[Chops]

I just found these today after doing a little cleaning up around the house. Honestly, I thought that these were long gone years ago, but apparently not. The "box" must still be around somewhere also. I'll have to look for it one of these days.

My father bought these cans years and years ago brand new, probably before I was born (1975). He recalls them as sounding pretty good and that they still worked when he last used them, also years and years ago.

I have never known these cans to work. I remember as a kid trying to hook them up to my stereo with the "box" that came with it. You had to wire it up to the speaker outputs of your amp/reciever. I could never get the things to work. I may not have been doing something right, or it wasn't getting power to it or something.

I would really like to try these cans out. They're quite heavy, but also quite comfy feeling as well, surprisingly enough!

Anyway, these are my questions...

1) Are these things worth trying out at all?
2) Does anyone know how they might sound if they are still functional?
3) Is there anyway of testing them with a multimeter?
4) Would these be wired the same way and be able to be used on current amplifiers designed for electrostats?
5) Does anyone here know anything at all about these particular cans, especially the specs?

Thanks in advance!

And now, some quality pics for your enjoyment and/or help...

 

[Duggeh]

Looks like a repackaged Koss ESP9, except with a Stax type plug on it. I wouldnt plug it into a stax amp though, the bias voltage is certain to be too high. Have you any manuals or anything?

 

[wualta]

They're Radio Shack's Realistic HP-100, based on Stax's SR-3. Even though they're 1969 tech, they sound pretty dang good, especially with some judicious EQ. If they've been lying unused for decades, as many have, they'll need to sit connected to their adapter box for about a half hour before they'll make any sound. You don't have to connect them to an amp, just the adapter box, and make sure the box is both plugged in to an AC outlet and switched to PHONES. Overnight and they'll sound even better. Channel imbalance will also even out overnight.

They may have been OEM'd by Stax, but they will not operate from any Stax equipment, even though they will plug in.

If you're used to the sometimes bright sound of modern 'stats, you'll be surprised at how mellow these are. State of the art? No. But good.



.

 

[Chops]

Oh yeah, I forgot to mention that I knew they were Rat Shack models.

At least now I know why these probably didn't make any noise when I hooked them up years ago. I didn't know they needed to "charge up" so to speak before they would operate. Now I really do need to find that darn box!

BTW, does it matter what kind of amp/receiver I use to run these with? Just asking because I have an old late 80's Pioneer receiver that puts out 100 watts per channel which has a very clean and smooth sound to it.

Now where the heck is that box?!?!

 

[wualta]

Yep, gotta have the box. And the Pioneer should do just fine.

.

 

[Duggeh]

If its based on the SR-3 and has the 6 pin Stax plug, then I dont see any reason why it shouldnt run from a normal bias amp or energiser.

Better yet, rehouse the drivers in something a little nicer and lighter!

 

[Chops]

Thanks!

I have a feeling I'm going to be tearing apart a couple of closets in the near future!

Hey look, my 400th post! wow...

 

[smeggy]

Congrats on the find, I hope you find the energizer cos I imagine it'll be hard to get a replacement these days.

 

[Carl]

Quote:

Originally Posted by Duggeh /img/forum/go_quote.gif If its based on the SR-3 and has the 6 pin Stax plug, then I dont see any reason why it shouldnt run from a normal bias amp or energiser. Better yet, rehouse the drivers in something a little nicer and lighter!

The Realisitic 'stats have a different pin arrangement, IIRC, so can't be used with a conventional 230v-bias Stax amp/adaptor without a retermination/recable.

I've heard that the HP-100 is at least reasonably comfortable, so rehousing shouldn't be necessary.


Quote:

Originally Posted by Chops 1) Are these things worth trying out at all? 2) Does anyone know how they might sound if they are still functional? 3) Is there anyway of testing them with a multimeter? 4) Would these be wired the same way and be able to be used on current amplifiers designed for electrostats? 5) Does anyone here know anything at all about these particular cans, especially the specs?

Thanks for the lovely pics.

1) Yes. They're free, and if they do indeed work then it'll be quite a nice headphone for one that is free.
2) Pretty decent, but not of the calibre of a modern high-end headphone.
3) I believe you'd have to test it while hooked up to its transformer box.
4) The pinout is different, but otherwise they're pretty much the same deal as any Stax headphone with a 230v bias. A proper electrostatic headphone amp with a 230v output such as the Stax SRM-1 would most certainly drive them - and to respectable but not jaw dropping levels - if you sorted the cable out.
5) They were an OEM headphone made for Radio Shack by Stax in the mid 70s, using the original 8µm SR-3 driver. They should have similar specs to the SR-3.

 

[wualta]

Like Carl and I said, the HP-100 won't work from any Stax amp or box. Not a problem, since the HP-100 transformer box is Stax made too.

If worse comes to worst, the HP-100 isn't rare on That Auction Site. The Magnavox clone of the Realistic uses a different looking box but the same connector. There's also a Marantz clone, but I don't own one and don't know if it's the same connector as the HP-100.

Some things to look for in the closets:

 

[spritzer]

I own two Magnavox sets and while they aren't bad these are probably the worst stat I've ever heard. The design is horrible, way to much padding behind the driver and the driver isn't fixed in place so the sound is very colored.

I'm planning to modify one of my sets by fixing the driver to a rigid plate and using my old SR-007 earpads.

It's very easy to change them so they are compatible with the Stax standard plug. If you open the left housing you can switch the wires in the right order but you would of course have to do the same to the adapter and that requires totally ripping it apart and some desoldering.

BTW. The Magnavox has probably the worst product name in history, 1A9217...

 

[Chops]

Well, I went through one closet so far today durring lunch and no luck... yet!

I've got a couple other closets to go through and a few boxes elsewhere to check as well. I'm bound and determined to find that transformer box thingy. I want to see what these cans can do.

 

[Chops]

BTW, thank so far to you guys with all the great info! That's why I like this place so much!

 

[wualta]

Dang! If that xformer box doesn't show up soon, it might be best to just rewire the cable so the HP-100 will work with a Stax box. I believe the instructions to do just that are cached somewhere right here on HF.

 

[Chops]

Quote:

Originally Posted by wualta /img/forum/go_quote.gif Dang! If that xformer box doesn't show up soon, it might be best to just rewire the cable so the HP-100 will work with a Stax box. I believe the instructions to do just that are cached somewhere right here on HF.

Yes, but then the question is... How much does one of those Stax boxes go for? I'm almost afraid to ask.