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The Headcase Stax thread


thrice

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Justin, do you prefer it to the SRM1/MK2?

Never tried one. But it's really, really hard to make an electrostatic amp and sell it for less than $1k. And that would be the cheapest design possible but still with decent parts in a nice looking case. It's the custom high voltage power supply and the low quantities that kill it.

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Direct-coupled new Woo 'stat amp with 5-pin XLR for HE Audio eh1.2b sounds just..about.. :prettyprincess:

I am liking the 1.2Bs enough that I just might have to give them a socket on the BH. I really wish they would have replaced this crappy cable with a Stax in the first place.

Buffalo->BH->12.B= :prettyprincess:

So far I am really impressed with the 1.2Bs. Glad I hung in there. Time will tell how they hold up in the long run.

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Never tried one. But it's really, really hard to make an electrostatic amp and sell it for less than $1k. And that would be the cheapest design possible but still with decent parts in a nice looking case. It's the custom high voltage power supply and the low quantities that kill it.

Pity, there's no end of expensive/super expensive 'stat amps out there but very little for those of us on a tight budget, and realistically, who's gonna buy a BH to run Gammas, SR-X, SR-5 or lambdas. It makes no financial sense and all we're left with is not so hot Stax amps. That's why I use transformers. I sold my 313s because they aren't very good and there's a whole lot more lower end Stax phones than Omegas or 4070s.

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I am liking the 1.2Bs enough that I just might have to give them a socket on the BH. I really wish they would have replaced this crappy cable with a Stax in the first place.

Yeah, I would've bought one of the preview/beta 1.2B units at the introductory price if it had a Stax 5-pin plug

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This was bound to happen sooner or later. Somebody is using my pictures on ebay... :rant:

It's not possible to beat the Stax SRM-313 for the price

Ditto though the SRM-1/Mk2 is the best Stax amp bargain you'll ever find. The later versions are better and if a P.P. shows up, jump on it.

I am liking the 1.2Bs enough that I just might have to give them a socket on the BH. I really wish they would have replaced this crappy cable with a Stax in the first place.

Buffalo->BH->12.B= :prettyprincess:

So far I am really impressed with the 1.2Bs. Glad I hung in there. Time will tell how they hold up in the long run.

Glad to hear that you like them. It may be time to buy one now and use that black PC-OCC cable I've been saving for just that... :P Can you post some detailed pics of the back of the earcups to show how the cable attaches to the drivers?

Yeah, I would've bought one of the preview/beta 1.2B units at the introductory price if it had a Stax 5-pin plug

I'm sure Alex could recable one for you... ;)

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Everyone goes O2 eventually >:D

LIES!

Team Budget-Stat, Unite!

Seriously though, what needs to happen is to get enough of us together around a pretty straightforward SS design (maybe an adapted SRM-1) so that we can group buy the expensive stuff and save some $$. If I had any skills at pcb layout I'd have a go at it but alas, I'm a fish out of water when it comes to that.

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A Sigma went for pretty cheap on Ebay. I was so tempted :sadcat:

It was a Sigma that started my madness... :o

LIES!

Team Budget-Stat, Unite!

Seriously though, what needs to happen is to get enough of us together around a pretty straightforward SS design (maybe an adapted SRM-1) so that we can group buy the expensive stuff and save some $$. If I had any skills at pcb layout I'd have a go at it but alas, I'm a fish out of water when it comes to that.

The KGSS can be scaled up and down some what so a group buy of PCB's, parts, chassis and transformers might be a good idea. I sure would love to build a small one to use as a desktop amp.

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It was a Sigma that started my madness... :o

The KGSS can be scaled up and down some what so a group buy of PCB's, parts, chassis and transformers might be a good idea. I sure would love to build a small one to use as a desktop amp.

I know colin is looking at building a kgss, I will point him at this thread.

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I'm guessing that we'd need ~10 of us to make this work. And I'm not sure how I feel about making the chassis part of it, that tends to be a very individual selection and given the cost impact in both raw cost and shipping expenses I'd prefer to leave it out. About the KGSS, isn't there a parts availability problem with some of the parts involved?

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I'm guessing that we'd need ~10 of us to make this work. And I'm not sure how I feel about making the chassis part of it, that tends to be a very individual selection and given the cost impact in both raw cost and shipping expenses I'd prefer to leave it out. About the KGSS, isn't there a parts availability problem with some of the parts involved?

I think that is just for the current sources for the BH.

edit nevermind the 2SK389 might be short supply. And it uses the 2SA1968 as well :sadcat:

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About the KGSS, isn't there a parts availability problem with some of the parts involved?

The 2SK389 I believe. But you can substitute it with another part, can't remember which, I've got it written down somewhere, Justin knows of course and I'm sure Kevin knows as well. I was lucky enough to come across a place that still had 2SK389 in stock, but it took like 2 months for me to get them.

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Yeah, I would've bought one of the preview/beta 1.2B units at the introductory price if it had a Stax 5-pin plug

That's what we kept telling them, but for unclear (to me) reasons, they absolutely refuse to just go with the Stax plug. They would absolutely sell more that way..

Of course, all my complaints about that 5-pin XLR will go away if HE audio introduces a killer direct-coupled tube 'stat amp at a reasonable price with the XLR ;D

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Grawk did point me towards this thread, and it is true, I am gathering parts for my own KGSS build. The unavailability of the 2SK389 isn't a big deal for us, as we don't need a P-Channel equivalent. Linear Systems makes a part called LSK389 that is, in their words, an improved second source replacement for the 2SK389. Seems like a good part to me (only have used them once so far though), and that is what I will be using for my build. BDent has all of the other transistors needed, though I have decided to change up the voltage regulators to something that doesn't use the 2SA1968, as they are bloody expensive. Anyone building this amp based off the schematics on headwize be aware, the power supply, as currently drawn in the article library, has some dangerous problems with it. Last I checked, an 800vct transformer with a FWCT rectifier isn't safe to use with a 450v rated capacitor input filter. Right now, I plan to use R80-46 from diyclub.biz, a 100VA R-core transformer with 300v-0-300v at 80mA,0-6.3v at 2A, 0-18v*2 at 1.2A, and 0-12.6v at 1A. It is $35, and the shipping quote I got to the USA is $30. I am gonna try and shoehorn it into a 12"x8"x2.5" Par Metals case (Nate will recognize it I suspect). Undecided at this point about doing it on protoboard or making a PCB, but I am leaning towards PCB right now. Their boards arnt the best I have seen, but I could probably get a PCB for this for $50 shipped from Advanced Circuits, on the student discount. Gonna stick with board mounted heatsinks though, probably 2" tall SK129 profile. Volume control will almost certainly be a 50k Alps RK40, using a differential shunting configuration. Only part I am not sure about really is the headphone connector (this amp is for ESP950, though I may reterminate for stax).

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I'm guessing that we'd need ~10 of us to make this work. And I'm not sure how I feel about making the chassis part of it, that tends to be a very individual selection and given the cost impact in both raw cost and shipping expenses I'd prefer to leave it out. About the KGSS, isn't there a parts availability problem with some of the parts involved?

The chassis is a bit of a pain so that might be left out but a common FPE design for the front panel might be a good idea to fit some chassis.

I think that is just for the current sources for the BH.

edit nevermind the 2SK389 might be short supply. And it uses the 2SA1968 as well :sadcat:

The 2SK389 are a problem but can be substituted with MAT02's but the 2SA1968's a problem.

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The chassis is a bit of a pain so that might be left out but a common FPE design for the front panel might be a good idea to fit some chassis.

The 2SK389 are a problem but can be substituted with MAT02's but the 2SA1968's a problem.

For the case, the Nabu from Surplus Sales of Nebraska with a FPE panel would be a decent choice I think. MAT02 could work to replace the 2SK389, or the LSK389. 2SA1968 isnt difficult to find, just expensive. Check BDent, they have it in stock, and I have always had good luck with them before.

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I'm guessing that we'd need ~10 of us to make this work. And I'm not sure how I feel about making the chassis part of it, that tends to be a very individual selection and given the cost impact in both raw cost and shipping expenses I'd prefer to leave it out. About the KGSS, isn't there a parts availability problem with some of the parts involved?

I can easily be fooled into something like this.

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