DIY asilker's Altec VOTT thread

Do It Yourself
I should note, 604-8k and the 904-8A schematics were never published.

Was close to 14 years ago I rebuilt my 604-8K cross-overs and as I recall they were identical to the 8H. Markwart's 604 crossover for the H III was based of the K. I think in his write up he actually notes he could not really improve on it.
 
Was close to 14 years ago I rebuilt my 604-8K cross-overs and as I recall they were identical to the 8H. Markwart's 604 crossover for the H III was based of the K. I think in his write up he actually notes he could not really improve on it.

That’s what I gleaned from his writing as well.
 
I am scheduled to pick up a rough pair of A7 500 tomorrow morning, and I am allowing myself to start a thread now and count my chickens before they hatch 🐣

Based on photos, it appears my set will include:
- 828 cabinets
- 421a woofers
- 511b horns
- 808 8a compression drivers with (presumably) old Symbiotik diaphragms *and matching NOS diaphragms
- third party PA crossovers

Goals
- Passive crossovers. I have plans for a fully DSP multi driver setup in the future, and that will go in another room. I would like a set of monitors to pair with amps as I continue to build.
- Avoid the "cart before the horse" mentality. I know from experience that Altec speakers can sound great, but I don't feel any compulsion to dial out inherent design limitations. I would like this project to lean toward thoughtful use of resources as opposed to all-out TOTL
- bass into the 30's hz (after room boundary reinforcement)

Plans
I am grateful to be able to follow the slipstream behind folks like Pano, who documented his progress with the A7 format HERE

- Add bracing to the midbass horn wings
- Cut a vented baffle so roughly 50 sq/in to assist the woofer in reaching into the 30hz
- use a 416 woofer or something very much like it
- find a midrange suppression circuit to address the 200hz hump

Questions / Opinions Welcome
- I am considering reconing the 421a with 416 recone kits. There are myriad AK threads from 2008ish-2012ish which mention adapting 416 onto 421a frames, like Gordon's post HERE. Would anyone like to push me toward, or away from this plan?
-
I am aware of the following passive crossover circuits, but I would appreciate any opinions or info regarding your subjective preferences: Markwart Model 19 / Altec 500hz and 800hz / Jean Hiraga A5. I have a strong preference for a crossover which features a midrange adjustment if possible.
- My experience with Alnico JBL D and K series drivers suggests that I might notice demag tendencies in the 808 8a CDs. I definitely want to stick with the 511b, but I am happy to run just about any CD, including contemporary B+C or Radian. Any suggestions for a 1" CD? * I will be using the 808 8a CD's.
- I am considering building a 16ohm system to pair with low powered tube amps. I realize that plenty of OPTs come with 4 and 8 ohm taps, but I am coming out of MOSFET and lower efficiency towers, so I'm interested in trying something different. Is there any glaring reason why I would avoid 16ohms? * these drivers all appear to be in good functional condition and they're 8 ohms. I'll stick with that.

Thanks for any and all involvement with my project, folks. I will post photos tomorrow when I am in possession
I have A7’s, reinforced cabinet with 1”x2” wood batons glued and screwed on edge in irregular patterns to prevent standing waves, filled cavities on one side with wool felt.

I used a Pete Riggle “Hiraga” crossover , don’t use the super tweeter bit but turn the volume on the compression drivers up to 75% roughly.

I changed my trble horns for wooden exponential horns done by Marcus Klugg in Germany.
 

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I have A7’s, reinforced cabinet with 1”x2” wood batons glued and screwed on edge in irregular patterns to prevent standing waves, filled cavities on one side with wool felt.

I used a Pete Riggle “Hiraga” crossover , don’t use the super tweeter bit but turn the volume on the compression drivers up to 75% roughly.

I changed my trble horns for wooden exponential horns done by Marcus Klugg in Germany.
Hey, this looks familiar. Everything but the cabinets.
 
I also replaced the back panels as they rattled (the Altec crossovers were screwed to a wooden plate and that screwed over a hole, also old screw holes worn loose).
 
Hey all (including @Rensselaer ) thanks for the continued outpouring here.

Work and family have been demanding this week, and I think I might need some time on a bike to get my head straight this weekend but I will drop back here soon with updates.

Right now I am going through another round of clearing out my shop and setting up saws etc. It has been genuinely encouraging to hear some of you discuss the same issues :tongue:

I tried a few approaches to form appropriate braces with the tools on hand, and they just will not do. Proper band saw and disc sander are in order. Next steps: braces for the mid horn, fill with something inert, cut and install baffles.
 
This week I purchased a Hitachi C10FL table saw. I am working on installing a riving knife (thread HERE).

I'm also installing new graphite blade guides in a bandsaw. Disc sander will be set up next too.

I am trying to let this VOTT project cross pollinate my other DIY goals for the next few years, which includes furniture repair, a full basement and bathroom reno, kitchen cabinets, and of course British style mini monitors (duh)

But all of these things require properly squared and serviced equipment.

My shop is roughly 20' x 20', and I have spousal clearance to use every square foot. So other to-do tasks include lighting and air circulation. Lots to do, but I am grateful to have the opportunity to set up my own space.
 
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This week I purchased a Hitachi C10FL table saw. I am working on installing a riving knife (thread HERE).

I'm also installing new graphite blade guides in a bandsaw. Disc sander will be set up next too.

I am trying to let this VOTT project cross pollinate my other DIY goals for the next few years, which includes furniture repair, a full basement and bathroom reno, kitchen cabinets, and of course British style mini monitors (duh)

But all of these things require properly squared and serviced equipment.

My shop is roughly 20' x 20', and I have spousal clearance to use every square foot. So other to-do tasks include lighting and air circulation. Lots to do, but I am grateful to have the opportunity to set up my own space.
NIce! You will have fun. Add a good track saw to your list if you haven't already.
 
Maybe Gavin @old_borg could measure the cabinets he has and report for you.
I don't remember the size of vent I ended up with
Late reply - the front vent runs rough opening runs the width of the cabinet by 12 3/4". It is lined with 3/4" material acting as a back stop for the cloth vent covers.

I'd post a picture but the space I am setting the cabinets up in is not photo ready.

Thanks again, @MrEd !
 
my head hurts just thinking about it.
Kitchen is more or less finished, first two bathrooms are finished. Living spaces and bedrooms are finished. Still a lot to go, but plenty of progress so far. Some days it feels rewarding, most days like I will be working on things for the rest of my life :)
 
Kitchen is more or less finished, first two bathrooms are finished. Living spaces and bedrooms are finished. Still a lot to go, but plenty of progress so far. Some days it feels rewarding, most days like I will be working on things for the rest of my life :)
Kitch & baths are the worst so I'd say you're almost home.
I'm not a fan of doing the remodel myself but after I get quotes, I get more motivated.
 
Some days it feels rewarding, most days like I will be working on things for the rest of my life :)
I started the renovation of our home in 1985 and kicked ass on it for over 30 years. The thing I wasn't prepared for was that now many things (furnace, fixtures, windows, etc.) are needing to be updated again. I'll admit I'm not feeling the love I had 42 years ago when I bought the place. I need a little inspiration refreshing.
 
I started the renovation of our home in 1985 and kicked ass on it for over 30 years. The thing I wasn't prepared for was that now many things (furnace, fixtures, windows, etc.) are needing to be updated again. I'll admit I'm not feeling the love I had 42 years ago when I bought the place. I need a little inspiration refreshing.
I hear you. I'm on year 3 and your story sounds believable.

We're looking at windows. The information I have makes them sound like longer term consumables. Its attractive to work with drivers that will last for a very long time VS watching the timeline for fridges, water heaters, furnace, windows.... You get the picture.

I have a Gibson J45 that won't need to be repurchased in 20 years.
 
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