Micro Acoustic tweeter array

[stan461]

I just purchased a pair of Micro Acoustic tweeters on Ebay.

They are in very good condition and sound does come out of all the tweeters.

Does anyone know how to hook them up properly?

Thank you for any help.

[stan461]

I just found the instructions in a PDF posted by JKent. Thank You!!!

I should have researched more thoroughly here (classic speaker pages) first before asking for help.

I apologize if I wasted anyone's time.

[Steve F]

These were pretty popular items 'back in the day.' I got a set on Dec 26, 1973--the day-after-Christmas-sale at Fred Locke Stereo in Avon CT--to go with my 2ax's. The Micros were on sale for $99.95, off their $117 list. Such a deal.

I remember wiring them up with on-off toggle switches connected to about 20 feet of speaker wire so I could do A-B comparisons from my listening position.

They worked and looked pretty cool. There were definitely "more" highs coming from the speakers with them than without them. I used them in the 3.5kHz position, turned up about 2/3 of the way.

I have to be honest--I tired of them within a short time and took them off the 2's. I did use them on my father's 4x's that I took to college the following year, but the 4's cabinet was a touch too narrow and the Micros' ends stuck over the 4's sides by a little bit. They sounded better on the 4's than on the 2ax's, to my ear.

I know GeneK says he has them and is unable to hear a difference with them on his 3a's or 2ax's (I think he said his bright room minimizes the potential difference), but hears a distinct difference with them on his 6's. I heard a definite difference with them on my 2ax's--"more" highs, as I said--but I ultimately preferred the 2's sans Micros.

I have often thought that 2x's or 1x's with Micro tweeters would be an intriguing speaker. I almost bought 2x's + Micros instead of 2ax's when I bought my 2ax's in Feb 1972. The sales guys at Fred Locke--who were anti-AR anyway--grudgingly conceded that 2x's + Micros would probably be a very nice set-up.

A few years later, I had LST-2's, and just for fun, I put the Micros on them "just to see" what it would look/sound like.

It looked great (people would come over my apartment and say, "What the heck are those?!?"), but the LST-2's didn't benefit from them sonically.

Steve F.

[JKent]

Those the ones that ended Dec 7? I was watching them but don't need another pair. If those are the ones, the backs are heavy cardboard, glued on. I recommend prying the backs off and replacing the capacitors. Each speaker has two 1uF electrolytics. Put in some nice film caps and while you're in there spray the pot and slide switch with some deoxit. You can glue the backs back on or do what I did and fasten them with #4 wood screws.

Here's a slightly out of focus shot of the innards. You can see this pair has those black and red Callins type PVC caps--VERY trouble-prone.

The threads here are a little hard to find. Here's one: http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=3251&st=0&p=69203&hl="micro%20acoustic"&fromsearch=1entry69203 You have to try different variations on the name when searching: Micro Acoustic, Micro Static, Microstaic, etc.

I've used them with KLH Twelves and plan to hook them up to my AR3a's. Some friends use them with big Tannoys. I like them but YMMV.

Kent

[stan461]

Thanks for sharing. Oh, to be back in 1973!

Anyway, I'm older than you. I started college in 1965. I heard of these when they came out way back when but never heard them.

So now, at this late stage, I'm experiencing them for the first time.

I believe Les Winter & Frank Marsi use these tweeters.

No combination of equipment, room and listener's ears are the same so I have no expectations.

They'll be attached to a pair or AR3a's fitted with HiVi Q1R tweeters. I really do like the HiVi tweeters. Thanks Roy.

I'll post a listening impression in the near future.

[stan461]

JKent,

Those Ebay Dec 7 are the ones.

Thanks for all the info. It sure makes things easier.

But first I'll try them just as they are.

[JKent]

Anyway, I'm older than you. I started college in 1965. . . .

They'll be attached to a pair or AR3a's fitted with HiVi Q1R tweeters. I really do like the HiVi tweeters. Thanks Roy. I'll post a listening impression in the near future.

Wow. You ARE old! I didn't start college until 1966

I have the same setup, but have not yet attached the Microstatics. Ditto your comment: Thanks Roy! Roy really has made it his mission to develop a tweeter replacement for the failing tweets on these old speakers. I know the R&D continues and we can look forward to more of the fruits of his labors.

I can understand your desire to try the Micros as-is and you certainly won't do any harm, but as Carl pointed out recapping can make a HUGE difference with these (especially if you have those PVC caps). So go ahead, but when you have a chance to pick up four 1uF film caps go for it. The backs can be pried off gently with a putty knife. Although I reinforced the backs of my 1st set with epoxy, that's not really necessary. You can just reattach them. Use glue or #4 x 1/2" screws.

The grille cloth on yours has "issues" according to the listing. Carl said removing the cloth makes for a big improvement so that's something else to consider. Replacing it could be a challenge: The cloth was cut to size and stapled to the front of the baffle. No place to wrap it around. Your replacement would have to be cut EXACTLY to size and you would need a fairly stiff cloth that won't fray on the edges. I don't know what to recommend.

Kent