[Carl]

Quote:

Originally Posted by Duggeh I was tempted to bid on those for possible staxification, but ive been saving my pennies for something even better...

Likewise.

So tell us, Duggeh, what are you planning.

 

[spritzer]

Well I might have time later for a proper worklog but the conversion is as follows


Earphones

Pull the earpad off the left earpiece and remove the 4 screws that are under it. Now pull the earpiece apart but watch out for the loose driver. Remove the foam to reveal the wires and swap the following wires:

Red -> Brown
Brown -> Green
Green -> Red

The red wire is covered by some plastic insulator, so cut that of and replace with some heatshrink.


Adaptor

Here you have to swap the wires that lead to the Stax connectors on a PCB marked "step up". You loose two screws on the bottom of the case and gently pull the board out of the case while being careful not to damage any off the wires. The wires are crimped to a connector that is in turn soldered to the board. It is easiest just to desolder these connectors, swap them in the right order and solder them back in place. Here are the wires that need changing. Leave the rest alone.

White -> Red
Red -> Blue
Blue -> White

Now your cheap and cheerful Magnavox 1A9217 is a real Stax phone. It is still badly designed and sounds like crap but they have huge mod potential.

I was also wondering if these could be turned into a pseudo Pro bias energizer by simply plugging them into 230v mains. I think the bias supply is simply a rectified voltage doubler that gives out a 230v bias with 117v input but 460v with a 230v input. I have NOT tested this but it could work…

 

[Carl]

Quote:

Originally Posted by spritzer I was also wandering if these could be turned into a pseudo Pro bias energizer by simply plugging the into 230v mains. I think the bias supply is simply a rectified voltage doubler that gives out a 230v bias with 117v input but 460v with a 230v input. I have NOT tested this but it could work…

You'd probably need to increase the spacer width in the drivers if you did that to prevent it arcing. Not exactly a sunday afternoon DIY project, but at least it's humanly possible...

 

[spritzer]

Well since my adaptor is now a normal Stax one I can just plug a pair of PRO stats into it. I will probably test it when I can fetch my second set of Magnavox phones from customs.

 

[Duggeh]

Quote:

Originally Posted by Carl Likewise. So tell us, Duggeh, what are you planning.

I bought the Ergo AMT.

 

[Carl]

Quote:

Originally Posted by Duggeh I bought the Ergo AMT.

Oooh, suits you sir!

 

[wualta]

Quote:

Originally Posted by Carl Oooh, suits you sir!

Well, you know him better than I do. Duggeh, you should know that ESS tried to sell an AMT headphone back in the '70s. I expect the one you bought comes with a nice EQ box that will give those poor Heils some bass. Report back immediately they arrive, soldier. Start a new thread.

 

[Jakke]

For the specially interrested: techsheet and usermanual.

 

[Carl]

Wow, that's cool.

The sheets don't list the polarising voltage. Well, I guess you could always ask Beyer themselves if you really wanted to know.

 

[Duggeh]

Quote:

Originally Posted by wualta Well, you know him better than I do. Duggeh, you should know that ESS tried to sell an AMT headphone back in the '70s. I expect the one you bought comes with a nice EQ box that will give those poor Heils some bass. Report back immediately they arrive, soldier. Start a new thread.

The amp is supposed to be equalised for the headphones yes, and i think this also applies for anythgin connected to the standard jack socket. So im looking forward to seeing how it pairs with my Floats.

Youll know about it when i get it.

 

[wualta]

Quote:

Originally Posted by Jakke For the specially interrested

Thank you, sir. Would we be correct in assuming the ET 1000's bias voltage was 300 volts, plus or minus 20?

Quote:

Originally Posted by Duggeh The amp is supposed to be equalised for the headphones yes, and i think this also applies for anything connected to the standard jack socket.

Ah, so it comes with a dedicated amplifier. I'll bet it's got a frequency response that looks like a backslash.

 

[Duggeh]

The frequency response could look like Richard Nixon for all I care, so long as they dont end up sounding like a can full of aids.

Only a few more days till Hirsch's magic parcel gets here and I find out.

300v on the beyers? Thats a lot less than other electrostatics isnt it? 500 for the HE90 and 580 for Pro-Stax?

 

[wualta]

Quote:

Originally Posted by Duggeh The frequency response could look like Richard Nixon for all I care..

Well, Richard Nixon's nose, yes. The reason I mentioned EQ at all is the '70s version of the Heil headphones had no EQ and they sounded great until you got below about 500 Hz and then they dropped like rocks. Weighed like rocks, too, since the nice little neodymium magnets hadn't been invented yet. Heil drivers, in other words, need lots and lots of help if they're expected to reproduce bass, so I'm going to be very interested to read how yours sound.

I don't know what aids sound like, in a can or out of it, but I'll bet it's no good at all.


Quote:

Originally Posted by Duggeh 300v on the beyers? Thats a lot less than other electrostatics isnt it?

Remember, the ET 1000 dates back to 1976. Everyone back then was using voltages that hovered around 300. I've never seen a 'phone from that era that used anything higher, but I'm open to the possibility. The era of the high-bias 'phone didn't start til 1983 or 1984 with the Stax Lambda Pro.

 

[Duggeh]

Quote:

Originally Posted by wualta Well, Richard Nixon's nose, yes.

Headroom has more than the nose it would seem.

 

[wualta]

[screams, faints]

[from floor]Oh, and big thanks to Spritzer for posting instructions for the conversion of the Staxclones to members of the Big Stax Family.[falls back]

[rises once more]Duggeh, wear those homemade K 1000s to the next audition of Pinafore. There's something nautical about them...[back down for good]