Zenith Allegro 1000

[Lance A.]

I love odd old speakers so when I saw a pair of these at Goodwill today without a price I took them up to the counter and got them for $20. Not great but the hobby time is worth it.

My first listen was surprising. They sounded quite good. I opened them up to recap them and they had 4 uf electrolytics in them. I check my cap inventory and had a pair 4 uf Dayton 1% poly caps, so I threw them in real quick.

They are surprisingly good with the new caps. They have a very nice sound stage which I've found only happens when the speakers are closely matched and are accurately reproducing material. One of my testing tracks is a binaural recording of a small group of strings and reeds playing the nutcracker (on youtube). Impressed is the word. They sound better than half the speakers in my collection.

 

[superdog]

Allegros have fans.I have some 3000 in the garage.

 

[bluepine27]

What’s the best way to get these open? I also scooped a pair from GW for about 5 dollars a speaker, almost thought they only had one but found the other on a different shelf.

Also think they don’t sound half bad and plan to give to a friend but would like to recap first and see how they sound after. Can’t feel a good route to get into it without wrecking it

 

[Fairlane]

If a speaker sounds good doesn't really matter what name is on it.

Enjoy them.

 

[HPMguy]

Six screws in the back hold the back panel on, drivers are attached to the front with sheet metal nuts from the back side. Grille does NOT come off.

Pretty good speakers for the age and size, big fat alnico magnet on the back of the woofer. Also very efficient, designed for flea watt amps back in the day (10 watts per channel, etc). Very VERY loud very quickly with any high wattage amp.

Probably should think about replacing the electrolytic cap on the crossover, it's getting close to 50 years old, these were new in 1975 or so.

 

[bluepine27]

Six screws in the back hold the back panel on, drivers are attached to the front with sheet metal nuts from the back side. Grille does NOT come off.

The back panels on mine don't have screws, just staples that are pretty far in. I gave the one corner a lift with a flat head and the panel started breaking up almost immediately. lol I feel like I'm bound to break something trying to get into this. I could maybe very carefully try taking the staples out?

 

[HPMguy]

I suspect the only way in is to pull the staples. Sadly MDF tends to get crumbly with age, and those are getting on to 50 years old! You may need to make a rear panel, it's just a flat piece with nothing attached to it, at least in the ones my brother has. Notch for the RCA plug cable.

 

[kirk57]

Drivers are ROLA and not bad. Cabinets are not great (5/8” particle board as I recall)
Seems they could be improved pretty easily by bracing the cabinets.

 

[audiojones]

For some reason I thought they had Foster tweeters in them, I could be mistaken though. Folks do seem to agree that they sound pretty decent.

 

[Romeo Wolf]

Speaking of the Allegro 1000 I have a single woofer that would've come out of one. It's a 6-½" made by Rola for Zenith. My driver has a ceramic magnet.

 

[kirk57]

For some reason I thought they had Foster tweeters in them, I could be mistaken though. Folks do seem to agree that they sound pretty decent.

You are right. Foster tweeters, ROLA woofers

Edit: not Rola/Foster in this later version, apparently

 

[bluepine27]

guys, I wrecked the cabinet. loll

I don’t understand how something could be so brittle yet so hard to break at the same time, almost threw my shoulder out trying to pry on this back panel. staples were in way deeper than I was expecting and the panel itself was thicker than imagined.

Also seems my 1000’s have a 2.2 cap in them, Luckily ordered a handful of varied value caps and will have some coming soon. Feels like it’ll be a false comparison to compare the old and new cap with this cabinet wide open in the back

I was going to give these to my friend who luckily does wood working so maybe that’ll be a nice project for us. As of right now, even making a new back panel doesn’t seem worth it after I wrecked the one side.

Any thoughts, recommendations for building speaker cabinets?

 

[Romeo Wolf]

guys, I wrecked the cabinet. loll

I don’t understand how something could be so brittle yet so hard to break at the same time, almost threw my shoulder out trying to pry on this back panel. staples were in way deeper than I was expecting and the panel itself was thicker than imagined.

Also seems my 1000’s have a 2.2 cap in them, Luckily ordered a handful of varied value caps and will have some coming soon. Feels like it’ll be a false comparison to compare the old and new cap with this cabinet wide open in the back

I was going to give these to my friend who luckily does wood working so maybe that’ll be a nice project for us. As of right now, even making a new back panel doesn’t seem worth it after I wrecked the one side.

Any thoughts, recommendations for building speaker cabinets?

Without the T/S Parameters for at least the woofer, you'd have to wing it. That appears to be a newer Allegro (date code 26th wk of 1977), using cheaper components. If you're going to be undersizing the enclosure, put it in a sealed enclosure so the chances of it shredding itself are less likely. At least that's what I intend on doing to my woofer.

 

[bluepine27]

Without the T/S Parameters for at least the woofer, you'd have to wing it. That appears to be a newer Allegro (date code 26th wk of 1977), using cheaper components. If you're going to be undersizing the enclosure, put it in a sealed enclosure so the chances of it shredding itself are less likely. At least that's what I intend on doing to my woofer.

What if the dimensions were pretty closely the same, and placements for the port hole, woofer, and tweeter were all in relatively the same placement in a new cabinet? Just looking at the definition of T/S parameters is making me feel like putting everything in a new cabinet all willy nilly, is a bit of an oversight. I'm just not sure what else to do other than dramatically repair the cabinet that I largely unhinged from itself, and would have to make a new back panel anyways?

Also when you say sealed, I assume you mean the back panel? Or even just all around the inside where the sides meet and the back panel? I feel like I should have went through the grill to get to the inside of these rather than the back panel. The cabinet wouldn't be wrecked, though I know the grill would have been unusable at that point but I think getting new grill cloth would have been easier than having to rebuild a new cabinet.

 

[HPMguy]

Just make a new back panel for it, and include some dampening material. Definitely NOT the same as my brothers, as they have a smaller enclosure, bigger woofer, bigger tweeter, dampening material (that was a surprise) and a rectangular port.

 

[bluepine27]

Ok, I think the original cabinet is salvageable but will just be a bit of a pain to make sure it's tight and back together. I really did a number on it.

And it's a bummer I found a lesser 1000 than what everyone else seems to love and have lol. I think it still sounded ok before I busted the one open and before a recap. I think they'll be nice first speakers for my friend who's helping me move and has been wanting a stereo system, pairing it with a Panasonic SG-20 I do love the grill shape aesthetics of these speakers.