The Stax thread (New) - Page 420

It refer to the voltage used to charge the diaphragms.
The first Stax earspeakers used 230 volts (Normal bias), while the later and all current ones use 580 volts (Pro bias).

Not sure if this was ever asked, but a higher bias voltage equates to ??? besides a more painful zap

Does higher bias lead to better sound quality?

What would be a good price to pay for these and are they worth it? STAX SR-5 (Gold)+ SRD-6/SB Electrostatic Headphones - eBay (item 120247772378 end time Apr-27-08 07:30:00 PDT)

Oh my! Can't remember every seeing five SR-Lambda's on eBay at the same time.

No more than $150-200 imo. If you're not a collector and NEEd them that is..
But as always its worth what someone is willing to pay.

The first Stax earspeakers had a 200v bias and this wasn't raised to 230v until the SR-Sigma arrived in 1977. If you have the instructions manual for the SR-X Mk3 then look up the specs. Why Stax raised the bias isn't clear and the difference in sound is minimal at best but it could be due to the different coating materials that they started to use in the 70's.

In a word, no. The bias sets the potential of the driver so with a higher bias you get more excursion but as with everything there are drawbacks. The upper limit of the bias is set by the inherent impedance of air which has a breakdown voltage of about 100v/mill and less then that if it is very humid. So if the bias goes up then the spacing between diaphragm and stator needs to be widened. It's also tough to insulate the voltages needed in such a small space.

Now some may wonder why a normal and pro bias headphones plugged into the same Stax amp have a very similar volume level? This is because the 580v bias wasn't chosen by accident. The normal bias headphones have a D/S spacing of 0.3mm while the Pro bias headphones have a spacing of 0.5mm so a bias point was needed that would yield a similar volume level at the same voltage on the stators. Since electrostatic force falls by the square root of the distance you need a much higher bias voltage for every new 0.1mm of D/S spacing. This is why electrostatic speaker even have as much as 12kV of bias and the Jecklin Float PS2 has 1500v.

The thing is, with so many Lambdas coming up at the same time, the price on one or two of them is liable to get down in that range too, in which case they are the better option. Of course, the Lambdas might also distract the people who would otherwise have bid on the 5 gold, so it may be a toss up. Throw that SR-X into the mix, and it's a big week for used stax on ebay.

What will the real sound difference be between the SR-X's and the SR-#s? I see a Lamda + SR-X on ebay now, but I have an amp, so I could use a transformer instead of an SR-X amp.

Also - what's the main difference between the Lambdas (the rectangular ones, right?) and the circular headphones? I seem to be getting the impression that Lambdas are better - are all Lambdas the same?

You are right indeed.
I have an SR-X/MK3 instruction manual and it does say "Polarizing voltage: 200V DC". So its Normal bias = 200v or 230v, and Pro bias = 580v.

So true!
There are currently five (5) SR-Lambda's on eBay, and some other Lambda's as well. A couple of them may not go higher than what I suggested for the SR-5 Gold, so there may be possible to score a nice deal.

I certainly have my eyes on a couple of them.

This has all been commented on dozens of times in this thread already. Try searching for full details. Basic notes, though:

A general ranking of Stax headphones might go (in ascending order)

Stax electrets
-gap-
SR-3 (and variants from other brands)
SR-5
SR-X, 5N (gold), SR-Gamma
SR-X pro, Gamma Pro
-gap-
SR-Lambda, Sigma, and a complicated range of Lambda variants
4070, Airbow Lambda
-gap-
Omega and SR-007 (opinions differ)

Heck, opinions differ on a lot of these ranks, but the biggest variations are in the way people rank the many versions of the Lambda, which is a decision besst made on long reading (or ideally, testing) to try to match personal taste.

After this, amp options are also key, very nearly as important and just a big a field of possibilities.

With circular you mean SR-007 (BL, A, MK2), SR-X/MK?, ... right?
The SR-007 are in a league of its own sound wise. The SR-X/MK? were monitor headphones and have a close resemble with the 4070. While the Lambda's were/are "average" 'phones for the masses.

There are lots of different Lambda 'phones:
* SR-Lambda
* SR-Lambda Pro
* SR-Lambda Signature
* SR-Lambda Pro Classic
* SR-Lambda Nova Basic
* SR-Lambda Nova Classic
* SR-Lambda Nova Signature

Then there are the SR-202, SR-303 and SR-404, which all are part of the Lambda family as well.

That's a lot of listening and collecting left for me to do I don't read much about the Nova Basic/Classic earspeakers, nor do I see them for sale nearly as often as I see the Lambda, L-Pro or L-Sig.

Spritzer, I may take you up on that offer once I get the rest of these phones here done I still have 4 more to go.

Just shoot me a PM when you are ready.

So that's what that wire cloth is called. Where does one get "wire bin"? UPDATE: Aha, you got it from a wire bin!


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