The Stax thread (New)
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Jun 16, 2013 at 8:36 PM Post #23,013 of 24,807
Its a switcher and there are significant current spikes.
I'm pretty sure the power brick says 1 amp.
Now I need to go find the power brick.
This is going to take a while.
No clue where they are at the moment.
 
Edit: I found the overheated one from the srm-xh its the stax model 1240
and its 12v 400ma
 
can't find the brick for the srm-212 yet.
I will ask birgir what his brick is labeled.
 
edit: one of these years i'm going to clean up this mess.
(that would be the entire house)
(probably easier to buy a new house)
 
Jun 16, 2013 at 8:52 PM Post #23,016 of 24,807
I *think* the stock power brick that came with the 2050a was rated 400mA, I've thrown it away now though, so I can't check.
 
It won't hurt to use a higher rated one, so why not? 
size]

 
Jun 16, 2013 at 9:01 PM Post #23,017 of 24,807
4 watts is the actual power dissipation of the pair of headphone amplifiers. I actually measured it at one point
with exactly 12.0 volts DC going into the unit.  The switcher is about 82% efficient, and is completely open loop
so if you actually give it 12 volts, then the real power consumption is more like 5 watts. Some of the power bricks
are regulated, some are not, some sink to 11 or less volts, which lower the power supply output to something
as low as +/-200 volts. It still works, but does not play as loud, and clips earlier. Also it lowers the bias voltage
to less than 500 volts. So if you want best performance, you want a regulated power brick that actually
supplies 12 volts under load.  That jameco brick is not regulated and is unlikely to actually supply 12 volts
under load.  Going over 12 volts is a bad thing because the electrolytics are only rated at 250 volts, and the
thing is designed to run right at 250 volts.
 
Jun 16, 2013 at 10:48 PM Post #23,019 of 24,807
Quote:
srm-Xh, srm-212,srm-252 are all exactly the same. 12 volts, 4 watts, outside is plus.
All are the same connector.
I own the first two, birgir now owns the 3rd. Do not use an unregulated transformer.
Switcher inside is not regulated, to high a voltage and parts fly.
12 volts 1 amp minimum.

Excellent, thank you very much!
I'll post the transformer before I purchase it to make sure it's alright.
Quote:
Quote:
Hmm, I need something like this so I can see what the voltage and polarity of the power plug so I can get a US transformer that works: 

 
The center pin on that amp is negative. Usually it is positive so buy one that has a negative center pin. Also, you need to know the diameter of that hole and the center pin so you can get the right size.

I'm fairly certain that it's the same as all the other audio gear I've dealt with, which is a 2.1mm connector. If someone could verify this, it would be greatly appreciated! :p
Quote:
 
 ​
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I think this part will work OK:
 
http://www.jameco.com/Jameco/Products/ProdDS/15368.pdf

Excellent, that's just what I was looking for! Thanks!
Er rather, Arigatou Gousaimasu!
 
Jun 16, 2013 at 11:03 PM Post #23,020 of 24,807
Jun 16, 2013 at 11:30 PM Post #23,022 of 24,807
Quote:
The tip size is about the same as the adaptors that supply power to your typical modem/router etc. The outer diameter of the tip is 5mm. Inner size is about 2mm.

So it's a 2.1mm by 5.5mm connector just like all of the other connectors I have? Sweet.
 
Jun 17, 2013 at 4:52 AM Post #23,024 of 24,807
It's not really a 'shock', it's a very mild tingling or vibrating feeling.
Many people report this for example when they touch their PC case when it's not grounded.
The problem with the house wiring in many old houses is that there is no ground wire, at least here in the Netherlands. See here the common type of socket we have without ground (scroll down): http://en.wikipedia.org/wiki/Schuko
If equipment is designed to be connected to grounded sockets, this can lead to the slight problem mentioned. I know this 'should not' happen, but it does quite often.
 
Quote:
There is something very wrong with this!
You should NOt get a shock when you touch your audio equipment, or any household equipment!
Is there something wrong with your house wiring?

 
Jun 17, 2013 at 5:54 AM Post #23,025 of 24,807

I think we should announce to the traditional audiophiles,
it is time now we all should migrate to computer audiophile systems.
To replace the spinning-CD transport with terrabyte SSD.
There's already ExactAudioCopy, RubyRipper, & else, (choose JACK, no ALSA, unisntall PulseAudio),
and no ErrorCorrectionCode, and using SSD inside laptops (no spinning HDD).
And in the future, many manufacturers will create more pure digital amplification like NAD M2 (bye-bye tube, bye-bye bipolar),
and interface like Berkeley Alpha USB,
so there are no analogs at all, even at the loudspeakers' terminals.
The sound ?
Even really challenge the 100,000 vinyl+tube systems, with the cost of under 15,000 !
 
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