[Chris J]

Correct.
So I need to get a non-switching transformer?

The wall wart should be a linear power supply,
not a switchmode power supply.

I can't recommend a source.

 

[miceblue]

A recommendation would be nice. What transformer do you guys use?

+1

It would be nice if the more educated members here could just recommend a specific wall wart that should technically work fine with a Japanese SRM-252S in the U.S.. I don't think we mind paying a little extra for quality and peace of mind but as a newb coming into the world of Stax international voltage issues it can get a little confusing when people say just buy any 12v 1amp wall wart. Just help us out by pointing to a few specific products that will/should work fine.

Yeah and now the wall wart needs to be linear instead of a switchmode one, which is news to me and I didn't know that when searching for one. -_-

 

[tyre]

Here's a possible solution for the SRM-252 power supply. This isn't really a recommendation as I haven't tried this one myself, just a suggestion. It could potentially be a piece of junk.

http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_162996_-1

12VDC at 500mA with a 7812 linear regulator and a 2.1mm x 5.5mm connector.

A polarity reversing adapter would be needed for center negative, otherwise the cable would have to be cut and the wires reversed. This one looks correct but I'm not certain. You'd probably want to check it first with a multimeter to be sure.

http://www.elliottelectronicsupply.com/2-1mm-jack-2-1mm-plug-reverse-polarity-dc-power-supply-adaptor.html

There's a 1A version of the power supply as well, but it uses a non-standard regulator IC that I've never heard of.

The proper wall-wart that Stax provides with the North American SRM-252 is model no. 1240, 117V 60hz input, 12VDC at 400mA output, unregulated.
 
Ultimately, it would be easier to buy a 120V to 100V step-down transformer from Amazon and use the Japanese wall-wart you already have.
 

 

[jjinh]

Quote:

A recommendation would be nice. What transformer do you guys use?

 
Do you have any wall-warts lying around at home that are 12V? You could use one of those if the plug size is correct BUT it may need to be rewired to make it neg polarity.
 
As for what I use it's the power supply that came with (or use to come with) the Australian SRM-252 amps... a massive power brick that weighs more than the amp itself!

 

[DefQon]

Typical router/modem wallwarts use the same tip and voltage rating that can be used on the Stax basic amp's.

 

[EveTan]

Quote:

 
Do you have any wall-warts lying around at home that are 12V? You could use one of those if the plug size is correct BUT it may need to be rewired to make it neg polarity.
 
As for what I use it's the power supply that came with (or use to come with) the Australian SRM-252 amps... a massive power brick that weighs more than the amp itself!

I'm pretty bad with anything that deals with DIY in general. So I normally just take the buy it route. 
 
Thanks for the suggestions though.

 

[jjinh]

Quote:

As for what I use it's the power supply that came with (or use to come with) the Australian SRM-252 amps... a massive power brick that weighs more than the amp itself!

 
(Quoting myself!)
 
Dug out my amp from storage. Here's a pic of it with the wall-wart. Midday and still no sun or light around here so crap pic...
 
 

 

[mechgamer123]

Quote:

Typical router/modem wallwarts use the same tip and voltage rating that can be used on the Stax basic amp's.

Hehe, I'll have to splice up some wallwarts in the near future then!

 

[M-13]

Quote:

Here's a possible solution for the SRM-252 power supply. This isn't really a recommendation as I haven't tried this one myself, just a suggestion. It could potentially be a piece of junk.

http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_162996_-1

12VDC at 500mA with a 7812 linear regulator and a 2.1mm x 5.5mm connector.

A polarity reversing adapter would be needed for center negative, otherwise the cable would have to be cut and the wires reversed. This one looks correct but I'm not certain. You'd probably want to check it first with a multimeter to be sure.

http://www.elliottelectronicsupply.com/2-1mm-jack-2-1mm-plug-reverse-polarity-dc-power-supply-adaptor.html

There's a 1A version of the power supply as well, but it uses a non-standard regulator IC that I've never heard of.

The proper wall-wart that Stax provides with the North American SRM-252 is model no. 1240, 117V 60hz input, 12VDC at 400mA output, unregulated.
 
Ultimately, it would be easier to buy a 120V to 100V step-down transformer from Amazon and use the Japanese wall-wart you already have.
 

Thanks for the effort. Utimately I think I agree with you that I should just use the step-down transformer just for simplicity sake. All this polarity/linearity talk is just way over my non-engineering head. I was hoping there would be a simple wall wart that would work without any DIY, but I guess not.

 

[mudihan]

Does anyone know if the design below would also turn a SRD-6/7 into a Pro adaptor? 
 
http://www.headfonia.com/stax-srm-1mk2-bias-modification/#comment-960617449

 

[tyre]

Quote:

Typical router/modem wallwarts use the same tip and voltage rating that can be used on the Stax basic amp's.

 
Quote:

Hehe, I'll have to splice up some wallwarts in the near future then!

 
I wouldn't. Kevin Gilmore specifically recommended against using an unregulated supply in this post.

http://www.head-fi.org/t/223263/the-stax-thread-new/22995#post_9532128

In all likelihood, the original unregulated 12V wall-wart was designed so that the output voltage would be "pulled-down" to the proper 12VDC under load. Unloaded (or underloaded) wall-warts typically output a much higher voltage. The wrong wall-wart may ruin your SRM-252. Remember that the voltage written on the power supply is correct only at the specified output current.

 

[jaycalgary]

I received an email news letter today from "The DiyAudio Store".  Looks like some new interesting things. http://www.diyaudio.com/store/

 

[EveTan]

So this would be all I need to change the voltage? 
 
http://www.voltage-converter-transformers.com/product_info.php?category_id=10016468&products_id=10061420

 

[wink]

Quoterepoman

Quote:

So I've been really enjoying the SR007 the last few weeks and haven't touched my HD800 rig since. I'm seriously considering selling my HD800 rig and getting the SR009. The cost of my amp and the HD800 should cover a good amount of the cost. 

 
 
Stax all the way huh?  Heck, you can sell the 007 and cover the full cost.

Don't sell the 007 until you've done a long comparo between the 007 & 009.
 
Then sell the one you like least, or better still, keep both.

 

[DefQon]

Quote:

I received an email news letter today from "The DiyAudio Store".  Looks like some new interesting things. http://www.diyaudio.com/store/

I don't see anything new or interesting there.