OK but what about CLC filtering with low DCR coils?! Or are the 470 Ohm for current limiting/safety reasons?
You are sure a low output impedance 12V supply will not make things better?! No feedthrough of the switching frequency!? I say this because using a switcher for the 12V makes results better.
You are sure a low output impedance 12V supply will not make things better?! No feedthrough of the switching frequency!? I say this because using a switcher for the 12V makes results better.
Last edited:
Not really. Since class A dissipation does vary with signal the least from all 'classes', it is least temp sensitive from all classes.
Jan
Jan now you are the party pooper 😉
Class A may not be the most temperature sensitive… it sure generates heat but with just 6W things are relative.
Class A may not be the most temperature sensitive… it sure generates heat but with just 6W things are relative.
Last edited:
I just saw the clock, I'm late for work, will pick this up later. Until then, you can look at this thread on another website:
SRM252mod | Headphone Reviews and Discussion - Head-Fi.org
Starting around post #7, a user named "borizm" did a very good analysis of the power supply situation of the 252A, which uses the same supply as the 252S. Some of his mods were heading in the right direction, but he made a couple errors and didn't have test equipment or circuit modeling to carry it through properly. He posted pics on the 2nd page. Power entry is upper right corner.
SRM252mod | Headphone Reviews and Discussion - Head-Fi.org
Starting around post #7, a user named "borizm" did a very good analysis of the power supply situation of the 252A, which uses the same supply as the 252S. Some of his mods were heading in the right direction, but he made a couple errors and didn't have test equipment or circuit modeling to carry it through properly. He posted pics on the 2nd page. Power entry is upper right corner.
Last edited:
From that POV, sure. But good luck accurately setting the diff balance. You remove the casing, temps plummet, and it goes haywire.
Interesting thread, he used SMD coils just like I was thinking but went the extra mile (bravo). Also the use of a good linear PSU. The internal switcher runs at 72 kHz apparently, I would investigate feedthrough.
The casing is very small and modding the stuff in such a small casing is a challenge in itself. I would not have a problem with a TO220 or the like bolted to the bottom cover. Never bothered with Stax but it seems a complicated way of doing things (when the design is hampered like it seems to be).
The casing is very small and modding the stuff in such a small casing is a challenge in itself. I would not have a problem with a TO220 or the like bolted to the bottom cover. Never bothered with Stax but it seems a complicated way of doing things (when the design is hampered like it seems to be).
Last edited:
As I wrote earlier, his overall analysis was good, much more accurate than ones I've read on other websites. There are some errors, though (including a couple components he installed in the wong place!) In the end, he walked back any circuit mod that drew more power from the supply. And his LC filters resonate right in the middle of the audio band.
I'm pretty convinced that adding a linear reg inside the case won't improve things significantly over a halfway decent regulated external supply. No part of the audio circuitry draws from the 12V rail. And I do not want to generate more heat inside, it already runs pretty warm.
I'm pretty convinced that adding a linear reg inside the case won't improve things significantly over a halfway decent regulated external supply. No part of the audio circuitry draws from the 12V rail. And I do not want to generate more heat inside, it already runs pretty warm.
You can recalculate and use other values for the CLC filters.....
I agree that a decent regulated internal PSU probably won't improve things over a decent regulated external PSU. The original way with an unregulated PSU is not the way to go. Although I think the Stax way is complicated I see a challenge in improving such a device. Never listened to one, let alone any other headphone type. After the Quad ESL's I was cured 😀
Do the current designs have design features in common with the older models? In other words: are the design imperfections as in this type solved? Can the devices and the headphones be interchanged?
I agree that a decent regulated internal PSU probably won't improve things over a decent regulated external PSU. The original way with an unregulated PSU is not the way to go. Although I think the Stax way is complicated I see a challenge in improving such a device. Never listened to one, let alone any other headphone type. After the Quad ESL's I was cured 😀
Do the current designs have design features in common with the older models? In other words: are the design imperfections as in this type solved? Can the devices and the headphones be interchanged?
Last edited:
Thanks, but my work on it is already done so I don't really need to explore this in depth. I only brought it up to point out to you that these little dollar-bill wallwarts might have some useful application for audio.
The other Stax model I have is an older one with stepup transformers, a very different creature. It also took a lot of work to make sound good. Their transformer design chops were quite poor. IMO, the fact that Stax got such a stellar reputation while delivering up such cr@p is indicative of how bad the headphones from other mfrs were back then...
The other Stax model I have is an older one with stepup transformers, a very different creature. It also took a lot of work to make sound good. Their transformer design chops were quite poor. IMO, the fact that Stax got such a stellar reputation while delivering up such cr@p is indicative of how bad the headphones from other mfrs were back then...
There is truth in that. I never bothered then to use headphones when good loudspeakers could be found.
Aye. As a singer/songwriter turned recording engineer/producer back then, headphones were unfortunately a necessary tool for me.
(To be fair, I think some Stax headphones are quite good to excellent; it's their amps and stepup boxes that sucked.)
(To be fair, I think some Stax headphones are quite good to excellent; it's their amps and stepup boxes that sucked.)
Last edited:
I ordered 3 which arrived today Priority Mail. Two in one style, one of another, but both 12.2V, under 3mV ripple with small load.
Thanks for the heads up, Jbau!
Thanks for the heads up, Jbau!
You're welcome, glad you found it useful.
I ended up getting six, and they are all the same as the one pictured in their listing.
I ended up getting six, and they are all the same as the one pictured in their listing.