Questions about my 215S cabinets

[CLD]

I have two 215S cabinets, one purchased new at Quigley Music in Kansas City in June 1971 (with a Sorado head - I was told this was the matching 215S cab) and the other one purchased used in 2007.  These cabinets are the ones with two ports, one on each side of the middle of the front. Stock ohm rating was 8.

I had the speakers rebuilt in the '71 cab a couple of years ago - the speakers weren't blown, just worn out.  The one I bought used needed rebuilding, too, as the speakers had a good full sound but were pretty fuzzy.  The speaker tech was asked to set each cabinet at 8 ohms, as original.

Anyway, I've had them both for awhile now and notice that the '71 is slightly louder than the other.  (Both cabinets sound great by themselves or together.)  A friend suggested checking the ohms, thinking that perhaps one cabinet was set up for 4 ohms by mistake and is therefore louder.  (I've tried using different heads and get the same result every time.)  So after 37 years of ownership, I finally opened the back of my bought-new 215S cabinet to look at the speakers, get serial numbers and check the ohm values, as well as the other one.

No matter what I do with either cabinet, when I try to measure ohms at each speaker, the cabinet jack, etc., the ohmmeter goes to 0.  This is the case when I plug a cable into the jack and measure the other end of the cable, too.  Any suggestions here?

Also, and maybe Conrad can help here, to my shock and amazement the 1971 speakers have round black labels with GUITAR TRANSDUCER and have absolutely no identifying numbers on them anywhere.  The other cabinet's speakers are square-black-label BASS TRANSDUCERS and have the following codes on them: 81.0010 and 67.7132.  I presume that means they were made by Eminence, probably in the 32nd week of 1971.

So was I sold the wrong cabinet with my Sorado?  Conrad, were "guitar transducers" also used for bass cabs?  (The sound always has been outstanding, so this possibility never even crossed my mind.)  And why aren't there any codes on them?

Some photos attached.  In the meantime, thanks for reading this far!

[mckinnon audio]

  Hi CLD,could be few different things going on.First your meter,is it on the R x 1 scale/range ? If it's an old analogue meter,(actual meter movement),make sure it's "zeroed" on the R x 1 scale. There could be a short from the spkrs. lead in wires to the frame,you could have a/pair of blown spkrs.,the 1/4" input jack could be bad.Check your meter and try measuring right on the spkr. terminals,disconnect a wire from each spkr. first.Hope this is of some help,good luck,Mel.

[loudthud]

Cool looking rig. Love the coil cord !!! You got me curious so I took the back off this cab I got on ebay a while back and have never played thru. It was a buy-it-now for local pickup, the seller had no idea what it was. It has the pre mid-69 grill cloth and the badge is missing. The speakers are black stamped frame with 137-746 visible and the round Sunn Guitar Transducer stickers. The speakers in mine appear to be 8 ohm. One measures 8.0 ohms and the other 8.6 ohms after deducting the shorted lead resistance of 0.2 ohms. Those readings seem high but I checked the meter against a known accurate 10 ohm 1% resistor.

The 81-0010 is the Sunn part number but I have no data. My guess is that Sunn used various vendors at different times and just slapped stickers on the speakers. I have a pair of Magna 1516's stamped 81-0146 137-7436.

You should check further, your cabinets may be mismatched.

[CLD]

Thanks, guys.  I am using the ohmmeter correctly, just not getting the desired result(s).  Tried another (older) ohmmeter with same experience.  I"ll continue to look into it, and will find another ohmmeter to use.

If anyone can share some light on the use of "guitar transducers" in what was sold as a Sorado cab I'd appreciate it.  The photo above looks just like the ones in my cabinet except mine don't have any codes stamped on the visible side. 

Plus I spoke with my speaker tech this morning.  Reflecting Loudthud's comments about the cabs being mismatched, he said a guitar speaker generally would run hotter than a bass speaker and he thinks that is the reason for the volume difference.  He thinks the one pair of speakers without a visible manufacturer code probably has it stamped on the inside of the basket.

If this is all it is, then I won't worry about it (assuming the ohm ratings match up).  My main concern was running unequal impedances into my Sorado head and causing a problem with it.    The cabinets look the same from the outside and both sound great (especially together).