avguytx Posted February 23, 2017 Author Share Posted February 23, 2017 New Solen caps plus 245uh coils should be in Friday (2/24) for converting the Type B crossovers to Type B-2. Also new binding posts for easier connections, too. I'm going to do the crossover first, finish up my ST-70 amplifier and tie into the system, then I'll ponder changing tweeters, etc. I want to hear them first without all the extras. I do need to re-cover the grills, too, at some point. But not a crazy important thing. I may use a couple of the newer "pie" shaped badges /emblems for now as I don't want to pay $95 for a pair of the originals. Unless someone here has some they want less for... Quote Link to comment Share on other sites More sharing options...
avguytx Posted February 24, 2017 Author Share Posted February 24, 2017 What's the latest B&C tweeter? Is it the B&C DE120 or the newer DE110? Are the Crites CT-120's using the DE120? Quote Link to comment Share on other sites More sharing options...
avguytx Posted February 25, 2017 Author Share Posted February 25, 2017 Well, it's something off with the speakers. I changed to a different amp and they still are dull and lifeless. Left speaker had no highs at all. After I get done with the antenna in the attic, backso will come out and drivers checked. I've got the caps and coils in to change them to B-2 networks so I'll find out if new drivers/diaphragms are needed. Quote Link to comment Share on other sites More sharing options...
jjptkd Posted February 25, 2017 Share Posted February 25, 2017 These old Cornwalls need fresh caps and mid horn gaskets at the very minimum, I'd even spring for the new CT-120 tweeters if you plan on keeping them. Lifeless is not how I'd describe my experiences with the Cornwall so I would suspect something is wrong somewhere. Quote Link to comment Share on other sites More sharing options...
avguytx Posted February 25, 2017 Author Share Posted February 25, 2017 Metered all of the drivers; woofers are at 3.9 ohm, mids 10.8 ohm, and tweeters 6.4 & 6.8 ohm. So, we're good there overall. Crossovers are out of the cabinets and ready to be updated from B's to B-2's. I checked capacitance on the old caps and they weren't too far off but I can't check ESR with my Fluke 112. They do look to be leaking a little on the tops, though. Quote Link to comment Share on other sites More sharing options...
avguytx Posted February 25, 2017 Author Share Posted February 25, 2017 Yep. Updating the caps took care of it. Changed them to B-2 networks too. 3 Quote Link to comment Share on other sites More sharing options...
jimjimbo Posted February 25, 2017 Share Posted February 25, 2017 Good news 1 Quote Link to comment Share on other sites More sharing options...
avguytx Posted February 26, 2017 Author Share Posted February 26, 2017 Now to deliberate on tweeters or not. Might listen to these for awhile and get a feel for 'em. Some Bob Seger playing now. Good stuff. 1 Quote Link to comment Share on other sites More sharing options...
jimjimbo Posted February 26, 2017 Share Posted February 26, 2017 Do some Joe Bonamassa (Beacon Theater), and Tower of Power (40th Anniv Concert).....those two will help you make your decision. Quote Link to comment Share on other sites More sharing options...
muel Posted February 26, 2017 Share Posted February 26, 2017 Here's the "WHY" on the B2: CROSSOVER NETWORK CHANGED: CORNWALL Vol. 20, No. 1 June 1, 1981 NEW DEVELOPMENT The product-evaulation program at KLIPSCH and Associates constitutes the lion's share of our Research and Development effort. We are now gratified to add another entry to the long list of performance improvements made in our product line over the years. Advances in the state-of-the-art of sound reproduction frequently result from innovation of new techniques of acoustic measurement, the aim being to utilize quantitative tests which closely corroborate the psychological sensations of the listener. Thus new measurement techniques or bolstered power and convenience of data-conversion bring excitement to the work of design, but always with the sobering constraint that new test results carry import only to the degree to which they have psychological significance. That is, the test format must be such that the genuinely most significant acoustic parameters receive the greatest emphasis during design. The latest in a long series of "technical papers" from KLIPSCH Engineering explains the operation of our unique "Anechoic Chamber With Optional Boundaries" (AES Preprint 1979) which facilitates deeper scrutiny of loudspeaker response characteristics. The KLIPSCH CORNWALL has taken yet another step in its evolution toward optimum performance. A complete re-design of the crossover network has made possible a significant improvement which we now happily share with the audio public. Briefly, the new design entails the following: 1) Constriction of the electrical signals received by each driver to the spectral band over which the driver displays optimum characteristics is a salient feature of the design. A) Boosted woofer output is obtained in the 400 Hz to 600 Hz region. Combined with a more rapid transition to an attenuating characteristic at frequencies above cut-off. Substantially decreased low-frequency energy is applied to the midrange driver. Though tremendous improvements are not possible in this regard, intermodulation distortion is somewhat reduced and the possibility of squawker failure is made even more remote. C) Dramatic improvement in the stop-band attenuation is provided by the highpass filter associated with the K-77MTweeter. Overall, this means that more energy can be derived from the tweeter above 6 kHz because of reduced current-flow into the tweeter in the mid-band. 2) Studies of the cross-correlation of woofer and squawker output waveforms have precipitated a substantial increase in coherence near the crossover frequency. A) The attenuation characteristics of the woofer (low-pass) and squawker (high-pass) filters are associated with a particular set of phase characteristics; the two are mutually dependent and cannot in general be manipulated individually. The roll-off rate of the woofer filter and the spectral location of the cut-off point of the squawker filter govern the relative phase relationship of their outputs in the crossover band. Only a special set of circumstances will allow optimization of filter phase characteristics without an associated deleterious effect on the amplitude attributes of the filters' transfer functions. Driver polarity does not affect the amplitude response of the driver in question, but does in fact greatly affect the steady-state response of the system considered as a whole. In this case, the mechanical location of the sources, the phase characteristics of the electrical filters, and the relative polarity of the drivers are manipulated in a harmonious manner to render the crossover-band response smooth and non-anomalous. Designated the Type B-2 Crossover, this new network is aimed at genuine improvements to the overall characteristics of the CORNWALL Loudspeaker System. The effective date of this change is approximately June I, 1981. We plan to make the transition in smooth manner, hence the early notice. As always, we will maintain stock of Type Networks and adequate repair facilities for CORNWALL owners. Since in general no change in drivers.or cabinet is associated with the network, an update from the Type B to the Type B-2 will be a relatively simple matter. Owners of older CORNWALLS are encouraged to incorporate up-to-date drive components (K-33E, K-55V with nested phasin plug, and K-77M) to maximize the benefits derived from use of the B-2 Crossover. An update kit (Type B to Type B-2) will soon be made available through the KLIPSCH dealer network. DAN BYNUM ENGINEER DB:rh Quote Link to comment Share on other sites More sharing options...
muel Posted February 26, 2017 Share Posted February 26, 2017 June 5, 1981 The updated B2 network, with steeper crossover slopes is phased in with no changes to the K-33-E, K-55-V and K-77-M driver compliment. Quote Link to comment Share on other sites More sharing options...
jimjimbo Posted February 26, 2017 Share Posted February 26, 2017 Thank you for that!! Always enjoy short and sweet, to the point technical articles like that. Quote Link to comment Share on other sites More sharing options...
avguytx Posted February 26, 2017 Author Share Posted February 26, 2017 So it's a second order filter but keeps the crossover points the same or changes them? I can tell there's some upper end missing I could hear on the CF-3's. Even with my limited top end hearing. I've got some Joe B on my server and for what I don't, there's Spotify. That's good stuff for sure. Quote Link to comment Share on other sites More sharing options...
avguytx Posted February 27, 2017 Author Share Posted February 27, 2017 Crossovers before and after pictures. I know they aren't fancy but they are soldered in and work well. I'm pretty sure the networks outputs are already reversed in phase so the speakers hook up to the terminals as they are? Quote Link to comment Share on other sites More sharing options...
avguytx Posted February 27, 2017 Author Share Posted February 27, 2017 Is it worth replacing the K-55 diaphragms with new diaphragms now that they're 39 years old? Or just leave them? I'm not really ready to shell out the $$$ for A-55-G's but $120 for diaphragms is doable...if there's any difference. Still debating on the tweeters too. Quote Link to comment Share on other sites More sharing options...
muel Posted February 27, 2017 Share Posted February 27, 2017 Assuming the diaphragms have never been changed I have some that are 49 years old. If there is a difference between those and ones I have that are much younger I can't tell. Quote Link to comment Share on other sites More sharing options...
jimjimbo Posted February 27, 2017 Share Posted February 27, 2017 Given your scenario and apparent desire to update to the A-55-G's, why don't you just sell the current 55's, take that and combine with the $120 you are willing to spend, and get the A-55'G's? Can't be too far off doing that, I wouldn't think.... Quote Link to comment Share on other sites More sharing options...
avguytx Posted February 27, 2017 Author Share Posted February 27, 2017 Thanks for the input, muel. I wonder if anyone on here has some used CT-120's or Elliptrac HF's they decided not to use or didn't like. Will have to post a WTB and see Quote Link to comment Share on other sites More sharing options...
muel Posted February 28, 2017 Share Posted February 28, 2017 21 hours ago, avguytx said: Thanks for the input, muel. I wonder if anyone on here has some used CT-120's or Elliptrac HF's they decided not to use or didn't like. Will have to post a WTB and see Might have a better shot at some CT-125's used since the 120's haven't been around as long. Personally, I like the K77's... the tweeter is about the last tweak I'd bother with but that is just my opinion. Tweeters are the sizzle on your steak. You can decide how much that matters to you. Shoot... now I just want some steak! Quote Link to comment Share on other sites More sharing options...
avguytx Posted February 28, 2017 Author Share Posted February 28, 2017 It just seems that there is upper end missing that the CF-3's do so well with. Like I stepped down in SQ. Overall, the CF-3's are still more balanced across the spectrum and, in my living room, still have better bass than the Cornwall's do. The CF-3's even sounded better than the KLF-30's I had...which sounded anemic even after cabinet bracing (fixing the "thwack" back panels) and updating caps, resistors, and tweeters..so they were sold off. I may wait to do any more on the Cornwall's till after the VTA ST-70 amp is finished and hooked up to see what that that combination sounds like. And I hate my living room, too. I can't wait to buy or build a new house and have a dedicated room for music. The living room in my house back in Texas sounded great. The one now sucks. Steak...it's what's for dinner. Or any other time. ha Quote Link to comment Share on other sites More sharing options...
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