JBL vintage drivers need cabs; C37 or C38?

[EddieJ]

I have a pair of JBL Signature (circa 1960s) D130 15" woofers with 075 and N2600 Xovers, but no enclosures.

Unfortunately I tossed the homemade enclosures. I was helping my aunt clean her basement and she asked me to put “those big old ugly speakers” at the end of the curb for trash pickup. Fortunately I removed the front panels with the drivers as well as the Xovers and brought them home.

The homemade enclosures that I tossed looked like they were based on the C37. The speakers were stored in a basement for about 30 years; I tested the speakers without enclosures and they sound good. Everything looks good too, no rot. This is my first post and I have a bunch of questions:

1. A pair of C38s with aluminum feet (no drivers) is for sale locally for around $500. Does that seem like a fair price?

2. Should I look for C37s instead? Or hire someone to build enclosures?

3. What size amp would be ideal for these JBLs? All my amps are SS and range from 15w to 22w to 85w to 105w to 200w.

4. I was told the alnico magnets on the D130s should be recharged, and that a weak magnet can cause the woofer to bottom out causing VC damage. Does that make sense to you?

These are my first set of JBLs and I look forward to the day when I can start enjoying them. Any advice you can offer would be appreciated.

[speakerdave]

I have a pair of JBL Signature (circa 1960s) D130 15" woofers with 075 and N2600 Xovers . . . .

Cool. Nice score.

. . . . A pair of C38s with aluminum feet (no drivers) is for sale locally for around $500. Does that seem like a fair price? . . . .

Too much money, and too small anyway.

. . . . What size amp would be ideal for these JBLs? All my amps are SS and range from 15w to 22w to 85w to 105w to 200w . . . .

Any low-distortion amp will do.

. . . . I was told the alnico magnets on the D130s should be recharged, and that a weak magnet can cause the woofer to bottom out causing VC damage. Does that make sense to you? . . . .

The Alnico magnets will need recharging only if they have been overpowered. I'm guessing in your case because of the history you have sketched that it probably is not going to be a problem.

Check our library for information on enclosures for that woofer, and choose the one you like.

http://www.lansingheritage.org/html/.../jbl-plans.htm

[BMWCCA]

Actually, history has shown a set of eight aluminum legs can bring over $400 on Ebay. All the planets must be aligned, I would think. I've owned the 030 system (D130/075/N2600) in a C37 enclosure for over fifty years and still enjoy them every day. I would not be so quick to condemn the smaller C38 or C36 only because others I respect on this site have often said the D130 actually performs better in the smaller box. I have no experience with this and find it kind of hard to believe, but others swear by the calculations. It might make sense based on the limited excursion of the D130, but I haven't had any desire to try it; I'm happy the way they are.

It is not unusual to find a pair of old C-series cabinets for free after the owner has unloaded the components. I have a pair of C35s stashed away I bought years ago for shipping costs. The legs you mention are the only part of any apparent value and it's not hard to find wooden legs that are a direct fit and close to correct for the earlier cabinets anyway. If you're convinced you want those cabinets you've found, perhaps sell off the legs and be in them for maybe $200. Might make sense if they're in good shape. I understand the appeal of using the components you've fallen heir to, but the reality is there are plenty of better-sounding JBL systems decades newer that won't cost you as much. But then there is something very satisfying in the way a D130 reproduces the sound of a cello, or a guitar, or full orchestra that is difficult to describe. On the other hand, the components you have will likely bring you close to $600, if not more on Ebay, if they're in good shape, so you've got some cushion to work with, which ever way you decide to go.

I've been very happy powering my 030s with a Crown D150 for the some thirty years, and currently a Crown DC300A-II. They sound best with the more powerful amp. Originally one was part of a mono system using a low-power Pilot tube amp and they sounded great then, too. I even powered one with the headphone output from a ChannelMaster transistor radio, back when I was about seven-years-old!

Good Luck.

[EddieJ]

Thank you Speakerdave. The JBLs were my uncle's and I would really enjoy getting these speakers up and running. He was an audiophile and I am just learning.

When you said "Any low-distortion amp will do" what does that mean? The main amp I use right now is an Onkyo A-809, 105w @ 8 ohms with no more than .0008% Total harmonic distortion.

The speakers are 16 ohm; will that be a problem.

Re: enclosures, based on your advice I am leaning toward the C37, if I can find a set. Do you really think the C37s will sound better than the C38s?

[speakerdave]

. . . . Do you really think the C37s will sound better than the C38s?

In one chart JBL says cabinets from 4 to 12 cu ft can be used. They would represent a continuum of various compromises. I figure the overall optimum will be somewhere in the middle and would avoid the extremes. Port tuning instructions are included.

http://www.lansingheritage.org/image...ans/page09.jpg

[BMWCCA]

Before I am chastised, once again , for not getting the gist of the discussion correct, here's a reference to the C38/C37 discussion. It really isn't all about the bass, but the overall performance of the D130:

http://audioheritage.org/vbulletin/s...1&postcount=20

[speakerdave]

Before I am chastised, once again , for not getting the gist of the discussion correct, here's a reference to the C38/C37 discussion. It really isn't all about the bass, but the overall performance of the D130:

http://audioheritage.org/vbulletin/s...1&postcount=20

Seems worth mentioning that part of that recommendation is to run a sub with them. I don't think the OP was contemplating that.

It does not make sense to me to choose a driver like the D130 and then choose an optimally flat configuration, unless you want to use it as a midbass driver. Used alone, it is best to expect a gradual roll off, make a cabinet you can live with and set it in the corner of the room. Someone who wants to fuss over flat frequency response should start somewhere else. OP seems to be interested in replicating a classic system. The referenced items in the library are his best guide.

[EddieJ]

To a novice like me, this is starting to get complex. I was not planning to run subs with the 030 system. But, if it makes sense I can look into it.

Since I do not have enclosures I have no way to know what this 030 system
even sounds like. You are the JBL experts. And I will trust your advice.

What would you suggest to a novice with an 030 system and no enclosures?
I don't want to sell them. And I don't want to be foolish and overpay for enclosures.

I always dreamed of owning JBLs and now that I have a pair I have no idea what to do with them.

[cosmos]

I always dreamed of owning JBLs and now that I have a pair I have no idea what to do with them.

Do you have woodworking tools and skills?

If not, consider having someone make cabinets for you.

The 030 system you have is not the "end all" or "be all" system. However, in a decent cabinet, you should like them alot.

[Harvey Gerst]

The C36/C38's were never an optimal match for the D130's except when the speakers were new (and had a higher resonance). As the speakers aged, the resonance would drop, and the C35/C37 sounded better with the D130's. For home built cabinets, we'd usually recommend 4 to 8 cubic feet as the best size for a D130 or 130A in a ported box.

[BMWCCA]

Harvey,

Thanks for dropping in again. The smaller-cab argument never made much sense to me, but I just listen to my speakers. :dont-know

I'm sure I'm not alone here in thanking you for taking the time to contribute to this site. It's the contacts, like you and others, with the original Lansing heritage that make this site so great—and owning these big old dinosaurs such a rewarding experience!

Hope you have a healthy and happy New Year.

The C36/C38's were never an optimal match for the D130's except when the speakers were new (and had a higher resonance). As the speakers aged, the resonance would drop, and the C35/C37 sounded better with the D130's. For home built cabinets, we'd usually recommend 4 to 8 cubic feet as the best size for a D130 or 130A in a ported box.

[4313B]

Harvey,

Thanks for dropping in again.

Hope you have a healthy and happy New Year.

Yes, thanks again Harvey!

[Harvey Gerst]

Hey, I didn't just "drop in"; I normally check the forums a few times every day to see if there's something I'm qualified to answer about stuff made in the 50's and 60's when I was working there. JBL was (and still is) an important part of my life.

[EddieJ]

Harvey,

It sure is an honor to get your expert advice. I will take your advice and look for C35/C37 enclosures. Or have someone build them for me.

Once I do that, should I recap the Xovers? Replace the wires? Any other tips to get this 030 system sounding good?

16 ohms is not a problem, correct? Just want to make sure I don't so something stupid that damages the speakers or amp.

I am not a woodworking guy, so if I could find C35/C37 enclosures that might be an easier and faster solution. Does anyone have any suggestion on where I could find C35 or C37 enclosures? Or should I just hire someone to build the cabinets? I could get the specs from the library section.

Thank you for all your help and suggestions!

[BMWCCA]

Even better!
Thanks for being an active member here.

Hey, I didn't just "drop in"; I normally check the forums a few times every day to see if there's something I'm qualified to answer about stuff made in the 50's and 60's when I was working there. JBL was (and still is) an important part of my life.