Help identifying K-120's

Help identifying K-120's

Postby jkstraw » Fri Jan 08, 2010 3:16 pm

I am having an issue trying to match up a pair of K-120s. My first purchase was a mismatched pair - 8, 16 ohms.

Today I picked up another 8 ohm. I just finished checking them out with my multimeter and got some unexpected results. I am new to all of this so I was hoping to get some input from someone who is a little more educated on such things :-)

Multimeter was set to range/scale of 200 (can't get any smaller). Here were the results:

Speaker A: 6
Speaker B: 5.4
Speaker C: 13.3

My thought is: A and B are my 8 ohm speakers. C is my 16 ohm

Very confused because all the speakers are labeled K-120 8 ohm....and one has "E-120" in black marker. I am not sure how to tell if any of them have been reconed or what affect this would have (i.e. why someone would label one a E-120?)

Here are some pics: http://picasaweb.google.ca/jkstraw/JBLK120#

Thanks for any tips.
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Re: Help identifying K-120's

Postby hogan » Fri Jan 08, 2010 3:32 pm

you're right about the ohmage for each speaker.
The one labeled e120 is probably a recone. I believe that you can only get e/120 recone kits for the k and d series speakers these days. That's not to say that there aren't k and recone kits available. They are all old stock though.
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Re: Help identifying K-120's

Postby strumminsix » Fri Jan 08, 2010 3:39 pm

Yup, all speakers I've ever tested are slightly under ohmage.
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Re: Help identifying K-120's

Postby jkstraw » Fri Jan 08, 2010 4:52 pm

Thanks guys,

A couple follow up questions if you don't mind....

How would a speaker originally rated at 8 ohms end up measuring 16? i.e. what has been replaced from the original?

I'll find this one out myself but.......how does the e-120 recone kit affect the sound of the K-120?

Thanks again!
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Re: Help identifying K-120's

Postby SarnoMusicSolutions » Sat Jan 09, 2010 9:35 am

If an 8-ohm speaker is measuring closer to 16, then it's probably a recone. Speaker "impedance" is based on AC measurements at certain audio frequencies. When we hook up an ohm-meter, that's DC resistance and while a close approximation to "impedance" (AC resistance), it's not the same. Most 8-ohm speakers will measure from 5.5 Ohms to 6.5 Ohms. A 16 ohm speaker may measure as low as 11 Ohms on a DC ohm-meter.

Most of the JBL 12" recone kits these days are the E-kits. I found that Ted Weber (RIP) was a HUGE fan of the 12" and 15" JBL's. He had some cone kits made that were much more true to the older, original JBL paper found in D and K series cones. They were not factory JBL parts, but re-makes that he had done. It may be wise to ask Weber VST if they still have some of these cone-kits for their re-cone jobs on K120's or D120f's. I had a 15" D130 reconed by Weber for a steel guitar Twin Reverb I had, and man that was a sweet speaker. The paper was thinner and more sweet sounding. The E-series cones seem thicker and denser and don't quite sound like the old stuff that tone freaks love so much. I haven't bugged Weber since long before Ted died, but I do know he was way into it and had very reasonable prices for these recone jobs. It's likely they still have those special D120/K120 cones in stock. It's my experience that you can get a more "true" K-series cone/tone by using a Weber kit than by using a JBL E kit.

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Re: Help identifying K-120's

Postby jkstraw » Sat Jan 09, 2010 10:33 am

Thanks Brad,

I will follow that lead up for sure. It will be nice to have confidence that the two speakers are consistant...though I had them mounted last night and played for a couple of hours and they sounded pretty good to me!

Slightly off topic - but just want to note that I am in love with SMS Classic! The poor Axe-Fx is relegated to an FX box for now :-) I have been putting everything through the SMS Classic and in to an MC 2105. The E-120's are great but a little high pitched in the small space I have them in. The K-120 (and reconed K-120) seem a little smoother sounding at the same gain on the SMS and 2105.

Thanks again for confirming some of the details and clarifying some of this.
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Re: Help identifying K-120's

Postby hogan » Sat Jan 09, 2010 10:40 am

I'm going to go ahead and say you aren't going to hear the difference of a half ohm difference between speakers.

E-120's are not all they're cracked up to be. Loud, strident and heavy, they are my least favorite of the D, K and E series. If I want to drive rats to water or torture terrorist detainees i use the e-120s.
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