Vintage JBL 4331A to 4333A conversion
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- เผยแพร่เมื่อ 10 ธ.ค. 2021
- How I turned my vintage JBL 4331A studio monitors into (almost) JBL 4333A 3 ways, using all JBL components.
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This is a great improvement for what are already fantastic speakers.
Just to clarify, the L300 is not a domestic version of the 4333A. They are similar in that the L300 has the domestic versions of the various speaker drivers, ie woofer, compression driver / horn and tweeter. However the enclosure is quite different.
jblpro.com/en/products/4331a-...
jblpro.com/en/products/3105-3...
The components in this speaker are:
15" Woofer - 2231A
Compression Driver - 2420
Horn - 2312
Diffraction Lens - 2306
2 way crossover (for 4331A) - 3131A (4333A has a 3133A 3 way x-over)
Super tweeter - 2405
HF crossover - 3106 - วิทยาศาสตร์และเทคโนโลยี
Great job man! Enjoy those beautiful speakers! Those alnico parts are getting more rare every day.
Great video, I liked how you went about explaining the steps you took and the rationale behind your choice of components. Also nice to hear the story about their ABC studios provenance. Cheers
Glad you liked it. Thanks for watching.
Gracias estimado, excelente trabajo y muy buen video.! Gracias!!! Felicitaciones.!!!
I wish we could get 4311As "without spending a huge amount of money" :) Unfortunately most vintage JBL monitors are out of reach for most, fetching $2000+ around these parts. Thanks for sharing a bit of the history on these!
You're welcome!
*Great HiFi speakers.* I can't keep up with my video
well done i own one pairs too the same as your very nice sound and i use it with 2440 compression driver and also sometime use with 2405 all very good sound
Fantastic! I'm sure you are enjoying them.
Great speakers. I've got a pair of 4343 whose bandwidth is a bit flatter but I find the sound of the 4333 more natural. About the L300/4333 debate, these have a slightly different form factor but basically these are the same speakers. In France the VAT rates vas 33.3% for the L300 (categorized as luxury products) vs 18.6% for the 4333 (categorized as measuring instruments) so in the 70's a pair of 4333 was cheaper than a pair of L300. If I had to choose I would pick a pair of 4333 instead of L300 just because they are easier to put on a stand. These speakers need to be kept off the ground to give a clearer sound.
Yep - stands is on the to-do list.
Great Speaker !
3106 connects after the original crossover.
3106 input connects from driver output from first crossover
Its cascade setup that controls both driver 16ohm and tweeter 8ohm crossover at 8000hz
Normally 3106 receives signal after fisrt crossover that sends signal to driver 800Hz
Maybe im wrong but your method conection apoears incorrect by several reason.
3106 is great for your aplication, only its not properly wiring.
Hope im wrong
Cheers from Acapulco
I reviewed the data, and I can't see any application notes in the data I have. I agree that there are advantages to having the 3106 downstream of the main x-over. The way I have it now, the 3106 sees all of the power, and the bass and mid drivers are fed through TWO crossover, with 2405 super tweeter seeing only the 3106. Theoretically this could cause issues with power handling, as the 3106 is rated at 50Watts. Practically however, if I fed these things 50Watts I wouldn't be able to be in the room.
If the 3106 was downstream of the main X-Over, then it would only see the power that would have gone to the horn compression driver. (with most of the power going to the bass driver). The bass driver will see only one crossover, whereas the horn and the 2405 will see two crossovers.
The challenge that I come to is practicality in installation. The 3106 has been designed to fit in the same cutout that the speaker wire terminal plate was mounted to. The data specifically says that the 3106 is intended to be used to upgrade existing speakers. This made me think that it is intended to go there. It just bolts on to the enclosure. Mounted as it is, you would wire it up as I have. There isn't really anywhere inside the cabinet to mount things. The 3106 is heavy and bulky, there is no-where to mount it, and if it was inside the enclosure, I would not be able to adjust the pot on it for x-over frequency (not that I ever use it!) It was easy to cable tie the speaker wire terminal plate onto a bracket so it wouldn't go anywhere, but I couldn't do this with the 3106.
It's probably worthwhile me revisiting it at some point - I think both options have their compromises.
Thanks for watching and commenting!
The reason why JBL has two different sets of speakers with different part numbers is due to marketing, one for consumer and another for professional. I think the domestic speakers the nominal impedence is rated at 8 ohms, and the professional is rated at 16 ohms. Each line is sold by a sperate dvision within JBL. Other than the model numbers, the consumer and professional components are almost identical.
The woofer is the JBL LE15, I forget what the pro designation is. The compression driver is the LE 175, this is the lowest model, there is a more expensive model called the LE85, and the price when it was available was 50% over that of the LE175. Both of these have a 1" throat, and a 1 3/4" diameter edge wound voice coil. JBL also made the 375 compression driver, it had the massive magnet structure of from the LE15 woofer, it weighed like 25pounds.
The super tweeter is a variation of the JBL 075 ring radiator, it is called the 077 slot radiator. The 077 will reproduce highs to 20k, whereas the 075 is only good to 15k. The 077 when you can find it costs nearly $1,000USD.
Thanks so much for this. I've added the JBL part numbers up in the description. Interestingly even the crossovers had domestic and pro part numbers. The N8000 is the domestic version of the L3106. The N8000 manual says "Permits adding the 075 or 077 for extended response in any JBL system using the LE175 or LE85 compression driver."
LE15 X 2215 (studio)
The woofer used in the L300 was actually the 136A, I have a pair and have reconed them to 2235H. The L300 also has a slanted front allowing a longer horn to be used with the LE85. If you ever want to do a significant upgrade you should build Nelson Pass’s crossovers, there is a charge coupled board out there that you can populate with the components. Quite the improvement! I know you didn’t want to, but it’s definitely worth the effort over the stock crossover
@@danhorton6182 interesting perspective. Could you please ellaborate a bit more the concept of the « Nelson Pass » filter? I have a wonderful Alnico L200b set and I’m thinking about 3way tweaking.
All speakers are ugly.
The only way to get a speaker that's appealing is to build your own cabinets.
I do and I have built many of my own, in the end it's just a big box inside with what is appealing to you on the outside.
It's all about the exterior trim work.
Good job man.