L300 Summit with Nelson Pass crossover mod and First Watt J2 Amp

[Murillo Moreira]

Hello friends, as a JBL fan I'm very happy in finding a place to talk about these awesome speakers.
L300 always were a dream speaker set to me, unfortunately I never had a pair, my experience with JBL were a Jubal and a 4315 that I had long time ago.
But both have 12" woofers and does not really gave me the deep bass that I love.
My main system uses a B&W 801 Matrix, and I really like them, but to me they do not play rock like JBL does, I like them more for listening classical and jazz because they are very precise, and also the bass is awesome, but it lacks the fun of the JBL, they are maid for rock IMHO.

My first try DIY with the L300 is far away from the original one, I just got a pair of 2215 woofers and made a box with the L300 measurements, and installed at the Mid and Highs scanspeak speakers, the 8545 and the illuminator, using a active crossover with 6 mono amps.



This gave me pleasure for a couple years, but now I really decided to go for the summits, and bought the following drivers:

2420 with 2307 horns



2405 tweeter



2235H woofer




I decided to go for the Mr. Pass crossover, I love his designs and to me I think it will be a good starting point for these drivers.
The crossover is well documented in:
http://www.firstwatt.com/pdf/art_l300.pdf

I will post here every step of this construction, and would like to hear advices from everyone.

I would like to know if somebody build this crossovers and what they sound.

Also, I wonder how this speaker sound with the Mr. Pass First Watt J2 amp, it's a very good sound amp, but unfortunately, as is Class A, has only 25W per channel and I'm afraid it will not make them sound their full potential.

Anyone tried this FW J2? I also have a Harman Kardon Citation II amp, it needs some work to do, change some caps and valves but if somebody has listened to this J2 + L300 or citation II + L300 I would love to hear their impressions, specially playing rock music, that's the main goal with these speakers for me.

Good night to everybody!

From Brasil, Murillo.

[Murillo Moreira]

Pass crossover







I made this hole in the bottom just to add more cubic feet to the 2215 woofers, but now I will remove it, also the box in the base, and will install all the bracement. I will put the pics after I done it.

[Murillo Moreira]

They are not in the L300 but it looks so nice that I will install them also...






As Mr. Pass crossover do not have resistors with the tweeter, I think I must install the L-pads to adjust for my taste.

[audiomagnate]

That's something you don't see everyday! Your cabinets look bottomless BTW, what's up with that?

[fpitas]

I'm using a FW J2 as a horn driver amp, in a tri-amplified active system (see signature for details). It's just about ideal as a horn amp, with no turn-on or turn-off thump, no crossover distortion, and in general a very clean sound. The 25W available may be too little as an amplifier for a normal speaker with a passive crossover, unless you always listen fairly quietly.

Francis

[Murillo Moreira]

That's something you don't see everyday! Your cabinets look bottomless BTW, what's up with that?

Yes you are right, they are very ugly and strange, but I'm fixing them now, installing the bracement and filling the mid and tweeter holes to receive the JBL drivers. BTW, anyone know the correct measurements for the tweeter and mid placement? Also I wanna know if the lens are really necessary.

[Murillo Moreira]

I'm using a FW J2 as a horn driver amp, in a tri-amplified active system (see signature for details). It's just about ideal as a horn amp, with no turn-on or turn-off thump, no crossover distortion, and in general a very clean sound. The 25W available may be too little as an amplifier for a normal speaker with a passive crossover, unless you always listen fairly quietly.

Francis

Hi Francis, thx for the info, I was wondering this, 25W is not a good amount of power to drive them. I will try with my citation II instead, 60W of KT88 tube sound.

[DavidF]

Yes you are right, they are very ugly and strange, but I'm fixing them now, installing the bracement and filling the mid and tweeter holes to receive the JBL drivers. BTW, anyone know the correct measurements for the tweeter and mid placement? Also I wanna know if the lens are really necessary.

If you are trying to emulate the original performance, then yes the lens is necessary. Otherwise, the sound dispersion from the straight sided conical horn will not blend as well with the woofer response.

Given the higher prices for the L300, and rare appearances in some markets, it makes sense to work up your own system. Good luck!

[Murillo Moreira]

Thx David for your advice.
There is a guy selling at ebay, it is the Kernrick Sound version, I will buy it.
Yes, the L300 is like an old Rolex submariner, it gets very expensive as the time goes by.
Here in Brasil, guys are asking $12,000 for a pair. That's too much, specially when I can buy a B&W 801 for 3,5k
The only solution is to build one from scratch.

Up to know, I spent:
2420 w 2307........................ $610
2405................................... $580
2235H................................. $800
Pass Crossover madisound..... $220
Foilcal labels.........................$130
Screws, l-pads, clamps,ie.......$100
2308 lenses .........................$130 (to buy)
Freight to Brasil....................$400
Total...................................$2970

So with 3k aprox. I can make a very good clone, that's very far from 12k

At ebay there is a par for sale for "only" 8k, but with freight and taxing charges it will be cheaper to buy here for "only" 12k.

[Murillo Moreira]

That's something you don't see everyday! Your cabinets look bottomless BTW, what's up with that?

Just to explain the bottomless, I was using with a 2215 woofer that requires 8 cu.ft. so I made another box in the base and a hole at the bottom, now, that I bought the 2235H I removed the hole and the box under it, so that it will be in the L300 measures.

BTW, if there is anybody can tell me how much worth a pair of 2215 woofers, I think about selling them at ebay but I do not know how much they worth, they are in good condition. The problem is with the freight that I think will cost at least $200 to send to US.

[Murillo Moreira]

\

So with 3k aprox. I can make a very good clone, that's very far from 12k

Just a coincidence as the original price on 1975 of the summits was 3k!

[Murillo Moreira]

Attachment 63776

Can any good soul tell me the exact measurements of:

A (tweeter center from top)
B (mid center from top)
L5

[Sepperl]

Attachment 63776

Can any good soul tell me the exact measurements of:

A (tweeter center from top)
B (mid center from top)
L5

A Tweeter Top to center 9,5 cm
B Horn -"- -"- 23,5 cm
Regards
Alex

[Murillo Moreira]

A Tweeter Top to center 9,5 cm
B Horn -"- -"- 23,5 cm
Regards
Alex

Including the glass?

God bless you Alex.

[Murillo Moreira]

A = 9,5cm
B = 23,5cm
C = ?
D = ?
E = ?
F = ?
G = ?
H = ?