The Headcase Stax thread

[spritzer]

I listened to KS once and I didn't like its bass either.  I bet if you take out all the damping material and give it a lot more open area at the back, the sound will be very different in a pleasant way.  

 

That is the plan.  I'll play with the amp a bit too but it's just bound for a nice rebuild. 

[spritzer]

First step in fixing the KingSound:

 

http://i.imgur.com/7zvcu6C.jpg

 

Unmasks other issues though...

[Torpedo]

The putty ring around the driver is your addition too or just the thin plastic film for dust protection?

[spritzer]

Ahh yes, me failing at putting things into perspective...

 

 

Here is how they look when opened.  The earpads just twist off counter clockwise and there are four screws to undo.  The screens are stock and also the only dust covers.  Seriously, the drivers Wachara is making are far superior to this stuff.... 

 

 

Here is the side that faces the ear.  These drivers are beyond cheap to make.  I also see no markings that point to matching them....

 

 

This shows the entire assembly.  The rings that seals the baffles looks to be cut by hand.

 

 

 

Here is the mod again, creating a seal so the rest of the housing is taken out of the equation.  The change is far from subtle, the whole spectrum is much more linear now but it does unearth smaller issues.  The biggest are the earpads as they are just idiotic.  Too big and nothing in the way of accommodating the shape of the head so they leak and there is some reverb too

 

So here is a question, what 110mm (11cm) earpads are there out there that I could try?  Pleather/leather and the smaller the opening, the better.  Thinner is also better.   

Edited August 30, 2013 by spritzer

[chinsettawong]

Those black foams inside the cup are indeed not a good idea.  Over time they'll deteriorate and become dust.  

 

Birgir, what material do you think the stators and spacers are made of?  

Edited August 31, 2013 by chinsettawong

[spritzer]

They are made of FR4 or something similar.  Nice enough but a far cry from the SR-007 drivers.  They are all glued together so it's hard to get a look at the stators... 

 

That foam is going into the bin and I'll probably coat the back with dynamat.  The plastic is truly nasty though so I wonder if it will have much, if any effect. 

 

The next big change will be the earpads.  Looks like the Denon D500 pads might fit but I'll have to do some more research. 

[RudeWolf]

Never thought I'd see this... Stax on Massdrop.

[chinsettawong]

Hi Birgir,

 

I've been thinking of the back wave blocking issue with KS phones.  Do you think that it's possible from the way they put the dust covers on?  From my experience, the dust cover on the back side of the driver affects the sound quite a bit.  If not done right, it's better not to have it.  I personally don't like to put it on. 

 

Wachara C.

[spritzer]

Well the dust cover is stretched tight onto the back grill so it's not helping matters.  It's needs to be thin and wrinkled to work properly and right next to the driver. 

[chinsettawong]

Right!  Tight dust cover can be a problem.

 

Wachara C.

[spritzer]

They sound ok now and I think new pads might turn them into something good.  Running them right now off this 007tA that is just now running 6S4A's and it sounds very nice indeed. 

 

One thing that has come up are the bias issues.  I don't doubt that these were designed for 450V as they really don't like Pro bias after a while.  This is just off the KingSound amp though as it runs just fine off both Stax and our DIY amps.  I think it has to do with the PSU in the M-10 as it is just fucked.  They pop like mad when I turn it off... 

[kevin gilmore]

sure because as soon as the amps turn off, the bias heads to the equivalent of about 900 volts

as the output caps discharge. that power supply is a real piece of work.

[spritzer]

Truly not sure how to fix this as there is no space to work with or any good through hole pads.  A first glance I thought they had stacked two 300V supplies as that would make perfect sense.  Then I saw it had just two diodes... 

[insanity]

Ok guys I hope this is the correct thread to post this:

 

Today I did a little for fun A/Bing with the Stax srm 727/sr 009 vs B22/Beyer T1 with the Ressonessence Invicta as a DAC. It is a single ended setup for the T1, where as the Stax is fully balanced. Although these setups have quite some differences in sound, to my surprise, I am not yet sure which I would consider the better combo (I expected this to be clearly in favor of the sr009). Although the stax naturally has a bit more detail, speed and a wider soundstage, I think the T1 combo is more euphonic and has more presence. With the Stax setup I often tend to turn up the volume to achieve that "presence" I like fro the T1. But then, I think especially the higher mids get too loud and it's still not where I want it. When comparing, I think I can clearly hear the deficiencies of the SRM727 as described in the sr009 review at innerfidelity. 

Therefore I am really looking forward to trying out the KGSSHV which I am currently building! I think it will be in ready for a first test in 2 weeks. I will probably try the spritzer mod for the 727 once i get the kgsshv running, but hopefully this will not be necessary because the kgsshv is sooo gooood 

 

Anyone else with similar experiences?

[n3rdling]

from my experiences the T1 is awful

[shellylh]

T1 = blech and I can't imagine that the B22 would help.

 

I've only heard the SR-009 with the KGSS but it was fantastic.  Remember to clean out your ears before listening to gear. 

[spritzer]

T1 is just mehhhh.  Not good... not bad... it just sits there but not in a good way. 

 

The 727 is not doing the 009 any favors though.  Pretty much the same as the steaming pile of fail on the top of the rack here...

 

 

So when I'll make it useable, should I change the color of the power button and the knob?  I'm thinking silver with amber led's... 

 

Frank Zappa - Dinah-Moe-Humm is utterly unlistenable on bass light transducers. Nothing but out of control bass...

Edited September 19, 2013 by spritzer

[s_r]

Are you going to post schematics & some measurements for the LL once all is said & done?

 

Also, silver & amber sounds like a good idea to me.

[eggil]

Your KGSS looks so much better than the Cavalli.

[DefQon]

Anyone here have the schematics to the SRM-1 amp? I do wonder what Stax headphone Stax originally sold it with the SRM-1 amp. I know the SRM1 MK2 and SRD-7sbmk2 was sold with the Lambda Pro's, SRD-(n) energizers with the other SR-(n) headphones, but I wonder what the original earspeaker was sold with the Mk1's as a complete package.

 

@Spritzer: What diodes did you replace the originals ones in your SRA-3S rebuild? Can the 1N4007 be a suitable drop in replacement? It is nearby 4x0.47uf 600v Toshie axial supply caps besides the two dual section 350v ELNA's .

[spritzer]

Are you going to post schematics & some measurements for the LL once all is said & done?

 

Also, silver & amber sounds like a good idea to me.

 

The schematics will be posted and some measurements but don't expect some fancy AP graphs like the one on the Cavalli site which break the laws of physics.  One thing off the top of my head, the PSU has 20 times the noise of the KGSSHV unit and drifts all over the place.  That's the good part of the amp though... 

 

 

I was changing the amp to 230V yesterday and decided that horrible knob had to go.  That one I got from Justin... 

 

I do think that this issue deserves a new thread so I'll probably start one later.  I'll also include new impressions based on some time with the Omegas, SR-X Mk3 Pro and the SR-003.  The last one was not a pleasant experience.  The output capacitance of the amp is roughly 7 times that of the headphones. 

 

Edit:  I've also found one major safety issue with the LL.  Complete fuckup and goes to show how clueless these idiots are.  Think ballast resistors rated at max 250V running at 600V.  Under normal conditions this isn't a problem due to the open circuit but if the bias shorts to anywhere this is your only safety mechanism.  Also, no output resistors on the amplifier.  Not a good idea... 

 

Your KGSS looks so much better than the Cavalli.

 

 

 

Anyone here have the schematics to the SRM-1 amp? I do wonder what Stax headphone Stax originally sold it with the SRM-1 amp. I know the SRM1 MK2 and SRD-7sbmk2 was sold with the Lambda Pro's, SRD-(n) energizers with the other SR-(n) headphones, but I wonder what the original earspeaker was sold with the Mk1's as a complete package.

 

@Spritzer: What diodes did you replace the originals ones in your SRA-3S rebuild? Can the 1N4007 be a suitable drop in replacement? It is nearby 4x0.47uf 600v Toshie axial supply caps besides the two dual section 350v ELNA's .

 

 

I never bothered to draw it up but this is what it looks like:

 

http://www.op316.com/tubes/schema/image/stax-srm1.jpg

 

Just fill in the values. 

 

Stax never did packages back in the day.  Some distributor may have bundled something together but the first official combo was the SR-5NB/SRD-7Mk2 in a cheap plastic container. 

 

1N4007 works just fine, nothing eating up 1A of current in there.  I would double up for a full bridge but that is optional. 

 

Those are the output caps btw. and I always replace them. 

 

In vintage Stax news I bought that SRA-7S in Japan.  A lot work to repair it but a perfect match for my SR-1's. 

Edited September 21, 2013 by spritzer

[DefQon]

 

I never bothered to draw it up but this is what it looks like:

 

http://www.op316.com/tubes/schema/image/stax-srm1.jpg

 

Just fill in the values. 

 

Stax never did packages back in the day.  Some distributor may have bundled something together but the first official combo was the SR-5NB/SRD-7Mk2 in a cheap plastic container. 

 

1N4007 works just fine, nothing eating up 1A of current in there.  I would double up for a full bridge but that is optional. 

 

Those are the output caps btw. and I always replace them. 

 

In vintage Stax news I bought that SRA-7S in Japan.  A lot work to repair it but a perfect match for my SR-1's. 

 

Holy shit thanks man.

 

SRA-7S? Wow didn't think there was one, going to post some pictures? Didn't see anything on YJ if that's where you got it from. 

 

EDIT: Just thinking of something else now any possibility of ECC99's in the 3S with/without extensive mods, like the T1?

 

Also just read what you've posted on the other site, I haven't had a proper look at the circuit but where should the output resistors go for safety sake?

Edited September 21, 2013 by DefQon

[insanity]

I just noticed that I am a retard   .

 

I had the input switch on the srm 727 set to rca although I was using xlr... Now it sounds quite a bit better!

 

Anyway, I am still looking forward to my kgsshv. Too bad constructing toroids takes some time...

[spritzer]

Holy shit thanks man.

 

SRA-7S? Wow didn't think there was one, going to post some pictures? Didn't see anything on YJ if that's where you got it from. 

 

EDIT: Just thinking of something else now any possibility of ECC99's in the 3S with/without extensive mods, like the T1?

 

Also just read what you've posted on the other site, I haven't had a proper look at the circuit but where should the output resistors go for safety sake?

 

It was on Y!JP but you have to know where to look. 

 

No way that the transformer would survive driving the ECC99's.  It's run on the edge as it is. 

 

You can put the output resistors directly on the socket.  They are simply there to limit the output voltage should any of them short to ground. 

[n3rdling]

I thought they're there to limit current to the stators?