[Chazman]

Very different winding techniques and core materials used.  Electrostatic step up transformers are an even further twist on this as they have their own requirements. 

Hmmm sounds like a bit of mine field of actually getting the right bits. Annoyingly I know a bit of the theory of how all these bits and pieces work but its information like this that is the real difference between something technically working and sounding great - so again thanks.

Think I will concentrate on getting the mechanical side of the phones done and perhaps keep my open for parts to plunder from relative things like other energisers or phones....

Chaz

 

[chinsettawong]

Winding your own step up transformers is indeed very difficult.  It might be easier just to look for some used Stax units.  It's cheaper than building it yourself too, IMO.
 
Wachara C.

 

[Chazman]

Yeah I think that is what I will end up doing (or find a pair of Koss ESP-6's, which are pretty cheap and simple dimantle for parts).
 
At the moment there is a Stax SRD-7 (around $125 USD) and a Stax SRM - T1 (around $500-600 USD) on ebay at the moment, obviously I know they are very different things but do you reckon the T1 is worth the extra money in terms of quality I might be able to acheive from this as opposed to a good Amp and SRD-7 set up?

 

[chinsettawong]

Quote:

Yeah I think that is what I will end up doing (or find a pair of Koss ESP-6's, which are pretty cheap and simple dimantle for parts).
 
At the moment there is a Stax SRD-7 (around $125 USD) and a Stax SRM - T1 (around $500-600 USD) on ebay at the moment, obviously I know they are very different things but do you reckon the T1 is worth the extra money in terms of quality I might be able to acheive from this as opposed to a good Amp and SRD-7 set up?

The best person to answer your question is Spritzer. 

 
Wachara C.

 

[spritzer]

The Koss ESP6 transformers are not a good fit.  Too small and too high a ratio.  Get a SRD unit to try out as you can always get an amp later on. 

 

[Chazman]

Quote:

The Koss ESP6 transformers are not a good fit.  Too small and too high a ratio.  Get a SRD unit to try out as you can always get an amp later on. 

Good advice thanks, do you know what the step up ratio is on the Koss? I know there bias is about 320v which is a little low for this headphone.
 
Also take it I probably want to be aiming for using the Pro bias from the Stax to get the 600v range rather than 230v?
 
Chaz

 

[spritzer]

The Koss were 1:60 but they were meant to be used from a headphone socket and are also used to supply the bias voltage.  Another small bit, they need the extra ratio since the back stators are grounded due to the closed back design. 
 
It's easy to get 0.5mm spacers but 0.3mm is less so.  The higher bias has obvious performance advantages as well so I'd go with that. 

 

[hifi2all]

Hello
 
A question to discuss - is there any sence to expertise in a laboratory a broken Stax 007 membrane in order to determine the chemical composition of the original coating? ... may be it's known?

 

[chinsettawong]

Quote:

Hello
 
A question to discuss - is there any sence to expertise in a laboratory a broken Stax 007 membrane in order to determine the chemical composition of the original coating? ... may be it's known?

 
Nowadays, there are many coating materials that can work just as well as the one Stax is using.  I don't see a real need to do that.
 
Wachara C.

 

[Chazman]

Quote:

The Koss were 1:60 but they were meant to be used from a headphone socket and are also used to supply the bias voltage.  Another small bit, they need the extra ratio since the back stators are grounded due to the closed back design. 
 
It's easy to get 0.5mm spacers but 0.3mm is less so.  The higher bias has obvious performance advantages as well so I'd go with that. 

Spritzer, may I lay down my hat in honour of your exceptional knowledge of everything headphone

 
I would post a wanted out on the forum for something like the SRD-7 but I have not posted enough yet (couple more to go!) but if anyone knows of one that would like to sell I would be exceptionally interested please......
 
Quick question about the stators (possibly towards to Wachara C as I seen pics of his), is painting them essential to their operation / protection? Also I take it you make the coating very thin? Does it not get in the holes and reduce the open area?
 
Thanks,
 
Chaz

 

[chinsettawong]

Hi Chaz,
 
You don't have to coat your stators if you don't want to.  It doesn't really make any difference in sound whether you coat them or not.  The reason why I coat is that the acrylic paint helps me with squeal problem.  With the paint act as an insulator for stators, a little dust that might find it's way inside the driver is less likely to cause a short between the diaphragm and stators.
 
I usually spray only a few light layers of acrylic paint on the stators.  The paint is so thin that it doesn't reduce the open area, IMO.
 
Wachara C.

 

[Chazman]

Quote:

You don't have to coat your stators if you don't want to.  It doesn't really make any difference in sound whether you coat them or not.  The reason why I coat is that the acrylic paint helps me with squeal problem.  With the paint act as an insulator for stators, a little dust that might find it's way inside the driver is less likely to cause a short between the diaphragm and stators.
 
I usually spray only a few light layers of acrylic paint on the stators.  The paint is so thin that it doesn't reduce the open area, IMO.
 
Wachara C.

Ah right, well I plan to put a moisture protector (or whatever it is called) between the ear and the driver but guess dust can get in to the backside that is not covered. On the moisture protector, I was thinking of using some EPDM self adhesive foam and mount the 2um mylar to that, taught but not especially tight, I am thinking this might be quite good (if I can get it stablise and not just collapse when it is in place) as the slight amount of flex in the EPDM will seal the driver in nicely to the head and will allow the mylar to move a little thus reducing any colouration, what do you think?
 
Sorry another one while I think about it, I have some anti static wipes (computer monitor ones) that I was going to give a go on the mylar, an idea if these will be ok? I guess I am looking to get a resistance across the sheet of a few mega ohms? Do you find a difference in using the gel rather than just the soaked wipes?
 
Thanks,
 
Chaz

 

[chinsettawong]

It's only fun to try. Just go ahead and try whatever idea you have and let us know how it goes.

Wachara C.

 

[Chazman]

Oh just another quick clarity point is the coating purely to get a high resistance coating or are there other properties required from it?
 
Chaz

 

[spritzer]

The coating has to be highly resistive and also impervious to moisture in the air.  Being super light wieght is also a plus. 
 
About coating the stators, the HE90 clones Wachara made for me are now pretty much free of any noise after a good clean.  The Stax Omega drivers are all uncoated and I just cleaned up a SR-007 set that had seen better days.  All the dust covers were gone when they got here and it took some trial and error to clean them properly but it can be done.