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Attic Find: Utah Speaker Pair

StarMover

StarMover

AlienToAllThingsAudio
My dad and I were discussing a HK 630 amp and a pair of old speakers he has stuffed into the bottom cabinet of his study.

I asked him what the make of the speakers is and he didn't know. Today he emails me that they are "Utah" speakers and sends me these pics. He didn't say the model number, but I believe I can see the outlines of the speakers through the grills in the photos. Doing some research on the web; I don't see many Utah's intact, mostly parts. I asked Dad for the model number, so if it's there I should have it shortly. He's going to drop them by the house soon so I can check them out. I'll bet they're old enough to have fabric surrounds. Perhaps they're even paper like the old Scott speakers. I'll keep you posted. Anyone recognize these? :scratch2:
 
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BTW, I left off the dimensions: 11" x 14" x 23" walnut veneer. I believe they are 3-way based on what I can see through the grills. (see attachment)
 
Hey StarMover,
I have a similar Utah bookshelf. It must be its little brother. Same styling and grille fabric. Designed to sit on its side instead of upright. Walnut veneer.

It is badged as a Utah AS-2A, two way. Not a bad sounding speaker at all. Very well balanced.

Yours might be a AS-3A but its just a guess. Im sure you will enjoy them.

RC
 
I found a Utah brochure in my files from 1975 and the closest match to your
speakers is a WD-90 -- 12" woofer-- 8" midrange-3.5" tweeter with crossover control
to the tweeter only. Cabinet is walnut veneer and dimensions listed as 14 x 23 x 10.
Shipping weight for one speaker is 33 pounds. RMS Power (Watts) 40--Impedance 8 Ohms--Crossover Frequency (Hz) 2,500/5,000. I realize that 1" is missing from your
measurements but they don't list an 11" dimension. Hope this is of some help to you.
cincy
 
OK, Dad chimes in. The speakers are Utah Model WD-90, 12", 3-Way, Acoustic Suspension System, 8 ohms, 60 Watts Peak. They probabally went with the HK 630 amp.
 
There's a fellow at AA called "DavidLD" (Debertin) who is a big proponent of all things Utah. You might want to look at the "Vintage" forum there for more Utah info, and/or at:

http://members.aol.com/_ht_a/Debertin/utah.htm
http://members.aol.com/_ht_a/Debertin/allied01.jpg

allied01.jpg
 
The mystery is solved. Another AK victory! Now all we need to do is plug those puppies up, put on our gold chains and disco pants and re-live 1975. Can you dig it?
 
The WD-90s are not bad, I actually try and find these (I only have two pairs so far). Words of advice, rebuild the crossover with new components (even if equal values, it will make a world of difference, you don't even have to go experimenting around unless you wanted to), then reseal the cabinets, and by reseal I mean reseal, check the back seal when playing loud heavy music, its probably leaking, they used some sort of rubber gasket to seal the back and they are getting pretty dried out here 30 years later. The big 12 incher's surround should be as good as new. What I like about them is they are very efficient, believe it or not it actually makes them good for using in home theaters setups, and they will play LOUD. For music I tend to find them bass heavy if you don't redo the crossover. If you don't want to rebuild the crossover just make sure those rear seals are tight, at least they won't sound boomy then.
 
That's a scan of a 1970 or 1971 Allied Radio catalog, from DavidLD's website. I think I provided the link above.
 
I have a pair of WD-90 right here. Decent sound, good bass and mids, a tweeter upgrade would make 'em really sweet.
 
A closer look...

I got into the WD-90s this weekend. I hooked em up and I wasn't hearing the tweeters. Someone had warned earlier in this thread about the caps needing to be replaced. I tested them and found that indeed they are shot, so I'm off to the electronics shop to find new ones. :D
 
StarMover said:
I got into the WD-90s this weekend. I hooked em up and I wasn't hearing the tweeters. Someone had warned earlier in this thread about the caps needing to be replaced. I tested them and found that indeed they are shot, so I'm off to the electronics shop to find new ones. :D
Click to expand...
Make sure you use the same values and consider an upgrade to Solen or a better grade of cap. Parts Express has many caps in stock (see link at the bottom of this page).
 
Here are some pics

Here are a couple of pics of the inner workings of the UTAH W-90s. The white crossover cap tested OK, but the blue one is bad.
 
StarMover said:
Here are a couple of pics of the inner workings of the UTAH W-90s. The white crossover cap tested OK, but the blue one is bad.
Click to expand...
Alnico magnets! :smoke: I'd go ahead and replace all caps...they don't cost much and you'll benefit from better sound.
 
Celt,

Can you suggest specs for replacement caps? I'm having trouble cross-referencing them. These are 50V NP, but from there I can't tell. I have a feeling the white one (the good one) has been replaced already, because it looks so much newer than the other one. I don't have a lot of experience with electronics.

One is marked: 4-50VNP
110249-1

The other: 52NP7304
+112049-2+
8MD 50V
 
If I recall its a pretty low value cap, want to say 10uf but for some reason looking at it when I have it typed out does not seem right... I wonder if I still have the paper I wrote the parts down when I redid them, been a few years since I redid the ones in the basement, I'll take a look around. Thing is I am not sure they all use the same caps, Utah marketed this design under a few different models, and oddly they had different frequency response specs. I highly doubt they did much to the design...

Make sure you seal up those things tight, that 12 has a rather long excursion (you'd be surprised), and though they seem pretty durable and I doubt it will be damaged if the seal is not good, the thing will be like one of those boomy car stereos. I have actually been curious about that 12 for a long time, I would love to be able to obtain one to try in a ported box to see what happens, but I can't hack up these perfectly good Utah speakers for an experiment. I mean the Utahs are not exactly the greatest but the cabinets are good and solid, contrast that to some of the junk out there, and when working properly they sound decent enough (and I'll point it out again, they are great for HT setups, really pound without a lot of power).
 
SM, I'd venture a guess that the first one is a 4uf cap by the description but I don't know for sure.
 
I've got the entire rear board with the cross over with me today. At lunch I'm going by the electronics store to get new caps and some fuses and lamps I need for other projects. Will keep you posted on the progress of this job.
 
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