The Stax Thread III

[Seele01]

Sounds like a home run will try thank you

 

[Svperstar]

Sounds like a home run will try thank you

You can swap Brainwavz pads in, and ditch the metal ring. Exposes more of the driver & increases bass response. Swapping pads gets addicting tho so be careful....

 

[Seele01]

You can swap Brainwavz pads in, and ditch the metal ring. Exposes more of the driver & increases bass response. Swapping pads gets addicting tho so be careful....

aren't we all? will try swapping the mk2 first and i'll take a look at theses. do they provide more bass than the mk2?

 

[Svperstar]

aren't we all? will try swapping the mk2 first and i'll take a look at theses. do they provide more bass than the mk2?

Yes, they also expose more of the driver to your ear. I've been using the "cooling gel" variety of the pads since Jan 2024. Working great. I think the leather pads would probably provide more bass but I have yet to try them

 

[TheAbyss2022]

Well this is a rare sight, an NB Stax Lambda Signature with a cable that allows me to use the Carbon CC by using the 230V coming from the Phantom.

The Phantom alone actually ran it really great on tube mode. The tonality was perfect and the timbre of the vocals and instruments were spot on. Adding 20hz Xbass gave the bass a lot better impact and physicality. I then added the Carbon cc and the overall technical performance and detail increased by a good margin. The bass was now crazy being fed 20hz Xbass with the Carbons added definition and impact made these bass monsters. Its an endgame headphone for sure on this combo. I also really like the soundstage of this headphone. It sounds really grand and tall whilst keeping the width to a nice point. Not too wide like the 2a but giving me a good amount of space which probably keeps the focus more on the mids unlike the 2a. Overall, I'm really impressed by how this headphone can scale and very happy to add this to the collection.

 

[honse]

Been using the 3d printed bracket for a while and I'd say that resin is too soft for that use case; on occasion a pin can pop out.

Currently looking at different materials to get the bracket printed.
Metal is an option, but cost and weight put me away from it; Pins filing the holes out is also a concern.
Carbon reinforced Nylon could be an option. It's a good bit stiffer than resin.

 

[Rob80b]

Been using the 3d printed bracket for a while and I'd say that resin is too soft for that use case; on occasion a pin can pop out.

Hi honse..are you making reference to this?

Thanks, but that's actually a spacer to help get more space with the original thin L300 pads, but if it could be made much thinner and smaller it might work.

I've the stock L300, L700 and the Ali pads on hand so having multiple pads mounts could really facilitate swapping as each pad gives the Stax a different character. So if one is in the mood for more intimacy and immediacy the L300 pads work best while the thicker Aliexpress pads place the music more at arms length.

 

[ludoo]

So today I did a thing...

A couple weeks ago I spotted a very (very) cheap Gamma Pro on Italian ebay sold as damaged, and thinking that I would at least be able to salvage its cable, bought it on the spot. A few days later I had it in my hands, and while one of the headband forks had a broken pin and pads were all squashed, the drivers sounded perfect. One of the greatest bargains I ever had: 40 euros + shipping.

I already had a Gamma Pro in the past which I sold, I did not like its sound but breaking it down for parts seemed a pity as it's still an irreplaceable piece of Stax history. This one was in pretty bad shapethough, so I set down to work today and transplanted the drivers into an SR-Xmk3 with busted drivers I had around.

The conversion takes some time but it's pretty straightfoward. The hardest parts are separating drivers from the Gamma baffles, and adapting the original cable to the SR-X cups.

To separate the drivers I warmed up the adhesive film that glues them to the baffle: I masked the drivers with cardboard and put them upside down on my 3d printer bed at 80C for 10-15m. After that they came off very easily and I was also able to quickly scrape the original film.

To adapt the cable, I trimmed down the original strain relief then reused the SR-X clamp that keeps the wire in place.

The rest of the conversion is much like refurbishing an SR-Xmk3. Here they are with new pads on. It's too early to form impressions, but they seem to have slightly more body to the sound vs their normal bias counterparts.

Edit

Put the SR-X pro on my flat plate rig and took some measurements. Here they are in red vs two of my SR-Xmk3.

FR is pretty much identical, as is impulse response (not shown above). FR is not all of course, and there are subtle differences when listening to them. But it's not a giant leap forward, their personality is a perfect match to their normal bias ancestors. If I were a cynic, I would take this as a great example of how we tend to over-rate whatever is very rare or very expensive, or both.

 

[LarsHP]

Well this is a rare sight, an NB Stax Lambda Signature with a cable that allows me to use the Carbon CC by using the 230V coming from the Phantom.

The Phantom alone actually ran it really great on tube mode. The tonality was perfect and the timbre of the vocals and instruments were spot on. Adding 20hz Xbass gave the bass a lot better impact and physicality. I then added the Carbon cc and the overall technical performance and detail increased by a good margin. The bass was now crazy being fed 20hz Xbass with the Carbons added definition and impact made these bass monsters. Its an endgame headphone for sure on this combo. I also really like the soundstage of this headphone. It sounds really grand and tall whilst keeping the width to a nice point. Not too wide like the 2a but giving me a good amount of space which probably keeps the focus more on the mids unlike the 2a. Overall, I'm really impressed by how this headphone can scale and very happy to add this to the collection.

Are you referring to a Lambda Signature with Normal Bias? Never heard of that model. I thought it was only made with Pro Bias.

 

[ericj]

Well this is a rare sight, an NB Stax Lambda Signature with a cable that allows me to use the Carbon CC by using the 230V coming from the Phantom.

The Phantom alone actually ran it really great on tube mode. The tonality was perfect and the timbre of the vocals and instruments were spot on. Adding 20hz Xbass gave the bass a lot better impact and physicality. I then added the Carbon cc and the overall technical performance and detail increased by a good margin. The bass was now crazy being fed 20hz Xbass with the Carbons added definition and impact made these bass monsters. Its an endgame headphone for sure on this combo. I also really like the soundstage of this headphone. It sounds really grand and tall whilst keeping the width to a nice point. Not too wide like the 2a but giving me a good amount of space which probably keeps the focus more on the mids unlike the 2a. Overall, I'm really impressed by how this headphone can scale and very happy to add this to the collection.

It annoys me when i see amps with more than one jack and neither of them is normal bias. It would cost them 3 more resistors.

 

[TheAbyss2022]

Are you referring to a Lambda Signature with Normal Bias? Never heard of that model. I thought it was only made with Pro Bias.

Yes, I think it was produced from 1979 up until the mid 80s. The earlier Stax models from the 60s also used the normal bias. Based on what I'm hearing with this pair, I don't understand why they switched to 580V. The technical performance, detail and bass is crazy on this headphone.

 

[Kabeer]

Yes, I think it was produced from 1979 up until the mid 80s. The earlier Stax models from the 60s also used the normal bias. Based on what I'm hearing with this pair, I don't understand why they switched to 580V. The technical performance, detail and bass is crazy on this headphone.

To clarify, the original Lambda Normal Bias was just called "Stax SR-Lambda"


Then came Lambda SR-Lambda Professional (pro bias)
Then after that Lamdba Signature.

 

[number1sixerfan]

It annoys me when i see amps with more than one jack and neither of them is normal bias. It would cost them 3 more resistors.

I really wish I had a normal bias jack. Unfortunately I needed the second jack for the HE90. Kind of prevents me from going down the vintage stax rabbit hole.. but heh, that could be a blessing lol

 

[aokman]

It annoys me when i see amps with more than one jack and neither of them is normal bias. It would cost them 3 more resistors.

i would guess there is more to it than just changing the bias. Different stax socket and the amp topology is designed around higher voltage rails.

Not a fan of dropping resistors, maybe some zener diodes or similar but I don’t think there is much market for running old crusty estats on amps at these price points.

 

[ericj]

i would guess there is more to it than just changing the bias. Different stax socket and the amp topology is designed around higher voltage rails.

Not a fan of dropping resistors, maybe some zener diodes or similar but I don’t think there is much market for running old crusty estats on amps at these price points.

It depends a bit on the power supply and bias supply design, i guess. The SRM-1/Mk-2 admittedly has dual bias supplies. I haven't investigated the bias supplies of amps i haven't owned.

The SRM-300 appears to have a fairly robust 580v supply for the whole system and the bias supply is just a 10M 1-watt carbon composition resistor as ballast. Dr. Gilmore's schematic says 600v, but adjusting the trimpot doesn't get it all the way to 600v here, and it's already configured for 117v mains. I calculated that about 1M and 630k in a resistor divider will give me about 230v. It'll be literally 3 resistors and swap a socket in from my SRD-7/SB. Got the resistors in from mouser the other day. May get that done this weekend. It is admittedly key not to burn too much current in the divider. The values i picked for the SRM-300 will burn about 0.00037 amps off of the total power supply current by themselves.

The SRA-3S schematic says it has a 590v supply but also that it runs off of 100v. My SRA-3S has a bad transformer -- seems to be a common issue -- and I am waiting on an R-core from ali to replace it. It may turn out that adding pro bias to the SRA-3S is about the same as adding low-bias to the SRM-300. Said r-core has more than enough 6.3v for ECC99 heaters, so it might be amusing to do a maxed out sra-3s some day with upgraded tubes and a CCS. I'd have to design my own CCS board that can mount to a pretty flat heatsink though. This would be silly, with four small signal transistors in the driver circuit. But silly hasn't ever stopped me.

As for the amplifier part, that's all the same. Just don't turn it up so loud that you blow out your low-bias stats - but that's always been a concern, and many SR-X were destroyed by people who forgot they left their stereo turned up too high when they switched on their SRD-7.