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The Stax Thread III
Nov 24, 2015 at 6:00 AM Post #7,262 of 25,558
judgment said:
  Would it be possible to convert the Japanese Stax SRM-727II 100 Volt model to operate on 230 Volt mains outlet? Not scared of doing soldering. Does the frequency difference 50/60hz make any difference?
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Yes this is possible, but difficult, since Stax cuts the wires very short on the transformers to prevent this. Therefore you will definitely have to do soldering. Your question has been asked many times before, and as is the unfortunate nature of this kind of fora, the answers are spread out across many posts. The best advice I can give you right now, is to do a thorough search, here, and on the other forum.
 
The frequency difference shouldn't matter. Stax amps used to have a voltage selector, and even though they don't have that anymore, the transformers for all voltages are the same I think. That's why they cut the windings for voltages they don't need and it is still possible to reconnect them. Stax doesn't use specific transformers for specific voltages and frequencies as far as I know.
 
Nov 24, 2015 at 8:00 AM Post #7,263 of 25,558
Gentleman (specifically UK users),
 
 
SR-009’s are now down to £3195 
 
The price for the new Stax L700’s will be £995
 
The 353X is going to be £895
 
There is also going to be a L500 + 353X package for £1395.
 
 
 
 
*takes a bow* 
 
(Not that I played a part in anything)
 
Nov 24, 2015 at 8:47 AM Post #7,265 of 25,558
For Judgment, the difference between 50 and 60 Hz does not make a difference.  My understanding is that Stax uses the same transformer for different markets, but just wires it up differently depending on the voltage.  Here is a post by Spritzer from 2008 describing how to change the voltage:
 
"This is posted without any guaranty but should work. There are two 0-100-120v windings on the transformer so you want to change from a parallel wired 0-100 over to parallel wired 120v configuration.

100v should be Gray and White connected together (they are the 0v points of the windings) and then Brown, Green and the other white wire (which is connected to the power socket) connected together.

117v should be White and Gray connected together (0v point) and then Blue, Purple and the other white wire connected together.

240v should be Blue and the other white wire connected together and then Purple and Gray connected together.

That means you have to move the jumpers as well as the white wire (not the one connected to the fuse!!!!!) over to the spot above the purple wire. You were dead on. 
smily_headphones1.gif


One thing to note is that Stax does sometimes cut the 120 windings on the transformer making this change almost impossible. Check and measure the primary windings before proceeding."
 
Nov 24, 2015 at 10:12 AM Post #7,267 of 25,558
jiml11 said:
  For Judgment, the difference between 50 and 60 Hz does not make a difference.  My understanding is that Stax uses the same transformer for different markets, but just wires it up differently depending on the voltage.  Here is a post by Spritzer from 2008 describing how to change the voltage:
 
"This is posted without any guaranty but should work. There are two 0-100-120v windings on the transformer so you want to change from a parallel wired 0-100 over to parallel wired 120v configuration.

100v should be Gray and White connected together (they are the 0v points of the windings) and then Brown, Green and the other white wire (which is connected to the power socket) connected together.

117v should be White and Gray connected together (0v point) and then Blue, Purple and the other white wire connected together.

240v should be Blue and the other white wire connected together and then Purple and Gray connected together.

That means you have to move the jumpers as well as the white wire (not the one connected to the fuse!!!!!) over to the spot above the purple wire. You were dead on. 
smily_headphones1.gif


One thing to note is that Stax does sometimes cut the 120 windings on the transformer making this change almost impossible. Check and measure the primary windings before proceeding."
Click to expand...

 
Basically what this says without the color stuff which changes from amp to amp, is that there are always 2 primary 0-100-120 windings on the transformer. You either connect them in parallel to keep the voltage the same, 0-120 and 0-120 for 120VAC USA for example, or connect them in series to add the voltages together. So then 0-120 and 0-120 in series works for 240VAC. And then anything about within 10volts falls within each range. What makes it bit more tricky is often stax has a daughter board with various bar fuses that might need to be changed out for the correct rating as well.
 
Nov 24, 2015 at 10:46 AM Post #7,268 of 25,558
potkettleblack said:
  Gentleman (specifically UK users),
 
 
SR-009’s are now down to £3195 
 
The price for the new Stax L700’s will be £995
 
The 353X is going to be £895
 
There is also going to be a L500 + 353X package for £1395.
Click to expand...

 
Thanks for the info.
 
Also:
SR-L500 for £545.00
http://hifilounge.co.uk/stax-sr-l500
 
Nov 24, 2015 at 3:28 PM Post #7,270 of 25,558
tinkerer said:
   
Basically what this says without the color stuff which changes from amp to amp, is that there are always 2 primary 0-100-120 windings on the transformer. You either connect them in parallel to keep the voltage the same, 0-120 and 0-120 for 120VAC USA for example, or connect them in series to add the voltages together. So then 0-120 and 0-120 in series works for 240VAC. And then anything about within 10volts falls within each range. What makes it bit more tricky is often stax has a daughter board with various bar fuses that might need to be changed out for the correct rating as well.
Click to expand...

 
 
Ok, external transformer it is:) Too much hassle after all to start rewiring the unit.
 
Nov 24, 2015 at 7:04 PM Post #7,271 of 25,558
hauge said:
 
Ill se if i can find a place here in Denmark, where they sell audioXpress! - As the holidays are just a month away, its not time for a subscription right now... :wink:
Click to expand...

 
So if for some reason you can't find it for sale, you can also see an extended discussion on the internet - actually more detailed due to word count limits for the AudioXpress articles.  Do a Google search for "kevin gilmore SRX revisited."  The AudioXpress article has nicer looking schematics.  If you don't want to build it point-to-point there are board files on Kevin Gilmore's website under srx6 - this is just for the amp.  They can be sent to a professional board maker to make the board.  I am going to try to design a board for the power supply but I will have to download board design software first, and learn how to use it.  :)
 
Nov 25, 2015 at 5:34 AM Post #7,272 of 25,558
jiml11 said:
   
So if for some reason you can't find it for sale, you can also see an extended discussion on the internet - actually more detailed due to word count limits for the AudioXpress articles.  Do a Google search for "kevin gilmore SRX revisited."  The AudioXpress article has nicer looking schematics.  If you don't want to build it point-to-point there are board files on Kevin Gilmore's website under srx6 - this is just for the amp.  They can be sent to a professional board maker to make the board.  I am going to try to design a board for the power supply but I will have to download board design software first, and learn how to use it.  :)
Click to expand...


Hi again JimL11!

Thank You for Your very kind help! The amp look very well designed, and reading the tread gives a perfect insight of how it works. Im really grateful, for You and the other contributors great work!
Let the hunt go in for the needed parts! :) 
 
Nov 25, 2015 at 5:55 AM Post #7,273 of 25,558
potkettleblack said:
Gentleman (specifically UK users),


 


 


SR-009’s are now down to £3195 


 


The price for the new Stax L700’s will be £995


 


The 353X is going to be £895


 


There is also going to be a L500 + 353X package for £1395.


 


 


 


 


*takes a bow* 


 


(Not that I played a part in anything)
Click to expand...

 



Thanks potkettleblack,

Keeping an eye on the L700 reviews.

I have Lambda Sigs, LNS, 207's and 507. Something may have to be sold for the L700's.
 
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