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Update... Allison CD7 Project

BPFisch

BPFisch

Active Member
Previously I posted about some empty Allison CD7 cabinets that I bought. I thought I'd provide an update (with pics) on how they turned out after I did a little refinish work and put some after-market drivers in.

When I got the cabs they were in pretty good shape with just a few little character marks here and there. I decided to lightly work out a few of the marks with some steel wool and leave just enough character behind to indicate their age. Then I freshened up the finish with some tinted oil base and finally with some Watco Danish Oil.

The original Allison woofers and tweeters weren't included with the cabinets, but the crossovers were, so I decided to try to find some drivers that would work with Roy's crossovers.

The woofers I got are Goldwood GW-8PC-30-4 8 inchers. These met the original specs very closely and are nice and heavy with the cast frames and rubber surrounds. I had to do a little bit of custom work with the router to get these to drop in, but it was very minor (removed 1/16" around the top edge of the original woofer cutout). Sealed these in with some rope caulk.

The tweeters were the real pain to find a substitute for! Roy's original tweeter simply does not have a modern day equivalent! I looked at a lot of different designs and finally found a great deal on some Dayton RS28A-4 tweeters. Again I had to do a little custom work. This time I removed just a little off the edge of the mounting flange on the tweeters and had to enlarge the cutouts in the speakers where the wire connections go.

I settled on these tweeters after doing a lot of research. Roy's original tweeters were designed for excellent sound dispersion and there just aren't any modern designs that emulate this in a 4 ohm tweeter that can crossover at 2kHz or lower. The Dayton is pretty close. The recommended replacement according to Madisound is the Audax TW025A2 and then there are a few others that are also close in specs. I decided on the Dayton units because of the good reviews and because I got a great price on the pair!!

Once I got everything put together I moved my ADS L710's out of the great room (temporarily I think) to give these a test run. They really sound great! Maybe not as full as the ADS's, but very clean and open. Eventually I think these will end up either in the bedroom system or maybe going into a new system I'm planning on setting up.

Here's the finished product...
 
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Nice job on the cabinets! I've got a pair of walnuts that look faded- they've been sitting for years with rotten surrounds. This makes me want to pull them out, get them fixed up and use them, but I got nowhere to use them!!

Do you have a step by step with what you did and used on the cabinets?

Mine are only the 7's not CD7.

Chris
 
The steps I used on refinishing the cabinets are:

1. Lightly steel wool all finished surfaces. Remove or reduce all marks you want to work out or make lighter. Be careful during this step... some veneers are really thin and sandpaper can eat right through, especially around edges (that's why I stick to steel wool). Also be careful to remove old finish from the surfaces as evenly as possible so that you reduce the risk of a blotchy finish when done.

2. Clean surfaces very well! Use a couple damp rags or cheesecloth to remove dust.

3. For depth I started with a tinted oil. I used Minwax Wood Sheen in rosewood to add a little color. I applied the first coat and let dry overnight. Then lightly steel wooled the surfaces again, cleaned them, and applied a 2nd coat and again let dry overnight.

4. Steel wool again, clean, and then apply a coat of Watco Danish Oil. And then did this once more the next day.

5. Finally I used a good quality furniture paste wax and applied one good coat, let dry, and then buffed.

Done.

This is more involved than you have to get depending on what you want for your end result. But it sure makes for a beautiful, deep, protective finish.
 
Nice job on those. I bet they sound good.

I have some CD-8s and I really like the look of those cabinets.

Not often, but sometimes the plastic grills for the top woofer and front speakers becomes available on Ebay.

Snade
 
They do sound good! I'm really happy with the end result, both the refinished cabs and the new drivers. They don't seem to be able to hang with my ADS L710's in my main system for our great room, so I've moved them to the den for now. They are extremely clear and clean and have a very open and airy sound, but they fall a little short on bass and they don't fill the space as easily as the ADS's. They do seem to image a little better though, but it's pretty close.

I am playing around with the idea of building some fabric grills for these with a semi-sheer fabric. I eventually want some kind of grill whether original or homemade, but not sure what direction I'm gonna head with it.

If I can come up with a design and material for the frame, I may try the fabric idea since these aren't original anyway. I need a material that is acoustically transparent, but I think it would be kind of cool to have the material be somewhat optically transparent too. Then again, it might look really stupid! If I find a sheer fabric that works, I'm thinkin' maybe a tan color to give these a different look and help the black drivers pop out a little. Heck, I don't know! Decisions, decisions!
 
Nice job -- I'm glad you opted for steel wool instead of sandpaper to avoid damage to the veneer. :yes:

It's also good to know that there are some good options for replacement drivers for the day I run out of spare parts for all of mine. :scratch2:

I'd love to compare originals to a set with the new drivers. :yes:

Keep those Allisons running! :thmbsp:
 
Yeah, now that I've got this pair of "Franken-Alli's", I'd like to hear a pair of originals so that I could see what the differences are. I would really love to hear and compare the original tweeter next to the Daytons I used or some of the other recommended replacements!
 
Nice work! Thanks for posting the details on components you were able to replace. This should help anybody looking to do the same in the future.

Post some pics once you've gotten the screens in place. :)
 
Has anyone tried this speaker http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-1016 as a sub for the tweeter in any of the allison speakers? It seems to cover the range of the original and appears to have similar dispersion characteristics. I have one pair of CD7's with damaged cones, so unless there is a suitable repair/fix I'm thinking of replacing since originals are bloody hard to come by and expensive. Mine are currently working, but I can't imagine for long.
 
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