I'm pretty surprised the Gamma Pro went for $330 on Ebay, I didn't think they were very good. And this was out of a hot source and amp.

Hmm, interesting. I've been rather interested in hearing one though I'm not expecting to hunt one down in the near future.

First off, the SRD-7 isn't a Mk2, just a normal 70's type SRD-7.

SB is in no way inferior to the AC biased designs and they could even sound better with no crappy AC inside the unit. They are the same more or less except there is a small transformer that borrows a bit of AC of the Right+ line.

The Mk2's are highly sought after and can go for way more then 200$. That's certainly what I just sold one of mine for but it is NOS.

I'm pretty surprised the Gamma Pro went for $330 on Ebay, I didn't think they were very good. And this was out of a hot source and amp.

They aren't worth that much but the Stax hype knows no bounds. It was also in terrible condition. An Alpha Excellent would be worth that much but only to us crazy collectors.

SB is in no way inferior to the AC biased designs

I've once had a SRD-7 SB and I guess they are similar in that regard to the Pro varieties.

When you listen to music that unlike modern overly compressed pop music does actually contain decent dynamic range you get audible loudness fluctuations with the SB types.

The Mk2's are highly sought after and can go for way more then 200$. That's certainly what I just sold one of mine for but it is NOS.

I'll make sure never to let this baby go.

I've once had a SRD-7 SB and I guess they are similar in that regard to the Pro varieties.

When you listen to music that unlike modern overly compressed pop music does actually contain decent dynamic range you get audible loudness fluctuations with the SB types.

There was clearly something wrong with the unit or is was a very early SB as there is enough energy stored in the bias supply to keep the headphones going for at least an hour without any power coming in. The Mk2's used a pretty high ratio transformer coupled with a double zener input so the bias supply would always be fed even if the input voltage was pretty low.

They aren't worth that much but the Stax hype knows no bounds. It was also in terrible condition. An Alpha Excellent would be worth that much but only to us crazy collectors.

I was all in at $325, but shilled on the snipe - allegedly the STAX hype is over, but, alas, not just yet. It was interesting no one else was over $220 except this bidder, so I'm thinking it was Laurent himself (the seller) as I had tried to buy these outright from him prior to the listing. Fucking pussy.

That said, someone else would have taken them after I'd listened a bit to further my journey of self discovery.

I'm simply waiting for the right set of Gamma Pro's as I'm a bit particular about the condition so I would be prepared to well over 400$ but not for the set on ebay. One problem with the Gammas is that there are no pads to be had from Stax which really blows and the headpad is the biggest piece of crap ever. It turns into this black powder and since it was meant to be cheaper they are a bitch to remove and clean properly.

I sure hope that the Stax hype is over or may God help those poor souls that stand between me and the few phones I'm missing...

There was clearly something wrong with the unit or is was a very early SB as there is enough energy stored in the bias supply to keep the headphones going for at least an hour without any power coming in. The Mk2's used a pretty high ratio transformer coupled with a double zener input so the bias supply would always be fed even if the input voltage was pretty low.

Maybe it was defective.

I did have so many of these units over the years and when I think about it the SB unit wasn't even a SRD 7.It was a SRD 6.Since then I had avoided the SB types, maybe for wrong reasons, but later I have read about loudness fluctuations in combination with SB units happening to other owners, too.

Do you know why Stax had decided to sell non-SB units? There must be a technical reason since the SB types are cheaper to produce.

The SB's are more expensive then the AC unit's. A transformer is always more expensive then a AC cord and that is the only difference in the Mk2's. The old SRD-6's used a multiplier without a transformer so you are very dependent on the speaker input level to maintain the bias. I've never had any issues with the SB's but then again I don't listen to a lot of music with quiet passages.

The SB's are more expensive then the AC unit's. A transformer is always more expensive then a AC cord and that is the only difference in the Mk2's. The old SRD-6's used a multiplier without a transformer so you are very dependent on the speaker input level to maintain the bias. I've never had any issues with the SB's but then again I don't listen to a lot of music with quiet passages.

Okay, sorry I'm confused. Are you saying the SB can be used with pro-bias earspeakers?

The SB's are more expensive then the AC unit's. A transformer is always more expensive then a AC cord and that is the only difference in the Mk2's. The old SRD-6's used a multiplier without a transformer so you are very dependent on the speaker input level to maintain the bias. I've never had any issues with the SB's but then again I don't listen to a lot of music with quiet passages.

Thanks for letting me learn something ....

Okay, sorry I'm confused. Are you saying the SB can be used with pro-bias earspeakers?

No, only the SRD-7SB Mk2 can be used with pro earspeakers. You could also convert your SRD-7 by building the Mk2 bias supply.

Thanks for letting me learn something ....

No problem. I think I have this need to spew electrostatic facts around as I'm suffering withdrawals from the usual flood of HF PM's. \

No, only the SRD-7SB Mk2 can be used with pro earspeakers. You could also convert your SRD-7 by building the Mk2 bias supply.

Come to think of it, how much do you reckon building your own adapter would cost?

And perhaps DIY can produce something on the quality level of the Illusion.

Come to think of it, how much do you reckon building your own adapter would cost?

And perhaps DIY can produce something on the quality level of the Illusion.

The bias supply costs about 20$ to make with MKP caps and other nice things but the transformers are the real problem. The Luhdahl alternative is expensive but you could get Just Real Music to make transformers that are relatively cheap. Another option is to buy any SRD-6 or 7 of ebay and use the transformers. Solder new leads directly to the windings (cut through the paper on each side to reveal the solder connections) and bypass all connectors and switches.

edit: also if anyone sees one of these around, give ole postjack a buzz. Afro

There is one on ebay now, but it comes with a gamma pro and has a BIN at $400.

I'm simply waiting for the right set of Gamma Pro's as I'm a bit particular about the condition so I would be prepared to well over 400$ but not for the set on ebay. One problem with the Gammas is that there are no pads to be had from Stax which really blows and the headpad is the biggest piece of crap ever. It turns into this black powder and since it was meant to be cheaper they are a bitch to remove and clean properly.

Your deal with Carl fell through in the end, I presume? I've always assumed that the black powder on the headpad was from the dye stax used on it, and soaking the headband assembly seems to get rid of it easily enough.

Your deal with Carl fell through in the end, I presume? I've always assumed that the black powder on the headpad was from the dye stax used on it, and soaking the headband assembly seems to get rid of it easily enough.

I guess Carl and I are both a little forgetful so we never finished the deal. \

A brush and lots of water helps to remove the top layer. I spent a few hours on it with the Gamma's Thrice sold me but the end result looks great. So are in good shape though after all these years like my Lambda Spirit. Even the lettering is mostly intact.

There is one on ebay now, but it comes with a gamma pro and has a BIN at $400.

This seems to have been sold already...

*learns lesson* Posting about ebay auctions on a headphone forum is always a bad idea

On the other hand, now I know _the_ ebay ID I should avoid getting into bidding wars with when bidding for stax items

There is one on ebay now, but it comes with a gamma pro and has a BIN at $400.

Bah, you should have sent me a PM.

Thanks for the heads up though.

Oh haha, bidding war among us, aye?

No, I didn't bid. Gave it a brief thought though.

*learns lesson* Posting about ebay auctions on a headphone forum is always a bad idea

On the other hand, now I know _the_ ebay ID I should avoid getting into bidding wars with when bidding for stax items

I was watching it before I logged onto head-case yesterday. I've been doing this for far too long to miss something like this...

As it turns out the seller is a Stax fan as is saving up for some Omegas. I was only too happy to help.

Say I get a low power push pull tube amp. Is it possible to tap the push pull for use with 'stats? Are there special factors that I need to take into consideration?

You need output caps to eliminate all DC off the stators and resistors to restrict the current flow.

You need output caps to eliminate all DC off the stators and resistors to restrict the current flow.

Cool, thanks. Is this potentially a higher quality solution than using transformers (building your own) with a SET amp?

I'm guessing it'll basically be a capacitor quality vs. transformer quality fight? Any thoughts?