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Grundig drivers, need enclosure suggestions

cubby01

cubby01

aka Buck
Hope someone has some knowledge of these. I was given them out of an early '60s Grundig tubed console (I think a Grundig Majestic, maybe 7048 model?). The woofers are oval, with frame dimensions of about 7" x 11". They have a tag on them that says:
7048-3
75-75 ABR8
5 ohm 6 watt
The red plastic magnet cover says "MagnetFabrik Dortmund". I have seen pictures of this woofer described as Telefunken and as Grundig.

The tweeters are electrostatic in a molded plastic. Center back has the Grundig trefoil logo molded in.

Anyway I think the woofers should sound pretty good and giving a test listen just hanging from a hook I think they are pretty high effeciency too. I need suggestions for an enclosure or baffle mount. Also are these best oriented vertically or horizontally?

I don't know anything about electrostatic tweeters. Do these need special transformer or wiring or do they hook up into a crossover just like any other tweeter?

Thanks all,
 

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When they were in the console the enclosure volume would have been pretty large and not sealed...more of an infinite baffle than an enclosure. You might try just mounting them to a reasonable sized baffle and see what you get.

Not too sure about your tweeters but if they are truly electrostatic they would need the proper power transformer.
 
Chazb11 said:
Not too sure about your tweeters but if they are truly electrostatic they would need the proper power transformer.
Click to expand...

I wondered about that. I suppose that info would be in a schematic if I can dig one up. .... :scratch2: might go back to see if any other parts from the console are still available.
 
From what I've been told, a lot of better German consoles of that era have electrostatic tweeters. I have a pair that came with my Blaupunkt, and there was no special power supply for them, just the receiver's output transformers.
 
open baffle all the way !

and actually, those oval German drivers barely need a tweeter . . .never measured one, but my Isophons (on open baffles) although 'beamy' play cymbals and other HF material without the need of a tweeter . . .

if you have the room, go J E Labs :

http://members.myactv.net/~je2a3/open.htm

BUT . . . if you need the floor space, just do something like I did :

http://www.audiokarma.org/forums/showthread.php?t=104336&highlight=isophon

The tweeters are no longer used with these . . .they sound great with a little tube amp . . . and they're heading to Jim W if I gewt off my butt and contact him :D
 
Are you sure those tweeters are electrostatic? Could be ribbons too :scratch2:

Look nice and I have heard they are sweet sounding and high efficient!!
 
cubby01 said:
Cool, thanks. OB it is then. Don't have a lot of room so will play with dimensions a bit. :yes:
Click to expand...

you could even make them even smaller than mine and just use a little powered sub,since you wouldn't get much output below 100 Hz . . . .
 
I was actually lucky enough to see and hear a grundig with these speakers. This was probably 2-3 months ago.
I didn't measrue the unit but by memory the speaker box was about 26-28" long, about 16-18 tall and about 16" deep. It was open on the bottom back, in other words the back of the box was ported the entire length with an opening about 3-4". The internal of the box was padded on the top, bottom and one side. One side and the back were bare wood.

These are very rough guesstimates but that is what I remember.

It acutally had some pretty decent sound too. I bet these are pretty forgiving speakers. Anything close to this construction would probably sound good.

Good luck,
Mark
 
markus said:
Hi Micha,

I didn't see any pictures of the back of those cabinets . . are the enclosures sealed, or are they similar to many console backs, where there's a number of 'vent' holes ?
Click to expand...

One of those pictures shows a board laying under the speaker. It has an array of holes behind each driver.

17grl1024-1.jpg
 
The speakers I have came out of a console phonograph that looks almost but not quite like the picture at the bottom. Slight difference was the radio faceplate was ivory colored and the TT was missing :-(.

Rolf Zetterberg said:
Or copy these-a large square hole below the oval driver is just about visible.And they have no damping inside-I know because I have two of them::
http://www.german-vintage-loudspeakers.com/navid.429/grundig-hifi-raumklang-box-iva.htm
Click to expand...

Rolf, those are way cool. Love that styling. If I could copy those curves I would. Might even try. How do they sound?

I wonder if adding a wizzer cone would extend the highs a bit more :scratch2:
 

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I love those tall, curved Grundigs. If I could figure out a good way to bend some plywood, I'd take a shot at making a miniature version for my Blaupunkt drivers.
 
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