Allison CD7 Project - pics
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BPFisch
Active Member
I've found a pair of woofers that should mate up well with these and they are on the way. I have narrowed the tweeter choices down and have pretty much made a decision on what I think I'd like to try first.
The original Allison crossovers were included with the cabs and they test out fine, so I'll simply leave them in place and work the speaker choices around them.
Here are pics of one of the crossovers...
The original Allison crossovers were included with the cabs and they test out fine, so I'll simply leave them in place and work the speaker choices around them.
Here are pics of one of the crossovers...
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BPFisch
Active Member
The speaker cabinets have a few little "character marks" here and there, so I'm working to soften those just a little. My plan is to gently work out some of the more evident marks with steel wool and then rub down the the cabs with a few coats of Watco Danish Oil and finally finish off with paste wax.
Here are a few pics, one showing some of the marks and the others showing the speakers after a little work with the steel wool...
Here are a few pics, one showing some of the marks and the others showing the speakers after a little work with the steel wool...
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BPFisch
Active Member
I saw the Allison tweeter auction and I'm tempted! I originally made up my mind to just buy the cabinets, refinish them, and experiment with different woofers and tweeters to see what results I get. I want to mess around with a few things like ceramic dome tweeters or even possibly a coaxial design if I can find one that fits the cabinet opening. So I might eventually dig for some original drivers to do a full-fledged restoration, but for now I think I'm just going to experiment.
Here's the tweeter I'm thinking seriously about playing with first:
Here's the tweeter I'm thinking seriously about playing with first:
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BPFisch
Active Member
Got to agree Chazb11... someone on the Allison production staff got a little "glue happy" when they were constructing the crossovers!
Question for those of you that have experience with crossover construction (or at least know more about it than me!) How should the wiring connect once I'm ready to wire in the woofers and tweeters?
I'm handy enough with the multimeter to check the individual components and make sure they're still in spec, but don't know much at all about the overall config. From what I can decipher, the black and white wires should hook to the neg. terminals and then the red wire from the top of the larger inductor should go to the positive woofer terminal and the orange wire should go to the positive tweeter terminal. Can anyone confirm that?
And my woofers arrived today!! So one step closer to getting these up and singing!!!
Question for those of you that have experience with crossover construction (or at least know more about it than me!) How should the wiring connect once I'm ready to wire in the woofers and tweeters?
I'm handy enough with the multimeter to check the individual components and make sure they're still in spec, but don't know much at all about the overall config. From what I can decipher, the black and white wires should hook to the neg. terminals and then the red wire from the top of the larger inductor should go to the positive woofer terminal and the orange wire should go to the positive tweeter terminal. Can anyone confirm that?
And my woofers arrived today!! So one step closer to getting these up and singing!!!
Snade
humble AK member
I've got the CD-8 speakers.
Few quick thoughts:
- original Allison drivers are hard to find and do not come up that often on Ebay. I expect they don't sell cheap if in good shape.
- there is a Yahoo Group devoted to Allison speakers with several members that worked at Allison and some are engineers, designers and know a ton of stuff about speaker making and answer questions regarding mods, original specs of Allison drivers, possible replacement drivers, etc. Roy Allison also participates, he is a legendary speaker designer that made the AR 3a and AR 4x before making his own speakers at Allison.
- Most Allison speakers use the same drivers in different cabs. The CD series was a new series in the 80's when the marketing people at Allison said we need something that looks better than a square bookshelf and fits in with modern living rooms so they hired a design firm to design a new, slender cabinet and those black mesh grills.
Have fun, Snade
Few quick thoughts:
- original Allison drivers are hard to find and do not come up that often on Ebay. I expect they don't sell cheap if in good shape.
- there is a Yahoo Group devoted to Allison speakers with several members that worked at Allison and some are engineers, designers and know a ton of stuff about speaker making and answer questions regarding mods, original specs of Allison drivers, possible replacement drivers, etc. Roy Allison also participates, he is a legendary speaker designer that made the AR 3a and AR 4x before making his own speakers at Allison.
- Most Allison speakers use the same drivers in different cabs. The CD series was a new series in the 80's when the marketing people at Allison said we need something that looks better than a square bookshelf and fits in with modern living rooms so they hired a design firm to design a new, slender cabinet and those black mesh grills.
Have fun, Snade
Snade
humble AK member
I'm not an expert, but I think you may want to build a new crossover from scratch. Allison speakers are very well engineered to meet Roy Allison's standards and the stock crossover is designed to the specs of original Allison drivers. The Allison tweeter is the famous convex Allison driver. If you connect other drivers to the stock crossover I don't know what you will have, but it won't sound anything like an Allison CD7 (I think).
So I think you either rebuild it with Allison drivers (if you can find them) or build a new (more simple) crossover with your non-stock tweeter and woofer. The stock Allison crossovers are complicated because of the amount of design and engineering that went into the entire package.
Again, just my two cents and I'm not a speaker maker. Snade
HepcatWilly
Just trying to be Hepful
Red and black to the woofers, orange and white to the tweets. Orange positive, IIRC.
Allison used 'computer-grade capacitors' on his crossovers, and I've not yet found anyone who has bothered to recap them.
Check the specs on the Boston Acoustics A-series tweeter. According to another Allison afficionado, Soundweasel, Mr. Allison helped design it. If that's a reasonable match, Thedelihaus has a bajillion of them hanging around.
Allison used 'computer-grade capacitors' on his crossovers, and I've not yet found anyone who has bothered to recap them.
Check the specs on the Boston Acoustics A-series tweeter. According to another Allison afficionado, Soundweasel, Mr. Allison helped design it. If that's a reasonable match, Thedelihaus has a bajillion of them hanging around.
soundweasel
Super Member
I said that?! :scratch2:
Hmmm. I wonder if was right?
Seriously, I recall saying that the BA tweeters had similar dispersion characteristics to those of the Allison tweeters. Specifically, I'll be sitting outside the sweet spot, often with my back to the speakers, and all of a sudden I'll hear an instrument -- typically strings -- just over my shoulder! It's scared the s**t out of me on several occasions!
ara:
HepcatWilly
Just trying to be Hepful
I thought you did, and I wasn't drinking that lunch!
HepcatWilly
Just trying to be Hepful
I red it on the intertubes, it must be troo:
http://www.dograt.com/2007/01/25/oh-allison-his-ears-were-true/
Besides having an excellent ear for neutral sound reproduction, Roy Allison is a true gentleman. He helped a competitor, Andy Kotsatos, start the still-extant company Boston Acoustics. (I also own a pair of Boston Acoustics A40 speakers, purchased in 1983.)
http://www.dograt.com/2007/01/25/oh-allison-his-ears-were-true/
Besides having an excellent ear for neutral sound reproduction, Roy Allison is a true gentleman. He helped a competitor, Andy Kotsatos, start the still-extant company Boston Acoustics. (I also own a pair of Boston Acoustics A40 speakers, purchased in 1983.)
soundweasel
Super Member
BPFisch
Active Member
Fantastic advice guys! And I appreciate every bit of it!!
Snade - Thanks for the info on the Yahoo group!! Gonna check it out and see what I can learn!
And HepcatWilly & soundweasel - Didn't have a clue about the Boston Acoustics tweeter possibly being a close match... thanks for the heads-up!
The whole "instrument - typically strings - just over my shoulder" thing... just exactly what I'm looking for!
Snade - Thanks for the info on the Yahoo group!! Gonna check it out and see what I can learn!
And HepcatWilly & soundweasel - Didn't have a clue about the Boston Acoustics tweeter possibly being a close match... thanks for the heads-up!
The whole "instrument - typically strings - just over my shoulder" thing... just exactly what I'm looking for!
HepcatWilly
Just trying to be Hepful
Be careful! I don't trust my own advice!
I'm on the Allison group, and it's a really good one. Take a look at classicspeakerpages.net, they have a forum devoted to Allison as well. You can often pick up pieces there.
I'm on the Allison group, and it's a really good one. Take a look at classicspeakerpages.net, they have a forum devoted to Allison as well. You can often pick up pieces there.
klama2006
Super Member
Allison speakers are really nice. I think you will be happy with them, once you get your project completed.
If you ever see an orphaned 4, pick it up. A few of Allisons models use two tweeters per cabinet. If your patient, and keep an eye out, you might get lucky. I was also watching that auction. Your cabinets look to be in great condition.
If you ever see an orphaned 4, pick it up. A few of Allisons models use two tweeters per cabinet. If your patient, and keep an eye out, you might get lucky. I was also watching that auction. Your cabinets look to be in great condition.
BPFisch
Active Member
Well, I've got time to do some more research on the tweeters before I make a purchase. I want to get the cabinets refinished and that will take a while at the pace I'm going. I'm definitely going to take a look at the Yahoo group and I've already done quite a bit of reading on the Classicspeakerpages site.
I may still end up doing some experimenting with different tweeters even if I do finally end up right back at the beginning by installing some original Allison units in these. The ceramic domes intrigue me and at $20+ each it might be worth the money just to see what they can do. Plus experimenting with a few different units will buy me the time to watch for some originals for the right price.
I may still end up doing some experimenting with different tweeters even if I do finally end up right back at the beginning by installing some original Allison units in these. The ceramic domes intrigue me and at $20+ each it might be worth the money just to see what they can do. Plus experimenting with a few different units will buy me the time to watch for some originals for the right price.
