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The Headcase Stax thread


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Isn't everybody glad that I'm crazy enough to buy this stuff and have Kevin rip it apart?   

I have compared the 009 and 009S running from the same amp (T8000) today. The room was somewhat quiet, but I had only two source options: my iPhone (connected through Apple's lightning adapter direc

Ok...I had an interesting morning.  It isn't every day that one takes apart HE90 drivers.    Sorry no picks as I was too freaked out while handling something so delicate and well...fucking unobtainium

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I'm still new to the to the "moar power" tendency.. :huh: I predominantly suffer from the "moar quality" tendency.  :ph34r:
But I have to admit I didn't realize immediately that MSB had an electrostatic amp. I usually tried not to delve this deep into "unobtanium" class equipment. But I am failing in this lately:blink:  
Thanks for bringing me up to speed though!

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Since we've had some more talk about garbage like Lampi dacs...there is something else we have to discuss - the ifi iesl.  Long story short, I was asked to look into this for a mafia member and well... I wouldn't connect my phones into this. 

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So let's start at the beginning, the transformers have either a 1:16 ratio or 1:32 depending on the impedance switch.  The former is certainly on the low side so you need some power to push this.  Their claims for the transformer construction is all fine and dandy for output transformers but they never touch on the stuff that actually matters for electrostatic step up operation.  The transformer capacitance is paramount and so is to keep the inductance in check.  Let's just focus on the shit that doesn't matter instead...

Now onto the bias supply and their capacitor "battery" claims are just so full of shit that it isn't even funny.  First of though, how is the high voltage for the batteries generated?  I can't see any transformer that could do that from the low voltage DC input.  There are some chokes but nothing substantial enough.  Also, how are they switching the bias?  Those cheap arse switches?  Sure fucking hope not and no normal relay can handle these voltages. 

Now for the really bad news, see the first picture, the string of resistors in front of the 5 pin connectors?  Those pretty much have to be the ballast resistors run in series to increase the voltage handling.  They are also high value resistors but I can't quite make out the value of them.  Now follow the trace on left and see the cap that is there?  Yup it is 10nf/1kV so it sure looks like the fucktards put a cap after the ballast resistor.  Never, ever do that if you like the coating on the diaphragms...

As for the whole capacitor based supply claims, if they run them in parallel then they have 3uf roughly of charge which is quite a bit and I for one wouldn't want to have that sitting on the bias supply should anything go wrong.  I also wonder if their dielectric claims extended to the rest of the circuit?  The PCB's leak at these voltages as do the switches and connectors. 

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Good grief. I posted about trying this pile of feces at a meet earlier. It could barely make a sound. At max volume, it sounded like a Carbon at about 9:30 o’clock.

I made the mistake of plugging my 007A into it, and yanked out the cable about 90 seconds later when I realized that, considering it doesn’t work as an amp, that it probably got the bias circuitry wrong, too. Which seems indeed to be the case.

How much damage do you figure I did to the diaphragms? ?

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hi everyone, i've been reading some of the fascinating threads on this forum for past 2 weeks. thank you all for very informative and entertaining posts.

i'm new and i don't have experience with stax headphones. although some months ago i've got a chance to listen stax sr-5 gold at my home for a week. i was surprised, they sound really good. is there any recommendation for cheapest good old stax i should look at? i also have toshiba hr-810, is this headphone anywhere near stax level? i could only listen them at 300ohm. when i switched to 1000 ohm all i got just distortion. thanks before

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I did a funny test on the weekend with my new Carbon / SR-009 Setup and checked the audible frequencies with an online tone generator.
I knew my upper hearing limit is 16 kHz but I was rather astonished to be able to hear even the 3 Hz signal.:o It's really a big surprise that I can still hear signals from 3 Hz to 16 kHz. :blink:

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3 hours ago, JimL said:

Below 20 Hz what you may be hearing is the harmonics of the tone rather than the fundamental - i.e. what you may be hearing is distortion, especially if you cranked it up.

Definitely this.

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6 hours ago, mypasswordis said:

Sinusoidal waves tautologically don't have harmonics. I have tried the same test a long time ago (not with a Carbon) and you will hear something, in the form of flapping noises.

What goes in may be sinusoidal, what comes out may be sine wave plus harmonics, i.e. distortion. For example, I have driven a woofer with progressively lower frequency sine waves, and at some point the pitch suddenly seemed to double because it was producing enough 2nd harmonic distortion that I heard the distortion as much as the fundamental, and the pitch sounded an octave higher. In fact, the term "doubling" refers to this phenomenon.  So, yes, flapping can occur, or doubling (or tripling, or higher harmonics).

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17 hours ago, Jensethi said:

I did a funny test on the weekend with my new Carbon / SR-009 Setup and checked the audible frequencies with an online tone generator.
I knew my upper hearing limit is 16 kHz but I was rather astonished to be able to hear even the 3 Hz signal.:o It's really a big surprise that I can still hear signals from 3 Hz to 16 kHz. :blink:

Nah, you heard an upper harmonic of the 3 Hz tone (probably distorted at that, probably by your source).

(arghh... reacted too soon, without reading the rest of the thread; consider this deleted)

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17 hours ago, wink said:

Infrasound

That's certainly not wrong, but that sounds more like a physiological term, I was trying to think of the psychoacoustic term, if that makes any sense.  I know there's a relationship between the distance between your earholes and the ability to localize a frequency (which is why we only need one subwoofer as long as it does not generate any frequencies above that frequency), but I thought there was another name for it -- The ___ Frequency -- Oh, well, I may be almost remembering something wrong...yet again.  I'll go with 'infrasound'.  Thanks.

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11 hours ago, Dusty Chalk said:

That's certainly not wrong, but that sounds more like a physiological term, I was trying to think of the psychoacoustic term, if that makes any sense.  I know there's a relationship between the distance between your earholes and the ability to localize a frequency (which is why we only need one subwoofer as long as it does not generate any frequencies above that frequency), but I thought there was another name for it -- The ___ Frequency -- Oh, well, I may be almost remembering something wrong...yet again.  I'll go with 'infrasound'.  Thanks.

I've needed to refresh my knowledge. I haven't found the name for that frequency, which is around 500-800Hz depending on the distance between your ears. It's said to be the frequency whose half wavelength equals the head diameter. Brent probably can locate sounds of frequency as low as 30Hz.

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