Datasheets for JBL D120 &D120F

[retnev]

Thanks Grumpy, the second link basically puts and end to my questions:
If Harvey Gerst Specifies it as 60W RMS max, then that is what is.
Hopefully Harvey made sure not to have considerable Hang-Time at the higher power test levels that would blow a speaker way before it's actual rating. We will never know.

So I will treat any Original Cone D120F as 60Wrms continuous and the D120F with E120 coil reconed as 100W rms, the latter which would be accurate if the K120 and the D120F uses the exact same magnet.

Power specifications for the F series were nominally 35 to about 60
Watts. How did I arrive at these figures? Pretty simple, I played guitar
and bass through them and kept increasing the power till they blew. Then
I downrated them from the power that fried them. Pretty hi-tech, huh? It
seemed to work pretty well (of course we didn’t have synth players back
then).

Had to be over 40w each to survive for long in a cranked Twin Reverb ... the second article may be more helpful (thanks Earl ... found a post from 2003)

https://pro.harman.com/insights/harm...of-jbl-fender/

http://www.jt30.com/usenet-articles/...f-history.html

[edgewound]

Thanks,
Now we are seemingly getting somewhere.
So D131 aside, you claim the D120F is actually just a K120.
Meaning it is a 100W rms continuous, 200W peak speaker.

Do you have a source for this information, or did you hear it from someone.
I just want to make sure it is defined somewhere by JBL or in a datasheet.

When JBL supplied the D120F to Fender, they must have given them some official specifications or a datasheet. else fender would not know in which amplifier to use it within it's power rating. the web wisdom is all over the place..

Nice videos.
I used E120 (150WRMS/300Wpeak) coil/former to recone my latest D120F. Sounds absolutely spectacular.
Using the E120 coil/former (150Wrms/300Wpeak) I am sure of at least 100W rms continuous rating.

Regarding the aluminum former.
I have some lying around here but think they are Waldom (VC9500) printed on former)
Did JBL ever use Aluminum formers and if so, which years and models ?
That will make a huge difference in the upper frequencies.

I've been factory authorized service for JBL Professional since 1988. My source comes from factory specs, mainly from the 1976 Professional Series catalog, of which I have a copy, but it's also viewable in the Forum Library. There was not an individual cut sheet for the K120, to the best of my knowledge.

http://www.lansingheritage.org/image...pro/page11.jpg

I will reiterate, there are four different foilcals for the D131F/D120F . The original grey frame with the silver and gold label. This is the first generation that was a modification of the hifi D131 that became the D131F, along with the 15" D130F. Kraft paper voice coil former, aluminum edgewound wire, 30-60 watts power handling, all paper cones, treated with "goop" on the surrounds.

Then came the D120F, silver/gold foilcal. About 1963-1975.

Fender commissioned the Fender Signature Speaker D120F, grey frame, silver/orange foilcal. Identical speaker to the JBL D120F. Not sure what dates this was done as an OEM upgrade option. Maybe early 1970s.

Around 1975, Fender wanted to continue the D120F model. JBL was in the process of updating the model line to the K-Series, but were not done with the update since new models K145 and K151 were added. JBL were now using nomex voice coil formers to increase power handling and the double half-roll...m-roll...surround. Fender had JBL make the D110F, D120F, D130F, D140F orange frame with black motor/magnet pot. All of these orange frame models are, in fact, K-Series speakers. Fender had Gauss do the same thing with their musical instrument models. The JBL K-Series was formally introduced in 1976. Voice coil former material started with Nomex and then added Kapton. Doubled the power handling of the Kraft Paper formers.

The E-Series was introduced in 1980. The voice coils were updated with an aluminum/kapton composite which brought the power handling up to 150/300 watts, the ceramic magnet motor has more energy in the gap at 13,500 gauss vs, 11,500-12,000 gauss for the AlNiCo models. Sensitivity over all is up about 2dB, and 1dB from 500-1,000 Hz, making for a flatter, fatter midrange response.

I hope this info is useful. I've been doing this for 32 years, since JBL Pro put me in business. You're right, the web wisdom is all over the place, but you can be sure, mine is correct. BTW...Waldom voice coils are NOT edgewound aluminum. The high frequency reach quits at about 4KHz.

I have many more videos on my Facebook page, linked from my website....or here: https://www.facebook.com/UplandLoudspeaker

[retnev]

Here is a photo of an aluminum former and coil that came out of the D120F. Is this not a Waldom former/coil ?
https://i.imgur.com/5ur0Twu.jpg

I will carefully go through your response. I need top set up a timeline as it is quite crucial. the changes you mentioned has several power handling changes.

The "60W" rating for the D120F that Gerst specified as was posted by grumpy, for which of the versions you listed would that be?. It cannot be for the version that is basically a rebranded K120 as that is 100W rms continuous. So I wonder which he referred to as 60W rms continuous. It also cannot be the gray paper surround D120's as those were 25W rms.

[edgewound]

Here is a photo of an aluminum former and coil that came out of the D120F. Is this not a Waldom former/coil ?
https://i.imgur.com/5ur0Twu.jpg

I will carefully go through your response. I need top set up a timeline as it is quite crucial. the changes you mentioned has several power handling changes.

The "60W" rating for the D120F that Gerst specified as was posted by grumpy, for which of the versions you listed would that be?. It cannot be for the version that is basically a rebranded K120 as that is 100W rms continuous. So I wonder which he referred to as 60W rms continuous. It also cannot be the gray paper surround D120's as those were 25W rms.

60 watts pink noise=30 watts sine wave. Same power among ALL original grey frame D131, D131F, D120, D120F. As I said, the orange frame D120F is actually a K120 with actual K120 specs. Power handling back in those days was a close “guesstimate”. AES power handling standards had not been established yet.

Yes...your photo is of a Waldom voice coil with round copper wire. Not up to JBL worthy standards.

[retnev]

Thank you for the specific answer. It was what I was looking for.

Last questions:

1) Since the Orange frame D120F is a K120, (just want to make sure), it will be 100W rms continuous same as the K120 ?
I ask since a different magnet with the same cone and coil will create a different impedance curve and can result in the impedance become more resistive and blow the coil prematurely. If the magnets are also exactly the same the impedance curve will be similar and the rating the same. Both the magnet and the coil/former and gap as a minimum need to be the same for the D120F to be a K120

2) Were there any JBL speakers issued with aluminum formers same as the Waldom I replaced. Nobody could ever answer this question on the web.

[edgewound]

Thank you for the specific answer. It was what I was looking for.

Last questions:

1) Since the Orange frame D120F is a K120, (just want to make sure), it will be 100W rms continuous same as the K120 ?
I ask since a different magnet with the same cone and coil will create a different impedance curve and can result in the impedance become more resistive and blow the coil prematurely. If the magnets are also exactly the same the impedance curve will be similar and the rating the same. Both the magnet and the coil/former and gap as a minimum need to be the same for the D120F to be a K120

2) Were there any JBL speakers issued with aluminum formers same as the Waldom I replaced. Nobody could ever answer this question on the web.

You answered your first question yourself from what I explained before. Since the orange frame D120F is actually a K120, would it not make sense that the specs of the orange frame D120F being a K120 have the same specs as the K120? The motors are identical and interchangeable. I don't know where you get the idea that the magnets are different and can blow the coil prematurely. The magnet doesn't make the coil more resistive. Power compression can do that, though, from a structure that does not have enough heatsinking ability to remove heat from the coil. The voice coil assembly itself will also have thermal power limitations based on the material of the voice coil former and it's adhesives. Kraft paper voice coil formers are the lowest power handling of all. Nomex, kapton, and aluminum are all flame resistant. The adhesives used become the limiting factor before things go up in flames...which they can and do based on either total input power, clipping, or DC current, where the coil simply doesn't move and becomes a heater element before burning up.

JBL never issued speakers speakers with aluminum formers same as Waldom. Nobody could ever answer this question? I just did.

Go to my website and read the quote at the top of the page from Harvey Gerst. The link is in my signature.

[retnev]

Thank you for settling this. It is the first time I get straight answers in years and I understand better what the D120F was designed as.
I really appreciate it!

Speakers have to deal with the same issue as e.g. core saturation transformers have to deal with and other issues in more or lesser degrees..
A speaker is just another form of transformer, falling prey to similar fault conditions of which flux saturation and variation, even collapse is no exception for a speaker.

The magnet establishes a static Flux. It is basically a transformer with a Flux offset and a moveable coil. Any change in magnet design will influence the impedance as the Inductance is dependent on the flux and the impedance reactive component is dependent on the Inductance.

In fact Inductance is defined as the ratio between the linked Flux and the current through the coil.
So clearly the magnet which establishes the properties of the flux together with the core metal, will influence the impedance curve fundamentally.

That is why I needed to know if they use the same magnet.

If I understand correctly what you wrote, you said the K120 mechanically IS the D120F, then if so, in all respects including magnet, then the specifications will be the same.

Thanks you were a great help.
I appreciate it.

[edgewound]

Thank you for settling this. It is the first time I get straight answers in years and I understand better what the D120F was designed as.
I really appreciate it!

Speakers have to deal with the same issue as e.g. core saturation transformers have to deal with and other issues in more or lesser degrees..
A speaker is just another form of transformer, falling prey to similar fault conditions of which flux saturation and variation, even collapse is no exception for a speaker.

The magnet establishes a static Flux. It is basically a transformer with a Flux offset and a moveable coil. Any change in magnet design will influence the impedance as the Inductance is dependent on the flux and the impedance reactive component is dependent on the Inductance.

In fact Inductance is defined as the ratio between the linked Flux and the current through the coil.
So clearly the magnet which establishes the properties of the flux together with the core metal, will influence the impedance curve fundamentally.

That is why I needed to know if they use the same magnet.

If I understand correctly what you wrote, you said the K120 mechanically IS the D120F, then if so, in all respects including magnet, then the specifications will be the same.

Thanks you were a great help.
I appreciate it.

You're welcome.

Please understand that only the Fender/JBL ORANGE frame D120F is, in reality, a K120.

The AlNiCo magnet D-Series models from about 1963 through the updated K-Series models are all dimensionally identical.

[retnev]

I will definitely buy all my JBL recone kits from you in the future at Upland.

This year I reconed a few, but somehow did not buy from you and used simply speakers and speakerexchange, the latter who helped me a lot with Fane, but I am sure what I will get from you will be the closest to authentic after our discussion.

I am moving further and further away from modelling and back to speakers and authentic amps. I guess once a tube amp and good speakers helped you reach nirvana on countless gigs there truly is no way to really use modelling unless there is no other way, (e.g. a soyboy act where there may be no sound on stage)

So I am restoring my myriad of blown speakers I kept over the years and some newly acquired JBL's removing the crappy waldom cones/coils with something more authentic.

[edgewound]

I will definitely buy all my JBL recone kits from you in the future at Upland.

This year I reconed a few, but somehow did not buy from you and used simply speakers and speakerexchange, the latter who helped me a lot with Fane, but I am sure what I will get from you will be the closest to authentic after our discussion.

I am moving further and further away from modelling and back to speakers and authentic amps. I guess once a tube amp and good speakers helped you reach nirvana on countless gigs there truly is no way to really use modelling unless there is no other way, (e.g. a soyboy act where there may be no sound on stage)

So I am restoring my myriad of blown speakers I kept over the years and some newly acquired JBL's removing the crappy waldom cones/coils with something more authentic.

Thanks for the kinds comments.

I've had quite a few customers that bought a parts kit from other vendors for the JBL speakers, only to find that it's not as easy as it might look to recone these properly, and then sent then to me to do for them.

Amp modelers are cool for the convenience factor of plugging straight into the board for gigs...especially small room gigs...but you're right, there is no replacement for the visceral connection between you, guitar and amp with an amazing speaker that lets every bit of tonal nuance to escape out of the amp and into the air. It's been my mission to keep these great speakers alive so people everywhere can enjoy them to their fullest capability.

Happy Holidays!

[retnev]

Edgewound,
I see that I somehow missed one of your posts, which would have made this thread much shorter. Sorry about that.

You said and I quote

"The E-Series was introduced in 1980. The voice coils were updated with an aluminum/kapton composite which brought the power handling up to 150/300 watts, the ceramic magnet motor has more energy in the gap at 13,500 gauss vs, 11,500-12,000 gauss for the AlNiCo models. Sensitivity over all is up about 2dB, and 1dB from 500-1,000 Hz, making for a flatter, fatter midrange response."

This settles my opinion of why I found the E120 different from the D120/K120

I quote what I posted on a group before joining Lansing, about comparing the E120 with the D120 before I was accepted to post on Lansing.
What you stated above seems to be right on the money !!!!

The E120 is a different beast I haven't figured out what it can contribute.

Beautiful speaker but sound quite different from the others (K120,D120) and something I do not know where it fits.


The E120 has a ceramic magnet (obvious) as Alnico became prohibitive in price and they probably tries to get exactly the performance of a D120 with the Ceramic replacement. Soundwise I would guess (E120) it is slightly more towards a brighter Celestion Vintage 30, which is a speaker I just cannot seem to like. Have 4 of them and they underwhelm compared to the older G12's or Creambacks, but that is my taste. It is nothing in the direction of an old celestion alnico blue either. To me, more like an EV Force which is the closest comparison I can make.

[edgewound]

Edgewound,
I see that I somehow missed one of your posts, which would have made this thread much shorter. Sorry about that.

You said and I quote


This settles my opinion of why I found the E120 different from the D120/K120

I quote what I posted on a group before joining Lansing, about comparing the E120 with the D120 before I was accepted to post on Lansing.
What you stated above seems to be right on the money !!!!

I read through your posts at the other website.

Thanks for confirming my knowledge on these speakers.

I am a guitar player of 47 years with lots of experience in how these speakers both sound AND feel. The tactile response of these speakers forces you to be a better guitar player...the E120 of which is the most sensitive, due to the increased motor strength. I play through one my self with my True Reproduction E120 recone kit.

[retnev]

I have been gigging since the late 70s, and by necessity had to recone my own and bandmates speakers since the 80s. I grew up in the British Colonies and all we saw was Vox/Marshall/Wem/Hiwatt/Laney etc and speakers Celestion/Fane/Goodmans. Fender were rare. It only got traction there after Knopfler appeared. At the time a bandmate played an Elk ( Fender Deluxe copy ). It had a JBl D120 in it. The treble was too much for me and he liked to lift the Deluxe 4 feet high and blast straight into my ears. This idiot made me dislike any silver domes or presence dome speaker ever since and I instinctively avoided them for decades.

It was not since I live in the USA that I tried JBL's again. Now that I could listen to them "unjerked" , they are truly fantastic. It is absolutely unthinkable what I have been missing not playing them all these years. Fane Crescendo and other Fanes are still my favorites, but the JBL D120/K120s I have really opens up other worlds for me and it is amazing the difference they can bring.

They will become a permanent resident in my cabs. For sure.

Thanks a lot for your help.