K-77/crossover issue? or Why is it so hard for me to name a thread, won't you read it anyway regardless of the title? Maybe not, though,now that the title is so long...

[ben.]

So, I was excited to bring home the Mc30s again, as they had been out for a power supply rework & to correct a "barn job", as my tech put it. I lugged them home and got them all wired up, let them warm a bit, and hit play on the Coldplay disc that already was in the changer. Ahhhh, now that's nice. Even Shannon commented on how much nicer they sound than anything else we've had. I started playing with the output gains on the Paragon to dial in the balance, when my heart sank a bit. Left side sounded like crap. As Shannon put it (I love this), "It just sounds like a speaker!" I couldn't quite put my finger on it ,and it was late, so I just swapped ICs and flipped a few switches, and was able to rule out the preamp. Didn't feel like swapping speaker cables around, so I popped a movie in and tried not to think about it.

The amp that seemed to be suspect was the one that had started motorboating due to completely amateur work (wrong value resistors-clusters of caps with leads just twisted together). That the amps sounded so good and held up for so long is a testament to the design, I suppose. My concern was that my tech missed something. He's cheap, quick, and honest. That I was sure of, and up until that point, I had confidence in his abilities. The diversity and quantity of gear in his shop every time I had been there was notable. Big ole SS Mcs, Plinius behemoths, big professional digital mixers, run of the mill TVs, guitar amps, record players, Acrosound split-chassis mono amps, even the old Volvo out front smacked of a talented technician in high demand. I mean, this guy is always busy, and this town isn't big enough to lack considerable repeat business and be that busy. So, I choked down my misgivings for a day, as I really didn't have any good reason to suspect his work, and I had not even had time to give the matter much serious consideration.

This evening, I took a deep breath and a few (ahem) swallows of Old No. 38 Stout, and set to tackling the issue, half expecting a somewhat drawn-out troubleshooting session. Having settled on the issue being amp or speaker related the night prior, I switched speaker cables then powered up.

Ok, this is wierd. As I'm typing this, my wife calls from the living room, saying there's no sound all of a sudden in the movie she's watching. Super! I go in, tap a few switches, confirm that she hasn't touched anything, and turn on the tuner to try another source. Hmmm, tuner sounds fine. Flip back to DVD. Nada. Press stop. Press play. Back in business-audio's back. Walk away and try not to worry. I'm happy with relatively cheap digital if it dies anyway.

Back to the matter at hand.... The problem follows the speaker cable, ruling out the amps. Good. My faith restored in my easy access to and friendly relationship with the great tech that is local and not about to keel over from old age and solder fumes, I set about thinking of what could be amiss with left Khorn. It just sounds midrangey and very slightly distorted. (Like she said, a speaker.) I'm not sure if the distortion I'm hearing is due to it sounding midrangey, and the source being cheaper dig., but that's what I hear. I get up and do the "ear by the horn lens" maneuver. Yep. No tweets. Plenty squawk. A bit woof shy, maybe.

That brings you up to the moment, folks.

My preliminary diagnoses:

-blown tweeter, which doesn't explain the lack of bass, but that was subtle, and could be a psychoacoustic thing, or even new caps breaking in in the Mc30s

-crossover hinky- I'll loosen and retighten the terminal strip screws as soon as I have the werewithal to take the stack of record off the speaker and get back there. Same goes for swapping tweeters between the two.

Any other ideas, and suggestions for course of action? I'm thinking that if the tweet's shot, sending the pair (and maybe the K-55 while we're at it) to someone for rebuilding (Bob Crites does that, right?) and recharging the Alnico magnets. If it's in the network, I'd probably just try a new type A.

What am I missing?

[Tom Mobley]

bob can bring the drivers up to snuff and provide crossovers. One-stop shop, you're in luck.

So what's wrong with the title again??

[Dylanl]

The only reason I looked was because of the length of your post. Your right, you did get my attention. GOOD JOB! It does not happen much since many have said I have ADD, but your verbose title did it.

[Dylanl]

Sorry, double post. My bad

[jorjen]

Bc,

Are your current A networks stock? If so, do they have the small, bare wire that ties all the negative terminals(screws)together? If so, make sure you did not overtighten one of the negative screws(the ground wire will actually wrap around the screw and pull out the loop beneath the pos. term.) as it can pull the ground wire up beneath the adjacent positive terminal until they actually touch and short. I had this happen on a stock A once and the sound was exactly as you describe. Just a thought.

[Deang]

Those near 30 year old crossovers are probably filthy. I would yank them and clean them. Use denatured alcohol on the terminal strips.

I hate the grounding scheme on the old Heritage networks.