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Help w/JBL C50 Olympus

byoungman1

byoungman1

Vacuum tube mafia kingpin
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I have finally come to terms with the fact that my JBL C50's are seriously bass-deficient (inherently, it seems).
There's just not much going on below 500Hz.
Rather than trying to re-edge the original LE15 woofers, I am considering a more modern JBL replacement...seems that 16-ohm 2215's would be a pretty ideal choice, from the specs I've seen.

Are there any C50 owners out there who have had a similar experience, or that have remedied the no bass problem?
Thanks in advance.
 
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I've got some ported C50s. I think they sound great.

LX5 crossovers do have caps in the LF section.
 
I have my C50s biamped with 200 watts on the le15a woofers and I have awesome bass. I would look at the crossovers. May need a recapping.
If your LE15s have the original tan surrounds, they can get very hard and stiff and that would be a probable cause.
There are some temporary remedies on the net, break fluid and such, but I wouldn't take a chance on damaging the cones.
My LE15s have been refoamed and work well. I also have a set of 2215s that have been a/b tested by me and they do have a bit more dynamics than the LE15s, but not enough to swap out proper functioning LE15a IMHO. Don't trash the LE15a woofers what ever you do, they are very much worth spending the money for refoam if you can't do it yourself.
I found that biamping with an active crossover, 200watts on woofers ( high current with great dampening factor), tubes on the LE85s, and SS state amp on the added 2405 tweeters brought them alive. I have the original crossovers, but I love them triamped with more control with the active crossover. Just my 2 cents.
Great speakers ,
Enjoy
J.T.
 
Thanks for the replies.
More info: I had the opportunity to buy/audition another set of C50's years ago and they sounded exactly like mine...not much LF activity.
The surrounds on mine are in fantastic shape and are not hindering the movement of the cones. I thought about the crossover caps, but one speaker would theoretically sound worse than the other if that were the case, I think.

jtee: A friend of mine also thought bi-amping might be the trick. Though I do have the equipment to do so (MC225, MC2105), that seems like a daunting task, and these speakers really don't strike me as being power-hungry. I'd love to hear your setup.
 
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If the crossovers are original and the same age, they should sound about the same since both have caps that have aged together. I would think, but who knows.
Bi-amping is really easier than you might think. I use an Ashley 4 way crossover. There are 2 ways that would work great for a lot less money. Rane makes a good one. Usually available pretty cheap.
You just come out of your preamp mains into the input on the crossover, then each amp is connected to the crossover outputs. One amp conected to the LF and the second to the horns.
My Ashly crossover uses 1/4" plugs, so I just made some 1/4" to rca cables. Each amp goes to the speaker it is powering.
I set the crossover for 400 hz and below to go to woofers the rest is set up for the horns and tweeters.
You use the crossover to control the amount of power going to the horns and (and in my case) tweeters since they don't need the power that the woofers do.
I love the tubes on the horns. Really smooth. The SS on the woofers will give the woofer action you need to get the good bass.
And yes, you do have almost everything you need, as the C50s sound great with MAC.:thumbsup:
J.T.
 
" not much activity below 500Hz" sounds like your woofers(which happen to be crossed over at 500HZ) are not working?
My C60 Sovereigns put the B in bass quite effortlessly.
 
tubed said:
" not much activity below 500Hz" sounds like your woofers(which happen to be crossed over at 500HZ) are not working?
My C60 Sovereigns put the B in bass quite effortlessly.
Click to expand...

+1

I was wondering if he meant 50hz by mistake. If it really is 500hz then something is very wrong with the woofers.
Do the woofers move at all by hand? You mention the surrounds are in great condition. I would have suspected they were preventing cone movement
 
If it really sounds like a 500 hz 'suck out' then it sounds like the woofers are wired up out of phase with the rest of the system.

Check your wiring closely. Use a signal generator to sweep the audio range or something like Room EQ Wizard (google it) to help objectively evaluation what's happening.

Cheers,

David
 
dshoaf said:
If it really sounds like a 500 hz 'suck out' then it sounds like the woofers are wired up out of phase with the rest of the system.

Check your wiring closely.
Cheers,

David
Click to expand...

Great response. Hadn't even thought of that...would sure explain my problem. Opening them up today to see!
 
I have bass again! Oddly enough, the issue was with my McIntosh C504 preamp.
That will be a whole other story, but I have my Scott 122 running now...Toy Matinee is making the walls shake at reasonable volume with the tone controls flat.
Anyway, thanks again for the input & guidance.
Man, these speakers are unreal.
 
Awsome find.
Glad to hear you figured it out.
Now sit back and listen to a fine set of speakers.:rockon:
J.T.
 
Yeah, I'm going to swap around some gear and get them dialed in. Looks like I'm in the market for a SS Mac pre.
Wish I could get the speakers off the floor about 2' without compromising the aesthetics of the setup (photo below).


MC225_JBL.jpg
 
Whoa. Beautiful. I guess you could put classic MCM wooden legs under all three units, but that would be a major undertaking.
 
Zonker92 said:
Whoa. Beautiful. I guess you could put classic MCM wooden legs under all three units, but that would be a major undertaking.
Click to expand...

Yeah, the speakers are about 130 pounds each, and the console has to be 175 +...legs would have to be industrial-grade.

I was thinking of buying or making some sort of solid raised platform, but that's a 12' wide wall you're looking at, so that would probably be waaayyy expensive to do.
 
byoungman1 said:
I have finally come to terms with the fact that my JBL C50's are seriously bass-deficient (inherently, it seems).
Click to expand...

For my C50s, I had the 130A woofers reconed and remagnetized and also had replacement crossovers built (original crossover is intact but bypassed) As the woofers have broken in, I find the bass to be satisfyingly deep and tight with a Scott 299B driving the JBLs.

Your LE15 should go nearly an octave lower than the 130A woofers. I'd start with the crossover and, if that doesn't do the trick, recone and remagnetize.


13567224_10154429421083900_5127475750927400250_n.jpg 13567140_10154429421398900_3335883978184883321_n.jpg
 
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byoungman1 said:
I have bass again! Oddly enough, the issue was with my McIntosh C504 preamp.
That will be a whole other story, but I have my Scott 122 running now...Toy Matinee is making the walls shake at reasonable volume with the tone controls flat.
Anyway, thanks again for the input & guidance.
Man, these speakers are unreal.
Click to expand...
Last Plane Out ...
 
So what was the issue with the Preamp? And what JBL driver load do you have in your C50, single or single/passive woofers?
 
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