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Stax SRA-14S pictures


Quad
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Finally I was able to acquire an SRA-14S and it has arrived now!

No phono equalizer modules however.

A previous owner had been cutting copper tracks on the input/switching pcb and added a lot of wires (in different places than the cut traces).

Neatly done, but still....

Maybe he had some problem with the switches?

So restauration will be a major undertaking without documentation.

Can anyone help me with the service manual and/or schematic diagrams? That would be highly appreciated.

Paper copy or electronic, everything is welcome.

The headphone amp looks at first glance like the circuitry of the SRM-1 (of which I also have no service manual), but the power supply looks a lot better. A vastly larger transformer of much better quality than usual for Stax. So it may even sound a bit better.

I switched it on briefly and it sounds very promising.

This is the version which has the power supply built-in.

Previously I did not know that this existed, but it turns out to be completely original!

It uses the same components as otherwise in the external power unit.

Much more convenient this way! The transformer has a specially wound core, so the stray field could be low enough for this.

If there is any interest, I can post some pictures of the innards.

Thanks in advance for any help with the service manual!

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Hi Spritzer,

Here they come.

The IS amplifier is on a separate board, with somewhat lower gain than the SRA-12S. That is a good thing. Less noise also.

The gain without the IS is sufficient though (as is the case with the SRA-12S, i.e. 60dB), and then there is no audible noise at all.

All switches are connected by flat bowden cables to the front. Not easy to service this way.

Do you happen to know any reports about bad switches? It is not (yet) clear to me why there are so many cut traces and added bridge/jumper wires on one of the switch-boards. (Maybe on the other switch-board too, I have not yet looked at the copper side)

Also one of the HV electrolytic capacitors is missing, but the missing one has been paralleled with the one next to it.

It has a very small hum which strangely enough disappears when I engage the IS.... So I suspect it is caused by the changed boards.

The tracks have been removed very neatly, so it is barely visible where the original traces have been.

With a circuit diagram and a pcb drawing things would be a lot easier to follow.

All I have so far is the instruction (= user) manual. Nice to have though.

Well, so far I am happy with my SRA-14S, and I hope that a service manual and some input modules will turn up somewhere. Then there will be a full restauration. For now I will leave the SRA-14S as it is.

Best wishes.

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The only Stax gear to use those switches in bulk were the preamps and they are rarely talked about so data is limited. They were also used in the SRM-T1W and I haven't heard of any issues.

If this amp has no serial number then it could also be a late prototype and/or very early production model since AFAIK, the SRA-14S should have an external PSU.

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Yes, that is also what I have always assumed.

Thanks for the information on the switches.

No s/n, but the sticker or plate could have been removed someday.

Even at a prototype you would expect some indication.

Since I never saw pictures of an SRA-14S with internal power supply, there is very little to compare to.

There is no text "Serial No._____" on the back, like on the "standard" version.

Although I knew on beforehand that there was no s/n on it, I still bought it.

Always wanted to have an SRA-12S and an SRA-14S.....

Well, I have both now ;)

As soon (or not soon....) as I have more technical info I could start with the restauration process.

By the way, the internal mains wiring looks original, so indeed it could very well be a kind of protoype.

There should be some more around, but maybe only in Japan.

The 2 little "handle-bars" on the bottom side of the front panel are missing. It is not to disturbing though.

The seller will try to bring me in contact with the previous owner of whom he seems to have bought it about 3 years ago on Ebay.

With some luck it might be possible to follow part of the history back.

I find that always nice to know.

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  • 2 weeks later...

Hello. I'm new to this forum, but I wanted to comment on your posts regarding the Stax SRA-14S. I happen to be the proud owner of 2 of these very cool units. I purchased them as NOS a few of years ago from a dealer friend of mine on the West Coast. I too found a problem getting a hold of a service manual for this model. However, I did previously communicate with the STAX US distributor, Yama's Enterprises, and they indicated that they could indeed repair this model, if necessary, but would not or could not supply me with a service manual. As you're probably aware, this model was made during a tough financial period for Stax. Very few were made, which of course accounts for their rarity. I'm using one of mine with the Stax model SR-404 ear speakers and I love the combination. As you know, there were 3 phono cartridge modules that were made to be used in this unit. One was for MM cartridges and one was for MC cartridges. The third one was made to be used with their own model CP-Y cartridge. Needless to say, when plugged into one of the 2 slots on the rear of the SRA-14S, the idea is to utilize its power supply. You make mention of an outboard power supply. I did not realize that the SRA-14S would actually work without the outboard power supply. Yours is the only one I

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Hello htless,

Thank you for your additional information and your photos !

All very interesting stuff.

The PS-3 power is made specifically to use as a phono pre-amp unit with one of the available SRA-14S cartridge modules as a head-amp for one of the SRM-amplifiers.

This way you could create a (I presume very high quality) phono input on a line-only amplifier.

Probably a good way for Stax to sell the separate modules.

The PS-3 cost about a quarter of a complete SRA-14S in Japan.

All pictures I have seen so far from an SRA-14S are with an outboard dedicated power supply unit.

Mine could very well be an early (or late??) model model for other uses than the consumer market or perhaps it is a kind of pre-series or prototype. Never seen one like this, so without more information it remains just guessing.

I would be very interested however in some good resolution internal photo's both of one of your your SRA-14S and of the SRA-14S power supply unit (or of both, if there are any (small) differences).

That way I can ascertain that the built-in power supply is made of exactly the same components, which I guess it is.

And some (large) electrolytics have been replaced in my unit, so it would be nice to see their original value.

It would also be nice to see how things are arranged internally in the SRA-14S when the power supply is separate.

Thanks again!

Some day I hope to get hold of some service info on the SRA-14S....

Best wishes.

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I just looked at all my pics of SRA-14S amps and sorry, no detailed internal pics. It did how ever confirm my believe that your particular amp is a prototype as it lacks all the ususal markings found on all Stax amps such as the full company name, input voltage and Made in Japan.

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My pleasure!! I hope it helped a little bit. Unfortunately, I don't have any pictures of the inside of my units. My son, who lives in California, took the great pictures of the PS-3 for me early last year. He'll be back here in a couple of months and I'll ask him to take some pictures then. However, I did find this cool web link to a page in Japan that has quite a number of pictures of the inside of the SRA-14S and the power supply. Maybe these will help you somewhat. Check it out at:

[url=http://earsp.web.fc2.com/kako-d/sra-14s/sra14s.htm]STAX

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I just looked at all my pics of SRA-14S amps and sorry, no detailed internal pics. It did how ever confirm my believe that your particular amp is a prototype as it lacks all the ususal markings found on all Stax amps such as the full company name, input voltage and Made in Japan.

Hi Birgir,

Yes, somehow I feel that you are (again) right. Onto the other Stax equipment the usual text is screenprinted. Nothing on this one however...

Thanks again.

He'll be back here in a couple of months and I'll ask him to take some pictures then.

Hello htless,

Thanks. That would be appreciated.

And yes I had found this japanese site some time ago. No detailed pics of the SRA-14S.

They also have a section with brochures/user manuals. The links to the brochure of the SRA-14S (2 pages) do not work....

Maybe someone has an original brochure of the SRA-14S. A copy or high-Q scan would not go amiss :)

I would not even say no to an original one :P

Let's hope the service manual and one or two of the equalizer-modules come my way someday.

Thanks for your contributions.

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Are those internal pictures of the SRA-14S and the power supply on that site not detailed enough for you to find what you're looking for? They appear to be more detailed than anything I've ever seen, with regards to the model & PS. If not, I'll have my son attempt to get more close-up pictures when he comes home.

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Hi htless,

Some more detailed ones would be helpful.

Would it also be possible to get some high resolution pics of the EMM-1 -module? top and bottom and some at an angle to see the components and mechanical construction better?

Maybe some day I will try to rebuild it..... if I can get enough info on it, that is.

And I will try to make a JB-1 (line level input) module. Just to have a nice view at the back of the SRA-14S, and see the appropriate led light up on at the front panel.....

Thanks.

best wishes

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  • 9 months later...

Hello again. If anyone is interested, I am going to be selling my two model SRA-14S preamp/earspeaker amplifiers in the next week or two. One of them is a solid 9 out of 10 and the other would easily be a 7.5 or 8, because of a few VERY minor marks, but nothing major. I will also be selling one new/unused Stax model EMM-1 moving magnet phono card, 2 pair of Stax SR-404 earpeakers (1 new pair, 1 pair used, but a solid 9.5), and two Stax SRE-725 extension cables ( agian, 1 new and 1 used, but a solid 9.5). I thought I would make you folks aware of these being for sale, before I place them on Audiogon. Please let me know if anyone is interested. BTW, I will pay for FedEx Ground shipping and insurance for any of the lower 48 states and I will cover the PayPal fees, if that's how you would like to pay for your purchases.

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Hello Georg,

Unfortunately, I do not have any pictures of my particular units, but I can guarantee that the description of my units is accurate. If you want to check my honesty, please go to the Audiogon website and look me up under my member name, htless. Here is the link to that website: AudiogoN high-end Audio for sale, high end HiFi classifieds, audiophile auctions, audio forums . I am going to be asking $600 USD for this unit and slightly more for the other one. The unit you are interested in has no actual scratches, just some superficial marks here and there, but they do not actually take away from the beauty of this unit. Also, I would be shipping this unit in its' orginal box and packing. I would consider shipping to Germany, but I would have to check out what the costs would be and then let you know how much additionally that would cost you. If you are interested, let me know and I will look into that.

Stephen

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  • 4 months later...

Hello Quad,

I'm a little late to the party (by over a year!), but I do have a lot of technical information on the SRA14S and other Stax products.

If you are still interested, let me know.

Best regards,

Linear

Some day I hope to get hold of some service info on the SRA-14S....

Best wishes.

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  • 1 year later...

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