I'm going MONO!

I rose up early today, which was not a norm. I was in the mood to clean and play some records. Pulled out my early 1980's British reissue A Collection of Beatles Oldies (PCS 7026, bought new but never cleaned), cleaned it and played it loud. It was at the last track of side one -Yellow Submarine when Ringo's vocal suddenly diminished. Weird, I didn't remember that the song was mixed that way. I have blown the right loudspeaker!

The right channel Rogers LS3/5A was not completely muted - no sound came out of the bass/mid range drive; the tweeter sounded thin. It must be the crossover in the right speaker. I swapped the left/right speaker cables to make sure the amp was not acting funny. The amp is OK and my headphones sound normal.

I found The Unofficial LS3/5a Support Site and will do more research on getting it repaired. Any suggestion or recommendation will be much appreciated.

In the mean time, I think I'll just move the left speaker in front of the TV and play DCC LPZ-2006 Beach Boys Pet Sound all day long with the volume dialed up by 3 dB. (It's a good thing that I bought a 2nd copy after the first one's jacket was dented by USPS. ) Thank you Master Steve for choosing Brian Wilson's mix on this one. I need the happy music to cheer me up so no Sundazed mono Bob Dylan for the time being.

 

Thanks for your reply, Master.

Not real loud. The volume control of my amp was set at about 11 o'clock, and I had played louder than that. I think it's just too old - 17 years.

My next door buddy and I just took it apart and took some measurement with a multimeter. The impedance of the tweeter is 7 ohm but the midrange/bass driver's is open! Such to be sure we also checked the other speaker and it was measured 7 ohm/7.1 ohm. So it must be the coil inside the KEF B110 SP1003 drive unit.

Time for a new drive unit. Maybe I should get a matching pair, or a new pair of speakers.

 

Consider fusing your mid's. Fuses degrade the sound somewhat, but the trade off might be worth it. I learned the hard way, I have box full of blown Emits. Hard to lay off the volume controll when a good mood, or tune strikes you.

Just a thought.

 

I probably won't fuse the mid range drive units, not the blown one at least. Blown drivers are just life. I can't complain after almost 17 years of good service in two continents (three including the manufacturing site).

I have too many stereo records and don't want to waste half of the amp power. So I am connecting both pairs of speaker cables to the good LS3/5A. This is the only occasion that I love the spade connectors - can't do that with banana plugs. Hey, I'm having my own mono mixes. I'll be careful with the volume control or it's going to be headphones only for a while.

 

Hey Steve - my cobwebbed, slightly rusty speaker building self says those speaks were definitely not designed for crank 'em purposes - seems like the mid/woof had a 1" voice coil, and trying to get some loud listening for extended periods would lead to a quick demise. I once toasted a pair of Peerless 5" mid/woofs when cranking Zeppelin II Heartbreaker at killsonic levels (the Morel Dynaudio knockoff tweeters kept right on playing, and my he-man subwoofer thumped away nicely) - 17 year old drivers are definitely a testament to good design - the KEF folks did a nice job - they made EXPENSIVE drivers I could never afford on my tight budget... Paul - try and find a matched pair - as tight as the tolerances were, it's really tough to match drivers batch to batch. I always tried to keep a spare of each driver when I'd have a project. Also, keep in mind that the older woofer is mighty broken in at this point and a new driver will take awhile to break in, giving you some possible disparity sonically. Hey, anybody else wanna play speaker fixer-upper???

 

Whoa! Are you connecting both the left and right outputs from the power amp together? Yikes!

This is a good way to damage most any direct-coupled amplifier, and is not a good idea. I suppose it's rather benign if the amp is driving the load through transformers.

In any case, it's probably much safer to set your preamp to mono and use just one channel of the amplifier.

 

If it ain't smokin' it ain't brokin'.