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jpc2001

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  1. On Monday this week I picked up a pair of 1968 Heresies for FREE! O_o Rough cabs but the grills and badges are pretty nice. All six drivers work and they sound good together. Serials are 1F597 and 1F599. Oddity #1: one measures 12 ohms at DC, the other measures 16 ohms. Oddity #2: the polarity markings on one of them is reversed. If you hook them up "correctly" the sound is out of phase, reversing the leads to either one brings it into proper phase. Huh. Either it left the factory with a bug (inconceivable!) or someone's been in there messing about. I'll have to QC the internals. They sound great and they sound alike. They throw a nice sound stage. Now my living room can finally sound like a Chipotle 😉
  2. WTB an OEM phenolic tweeter diaphragm (or a pair) for the original Forte tweeter. (Is that a K-75-K?) Maybe you upgraded to titanium and the originals are collecting dust? Backstory. I have a set of Fortes. One of them had a weak tweeter, not dead but it didn't like to sing. Cleaning it didn't help; polarities were correct all around; impedance measured normal. Who knows why. Maybe it got damaged. Maybe it never worked right. So I swapped in a set of titanium ones. Now every high-hat is the same tinny crunch. Guess I'm not a Ti fan. The speaker with the one good phenolic tweeter sounded beautiful before. It would be nice to have two of those.
  3. It will be worth verifying that the new crossover was installed with correct phasing for each driver. Note that in the Forte I crossover the squawker is intentionally "backwards" with its negative terminal connected to the 2-tap on the autoformer, and its positive terminal connected to "ground" (the black input terminal.) Whereas the tweeter and woofer are connected the way you would expect -- negative to ground. That's true of the factory crossover, and of Bob Crites' replacement Forte I crossover which uses the same schematic as OEM. EDIT: On my Forte Is, the squawker terminals aren't marked '+' and '-'. Instead one is marked with a yellow dot and the other unmarked. That yellow-dot terminal is connected to ground -- so it would be the positive squawker terminal -- assuming nobody messed with these in the ~30 years before I got them. That's the convention, dot usually means positive. A red dot definitely would. A yellow dot probably does too, unless it doesn't. Ugh. Would it be so hard to write '+' and '-'? What if I gave you a car battery with no markings on either terminal except a yellow dot, would you like to install that in your car?
  4. What changes might a Forte IV bring, apart from swapping out the Ti mid driver? The Forte III already has most of the technology that the rest of the heritage line has. It already has the tractrix mid horn with mumps, and a steep slope crossover. What's missing? Another possibility is that the F4 will introduce new tech to the Heritage line, much as the F3 did with the tractrix+mumps horn. The Forte seems to occupy a "gateway" between the heritage lineup and more modern products. It could make sense for it to drive new technology.
  5. Factory Forte I crossover measurements: Series resistance of the 3.0mH inductor is 3.0ohm The 47uF bipolar electrolytic measures 51uF (not bad, did it take a DeLorean here from 1985?) Series resistance from pin 0 to pin 2 on the autoformer is 0.7 ohm. From pin 0 to pin 5 is 1.1ohm. Crites crossover: 3.0mH inductor: series resistance is 1.6ohm The 47uF bipolar electrolytic measures 54uF. We can't blame B&K sound, they use a 5% part. Is my DMM accurate? Series resistance from pin 0 to pin 2 on the autoformer is 0.5 ohm. From pin 0 to pin 5 is 0.8ohm. Wish I could measure the ESR of the smaller caps, maybe that's where the added "air" of the new crossover comes from. And there is air! You might expect the new crossover, with its lower-parasitic woofer inductor, to tilt the sound toward the bass end. But the most obvious effect is it sounds airier, like there's more treble extension and better definition HF transients. A stock Forte sounds a little "syrupy" next to the modded one, the modded one sounds brighter. But enough subjectivity.
  6. jpc2001

    Boston Belles

    No affiliation. https://boston.craigslist.org/bmw/ele/6252233381.html
  7. Back to topic: how many pairs of adjacent 90 degree corners are there?
  8. Seller confirmed original hardware is not included.
  9. Search doesn't find anything in that thread for Volti, V-Trac, or tractrix. I have too much gear, somebody else please go get these "no-brainers". Hopefully that doesn't refer to the lobotomy of the original components
  10. No affiliation. https://boston.craigslist.org/gbs/ele/6153424858.html The seller doesn't mention the inclusion of the original khorn components. What's the consensus on the Volti mods and tractrix mid horn? Are they an upgrade? Has anyone made measurements of them? I've seen a few subjective reviews. I love the Tractrix horns on my KM-6s (if I may make a subjective review myself.) How do they change the sound of vintage heritage stuff?
  11. In case you don't find a twin for this rare bird: The Khorn is an excellent mono speaker and plenty loud to fill a big room on one amp channel. Mono has a lot going for it, every spot in the room is an equally sweet spot. You could always biamp it if you want to use both sides of a stereo amp It's much easier to find a room that works with one Khorn than two. You just need a single corner, not need for an ideal-sized wall with two adjacent usable corners.
  12. Argh, the link moved again: https://hartford.craigslist.org/ele/6144114715.html This link is likely to remain working: https://hartford.craigslist.org/search/ela?query=horn
  13. The seller started them at $600.
  14. Original link broke, now they're relisted with a price cut @ https://hartford.craigslist.org/ele/6141125723.html
  15. Did you find another amp that works better? Fortes only sound right with certain amps. They must not be the easiest things to drive. I have KG 5.5's, DIY Khorns, Pioneer CS-33A's, B&W DM302's. All 8 ohms nominal and probably in practice too. None of those really care what you drive them with (except for the noise-floor-sensitivity of the Khorns.) Fortes do though, they wake up with the right amp and fall back asleep with the wrong one. My Fortes are stamped as 4 ohms nominal, and while later ones claimed 8 ohms, the innards didn't change IIUC.
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