DCM TimeWindow^2 Crossover Rebuilds

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I got a pair of TimeWindow^2 a while back and figured it's time for a recap. I had always heard that the crossover was crazy-complicated but I had never seen a picture of one, or a schematic.

Popped-the bottom cover off the "hat" portion of the speaker and here's is what I found.

Looks to be about.....

5 Pots
12 Coils
6 Electrolitic caps
10 Film caps
9 Resistors

Going to order some nice replacements for the electrolitics tomorrow.

Here's a look....

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Just tried looking at your image files and was informed that I don't have permission. I was going to offer a great source for a ton of TimeWindows info but....now I'm not so sure I should tell you.
 
Still getting use to the new format... should be viewable by all now.
 
I was going to offer a great source for a ton of TimeWindows info but....now I'm not so sure I should tell you.

I have plenty of sources - no need to divulge your private stash. Jeeze.
 
Hey Donkey! Long time no type.

I am hoping new 'lytics will solve my problem. Right now, they sound like a$$. Really weird pattern: No matter what the wattage, they start to sound horrible at about 1/2 volume. I have tested with the following sources:

Scott 299B - 31 watts/chan
Dynaco mono blocks - 50 watts/chan
Pioneer SX-880 - 80 watts/chan
Toshiba SA-7100 - 110 watts/chan
Yamaha MX-1000 - 260 watts/chan

When I get to about 1/2 volume, everything starts breaking up as if the drivers are damaged. Anything below 1/2 volume, they sound amazing. Again, doesn't matter what the potential watts of the source are (31 to 265), they ALL start to sound bad at about the same position on the volume knob. Weird.

Even at 1/2 volume on the big Yamaha, they still don't seem to "wake-up". Very muted and veiled sounding - and the bass is anemic at best. Something is wrong somewhere for sure.
 
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Steve Eberbach was a real believer in Phase and time alignment. Albet looks like a mess he knew what he was doing ! I owned TW 1 and TW 3 and regret selling them almost 30 years later !
 
I agree C.A.P. Big DCM fan here.

I have TW (original series, but w/round woofs not hexagonal), TF400, TF600, TF700 and CX-17's. Bucket list is TF 1000, TF 2000, TW 3 and of course the mythical TW 7!

Every DCM I have is good with ANY type of music and good with virtually ANY source driving them.

Steve E. captured magic in a bottle for sure.
 
Donkey. When the "Hats" are disconnected, the bottom section still distorts at about 1/2 volume. That tells me there must be a cap or something in the bottom as well.

Pulled he grills off the bottoms tonight. Popular rumor is NOT correct - the grills are not glued to the cabinet. They are held in place by 6 brad nails along the perimeter.

What's under the grills??? You guessed it...... Black Death. UUUGHHHH! Maybe tomorrow. I'm not heading down that road tonight!
 
Hey Donkey! Long time no type.

I am hoping new 'lytics will solve my problem. Right now, they sound like a$$. Really weird pattern: No matter what the wattage, they start to sound horrible at about 1/2 volume. I have tested with the following sources:

Scott 299B - 31 watts/chan
Dynaco mono blocks - 50 watts/chan
Pioneer SX-880 - 80 watts/chan
Toshiba SA-7100 - 110 watts/chan
Yamaha MX-1000 - 260 watts/chan

When I get to about 1/2 volume, everything starts breaking up as if the drivers are damaged. Anything below 1/2 volume, they sound amazing. Again, doesn't matter what the potential watts of the source are (31 to 265), they ALL start to sound bad at about the same position on the volume knob. Weird.

Even at 1/2 volume on the big Yamaha, they still don't seem to "wake-up". Very muted and veiled sounding - and the bass is anemic at best. Something is wrong somewhere for sure.

Personally, I don't feel your distortion issue is totally speaker related. It's strange that all those different amps exhibit the same issue. Plus, it just strikes me as very odd that both speakers would behave exactly the same way too. As such, have you tried a different preamp, since the distortion only occurs past a specific area of the volume pot. Maybe a cleaning is in order? Also, try a different source. I'd even swap to different front end interconnects too! You just never know! :eek:
 
It is very odd StimpyWan. I agree that it really does not make good sense what I am experiencing.

I have tried all of your suggestions. Multiple sources, multiple preamp/amp combinations, wiring, cabling... on and on and on....

The Scott, the Dynaco's, the Yamaha and the Pioneer are all part of separate, complete systems - different interconnects, wiring, sources etc. Also, I have other speakers on these same systems that sound fine including Dahlquist DQ-10, Infinity RS-4B, Klipsch Chorus II and Timeframes 700.

As far as them being identically "bad", I will say that the left speaker is much worse than the right one - although the right one will distort as well, just not as severe.

I just keep going back to a crossover problem for the simple fact that they just cannot seem to open-up even with the big Yamaha. I realize there is a massive, wattage-robbing crossover and they are 12 Ohm impedance to begin with but I think I should be hearing MUCH more SPL than I am getting. And any reasonable volume should be without distortion of course.

I appreciate your inputs. I am at a loss to explain this one - but I will get to the bottom of it.

Keep the ideas coming folks. I am open for any suggestion.
 
Sounds to me you have eliminated back to inside the cabs. Open to missing something here. I am sure you will get there, could very well be a Kernel Mustard in the Library with the Pipe Wrench working your way through the film stacks, pots, resistors, elecs... When diagnosing the 3's all four tweeters were dead between both towers. It turned out to be each had a bad lead running from the xxovers to the tweeter pots. Was interesting to me that two never opened +20yr old speakers with more internal wiring than a VW Karmann Ghia both shared the same toasted wires.
 
I ordered one of those flexible endoscope cameras this morning. Figured I would poke it through the one of the ports on the base and have a look around first before trying to disassemble. Worth a shot - they are cheap enough at < 20 bucks.
 
Remember I said I thought there must be another crossover in the lower section... well after and evenings-worth of fun with "Black-Death", I got my first look.

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Quite impressive!

Immediately noticed a round black disc (resistor???) that didn't look right. I touched it and it crumbled.

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Looks like it exploded!

Oh Boy... gonna be fun to figure out what will replace that! Hopefully there will be SOME markings on what's left that I can read. Forget about finding a schematic.

Not sure how I am going to get the board out to work on it. It doesn't look to be screwed in place so maybe I will be able to pry the glue loose.

Here's a couple more shots of the cabinet construction. A pie-slice shaped wedge created out of plywood to divides one part of the cabinet away from the other. I assume the bottom of it is open-ended with the rest of the cabinet and this constitutes the transmission line.

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I guess the state of this crossover explains the poor sound. I will admit that I am a bit concerned that I may not have the skill-set to pull this one off.

Interesting that the feed wires are split before the bottom crossover. Full range signal goes both to the base crossover and the hat crossover. I will continue recapping the hats - I got my goodies from PE the other day. Maybe I can get them sounding nice and that will provide motivation for me to tackle the bottoms.
 
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You know after thinking about it, I have a question:

Let's say you have your source signal into the speaker and it splits into 2 separate paths. Path 1 goes to crossover "A" which feeds bass drivers. Path 2 goes to crossover "B" and feeds the mids and tweeters.

So here is the question: Does crossover "A" and "B" have any interaction with each other? That is to say, If I remove "A" or "B" from the signal path, would the remaining crossover change in behavior? Maybe better stated, are "A" and "B independent of each other?

The reason I ask is, it just seems like a hugely complex crossover in the bass sections to just bleed-off the high signals that would normally be routed to the mids and tweeters. I was under the impression that this was accomplished with a big-honkin' cap and that's about it.

I guess the bases may be doing some mid-bass to low-midrange duty as well so that may explain the more elaborate crossover. I dunno :dunno:

Thanks for any pointers.
 
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Got both base cabinet crossovers out and ready for recap. I am still trying to determine a replacement part for the burned/exploded one. Turns out, these are polyswitches - used to keep from over-driving a speaker. There is one for the woofers, one for the midranges and one for the tweeters. Of the 6 total in all the cabinets, 4 of them are toasted. Once I determine the correct replacements, I'll get an order into PE and finish the crossover rebuilt.

One interesting thing about the bass drivers. The EIA code is 575 which according to my research says it was made by Heppner Manufacturing Company. I thought they went out of business before DCM produced these speakers in 82-84?? Anyone know any Heppner history?

They are 8" woofers and the entire code is 3077 575250

So if Heppner was still around, these would appear to be from the 50th week of 1982.
 
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Happy Turkey-Day everyone!

Crossovers are finally rebuilt. I only replaced the electrolytics, but it was still quite the adventure. 24 caps and 6 poly switches (2 of the poly switches were vaporized). Now time to put them back together!

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btw: here is what an AKer's Thanksgiving table looks like :thumbsup:

I have the most understanding wife EVER!

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Ready for a test-run. Not sure what to do about the grills yet. I would like them to be a little more removable than nails, but haven't quite figured it out yet - the frames themselves are flimsy. Considering Velcro, small button neodymium magnets or maybe just brad nails?

Also, opinions: Transmission line ports to the inside? Or like I have them, to the outside???

How do they sound you ask? One word: AMAZING! These things go LOW too!

Gotta get a pair of TW-3's now...

Thanks to all who helped out with the tune-up.

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