[telecaster]

Quote:

I use a SR307 with a SRM1 MK2 and I'm very happy with this combo.
Is it worth to make a step to SR507 or SR404LE? Or better to go for Omega 007?

I would believe 307 is already very good, step up to 009 maybe.

 

[pschelbert]

Hi Duncan1 and DefQon,
 
great advise. I will now go forward and try it. No soldering required, even easier.
Tahnks
 
Peter

 

[MDR30]

As I mentioned it a while back, here is a super small Stax tube amp.  




Design isn't finalized yet but this thing will not swing a whole lot of voltage (500+Vp-p) or be very powerful but it is cheap and cool.  The small PCB in the back is the HV supply which is driven off 12VDC which also powers the heaters.  It's a switcher but it was very cheap.  Fully balanced from input to output but not really portable as it needs 12W just to light up the tubes. 

Looks very interesting, and simple enough even for me to assemble. Would boards and parts be available? What tubes?

 

[spritzer]

Quote:

Jumpers 1,3 and 6 is definitely 100v
2,5 is definitely 240v.
2,4,6 is 120v.
3,5 is 220v.

Credits to kg and spritz as the above worked for my 323S.

 
Yup, this is the correct setup so just rearrange the "fuses" and it's good to go.  Not all of the Stax amps are this easy to work on though. 
 
Quote:

My SRM1-MK1 went kaputz this morning. No smoke, or burnt smell, still seems operationally fine. Still using stock cap's as well. Sound comes out of the Right channel but no sound on Left. Even fed a RCA wired cable directly to the Left-input solder pad underneath the PCB and no sound. Both the normal bias jacks don't produce sound on the left side.
 
Rewired the RCA connectors just few days ago and cranked it up this morning, I did see a small blue spark from the white 630v bias wire that connects to the copper bridge across the 4 transistors. The problem was the white cable was just dangling on top of the bolt not secured down properly with the washer. 
 
Any ideas? Kg/spritzer?

 
Nothing good comes to mind.  If the transistors are shot then the odds of finding replacements are pretty much zero. 
 
Quote:

Looks very interesting, and simple enough even for me to assemble. Would boards and parts be available? What tubes?

 
I would never offer boards outside of my small cache of proto units but the Gerbers will be made available.  It's bit deceptive this one though as the tubes are an utter pain to install.  I'm using the Soviet 6H17B's and US made 6814 as output tubes and the the Soviet are difficult since there is no easy way to see which pin is which.  I just found the heaters, tested them and the rest just follows the pinout on the board.  No sockets work for these as they were intended to be soldered in. 
 
The switcher is off Taobao but a linear supply would be even better.  This one was just bought for the hell of it and it was less than 10$ shipped to me. 
 
It's been tested and it works but I'm waiting for my chassis to arrive for some more complete testing.    Here it is on a temporary testing setup:
 

 
One thing I might do is use that layout to make balanced GES.  Just need to replace the "sockets" and make some caps and resistors bigger and voila... instant GES. 

 

[ericfarrell85]

Anyone know where to purchase an SR009 under $4000 usd without backorder issues? The price is great at pricejapan, but they're back ordered for several months.

 

[jcx]

Justin, other dealers with stock probably paid more wholesale than current priceJapan since the currency drop
 
even in the forsale forum people are asking more for used than the priceJapan prices for top Stax new

 

[SoupRKnowva]

Quote:

Justin, other dealers with stock probably paid more wholesale than current priceJapan since the currency drop
 
even in the forsale forum people are asking more for used than the priceJapan prices for top Stax new

 
Exactly, if you want to get one for 3500 brand new, you have to just wait for price japan. Thats what ive resigned myself too.

 

[davidsh]

I dont understand how they can do it so cheap?

 

[pschelbert]

Hi
 
I just opened and removed the fuse-board.
I discovered that on metal-bar 2 and 5 there is no wire soldered to...
 
I think I have to go deeper.
 
Helpful if I would know about the windings on the primary side:
 
There are the following wire-colors, from left to right (see picture):
 
a) yellow
b) white
c) green
d) no wire attached to the copper-color wire coming out of transformer
e) grey
f) brown
g) no wire attached to the copper-color wire coming out of transformer
 
would be helpful to have a schematic.
 
I read there are two 0-100V-110V windings. Which colors are what?
 
Peter

 

[Solude]

Quote:

I dont understand how they can do it so cheap?

 
Actually $3400 to your door right now and that's what happens when you cut out the middle man

 

[davidsh]

They also delivers to shops and such? Too bad it wouldn't be worth while considering the taxes...

 

[Solude]

You don't pay taxes on local buys?

 

[davidsh]

Quote:

You don't pay taxes on local buys?

Right about that. And the holiday goes to... Japan! 

 
Just found that Slayer's south of heaven (the album) doesn't sound bad on my Stax. Actaully it sounds surprisingly good, most metal sound quite bad or mediocre from my experience.

 

[DefQon]

Quote:

Nothing good comes to mind.  If the transistors are shot then the odds of finding replacements are pretty much zero. 

I know aye. Even no luck with ebay for the specific transistors I may be after if they are the culprit. I found one supplier online who has limited quantities and have shot them an email inquiry regards about it, fingers crossed they will give me a positive "ok, all good" response.
 
Ok I've done some measuring across the parts that could end up being a culprit. I've even ordered extra 470kohm 5% 1/2watt carbon resistors off RS last night as one of the resistors on the PCB, I've accidentally scratched off the coating and then applied black nail polish to protect it but I'm not sure if that was a good thing to do. 
 
Apart from what looks to be power diodes near the coupling ceramic caps in between the two 350v 47uf ELNA caps could also possibly be the problem? I haven't measured the 4 diodes but I did find one weird thing when I measured those ELNA 350v caps.
 
One of the cap's measure 0vdc on the negative pole, approx 315-320vdc on the positive pole. But the other ELNA cap (as seen in the pictures) next to the white 600v+ bias wire connecting to the copper bridge, the neg pole measures 315-320vdc (shouldn't it be 0?) and the positive pole measures 620-630vdc. The cap does not emit burnt smell or hot temperature or so.
 
The first two bolted down transistors also measure half of 600vdc when measured underneath the PCB directly on the soldered points and the last two transistors next to the ELNA cap's measure 620-630vdc on top and bottom.
 
 
Enough yapping from me, here are some pics.
 

 

 
 
Quote:

Hi
 
I just opened and removed the fuse-board.
I discovered that on metal-bar 2 and 5 there is no wire soldered to...
 
I think I have to go deeper.
 
Helpful if I would know about the windings on the primary side:
 
There are the following wire-colors, from left to right (see picture):
 
a) yellow
b) white
c) green
d) no wire attached to the copper-color wire coming out of transformer
e) grey
f) brown
g) no wire attached to the copper-color wire coming out of transformer
 
would be helpful to have a schematic.
 
I read there are two 0-100V-110V windings. Which colors are what?
 
Peter

Post a picture, you might need to solder a wire as Stax might've ripped them out for a complicated voltage conversion.
 
Quote:

They also delivers to shops and such? Too bad it wouldn't be worth while considering the taxes...

Sucks to be you due to the Euro import tax. 

 

[jjinh]

Quote:

They also delivers to shops and such? Too bad it wouldn't be worth while considering the taxes...

 
What happens if they misquote the purchase price of the headphones on the package? For imports into Australia if the seller hypothetically puts a value less than AUD1000 on the package customs ignores it (meaning no taxes are payable).