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Old 06-08-2015, 05:51 AM
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Quote:
Originally Posted by imstillatwork View Post
I just happened across a pair of TF-2000's serial # 422 and 423 I think. Anyways. Dirt cheap on Facebook. Picked them up and plugged them in to a HK AVR254, and later a Onkyo somthingrather.

They are a bit beat up, the socks was torn several places, faded, ripped and full of dog hair, so I cut it off to check the drivers. They look great! dusty, but good surrounds and all in tact. On lower woofer dust cover was dented in a bit, but seemed ok. All drivers moved freely if gently pressed.

Plugged them in to give them a test...

At low volumes they seemed to have phenomenal staging. Really decent clarity too. I don't know, they sounded big and expensive, right?
As the volume comes up though, the bass just never comes on. No bass. The mids were pushing harder than the woofers. The woofers were ALL functioning, but the output is terribly low.
At high volumes the mids and highs are just absolutely overwhelming. Oh My. Clear, Loud, but no bass still. *Some bass* just not anything CLOSE to what I would expect form this speaker.
My little 5.5" zaphs ZA5's thump harder than these.

Should I just try rebuilding the TF2000 crossovers first before I worry about anything else? The caps have got to be dried up at this age, right?

Aesthetically they aren't in great shape, but the drivers themselves looks fine - I'd like advice before dropping money into these.

If anyone wants pictures, measurements, etc, let me know - I'll be popping the rear covers off in a few weeks when I have some time to get to it.

thanks!
A few possibilities I can think of here;
first, you could be on the right track; something could be going on with the crossover or the like. I would definately check that even though crossover tend to affect bass much less than mid or treble as far as overall perceived output.
Second; check phase, check phase, check phase. Not only on your speaker wires but verify your amp/ receiver outputs for phase as well as internal wiring in the speaker cabinet. this effect bass moreso than percieved output from mids/ tweets.
third. the bass output from these speakers is usually deep and clean but compared to other designs and styles it has little output for bass heads. i went though this myself when i first started listening to vintage DCMs. On tracks that were not bass heavy they always sounded great, but when I was in a bass heavy mood, they would never satisfy. That's just the way it is because of their design. My ears and listening tate developed over time and though i still like more than these speakers can produce at times, i have developed and learned to hear the other things I was missing in the music when i was so focused on the bass.

I love vintage DCM and have an extensive collection. the TF-2000 is not one that i have and would love to own. Not trying to talk you out of them at all. check them out thoroughly and do your best to find out what's going on. You will probably end up loving them , even if it takes a little time. BUT, if you don't and want to get rid of them Please let me know. I would gladly pay you a fair price for them. definatley more than dirt cheap that you got them for.

DCM: TW1, TW3, QED, QED1a, TFV8.0, TF1000, (3pr) TF600, Time Piece, (3pr) CX27, (3+pr) CX17, (3pr) CX07, CX Center.
Polk: RTA12, SDA1C, SDA 2A, SDA SRS, SDA SRS 1.2TL, 5Jr., Monitor 5, Atrium (2pr).
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Old 06-08-2015, 09:42 AM
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Thanks, great tips. I checked and double checked the speaker leads. Then checked again when we tried a different receiver.
Honestly I only played them for about 15-20 minutes. I REALLY want to enjoy these, especially hearing how rare they are, and how much the tf1000 owners rave about theirs. My math says the tf2000's have to be AT LEAST twice as good as the 1000's Bonus points for naming a product using '2000' before the year 2000, you just can't argue that kind or marketing.

I don't think my expectations are too high for the performance of the low end. Like I said, I currently listen to Zaph Za5.3 MTM's with 5.5" drivers without a sub, and they go plenty low for casual listening (and plenty loud too!)

I'll post back when I get more time with them at my house - they are still at a friends house where I initially tested them out. I've got a bit more power then his setup, but still only an HK avr3600. I'd really like to pop the rear panel off and see what sort of shenanigans are going on inside.

I'm starting to see how lucky of a find these were, thanks for looking/helping.

-kevin
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Old 06-08-2015, 11:15 AM
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Regarding left & right placement, should these be drivers on the inside edge, or drivers on the outside edge?
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Old 06-08-2015, 07:33 PM
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More infoon my site if anyone follows this thread still!
http://lot-o-nothin.com/audio/dcm-ti...-tf2000-part-1

Now even more photo-y.


Last edited by imstillatwork; 06-11-2015 at 09:00 AM.
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Old 06-11-2015, 10:12 AM
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Is this the correct DCM badge for TF2000s? It seems so small...

http://www.ebay.com/itm/Vintage-DCM-...item51d0fdfa89
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Old 06-21-2015, 07:53 AM
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Hey guys,

I am in the home stretch of building my theater room, centered around the TW7's!
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Old 08-18-2015, 12:15 PM
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I'm rebuilding a pair of TF-700s (recent purchase)

clearly, my crossovers have been mucked around with, and I'm trying to get them back into correct factory configuration

could not find a schematic for the TF-700, only for TF-1000... apparently, the only difference between TF-700 and TF-1000 crossovers is that resistor RA is 47 ohms in the TF-700 (vs. 100 ohm)

please note I believe I have a pair of *first generation* TF-700s because:
- terminal cup is small round 3" diameter (not large rectangular)
- crossover is crudely hand-made on a piece of scrap wood with messy point-to-point wiring (not nice and neat on a custom PCB board)

my understanding is that the first and later generations of TF-700 used the exact same drivers and crossover values, so should otherwise function and sound the same(???)

QUESTIONS:

Q1: does anyone have an actual TF-700 schematic?... do they even exist?
Q2: is it true that TF-700 and TF-1000 crossovers are the exact same (except for resistor RA)?
Q3: TF-1000 schematic shows presence of a resistor R1 (15 ohm, 2W, 10%), but THIS PART IS MISSING FROM BOTH MY CROSSOVERS!!!... can anyone confirm that R1 is supposed to be there based on experience with your TF-700s?... and if so, is your R1 15 ohms? (any pics greatly appreciated, especially showing R1's location)
Q4: is there a chance that first generation TF-700s did not have an R1?

any help greatly appreciated, thank you!


UPDATE:

I've been searching the web for photos of unmolested TF-700 crossovers... so far, I've turned up *3* different types:

1. handmade tangled mess on a piece of wood (like mine, probably first generation)... it's hard to tell if resistor R1 is present, but so far I don't see any
2. sleeker PCB style, with R1 present and 15 ohm value (sitting right beside C1)
3. sleeker PCB style, with R1 present and 47 ohm value (sitting right beside C1)

now I'm really confused... seeing as the TF-700s all have the same drivers, shouldn't the crossovers be the same?... perhaps I should add in R1 to bring mine up to date with the later versions?... if so, what's best value for R1: 15 or 47 ohms?

ATTACHED photos show the schematic for TF-1000, plus my crossover in its current *altered* state
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Last edited by ssouci; 08-18-2015 at 04:48 PM.
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Old 08-29-2015, 05:38 PM
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Thought these may be interest here as there are a number of DCM owners. The speakers were made by Steve E. before DCM was a going concern. The cabinet they are sitting on are 8' wide to give some sense of their size. They are wedge shaped cabinets made to sit in a corner. In an email from Steve E. (below) he describes the "Fans", which I believe these are. This pair uses 4 Philips 6 1/2" drivers (Octagonal frame) and 4 Philips tweets per cabinet. I got them after they had been re-capped and cleaned up nicely. When I got them a couple of the drivers had magnets that had shifted, I think one cabinet got bumped a bit in a couple of moves before I got them. I was able to repair both of the drivers, no more voice coil rub and they sound perfect.

The cabinets are really big, 4 foot across at the widest point, about 22" deep from the front of the curve to the back, 16" high. Needless to say, they sound as big as they are. Very clean, a live jazz recording puts you in the second row. I am running them with a Carver m200t, and are also running a pair of TimeWindows, with the same octagonal Philips driver and tweets (My serial's are 650 and 674) with another amp. So, adding up all of the drivers, that's 12 -6 1 /2" and 12 tweets. Needless to say, I'm in DCM heaven.

Here is what Steve had to say about them:


The "strange" speakers are early DCM time windows made before time windows were even named. These are floor standing versions of monitors (to work with Crown DC-100 amplifiers) derived from larger "fan" shaped monitors built at my house and at Fanfare here in Ann Arbor (PA company doing professional sound reinforcement for rock concerts) for the purpose of providing sound track for TV show called Don Kirchner's "Rock Concert" broadcast with simulcast stereo sound tracks ( FM and Cable TV) Saturday nights in early 70's on old RCA color TV projector at my house. The color TV came thru U of M Property Disposition from the Medical School where it had been used for televising surgery O.R. to classroom. I was able to restore it to operation for very low cost making such entertainment available before we "kids" could usually afford it. My house was packed every Saturday night. In those days Fanfare was doing PA sound for Alice Cooper on tour. Alice Cooper's roots, BTW were in good ol' Detroit Michigan.

These speakers were not sold in stores, only by direct order to local "friends". This was during the formative years before we began to establish a dealer network. The early pre-DCM monitors used up to eight Phillips 6 1/2 inch woofers and eight Phillips tweeters and went into studios and homes of various people interested in and working in audio, radio, cable TV, and music concerts here in Michigan and on tour. A couple of these stacked on either side of a 100 inch TV screen with a couple of strapped Crowns sounded pretty good, and loud, and live in a living room sized venue.
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Last edited by gib48189; 08-29-2015 at 05:41 PM.
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Old 11-06-2015, 09:41 PM
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Quote:
Originally Posted by ssouci View Post
I'm rebuilding a pair of TF-700s (recent purchase)

clearly, my crossovers have been mucked around with, and I'm trying to get them back into correct factory configuration

could not find a schematic for the TF-700, only for TF-1000... apparently, the only difference between TF-700 and TF-1000 crossovers is that resistor RA is 47 ohms in the TF-700 (vs. 100 ohm)

please note I believe I have a pair of *first generation* TF-700s because:
- terminal cup is small round 3" diameter (not large rectangular)
- crossover is crudely hand-made on a piece of scrap wood with messy point-to-point wiring (not nice and neat on a custom PCB board)

my understanding is that the first and later generations of TF-700 used the exact same drivers and crossover values, so should otherwise function and sound the same(???)

QUESTIONS:

Q1: does anyone have an actual TF-700 schematic?... do they even exist?
Q2: is it true that TF-700 and TF-1000 crossovers are the exact same (except for resistor RA)?
Q3: TF-1000 schematic shows presence of a resistor R1 (15 ohm, 2W, 10%), but THIS PART IS MISSING FROM BOTH MY CROSSOVERS!!!... can anyone confirm that R1 is supposed to be there based on experience with your TF-700s?... and if so, is your R1 15 ohms? (any pics greatly appreciated, especially showing R1's location)
Q4: is there a chance that first generation TF-700s did not have an R1?

any help greatly appreciated, thank you!


UPDATE:

I've been searching the web for photos of unmolested TF-700 crossovers... so far, I've turned up *3* different types:

1. handmade tangled mess on a piece of wood (like mine, probably first generation)... it's hard to tell if resistor R1 is present, but so far I don't see any
2. sleeker PCB style, with R1 present and 15 ohm value (sitting right beside C1)
3. sleeker PCB style, with R1 present and 47 ohm value (sitting right beside C1)

now I'm really confused... seeing as the TF-700s all have the same drivers, shouldn't the crossovers be the same?... perhaps I should add in R1 to bring mine up to date with the later versions?... if so, what's best value for R1: 15 or 47 ohms?

ATTACHED photos show the schematic for TF-1000, plus my crossover in its current *altered* state
I don't have a TF- 700 schematic, but after looking at the pics you posted and some from another forum, first I would not even look at the TF - 1000 schematic nor make references to things like R1 or C2 unless you have a TF-700 schematic.

Next, if there were changes in the TF-700 crossover, I would not check with Steve because that would be like asking William Shatner what was Kirk's safe combination was from the episode "This Side of Paradise". It was too long ago.

With that being said, it looks like someone just upgraded some (or just one) caps and some resistors to what they thought would be better quality pieces. The inductors are more than likely the original. I can't make out the value of the Solen cap, but check it against the value from the know TF-700 pics you have (regardless of what version you think they are because more than likely they're the same).

Make your own schematic and post it. You can read the cap and resistor values and trace the leads, leave the inductor values blank if you don't have a meter to check them.

Keep posting, I'm sure we can figure it out.
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Old 11-07-2015, 04:29 PM
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Jamie:


thanks for replying... good news is that I finally finished completely rebuilding my DCM TF700 speakers... they look perfect, and sound great!


after a ton of research, I finally made up my own schematic for the TF700, which must be used in conjunction with the official schematic for the TF1000 because that one shows all the part values


I have ATTACHED both schematics with this post


NOTE:
- all parts, drivers, and wiring appear to be the exact same for TF1000 and TF700, except that TF700 has RA = 47ohms
- R1 appears to be missing in early TF700s that used a non-PCB "point-to-point wired" crossover style (that was the case for me)... also, seems that some do have an R1, but it is 47ohms, not 15ohms... I ended up using 15ohms for R1 which is what some later TF700s have, plus that is what TF1000 uses... so I assumed that 15ohms was the "final design"


more info and pics for my TF700 rebuild/restoration can be found here:
http://www.audiokarma.org/forums/ind...ration.678556/


cheers!
-- Paul
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Old 11-07-2015, 08:17 PM
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I'm glad you figured it out, the research is half the fun. Good work and good listening!
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Old 01-26-2016, 09:55 AM
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Hello all,

Long time lurker, registered with the hope of gleaning some knowledge from the fine folks in this thread.

I've recently moved into a loft apartment with enough space to set up a proper surround system, and have a pair of TF-700 floorstanding speakers that are no longer constrained by a tiny room. I love the look and sound of these speakers, and would love to go for an all DCM setup if possible. I purchased a Denon AVR-S710W for a receiver (I'd go vintage, but wireless streaming is 90% of my listening, with vinyl coming out on special occasions), and so I need guidance on a center channel and rear surrounds.

From what I've read in this thread (and others), my top choices for a center channel that will timbre match the TF-700's are, in descending order:
SurroundScape Center (very hard to find, but there are some components on eBay that could potentially go into a DIY build?)
CX-17 (or maybe a CX-07?). Would require that I remount my TV to give the speaker sufficient vertical clearance.
CX Center
???

For rear surrounds, I've found the following options, although I'm not sure which ones would work best:
CX-007 (no data anywhere on these, but they're very small bookshelf speakers that would be easy to setup as satellites. Are they new DCM or old?)
CX-07
CX-17
CX-27 (probably too big for my purposes)
Time Piece (I can't find dimensions on these, and it appears the Time Piece name has been re-used by DCM for newer models)
Time Window (no model #'s available on Craiglist)

I appreciate any help in this search.
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Old 01-31-2016, 12:52 PM
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You may have to rethink your list of speaker choices. You would be correct if you had the TF-600's. If I'm not mistaken, the TF-700 used a different set of drivers, particularly Vifa tweeters. If that is the case you should be looking for the Macrophones or the Timepieces (originals).
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Old 04-28-2016, 12:04 PM
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A quick question for anyone who might know.

I have a pair of Timewindow 1A speakers, but the DCM badges are long gone. Is there a way to determine which speaker is the left and which is the right? Or doesn't it matter?

Thanks
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Old 04-28-2016, 12:14 PM
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Quote:
Originally Posted by Olecranon View Post
A quick question for anyone who might know.

I have a pair of Timewindow 1A speakers, but the DCM badges are long gone. Is there a way to determine which speaker is the left and which is the right? Or doesn't it matter?

Thanks
I've owned a pair of Time Windows, and they are both the same, so it doesn't matter which side they're on, and I'm pretty sure the 1a is the same way. There are two 6.5's and two tweeters in each speaker. I also have some Time Window 3's, and those do have a specific left and right speaker, as those have an 8" and 6.5" coaxial in each speaker, and the 6.5" are supposed to be towards each other.
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Old 04-28-2016, 12:50 PM
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Quote:
Originally Posted by 89grand View Post
I've owned a pair of Time Windows, and they are both the same, so it doesn't matter which side they're on, and I'm pretty sure the 1a is the same way. There are two 6.5's and two tweeters in each speaker. I also have some Time Window 3's, and those do have a specific left and right speaker, as those have an 8" and 6.5" coaxial in each speaker, and the 6.5" are supposed to be towards each other.
Interesting. For some reason I had in my mind that the crossover delayed the inside firing speaker so it arrived at the listener the same time as the outside reflected sound wave. Maybe that was on the 3's and 7's only.
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Old 04-28-2016, 02:00 PM
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Quote:
Originally Posted by Olecranon View Post
Interesting. For some reason I had in my mind that the crossover delayed the inside firing speaker so it arrived at the listener the same time as the outside reflected sound wave. Maybe that was on the 3's and 7's only.
I'm pretty sure the 3's and 7's are the only ones (of the Time Window series) that have an orientation.
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Old 04-28-2016, 04:01 PM
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Originally Posted by 89grand View Post
I'm pretty sure the 3's and 7's are the only ones (of the Time Window series) that have an orientation.
That's probably it. I also had some DCM TF-700's and I know the Timeframe series had specific L/R speakers so I might be mixing them up all these years later.

One final question that I'm hoping someone can help me with. I'm kicking around the idea of replacing the "socks". The 1a's have the nut on the bottom to remove the two end caps, but it's the actual grill material I'm curious about. I've seen a lot of reference to a specific foam material, but the grill material on the 1A don't feel like open cell foam. It feels more like a very loosely woven fabric. Does that seem right? It's even sewn together up the back side. I would assume foam would just tear apart?
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Old 04-28-2016, 04:33 PM
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My Time Windows had the open cell foam, your 1a's should be some type of material, a grill cloth type.

That's how my 3's are, There is a layer of auto headliner foam backed type material over the enclosure, and then a grill cloth type sock over the top of that.
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Old 04-29-2016, 04:10 AM
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Quote:
Originally Posted by 89grand View Post
My Time Windows had the open cell foam, your 1a's should be some type of material, a grill cloth type.

That's how my 3's are, There is a layer of auto headliner foam backed type material over the enclosure, and then a grill cloth type sock over the top of that.
I wonder if something like this would work.

http://www.parts-express.com/melloto...-wide--260-332
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Old 04-29-2016, 08:40 AM
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I believe that is exactly what I used on my 3's.
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Old 05-06-2016, 01:54 PM
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Quote:
Originally Posted by 89grand View Post
I believe that is exactly what I used on my 3's.
I'm going to give that speaker fabric a try, but I have a bit of a dilemma. They only sell it in increments of a full yard. I've measured (as best as I can) around the Timewindow 1A and it looks to be 36" inches in circumference. Supposedly it's got some stretch to it, so a yard should be hopefully just enough to go around it after losing a bit for the seam to be sewn. I would hate to have to buy a third yard (at $25/yard) just so I can make two 37" pieces.

I hope 36" is accurate. I looked up the dimensions, but it doesn't give circumference I'm going to refinish the wood cap while I'm at it.

I'm also kicking around the idea of recapping the crossovers. I think I've looked through all 50+ pages and haven't found a shopping list for parts that should be replaced.

Does anyone have a suggestions on which caps need to go, and which ones I can skip?
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Old 05-06-2016, 06:12 PM
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Quote:
Originally Posted by Olecranon View Post

Does anyone have a suggestions on which caps need to go, and which ones I can skip?
Replace them all. The NP electrolytics are probably over twenty-five years old and are
long past their useful life. The Orange Mylar caps need to go, too. They are more suited
to their intended use as pulse suppression caps. Resist the urge to 'go cheap' on the
replacement caps by buying Dayton caps and purchase Solen, Audyn, or Jantzen X-series
metalized Polypropylene caps. Solen is preferred and if you do some shopping, you can find
them to be the best value. Replacing the caps will make a huge difference in the sound
quality.

Replace the sandcast resistors with some Mundorf metal film resistors. They are only
about $2.50 a piece over at Madisound. You will be surprised at the difference they make.

You should also consider replacing the coils. The large square ones are hand-wound on the
plastic core. The windings are loose and not evenly laid down around the core. Because the
values of the coils were originally based on their DC resistance in an attempt to reduce
the parts count, the values measured with the Aluminum core in place are not the values of
the coils themselves. You will have to select a coil that is slightly higher in value and
then 'tune it down' using Aluminum washers in the center of the coil. You will have to also
insert some resistors in series with the replacement coils to maintain the Q of the filter
and the overall system impedance. They are best replaced with some Jantzen air core coils.

If you elect to replace the caps, resistors, and coils; you should buy more than you need
and carefully match the values of the components. Doing so will ensure that the frequency
response and timbre of both speakers are as close as you can get them to each other.
If you haven't already invested in a quality LCR meter and DVM, now is the time.
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Old 05-09-2016, 05:21 AM
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As already mentioned change the caps and the resistors. Quality of caps and choice should be as already described. BUT, if budget is a major concern the Dayton 1% caps are actually decent for the money. Either way new caps will make a huge difference, even if you choose modern electrolytics. But the electrolytics will generally sound the least good of all the other choices. However, the caps in delay circuits should be kept electrolytic so as not to mess this detail up in the design. Different types of caps have different phase responses and in the time delay circuits of the tweeters changing to a different the can easily mess the delay up.
As for the coils, there are definatly better coils out there these days but if you are not a very knowledgeable crossover designer, i would leave the coils as is. I say this because most of the coils on the old DCMs are not marked as to their value and if you do not know that value you must measure it. Something most people will not want to get into. DCR is easy o get with even a basic multimeter. But also,as previously mentioned, the aluminum plugs in the middles of the coils alrter their values and responses. Their orientation on the crossover board and their positioning near other crossover items (especially other coils) also effect their values and functions. So even though it is possible to do better, it is much more work than most people are able to or willing to do for the much smaller benefit you get over doing the caps and resistors.
So definitely change caps and resistors, its relatively inexpensive unless you just get the best caps on the market and makes a HUGE difference without having to even have much knowledge of electrical circuits as you can just read the current values from the old parts and replace with much better newer parts.
good luck and enjoy.

DCM: TW1, TW3, QED, QED1a, TFV8.0, TF1000, (3pr) TF600, Time Piece, (3pr) CX27, (3+pr) CX17, (3pr) CX07, CX Center.
Polk: RTA12, SDA1C, SDA 2A, SDA SRS, SDA SRS 1.2TL, 5Jr., Monitor 5, Atrium (2pr).
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Old 05-12-2016, 05:05 PM
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So I am kicking around the idea of selling off some of my collection to compromise for WAF. In case anyone was interested... TW7, TFV 10.0, 6.0, tf1000,tf700, tf600,tl tf400, surroundscape center, cx31,cx17,cx07.
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Old 05-16-2016, 02:09 AM
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DCM Lover. I sent you a PM.
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Old 07-18-2016, 11:45 PM
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Does anyone have a schematic for the Time Frame TF-275 crossover? I just picked up a pair and the tweeter in one appears to be blown. I haven't removed the socks yet, but pulled the crossovers to measure the resistance at the leads and noticed the driver leads were connected in a different order for the two speakers. So, I suspect someone else has been playing around in there. Not sure if they hooked up the leads incorrectly before, or after blowing the tweeter.

In any case, a schematic for the TF-275 would help me sort this out. I'll probably order a pair of the Goldwood replacement tweeters from Parts Express that are recommended as replacements for the TF-600 speakers as I believe the TF-275s use the same tweeters as the TF-600s.

Anyone know if the TF-275s also use the same midbass drivers, with the rubber surrounds, as the TF-600s? I suppose I'll find out when I pull down the sock on the one with the bad tweeter. These appear to be in pretty good condition (other than the blown tweeter) and I'd really like to avoid pulling the sock on the good speaker, dealing with the headliner foam and wrestling the midbass drivers out of the cabinet. In an ideal world, I'd just pull down the sock on the one with the bad tweeter, replace the tweeter, pull the sock back up, glue it in place, replace the top cap and be ready to go. I'll probably do a recap as well, as it looks easy (just two 3.3uF NP electrolytics and one 0.47uK film cap per crossover).
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Old 07-19-2016, 10:23 PM
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Quote:
Originally Posted by MCM_Fan View Post
Does anyone have a schematic for the Time Frame TF-275 crossover? I just picked up a pair and the tweeter in one appears to be blown. I haven't removed the socks yet, but pulled the crossovers to measure the resistance at the leads and noticed the driver leads were connected in a different order for the two speakers. So, I suspect someone else has been playing around in there. Not sure if they hooked up the leads incorrectly before, or after blowing the tweeter.

In any case, a schematic for the TF-275 would help me sort this out. I'll probably order a pair of the Goldwood replacement tweeters from Parts Express that are recommended as replacements for the TF-600 speakers as I believe the TF-275s use the same tweeters as the TF-600s.

Anyone know if the TF-275s also use the same midbass drivers, with the rubber surrounds, as the TF-600s? I suppose I'll find out when I pull down the sock on the one with the bad tweeter. These appear to be in pretty good condition (other than the blown tweeter) and I'd really like to avoid pulling the sock on the good speaker, dealing with the headliner foam and wrestling the midbass drivers out of the cabinet. In an ideal world, I'd just pull down the sock on the one with the bad tweeter, replace the tweeter, pull the sock back up, glue it in place, replace the top cap and be ready to go. I'll probably do a recap as well, as it looks easy (just two 3.3uF NP electrolytics and one 0.47uK film cap per crossover).
Ok, did my own detective work. I removed the top cap, following the usual procedure, and pulled the sock down to get at the suspected bad tweeter. The good news is the inner sock (headliner) is in great shape showing no signs of deterioration. So, that will make putting things back together easy. Here's a photo of the drivers, in situ, with the sock pulled down:



The suspect tweeter was, indeed, blown. After unsoldering the leads, I measured the resistance - infinity, open circuit.

Here's some more photos of the tweeter:





And, the midbass driver:



The surround is indeed rubber, or what actually looks like a rubber coated cloth. In any case, very pliable with no cracking or other deterioration and firmly attached to both the frame and the paper cone of the midbass driver. That's a relief. No reason to remove the driver from the cabinet and deal with the dreaded black dragon snot DCM used to secure the drivers in place.

The color of the tweeter leads changes somewhere inside the cabinet. I ohmed them out and they are:

at crossover -> at tweeter
White -> Black with Yellow Stripe (this is the T+ lead)
Green -> Black (this is the T- lead)

That leaves the red (W+) and black (W-) leads for the midbass driver. This makes sense. So, I guess I don't need that crossover schematic after all.

Just to verify the connections were correct, and there aren't any other problems in the signal chain, I used some alligator clip leads to temporarily connect a little Audax TW74A tweeter I happened to have on hand. Viola!! Success (at least temporarily). Here's my test setup:



I've been listening to it for the last couple hours. The Audax tweeter doesn't fit the black metal mesh, but at least it's given me a chance to hear the potential of these speakers and verify that everything is working correctly.

I ordered the Goldwood GT-302/S 1/2" Mylar Dome Tweeters from Parts Express that are the recommended replacement for the TF-600. I ordered two and plan to do both speakers so they are properly matched. This is Parts Express Part Number 270-175. This is the shielded version. My original tweeters were not shielded, and there is an unshielded version of this same tweeter (Parts Express Part Number 270-170), but its only 13 cents cheaper than the shielded version.

Given the excellent condition of the inner sock headliner material, and the fact that there is no reason to remove the midbass drivers, this should be a very easy repair. While I was at the Parts Express web site, I also ordered four 3.3 uF 400V Audyn Q4 caps to replace the original NP electrolytics and two 0.47 Audyn Q4 caps to replace the factory installed film caps. I would have went with the slightly more expensive Solens, but they were out of stock with no back in stock date available. So, I ordered the Audyns. I've used them in the past and they should be a nice, inexpensive upgrade over the stock caps.

Last edited by MCM_Fan; 07-20-2016 at 12:52 AM.
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Old Yesterday, 11:49 PM
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My package from Parts Express arrived yesterday afternoon. I installed the Goldwood tweeters and recapped both crossovers. Here's some photos:

Goldwood GT-302/S Installed on DCM Time Frame TF-275:



Original DCM Time Frame TF-275 Crossover with 2x - 330uF 100V NP Electrolytic Capacitors and .47uF 100V Film Cap:



Recapped DCM Time Frame TF-275 Crossover with 2x - 330uF 400V and .47uF 400V Audyn Q4 Metallized Polypropylene Capacitors:



As you can see, the Audyn caps are bigger than the original caps, but it wasn't difficult to get them to fit. I've been listening to them all evening and am very pleased with the sound quality, both of the Goldwood tweeters and the recapped crossovers. The Goldwood tweeters from Parts Express are a good deal at just over $3 each. I found the exact same tweeters at another well known vendor for $12.95 each. Not sure why there is such a price disparity, but add me to the list of satisfied users of the Goldwood tweeters as replacements for the DCM TF-275, TF-600 and CX-17 and CX-27 speakers.

I've used Audyn Q4 caps before and found them to be a good, basic MPK capacitor that are very reasonably priced. I also like to use the ClarityCap PX series. They are about 2x the price of the Audyn Q4 caps, but still very reasonably priced. They are also considerably larger and fitting them onto the TF-275 PCB would have been a challenge. In any case, the Audyns are a definite improvements over the original 30-year old non-polarized electrolytics.

With new tweeters and new metallized polypropylene capacitors, these TF-275s should be good for at least another 30 years.

All that I need to do now is pull up the socks, glue them in place at the top with some 3M Super 77 and tap the oak top pieces back in place and another project will be competed for me to enjoy.
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