[mikesc]

I currently own a pair of JBL 100t speakers from the 80s and I am wondering if a crossover upgrade exist or if I just need a rebuild?
Speakers still sound alright but I am looking for some input on a possible improvement. Thanks Mike

[Wayne1]

Many years ago, Troels Gravesen did an upgrade for a pair of L-100s for a friend. He published his work: http://www.troelsgravesen.dk/JBL_L100.htm

If you bring your speakers to Danny, I am sure he could measure them and make suggestions to improve them.

[pehare]

I bought a pair of those new back in the 80's.  Sadly they didn't sound that good out of the box and I sold them without breaking them in.  In those days I didn't know enough...

Wayne1 that is one good lookin hound on your moniker.  Love hounds I've had a few but man they like to roam w/that nose.

[Wayne1]

Thank you. That was Henry, a full blooded, Treeing Walker Coonhound. Unfortunately he has passed, but was a great joy to have around while he was with us.

[WGH]

I still have and use the original L100 speakers with the LE20-1 tweeter I bought in July 1972. I rebuilt the crossovers in 1975 using Kimber wire and Solen capacitors using the original values which improved the sound. I never did get around to making the Troels Gravesen design. Based on the review below the Dennis Murphy L100 crossover mod may be the one to do. Dennis designs the crossovers for Salk speakers.

Dennis Murphy New crossover design for L-100A
http://www.audioheritage.org/vbulletin/showthread.php?13105-New-crossover-design-for-L-100A

JBL L100 Crossover Upgrade - Troels Gravesen vs. Dennis Murphy
https://audionostalgia.co.uk/jbl-l100-crossover-upgrade/

The L100 used many types of tweeters over the years, the crossovers for the LE25 tweeter is probably different than the 035Ti or 035Tia tweeters used in the L100t. Luckily the L100t was a popular model so you have a few options. The wisdom if the internet proclaims the crossover for the L100t3 sound better than the L100t, below are schematics and discussions. You can spend from $ to $$$$ on parts.

L100T vs L100T3
http://www.audioheritage.org/vbulletin/showthread.php?7812-L100T-vs-L100T3

JbL L100T to L100T3 Crossover Conversion Cheat Sheet
https://audiokarma.org/forums/index.php?threads/jbl-l100t-to-l100t3-crossover-conversion-cheat-sheet.479505/

[mikesc]

Thanks for all the replies, I am going to do use these references for rebuilding my networks.