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-   -   Noresco/Isophon SR-2 (http://www.diyaudio.com/forums/full-range/228505-noresco-isophon-sr-2-a.html)

IG81 23rd January 2013 11:06 PM

Noresco/Isophon SR-2
 
I got these monkey coffins with the intent to experiment with the boxes, can't build much with the winter full-on, -25C today. I knew they'd have some Isophon drivers - didn't expect the PH2132E coaxial though!

http://imageshack.us/a/img854/6165/20130123175043.jpg

http://imageshack.us/a/img547/116/20130123175102.jpg

http://imageshack.us/a/img837/3093/20130123175128.jpg

http://imageshack.us/a/img46/9167/20130123175154.jpg

I seem to have the 4ohm version, both seem to work as well, though that cap might be somewhat tired. Very good condition overall.

I'll get to measuring the parameters, though I expect OB kind of Qts. Vas is a bit of a pain to get. Anyone measured these before, Planet10?

IG

planet10 24th January 2013 07:14 AM

Quote:

Originally Posted by IG81 (Post 3339437)
Anyone measured these before, Planet10?

Maybe. I've had 4 pair thru here, plus i have a 4 & an 8ohm single (from what was nomially a pair of Noresco).

Quite a special driver, not all that neutral but vry musical.

dave

IG81 24th January 2013 01:22 PM

Quote:

Originally Posted by planet10 (Post 3339795)
Maybe. I've had 4 pair thru here, plus i have a 4 & an 8ohm single (from what was nomially a pair of Noresco).

Quite a special driver, not all that neutral but vry musical.

dave

There is a large and broad peak at 7kHz, very apparent when right on-axis, but it smooths down when moving just a bit. Wonder if it's the tweeter's natural behavior or interatcion with the fullrange/midbass. This is preceded by a dip at 5kHz, so I'm suspecting the latter, at least in parts. Maybe reversing the phase could make it a bit better. I'll have to measure drivers individually. The crossover cap is a 5F, which suggests ~8kHz nominally for the 4ohm tweeter. I also have the apparently common busted rivets on the terminal strips. The tweeter's strip is actually screwed-down, a much better choice. Past Ebay prices for these might also preclude me from keeping them! ;)

IG

planet10 24th January 2013 09:29 PM

Quote:

Originally Posted by IG81 (Post 3340083)
I also have the apparently common busted rivets on the terminal strips. The tweeter's strip is actually screwed-down, a much better choice.

Very common. The screw is likely from someone fixing the issue. I usually use epoxy

Quote:

Past Ebay prices for these might also preclude me from keeping them! ;)
One of the reasons a cheer always went up when i found a pair of these when i was doing vintage drivers on eBay. Most i ever pais was $60/pr (and that same day i got another pair for $30)... Most i got was $320/pr and that from a jukebox collector in Germany who needed a single to restore one of his collection.

dave

IG81 25th January 2013 03:29 AM

Quote:

Originally Posted by planet10 (Post 3340727)
Very common. The screw is likely from someone fixing the issue. I usually use epoxy

The screw on the tweeter terminal "strip" seems original - it's the same golden slotted screw head as you find holding its mounting brackets.

Quote:

Originally Posted by planet10 (Post 3340727)
One of the reasons a cheer always went up when i found a pair of these when i was doing vintage drivers on eBay. Most i ever pais was $60/pr (and that same day i got another pair for $30)... Most i got was $320/pr and that from a jukebox collector in Germany who needed a single to restore one of his collection.
dave

That's about the max I've seen on completed listing too - BIN to boot. Lowest BIN was ~200$.

IG

planet10 25th January 2013 03:40 AM

1 Attachment(s)
Like this?

These are the older, most desirable, shallow basket aperiodic tweeters,

dave

IG81 25th January 2013 01:29 PM

Quote:

Originally Posted by planet10 (Post 3341125)
Like this?

These are the older, most desirable, shallow basket aperiodic tweeters,

dave

That same screw yes, but a simpler, 2-terminal strip, not aperiodic AFAIK. Maybe I'll remove one tweeter to measure the fullrange/midbass on its own, I'll snap a pic.

They do have their own sound. I jammed the cabinet's vent with a bunch of poly-fill to reduce the port's output, going towards ~aperiodic for this high-Q driver. Next will be listening with the back off. I'm only listening to one speaker in mono - has a weird sense of depth at times on certain recordings. The cone tweeter's large and broad peak is very similar to what Troels Gravessen measured on the very similar Saba tweeter. Thought it is very bright-sounding on-axis, the sound itself is not too harsh, as bit of taming its amplitude would help for sure though.

IG

tubo 26th January 2013 05:08 PM

2 Attachment(s)
Hi guys,

This is just a perfect timing.. I have just acquired a pair of these but have not listened to them yet as im very confused where to connect the wirings. Can someone please show how to connect the cables. I just dont understand how the mid and tweeters are connected with the 5uf capacitor. Pls explain...

Attached are the pics

Thanks guys

tubo 26th January 2013 05:21 PM

1 Attachment(s)
Can you also please tell me which is the positive and negative terminals of the mid and the tweeter.

Thanks guys

tubo 26th January 2013 08:13 PM

hi guys,

I was able to identify correct polarity for the mids and i suppose the terminal with the red wire on the tweeter is the positive side. Guys pls verify if im right with the tweeter polarity.

But i still could not understand how everything is wired with the 5uf cap.
It looks like that the mids are in series with the 5uf cap then to tweeter but what confuses me if they are in series is that the cap connects to the negative of the tweeter then the positive of the tweeter connects back to the positive of the mids.

can someone pls chime in... Very confused here


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