A7 Project Thread

[Voice_of_the_Llama]

A while ago I "inherited" some old Altecs from my grandpa (he's still alive). They were a model 800 and an A7-825, plus some H-808 horns with mismatching drivers.

At one point, someone had enclosed the tweeter and glued door panels to the side...













When a single A7-828 showed up on craigslist I jumped at the deal and brought it home. My project is to modify the 825 to match the appearance and sound of the 828, and then sand and repaint both speakers.

Here's my progress so far...

I pried off as much of the door skin as I could with a flatbar and chisel (I should've done it outside)





Preliminary sanding and filling... Also took of the port pieces







Here's a picture of the newly acquired A7 next to the unfinished box



More sanding and filling







The hardest part of the whole process - picking a color



Tomorrow it's back to sanding. Hopefully I'll primer the box and start gutting the other A7 so I can get to sanding it.

[Altec Best]

"Welcome to the Board" !

In the meantime upload your photos to a photo sharing site like Photobucket,Flickr,Image Shack,etc.... And when day 3 hits post them and try to get some good quality pictures of the HF drivers,horns,crossovers,woofers, and of the cabinets. Internally of the bracing and such.That should give Folks enough info so they can help you out.Looking forward to your pictures.

[gearfreak]

At one point, someone had enclosed the tweeter and glued door panels to the side...

Welcome and good luck with the project.

Door panels (assuming, household doors?) probably an attempt to quash resonances by stiffening the cab/ adding mass. If so, maybe sound better with them in place. You are the judge. Depending on what is left, you may be as well off adding new ply panels to the (damaged?) areas.

Color: If looking for 'altec grey' there are several threads on the topic here iirc. Otherwise, I like black myself. :-)

Tweeter: perhaps will be apparent from the pics, what was enclosed. The 811_ or 511_ horn that we may expect to be there could be mounted inside or outside the cabinet, by design. So we assume there is some sort of extension on the top?.

[Panomaniac]

There is a lot you can do inside the box to make it better. Stiffen and thicken the walls, brace and damp the thin wodden horn flares. That's plenty of work to get you started. Then you can work on the ports and the when you feel completely exhausted, attack the crossover. Welcome to the club!

[Voice_of_the_Llama]

Welcome and good luck with the project.

Door panels (assuming, household doors?) probably an attempt to quash resonances by stiffening the cab/ adding mass. If so, maybe sound better with them in place. You are the judge. Depending on what is left, you may be as well off adding new ply panels to the (damaged?) areas.

Color: If looking for 'altec grey' there are several threads on the topic here iirc. Otherwise, I like black myself. :-)

Tweeter: perhaps will be apparent from the pics, what was enclosed. The 811_ or 511_ horn that we may expect to be there could be mounted inside or outside the cabinet, by design. So we assume there is some sort of extension on the top?.

Yep... 1/4" door skins glued to the side. Ugly as hell and a b!tch to get off! The chips filled nicely with wood filler fortunately.

I'm going with a color that's warmer and a hair lighter than the original color.

Both cabinets have a green 511B on top. The new one has an 806a and the cabinet I'm working on has an 802c.

There is a lot you can do inside the box to make it better. Stiffen and thicken the walls, brace and damp the thin wodden horn flares. That's plenty of work to get you started. Then you can work on the ports and the when you feel completely exhausted, attack the crossover. Welcome to the club!

That sounds like a good idea. I'll search around but do you have any threads in mind to help me get started?

[Panomaniac]

Me? No way.
http://www.hostboard.com/forums/f700...s-journey.html

[VolvoHeretic]

brace and damp the thin wodden horn flares.

Is there something magical about the horn flare's internal volume including the oval speaker baffle? It would be very easy to make a template of the horn flare and make a perfectly fitting 3/8" secondary flare to glue over the exterior of the first one. Maybe even two. After installing, the woofer baffle hole could be belt sanded back to it's previous profile.

[Panomaniac]

Why not do the same, but behind the flare? Oh - some of the boxes have closed off flare, of course.

[VolvoHeretic]

Why not do the same, but behind the flare? Oh - some of the boxes have closed off flare, of course.

With the downward sloped floor of the horn, it's impossible to get a one piece panel in there not to mention all of the glue blocks plus it would be impossible to measure accurately. I'd like to do it with oak plywood, cover the rest of the outside also with Oak, add bull nosed oak front edging, and bull nosed corner covers, then sand with 100 grit paper along the grain to really bring out the oak wood grain, and then painted gloss black with all of the beautiful woodgrain shining through.

[Voice_of_the_Llama]

Primed the box. Looking fantastic if I say so myself :yes:



Cut and primed the new port pieces



I gutted the other speaker so I can start sanding it...

First coat of paint on one speaker. Here you can see the difference in color between the painted (left) and original (right).



Filling and sanding of the "new" speaker... Tomorrow I'll do the front edges and hopefully I'll get to priming it.



Sanded and primed some more... I cut/drilled a new woofer access panel for one speaker because the old one was a little gnarly. Ran out of primer before I could do the other access panel.



Just to see how it looks...