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Cornwalls in the house. I have a few questions


jhoak

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This past weekend I picked up a pair of CWO Cornwalls from a local estate sale. They're not "mint" but they're very very nice especially considering they set me back 5 Benjamins. They're "S" vintage (1978 I think) and bone stock, They're not consecutive serial numbers but only 3 apart.

Considering the effect that recapping had on my 83 Heresys I've already ordered the kit from Bob Krites. Those will go in later this week. If they make as much difference as they did on the Heresys I'll be in audio heaven. Don't get me wrong here. I'm very very pleased with the way they sound. I just think that they have a bit more to give if massaged just the right way. I especially like not having to fire up the subwoofer [:D]

OK... On to the questions...

1) I want to replace the backs with 3/4 MDF. Why? Well I want to change the terminal strips to binding posts that will accomodate my speaker wires (12G Tributaries) and their somewhat large spade connectors. The question is: what's a suitable replacement for the damping material fastened to the existing back? I have no interest in disturbing the existing material as I want to able to put the original backs away in case I ever need to return them to "stock" condition.

2) I could be wrong but my ears are telling me that my Heresys have better high frequency extension. There just seems to be a little more "air" there. Bells are clearer, cymbals are crisper, etc.. The Heresys have K-77Ms (square magnet) HF horns and the Cornwalls have K-77 (round alnico? magnets) HF horns. As the Heresys have been relegated to "surround" duty is there any reason to not swap the tweeters? I do plan to install Crites CT125s in both the Heresys and the Cornwalls when budget allows but I'm thinking that swapping them might just satisfy (yea... right) me in the mean time. Thoughts?

3) Until I can put together my ultimate "vintage" 2 channel system I'm using a fairly nice Yamaha receiver at the head end. In that my listening area will only accomodate a 5.1 system I have a couple of "unused" channels on the receiver and it does support bi-amping". The crossover circuit looks to be simple enough to break out the woofer from the squawker/tweeter circuit allowing them to be bi-amped. Has anyone done this? What were the results? Is it worth the trouble?

Thanks in advance for what I'm certain are going to be a pile of well considered answers and spot on guidance.

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I feel bad I had to look up which bill that "Ben" decorates, lol.

Congratulations on the Cornwalls. I think I would just wait until you do the crossovers before thinking about swapping the tweeters. They may clear up a lot with the cap upgrades.

Just enjoy for a while.

Bruce

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You should be able to simply drill out the holes and install the new binding posts. At most, because you may want to, or have to separate the binding posts more, you may have to fill in one of the holes and paint over the filler. This would be much easier than making new backs and having to worry about the damping material.

I agree with Bruce that the caps will probably take care of the high frequency issue. But the Cornwalls do have a stronger bass, so maybe they are just voiced more to the bass than the Heresy, and that's what you're hearing and may need to get used to. After you do the crossovers, try swapping the tweeters to see if you hear a difference. No harm.

I'l let someone else answer the biamp question. You can't just biamp through the existing crossover, you'll need an active crossover I think, or amplifiers with filters to act as crossovers, or new crossovers that are capable of biamp connections. I don't think it's worth doing.

Greg

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I use these. Do as Greg says, fill one hole and use one existing. You'll only have to drill one new hole. I distance them so that dual banana plug can fit and when you install, make sure to orient the holes through the binding posts in the vertical position before cranking down the mounting nuts.

The number of the photo is the Parts Express part number.

post-10755-13819465489414_thumb.jpg

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2) I could be wrong but my ears are telling me that my Heresys have better high frequency extension. There just seems to be a little more "air" there. Bells are clearer, cymbals are crisper, etc.. The Heresys have K-77Ms (square magnet) HF horns and the Cornwalls have K-77 (round alnico? magnets) HF horns. As the Heresys have been relegated to "surround" duty is there any reason to not swap the tweeters? I do plan to install Crites CT125s in both the Heresys and the Cornwalls when budget allows but I'm thinking that swapping them might just satisfy (yea... right) me in the mean time. Thoughts?



For no good reason, a few Cornwalls have passed through my hands. A significant number have had blown tweeters. It is not as easy to hear this awful problem as it might seem. Especially if you have heard Eric Johnson live, without ear protection; especially if you are over 45 years old. But you might just try playing music through the Cornwalls and, using a rolled up magazine or something held to your ear, listen exclusively to the tweeters. If you don't hear the tiz of the cymbals, you have a blown tweeter. Have Mr Crites send you his tweeter diaphragms, too.

Good luck. I love my Cornwalls. You will too.

Joe

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I'd forget the 'bi-amping' options of modern receivers. It's usually not true biamping but just using two amp channels which equals not twice the wattage of a single channel. With the receiver at full tilt boogie, there's not enough power supply to make that approach have any difference at all. 5.1 is fine. Don't worry about any 'unused' power.

M

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Well I just finished the crossover rebuilds. What a change!!! I guess the 31 year old caps had seen a better day :)

I'm going to let them play for a few days while I'm at work just in case there's something to the whole "burn-in / break-in" thing.

I do think I'll end up swapping the K-77-Ms out of the Heresys for the K-77s currently in the Cornwalls. From what I read the "Ms" have about 4K better range then the originals. Not like my 51 year old (concert trashed) ears could actually hear the difference but my 51 year old (beer soaked) brain is telling me they'll be "better".

Anyway... Much much thanks to Bob Crites for supplying the various bits and pieces so quickly.

Now... Back to the music. Next up... A little Pink Floyd... I'm feeling a little Dark Side of the Moon (SACD) in my immediate future.

Good night all...

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