[PointyFox]

215 width x 230 depth x 80 mm height not including knob.

 

[purk]

I am surprised that the D50 isn’t more popular.

 

[SolarCetacean]

I am surprised that the D50 isn’t more popular.

It likely falls in a pretty narrow niche among electrostatic owners. It's a compact DAC/amp that only serves Stax-plug headphones and has no line or parallel outputs, so it can only be an endpoint or a standalone unit, not an intermediary or source component in a chain. While it's a nice, small desktop unit, most people who are into Stax are already pretty deep in the audiophile game and most likely have their own DACs and sources and plenty of space for larger, higher-power amps. And if you wanted a portable amp, the D10 fills that niche while the D50 doesn't. It's also pretty expensive, and you're mainly paying for the form factor and DAC (using a chip that's over a decade old) over something like the 353X. So if you already have a DAC you like, and either a media rack or plenty of desktop space, there's not much to recommend the D50 over a dedicated amp.

All that aside, perhaps the D50 is more common in the Stax home market of Japan. I get the impression based on ebay listings that Japanese Stax users tend to keep to Stax amps and 3rd party amps like the KGSS or BHSE are even rarer there than in the rest of the world. Another very real possibility is sampling bias: the people who are buying the D50 (and there are, based on reviews on dealer websites like HeadAmp) aren't the same people who are active on Head-Fi.

 

[purk]

I have the DIY-T2 and I do enjoy listening to the D50 as well. The performance is decent on the D50 for the price.

 

[bmichels]

I am surprised that the D50 isn’t more popular.

Same. This device deserve more exposure !

 

[vrockz]

Anyone know if D50 would be able to drive Stax-x9000

 

[SolarCetacean]

Anyone know if D50 would be able to drive Stax-x9000

According to this review, the D50 will do in a pinch. Probably not optimal for the X9000, but it works.

 

[PointyFox]

I think it performs about the same as their upper-end mid-tier stuff but below their TOTL stuff.

 

[whatdidyoulearnabout]

Anyone have an issue with the VU meter clipping? I mean clipping in the most literal sense possible: it strikes the right-hand side of the dial range, making an annoying ticking sound. This only happens when I drive them off of a (line level!) DAC (Topping D70s, FWIW).

It also seems to happen gradually more frequently with age.

 

[SolarCetacean]

Anyone have an issue with the VU meter clipping? I mean clipping in the most literal sense possible: it strikes the right-hand side of the dial range, making an annoying ticking sound. This only happens when I drive them off of a (line level!) DAC (Topping D70s, FWIW).

It also seems to happen gradually more frequently with age.

The D70s has a line out voltage of 2.5V, which is higher than the consumer standard of 2V. Maybe the VU meter wasn't designed for input voltages that high? If you reduce the input level and raise the amp's volume to compensate, does the clipping go away?

 

[whatdidyoulearnabout]

The D70s has a line out voltage of 2.5V, which is higher than the consumer standard of 2V. Maybe the VU meter wasn't designed for input voltages that high? If you reduce the input level and raise the amp's volume to compensate, does the clipping go away?

Holy cow, great investigating skills here — I was foolishly over here thinking line level was line level. That's gotta be it.

The SRM-D50 volume knob has no bearing on the VU meter amplitude whatsoever, but trying to reduce the D70s output level is well worth it.

It turns out that this is possible, because deep in the manual, it mentions that D70s has both a "DAC Mode" which I've been using, and a "Per-Amp" [sic] mode which must be what I ought to try.

 

[whatdidyoulearnabout]

Extra comic relief: I thought the "Line Out" button would do the trick for me, but turns out it's checks notes "Invalid button"

 

[SolarCetacean]

I was foolishly over here thinking line level was line level.

Some DAC manufacturers like to have higher-than-normal line levels since it improves SNR. Since noise in the circuit is generally a constant level, the higher the signal, the bigger the difference between it and the noise level, so the SNR improves. It's a bit like stat-padding IMO, but it's a relatively common practice. Also, the measurement gear like the APx analyzers often have max input SNR at around 2.5V, so that eeks out another 1 dB or so in the SNR measurement.

I've read that some Topping DACs have line level adjustments so that you can choose the standard 2V or the native 2.5V line levels without needing to use pre-amp mode. Maybe the D70s has it. Another way is to lower the digital volume if the D50's software driver allows it.

 

[whatdidyoulearnabout]

Update: beautiful! After changing to the "Per Amp" mode, reducing the volume indeed reduces the SRM-D50 VU amplitude.

At -12.5 dB, I'm even able to get it to stay, courteously, within the black markings on the arc (no idea if the red region would actually lead to problems; I don't recall hearing any auditory issues other than from the meter itself slamming its dial).

Thanks again.

Interesting background on SNR stat-padding.

 

[kael13]

My first set of STAX have arrived! L700 mk2s. I'm beyond excited to give them a listen. The packaging and build is really rather lovely. Very retro chic.
Picking up a barely-used D50 tomorrow about an hour's drive away. I got a good deal so as long as it's all in working order, I'll be very happy.

I also bought a wooden headphone stand made of cherry and hornbeam to show them off. Made in and shipped from Ukraine. But that'll take a couple weeks to arrive.