Stax SRM-252S and iFi iPower2
09/06/25 14:37 Filed in: Audio
This article is a sort of community service announcement to clearly say that the iFi iPower2 works with the SRM-252S - at least for me. Something that was rather hard to find clearly spelled out elsewhere.
Why is this a data point anyone should care about?
After all it is just a 12V power supply and a device that accepts 12V.
It turns out that the SRM-252S does not work well with arbitrary power supplies and the iFi one is a lot more expensive than others (5 to 10 times the price). The cheaper linear alternatives are getting rare and the common switch modes sometimes work and sometimes don't and you can't tell from the spec sheet.
Sometimes satisfying an electrical load goes beyond meeting peak power demand and correct voltage and polarity.
While not a true Headphone wonk (I only own a dozen odd pairs), I do have a hobby level interest in headphones and audio. One of the devices I acquired a few years ago is the Stax SRM-252S; an electrostatic set of 'ear speakers'. While many may (correctly) argue that these are not Stax's finest or best work, they have filled a niche in my listening routine1.
One of the problems with these headphones is that they are supplied with a small 12V centre negative plug in power supply. Like most of its ilk these are the most likely part of the system to fail.
Replacing these power supplies is getting harder as the used to be common linear power supplies are getting rare, being replaced with switch modes and the SRM-252S interacts badly with some power supply designs causing the supply to switch on and off - ignoring the fact that audiophiles tend to be negative about the potential for introduced noise fro m switch mode power supplies.
The good news is that the iFi Power2 came with suitable plugs and a a centre negative adapter and everything worked out of the box.
The available power from the supply is well in excess of what the original supply provided and that may allow a bit better performance.
The audiophiles are going to ask 'does it sound better', and I will answer subjectively, I think so. However, that is a purely subjective and potentially biased, non-blinded opinion. Worth the price difference, really hard to tell, given the issues I was having in finding another moderately low noise power supply and not having to design my own filter circuitry, to me yes.
The Stax are an interesting headphone which I have been enjoying and the iFi worked allowing me to continue using them.
1. These are a corded, boxy looking set of phones. They are decidedly not portable. The biggest limitation of the Stax is you need to sit very still to avoid causing pressure changes in the chamber formed by the ear cushion. For me this is not a particular issue as I most frequently use the for my meditation practice.
One of the problems with these headphones is that they are supplied with a small 12V centre negative plug in power supply. Like most of its ilk these are the most likely part of the system to fail.
Replacing these power supplies is getting harder as the used to be common linear power supplies are getting rare, being replaced with switch modes and the SRM-252S interacts badly with some power supply designs causing the supply to switch on and off - ignoring the fact that audiophiles tend to be negative about the potential for introduced noise fro m switch mode power supplies.
Objectively
The good news is that the iFi Power2 came with suitable plugs and a a centre negative adapter and everything worked out of the box.
The available power from the supply is well in excess of what the original supply provided and that may allow a bit better performance.
Subjectively
The audiophiles are going to ask 'does it sound better', and I will answer subjectively, I think so. However, that is a purely subjective and potentially biased, non-blinded opinion. Worth the price difference, really hard to tell, given the issues I was having in finding another moderately low noise power supply and not having to design my own filter circuitry, to me yes.
Conclusion
The Stax are an interesting headphone which I have been enjoying and the iFi worked allowing me to continue using them.
1. These are a corded, boxy looking set of phones. They are decidedly not portable. The biggest limitation of the Stax is you need to sit very still to avoid causing pressure changes in the chamber formed by the ear cushion. For me this is not a particular issue as I most frequently use the for my meditation practice.