[spaceace1014]

I gave my UI artist the 717 that I just repaired and a pair of Baby Stax so that he can properly enjoy music while he works. That's left me with... not Stax and I miss them.

So I got the 727 that I ordered and the first order of the day is to correct the voltage problem. I could just buy a cheap converter and I'm sure that would be awesome but I rather like these projects and this is a whole lot less kludgy. I've searched around and while i've seen information on doing this conversion before It must be burried deep within the stax thread because I cant find it. (I can find the spritzer mod which I'll do next in another thread after I get used to the sound.)
 
So here are the photos of my transformer. I know I need some resistor leads and solder but that's about all I know. Where do I go from here? Can I simply A/B it with my 117v 717? 
 

 

 

 

[spaceace1014]

This is probably the important picture. 
 

 

[spaceace1014]

I just opened up the 717. It doesn't have a daughter board. It has a quick voltage change piece. So much for copying that. 

 

[spritzer]

You need to bridge those cuts in on the transformer, otherwise this will never work.  It's very fiddly to do and be super careful about keeping good distance from any of the other wires.  Remove the glue carefully and there should be a small piece of wire sticking out of the transformer.  You need to solder to that (it's coated with enamel so scrape it off first) and then bring that new piece to the disconnected terminal. 
 
Once that is done then you need to rewire the small side board.  Currently it is:
 
100v:
Gray+White
White wire from the  ACplug+Brown+Green
 
You need to change it to:
 
117v:
Gray+White
White wire from the AC plug+Blue+Purple
 
That means remove the link from brown to green and place it between blue and purple.  The white wire inline with the brown needs to be moved to the spot closest to the yellow wire, inline with the purple wire. 
 
That's it, power it on. 

 

[spaceace1014]

As always Spritzer thanks! 
So here is the visual version of what spritzer said. 

 
It was pretty easy to get this mod done. 

Heres what I needed:
Tools:
1.Lead cutters
2.Soldering Iron
3.Solder Sucker
4.Sponge
5.Wire Cleaner for the soldering iron
 
Disposables
1.Resistor for its leads 
2.Solder
3.Rosin.
4.Soldering wick
 
OK so heres what I did....
1. I popped the silicon plate off of the transformer. Its held on with tape.
2. I located the cut wires which are blue and purple. There is hot glue down the holes. I used a pair of needle nose pliers to pinch the glue and pull it off. It all came up for each hole in one go like a cork.
3. I used the soldering wick to paint a little bit of rosin on the tiny wire down in the hole and on the post that we need to connect it too
4. I heated up the tiny wires and the posts using my iron. The posts have a thick enamel coating on them make sure it comes off.  you'll know when its coming off. 
5. I prepped one side of a resistor lead with solder so that I wouldn't have to have three hands. If you're familiar with soldering wire its done the same way. I stuck this down one of the two holes with the tiny cut wire and applied heat. I had a bit of trouble getting this to stick at first and i just applied extra rosin and reapplied heat. 
6. I moved the now soldered lead around a bit to make sure it was properly connected because its difficult to see into the hole that I had soldered down. Be very gentle. if you break that little wire you're probably done. 
7. I pulled the lead over to the matching post and soldered it and cut off the excess. 
8. repeat steps 5-7
9. I added a bit of extra solder in each hole but not a tonne I didn't want it sliding too far down the wire. 
 
At this point you should have a fully functioning transformer. Now you need to do the rewire follow the picture above. Its very very simple. 
 
I wish I had more picture but somehow none of my pictures recorded properly which is too bad because I had detail shots of all of this. I'll take some photos when I open it back up for the Spritzer mod. 
 
This little mod saved me about a grand at the current exchange rate. 

 

[spaceace1014]

Its Alllive! 
\

 

[spritzer]

Glad it worked out and based on the SRM-007tA I got last week, they use the same setup.  Stax have always swapped out the voltage setup at regular intervals but the basics are always the same. 

 

[purk]

Birgir to the rescue again.  Thanks to you mate. 
 
@Space, 
 
What do you think of the 727 compared to the 717?  I love my 717 when I had it.

 

[schlaget]

Hello
After getting my KGSSHV done (besides front plate), I wanted to convert my 727 to 230V.
 
I manage to tap into the cut transformer winding, no problem. But I somehow don't understand how this transformer is wound and which wires need to go where on the voltage board. Could someone tell me this?
 
Thank you

 

[spritzer]

Which version of the voltage selection does this one use?  There should be a small PCB to the side of the transformer where all the primary wires go...

 

[Cortes]

hi guys,
 
  just bought a SR;-727A in Japan,  do you know how to convert it from Japan 100V to EU 230V?.
 
Do I need to touch the 'brando', or just the stax blue boards?.
 
Thanks!.  
 
 
 

 

 

 

[Michgelsen]

I cannot really help you with this, except to give some pointers for searching, although it's highly likely you'll have to touch both the Bando transformer and the blue boards.
Most of the information about voltage conversion of Stax amps is not in the current Stax thread, but in the previous one: http://www.head-fi.org/t/223263/the-stax-thread-new You can search in there, possibly via Google.
 
This post has some clear information: http://www.head-fi.org/t/223263/the-stax-thread-new/23625#post_9627206 . From what I gather, the procedure is the same for different amp models, but I do not take responsibility for anything. Good luck, and please post results or instructions for others when you're done!!!

 

[Cortes]

  I cannot really help you with this, except to give some pointers for searching, although it's highly likely you'll have to touch both the Bando transformer and the blue boards.
Most of the information about voltage conversion of Stax amps is not in the current Stax thread, but in the previous one: http://www.head-fi.org/t/223263/the-stax-thread-new You can search in there, possibly via Google.
 
This post has some clear information: http://www.head-fi.org/t/223263/the-stax-thread-new/23625#post_9627206 . From what I gather, the procedure is the same for different amp models, but I do not take responsibility for anything. Good luck, and please post results or instructions for others when you're done!!!

 
Thanks Michgelsen,
 
  jumpers are not the same as in 727. Uff this looks too risky

 

[Michgelsen]

I don't know how risky it is. Depends on how expensive a step-down transformer is.

But restoring the cut-off transformer wires seems the most difficult part. When that's done, you need to know how to hook up the blue board. Maybe people can help you with that elsewhere.

 

[Cortes]

  I don't know how risky it is. Depends on how expensive a step-down transformer is.

But restoring the cut-off transformer wires seems the most difficult part. When that's done, you need to know how to hook up the blue board. Maybe people can help you with that at elsewhere.

 
haha is true, they have cut the wires and put glue in the holes, they are mean at Stax!
 
I'm leaning now towards a less ambitious mod, and just solder the XLR cables as close  as possible to the board. I don't know if that will make a difference, but I bought some fancy OCC silver/gold  neotech wires to do my XLR connector. 
 
BTW I don't see much follow up of the Spritzer mod on the non-feedback circuit, which is reversible, even he doesn't seem to promote this mod very much.