L150, L150a or some other type of crossover?

[oznob]

http://www.audioheritage.org/vbullet...50a-crossovers

Above I have linked an ad for a pair of crossovers I have for sale here. I obtained them from the estate of a former JBL employee, William "Bill" McPhetrick. He sadly passed away recently and his significant other was selling some of his collection. The crossovers were in a generic JBL equipment box. Hand written on it, which is bit hard to read, looks like 2-N150AS or HS. Part of his collection was a new pair of NOS JBL 129H woofers, NOS PR300's and 044 tweeters. Basically the components for a pair of L150a's.

There had been a bit of a disagreement amongst "experts" if these are L150 crossovers, L150a crossovers, modified L150 crossovers, proto-types etc. I am looking for the opinion of a real expert(s) as to what they are if possible. I have included a photo of a L150 crossover inside the it's cabinet and one of mine. You will note on my crossover the small yellow caps tied to the bigger caps on both sides of the board that are not present in the L150 photo.

Any help would be greatly appreciated!

[JeffW]

There's a little info about the use of bypass caps here

http://www.audioheritage.org/vbullet...sed-Capacitors

The L150 wasn't used as an example, and was even in the list of speakers that could benefit - sort of implying the mod hadn't been implemented on them (yet?)

Anyway, the speakers that got bypassed seem to have an A suffix crossover, FWIW.

[oznob]

Thank you Jeff, that is very helpful information. It does lead me to believe this may have been an early pair of bypassed caps. Some comments were made about mine have blue boards which is common with the L150, not the L150a which had a lighter color board with slightly different component placement.

[rdgrimes]

Not sure how much you can tell by the construction. There were several different iterations. Masonite, particle board and plastic may all be seen in various years.

[Allanvh5150]

I would say they are modified L150 crossovers. The L150A's used different component values.

Allan.

[DavidF]

The un-mounted assembly is an original with bypass caps added a la later versions of JBL xovers. Looks like it was appropriately wired and can easily be reverted to stock, if desired.

[4313B]

The un-mounted assembly is an original with bypass caps added a la later versions of JBL xovers. Looks like it was appropriately wired and can easily be reverted to stock, if desired.

Yeah, I bought hundreds of those 0.01 uF and 0.005 uF bypass capacitors from JBL back when GT started using them and I retrofitted many old JBL systems. Otis Armstrong had an original pair of L300's that I did for him.

[oznob]

Thank you again for the information. It's nice to hear from members who actually know what they are talking about! Probably no way to know for sure but, is there a consensus that these crossovers were built by/at JBL?

[4313B]

Those are absolutely JBL crossovers.

[oznob]

Thanks for the confirmation 4313B, I really appreciate it!