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Vintage Stax repair and maintenance

post #1 of 165
Thread Starter 

Hi guys,

 

For those of us owning Vintage Stax gears from the 60s/70s/80s...

Or for those of us about to buy Stax gears that have been in a closet for 30 years...

 

What can go wrong with old Stax gears ?

How to identify well known problems ?

What can be fixed/maintained by the average guy ?

How to know when it's time to send them back to Stax support ?

What's the life expectancy of vintage earphones/energizers ?

 

I'm actually shopping for a used Stax system and I wonder if it's wise to buy old gears that may be about to die or unmaintainable.

 

Any hint or answer will be welcome.

 

Thanl you,


Edited by Headdie - 2/21/12 at 5:11pm
post #2 of 165

The problem with stax comes down to decaying foam and driver problems. If the dust gets into the drivers- expect bad things to happen.

High humidity is an issue too. But a lot of units last a long time with some care. I've got a pair of sr-40's (35 years old) that work fine.

As far as the electronics go, cap replacement and cleaning controls seem to be common. A used srm-1 mkII that's been re-capped and cleaned

should run for years more. An adapter like a srd-7 seems to run forever without any real problems.

I recapped my srm1 mkII myself. Not too hard to do with some basic skills. I'm old and half blind, so it came down to wearing those

flip down head visors with lenses to see what I was doing. You young guys shouldn't have any problems.

 

post #3 of 165

Hi

Ive just received my 1st venture into Stax and electret/electrostatic  Stax sr-80 pro and an SRD 4 adapter.

This combo is refered to an sr84 (1984)  I hope I have collected that info correctly

 

My 'earspeakers' have a huge imbalance 85% left and 15% right.  Im pretty sure its not the adapter at fault having tested both left and right outputs with the good left channel and vice verser.  SO definatley the right earspeaker at fault.

I have learned so far that this is not an un-usual fault over time (30 years or so) as the micro measurments of these devices are suseptible to dust. 

Like you I am not an expert at all but thought I might let you know what I have learned in the last week or so. 

Inside my earcups it appears that componets have been removed from the wiring, and then cut and shut back together,  either Ive been ripped off or this is a common modification, with a view to regaining the balance.  Im not sure but I have viewed around 8 different photos online and they all have 2 components per ear hidden in the earcup.  Diodes I think? 

Im putting off doing a continuity test as I dont have access to exposed wires at the earspeaker end and would rather not start hacking away at the insulation until someone can offer a miracle cure..(I can hope) 

I did a continuity check with the pins after reading an article and they are all open circuit as they should be.

Many thanks and good luck with research

 

 

 

post #4 of 165
Thread Starter 

Thank you both for the feedback.

 

The energizers run forever and the amplifiers can be cleaned and recapped...

 

So I understand that the earphones are the weaker link. Foam decays and dust gets in the drivers...

 

Fixing/replacing pads should not be a problem for me. But what about opening the cups to clean the drivers and replace the foam inside ?

 

Are the old sr-40 and sr-80 easy to open for cleaning and maintenance ?


Edited by Headdie - 1/7/12 at 7:42am
post #5 of 165

I haven't tried to open a set of sr-40. They work great, and all I would do is cause a problem. The real trick is to find a good set, then take care of them.

post #6 of 165
Thread Starter 

Buntudor,

 

I have an opportunity on a SR-84 system : sr-80 / srd-4.

 

The guy ask 250$ telling me that it's mint.

 

I'll meet him and listen to his Stax system.

 

Is there something that I should check to make sure everything's perfect ?

 

Thanks,

post #7 of 165
Quote:
Originally Posted by Headdie View Post

Buntudor,

 

I have an opportunity on a SR-84 system : sr-80 / srd-4.

 

The guy ask 250$ telling me that it's mint.

 

I'll meet him and listen to his Stax system.

 

Is there something that I should check to make sure everything's perfect ?

 

Thanks,



WOW - way overpriced.  Last set I bought was well under $100.00 (closer to $75.00)

 

post #8 of 165
Thread Starter 

Ok, I finally got SR-X Mk3 / SRD-7.

 

Do you know if some Stax earphones of that time share the same parts ?

 

I think I'll have to replace some parts on the Mk3, so I wonder which models I could hunt for parts...

post #9 of 165
Thread Starter 

Hi guys,

 

Actually, there's a severe lack of bass coming from my SR-X Mk3 and/or SRD-7. I understand that bass is not a strength of the SR-X, but this is clearly anormal.

 

The earpads are dead, so I'll try to prototype a new pair and get a proper seal, just to know if it's the cause.

 

That being said, what else could be the cause ? Could it be from the SRD-7 ? I assume it's undestructible, but I may be mistaken...

 

Any help would be welcome.

 

Thanks in advance,

 

Headdie

post #10 of 165

Let them charge for a few days.

post #11 of 165
I might hit these up myself...

http://www.audiocubes2.com/brand/Stax/product/Stax_Replacement_Pads_for_SR-X_MKIII_Earspeakers.html

P.S.-just ordered,will follow up.
Edited by 5aces - 1/26/12 at 6:34pm
post #12 of 165
Thread Starter 


They've begun to improve after a day of charge... I'd like to think they are charging :-)

 

Could someone explain simply what happen inside ? Same kind of magic I guess...

 

Thanks,

 

Quote:
Originally Posted by kevin gilmore View Post

Let them charge for a few days.



 

post #13 of 165

The diaphragm coating on these sets doesn't age well and contacts corrode which adds considerable resistance to the system. 

post #14 of 165

The coating on the diaphragm deteriorates over time.  And the resistance on the diaphragm surface becomes much higher than what it used to be.  Therefore, it takes a lot longer time to charge up.  If you can, just keep it charged at all time.

 

Wachara C.

post #15 of 165
Thread Starter 

Well understood, thank you !

 

It may be a stupid question, but does it mean I should stay with the SRD-7 non SB version ? This way, I could keep them on charge, without my NAD turned on...

 

BTW, I guess they're even better after two days on charge.

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