JBL L100 crossover kit--Murphy or Troels Gravensens

[sergiomordo]

Hi everyone. First of all, thanks a lot for all the detailed information on the crossover upgrade. I have been using my dad's L100s in my living room for a year now, powered by a Bluesound Powernode amp which is also hooked up to the TV so I not only play music through them but also watch movies and play games. As he passed away last year, I really want to preserve and use them for many more years to come. They are far from mint condition with pressed in tweeter domes and patched up woofer cones, some water damage on top of the left one from a plant. Also the mid on the left is noticibly quiter, not sure if that is a speaker or crossover problem. Yesterday I noticed a new tear on the left woofer and decided it is time to give them a refresh. I will likely get the woofers reconed and see if they can do anything about the tweeters, maybe replace the inner foam and definitely replace the terminals. While I am at it, might as well get the crossovers upgraded as well. I found a local shop that can potentially help me with this (Live in Toronto) I believe my father bought them around 1978 so they are a later model (photo attached). Would the Dennis Murphy crossover be suitable for the relatively newer model as well?

 

[z-adamson]

Would the Dennis Murphy crossover be suitable for the relatively newer model as well?

Got a pic of the front baffle? My understanding is that 70-78 the l100 is the same. If that is the case then it will work. I built this crossover for JBL 4311 speakers and it sounds GREAT. Much nicer sound.

 

[sergiomordo]

Here is a photo of the front. I read that there were very minor changes to crossover and the woofer but I doubt any change is significant enough that this crossover won't work, especially considering that it sounds great on 4311 as well.

 

[z-adamson]

As long as they are 123a woofers, I would say go for it.

Recone the woofers and tweeters.

 

[sergiomordo]

Thank you, I will get some quotes now, hopefully it won't be too expensive.

 

[z-adamson]

Thank you, I will get some quotes now, hopefully it won't be too expensive.

Be prepared to spend a lot on well done recones. Just recone kits to do the job yourself are spendy.

The crossover you can do yourself if you are good at soldering and can read a schematic. Quality components do get a little pricey.

All said and done, this is not going to be cheap. But in my opinion, it is worth it. The drivers are very nice and he Murphy network they sound very nice. A worthy project if the cabinets are good.