 I took yesterday when I changed the rotten speaker cables. Click on the links for full size pics.

That's a late model by the looks of it. I have one here with wax covered transformers (completely coated) and cloth covered wires dating back from the mid 60's.

Btw. is that a switch between the trafo's?

The one on the bottom? Switches from 110 to 220.

It's a bit strange that Stax used a switch for that when the SRD-7's of a similar vintage all have zener's on the input of the bias supply to step down the voltage...

If you want a pic of the bottom with a view of the switch, or close-ups of anything just ask, I can take them tomorrow when I get back upstairs.

Ah, I'd always assumed that the SRDs were sequential, so the -6 replaced the -5, and the -7 the -6. Clearly, I'm wrong in this assumption, not least because I have an SRD-6 SB, which is black in colour, and has the newer, 'straight' Stax logo, whereas my SRD-7 (mains bias) is silver and has the older, 60s-style 'ΞStaxΞ' logo.

Presumably these different models were available at the same time and varied in price, much like we have the 2050/3050/4040 systems nowadays?

That's true. Originally there were SRD's 1, 2 and 3 which all varied in price and features but none of them lasted long and the SRD-5 had taken over by the late 60's. The SRD-7 was released in the early 70's as a high end option and the SRD-6 released later to replace the 5 as a more cost effective option. The SRD-4 came later on and was an even cheaper models for electrets only.