Unusual oval full-range drivers

[devilsindetails]

Hoping to draw upon the experienced eyes and ears of DIY Audio members in identifying these unusual oval full-range drivers that I pulled from an 60s era "Kuba" 6GW8 tube based stereo-console.

Doesn't appear to be any rear-mounted motor structure so I'm guessing that the unusual flared rounded metal protrusions on the front and in the center of the cone are some form of motor.

They don't seem to exhibit any magnetic properties unconnected to the chassis so my guess is they become (energized) magnetized through the low voltage of the OTs.

The basket markings are a mystery to me and the only manufacturing marks on the cones is IREL? A search has yielded no information thus far.

Just wondering if anyone can identify these and offer any comments.

The design and finish are quite interesting and initial tests of these sans-enclosures seemed promising.

Thanks in advance!

[Wavebourn]

Here is something similar:

[devilsindetails]

How so? Rear profile of your example clearly indicates a magnet/motor structure, albeit, not a substantial one, and no front-mounted metal protrusion of any kind (I know they aren't phase plugs on mine)

Seen many of your examples but they aren't remotely similar to the drivers I have. (Are they perhaps, manufactured by the same "IREL" outfit?)

For some reason I am prohibited from posting pics larger than 175 (or so) kb so perhaps the images of my mystery drivers were too small for you to discern the details I was referring to.

Thank-you nonetheless Wavebourn. I appreciate any possible avenues of exploration.

[planet10]

I have run across a few IREL, i'd have to dig out an archive to confirm or not, but IIRC they are Italian.

Your picture is kind of small, but they are not unique in having a front mounted motor with an alnico slug. I have had both Dual & Pillips drivers with the same.

Anitoly, lovely surround on those, a precursor to the Fostex UDR.

dave

dave

[devilsindetails]

Yes, for some reason I can only post pics of 175kb or smaller. Perhaps because I am a recent DIY Audio member.

Thanks Planet 10. Any idea of the design rationale of a front-mounted motor? Space constraints weren't an issue in the console these were pulled from. What were your impressions of the Philips and Dual examples of such a design?

[planet10]

Originally Posted by devilsindetails

For some reason I am prohibited from posting pics larger than 175 (or so) kb

With 175 kb/image you could easily be posting 1000 pixel across images. I do note that your tiny thumbnails are hitting 45 kb... they should be 3-6kb given their size.

One way of getting such an anomalas size is to save a picture in photoshop as a jpg, This can balloon a tiny file like yours by embedding all sorts of metadata. If you are using PhotoShop, use "Save for Web"

dave

[Wavebourn]

Originally Posted by devilsindetails

How so? Rear profile of your example clearly indicates a magnet/motor structure, albeit, not a substantial one, and no front-mounted metal protrusion of any kind (I know they aren't phase plugs on mine)

Your speakers look like have the same type of front mounted motors.

Originally Posted by planet10

Anitoly, lovely surround on those, a precursor to the Fostex UDR.

They were called 3GD-38E. I still remember juicy sound of that speakers. I believe it is possible to restore production of this speakers.

[devilsindetails]

Originally Posted by Wavebourn

Your speakers look like have the same type of front mounted motors.

I don't see a front-mounted motor on your example though, which is why I am confused by it.

[devilsindetails]

Originally Posted by planet10

With 175 kb/image you could easily be posting 1000 pixel across images. I do note that your tiny thumbnails are hitting 45 kb... they should be 3-6kb given their size.

One way of getting such an anomalas size is to save a picture in photoshop as a jpg, This can balloon a tiny file like yours by embedding all sorts of metadata. If you are using PhotoShop, use "Save for Web"

dave

Thanks Dave. Will try that.

[planet10]

Originally Posted by devilsindetails

Yes, for some reason I can only post pics of 175kb or smaller. Perhaps because I am a recent DIY Audio member.

That is not it. The liit is actually 195kb, which is more than large enuff for posting on the forum. Your pictures, when resized & saved correctly should be on the order of 45-100kB

Your pictures are large (in kB) because of how you are saving them

For example the attached image is 49k,

dave