D130 DCR

[JBLOG]

Does anyone know the DCR spec for a 16 ohm D130 and a 16 ohm 075?
Thanks

[John]

Just a guess? D130-16 ohm around 9.5- 11.0
075-16 ohm around 7.9-11.0

[Thom]

If memory serves me right they rate impedance at operating frequency so the higher freq the driver is designed for the lower the DCR in relation to Z. If memory serves. I think JBL's woofers (to them a D130 is not) are measured at some 50 -500 warble or some such and I think full range are 1K but I could just be full of crap. The dcr will always be lower and I think I have measured a 16 ohm 075 at 8 ohms. no attempt has been made to mislead you.

[JBLOG]

I'm measuring a DCR=6.4 for the D130 and DCR=5.8 for the 075. Both drivers are labeled 16 ohm. Could these drivers be mislabeled? Could these realy be 8 ohm???
http://www.audioheritage.org/vbullet...ad.php?t=10691

[Thom]

They wouldn't have been mislabeled, (I don't think) but if they have been re-coned or had the diaphragm changed all bets are off. Can you tell if the 075 has been messed with? Does it still have seals intact. I'm not sure but it wouldn't shock me if that was right for 16 ohms Z someone should have one they could check. If not I have another hf driver I could check. Would expect to be about the same. Are you trying to determine impedance for general knowledge or are you troubleshooting something?

[JBLOG]

Thom,

These speakers were part of my fathers estate and I have a good 'family hsitory' of the speakers since there original purchase in the early 1960s. I have fond memories growing up with these speakers and there ancillary equipment (Fisher preamp, Dynaco monoblocks). The drivers are original and have not been reconed.

I'm intested to hear from folk with 32 ohm D130s. What is their DCR?

I did find this on this forum:

"Originally Posted by Harvey hifi Gerst
While we did maintain pretty tight tolerances, our 16 ohm speakers were really about 8 ohms and our 32 ohm speakers were closer to 16 ohm. Why? To make them a little louder. Remember, these were tube amps we were feeding. If you have a big hunk of iron for a transformer, tube amps are a little less fussy about lower impedance loads. Later, JBL just added "8 - 16 Ohms" on the label"

[Maron Horonzakz]

I have two 130B 32 ohm speakers & DCR is 14 ohms.....Any body want to buy them contact me.

[JBLOG]

Might be premature to establish a trend but maybe Harvey's post was indeed true. This is rather disconcerting that the impedances would be misrepresented on the drivers...
OPT impedance matching by trial and error.

[Zilch]

Is Harvey right?

Yes, of course.

JBL played fast and loose with the specs. Back then, there was no industry standard for measuring or stating impedance.

Even today, you have to actually measure and interpret driver impedance when precise determinations are required. Any specified impedance is "nominal."

The good thing is that the mechanical specs for the windings themselves have generally remained constant over the years....

[4313B]

Does anyone know the DCR spec for a 16 ohm D130 and a 16 ohm 075?
Thanks

D130 (8) (16) 5.8 to 6.8 ohms
D130F (8) 5.8 to 6.8 ohms
D130F-2 (4) 3.0 to 3.4 ohms
D130F-6 (16) 11.9 to 14.1 ohms
D130H (8) 5.7 to 6.9 ohms

075 (8) (16) 5.7 to 6.7 ohms

[JBLOG]

Thank you all for your input!