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boudu
08-08-2003, 01:31 AM
Before excuse me for my poor english.
A few weeks ago, I buy a beautiful pair of L300 in exellent cosmetic and technical condition. The speakers are in exellent condition too, the crossover is the same of the 4333 with the possiblity of bi amplification. I used them with a pre Mcintosh C22 vintage and for amplifier with a pair of OTL Reference by Silvaweld (100W per ch). My room is 16 X 16 feet, floor is made of wood.
My problem is that the bass are boomy and noisy, if I do anything on the preamp and with the button 'presence ans brillance", I heard only the bass speaker. I'm very disappointed because before I had Klipschorn and I do not have this problem. If speakers are a little bit raised, it is a very little better but the problem is the same. I don't know if I must sell them or try to find a solution. I need some help.
Thanks

Regards
Boudu from France

Guido
08-08-2003, 03:32 AM
Hello Bodou!

First you don't need to excuse for bad english as I guess most of the board members speak only one language. You at least two:D

OK!
The L300 should definately not sound boomy. Did you check every speaker e.g. mid horn and HF if they work properly?

boudu
08-08-2003, 05:19 AM
I don't have checked speakers, but I heard them and when I play with adjustment it works. Do you think I must test each speaker separately ?
BR
Boudu

Guido
08-08-2003, 06:01 AM
Yes, you should disconnect the speakers from the x-over and then listen to wach one as single speaker.
Just to make shure that each speaker works and have the same sound level than the correspondent speaker from the other channel.

E.g. you compare both tweeters with each other.
Next each mid driver
Next each bass cone

Let us know what you hear.

Guido

boudu
08-08-2003, 07:02 AM
I will test each speaker and I will describle what I hear.
BR
Boudu

Mike C
08-08-2003, 07:14 AM
hey guys, I owned a pair of L-300's a few year ago. Boomy they were not!, they had the most full and revealling bottom end of any loud speaker I have heard. I think the problem you are hearing is most probably in the network. Remember the caps etc are now more than twenty years old and are probably are a little wornout. Please have them checked out properly. I sold mine thinking there was something out there that was better, believe me there isn't!!!!!!!! They are a great sounding speaker if all the components are working as they should.
Regards Mike,

Guido
08-08-2003, 08:59 AM
@Mike

I'm not shure with your x-over theory.

My 4343 networks are more than 25 years old and work perfect.

I think JBL used foil caps that do not have this aging problem. But I'm not shure for that.:confused:

I think testing the balance of the speaker against each other will show it.

Let's give it a try

boputnam
08-08-2003, 09:52 AM
Hello, Boudu...

I agree with Guido - at least I have no problem with my 4345's, all original. So, unless your L300's were damaged (doesn't sound like it), there is something else.

It seems you know what you are doing, but are the L300's connected exactly the way the Klipsch were? Have you changed anything? Is there an EQ or other processor in the signal path? You might try going from the pre-amp to amp direct to L300 and see if any difference. Have you connected (+) to RED on the L300? :hmm:

Mr. Widget
08-08-2003, 10:04 AM
"if I do anything on the preamp and with the button 'presence ans brillance", I heard only the bass speaker."

Well, I have two thoughts. First, the presence and brilliance L-pads are notorious for getting dirty, and needing to be cleaned or replaced. You might try shorting/bypassing them to see if that helps.

The second thought is location. Your Klipschorns were designed to be located in the room corners. The L-300s are not. Do you have the L-300s in the corners? Corner placement will increase bass output as much as 6dB.

boudu
08-08-2003, 11:32 AM
Yes L300s are today in the corner where was my klipschorn. The red is on the red and the blk on the blk but I don't know inside them because I didn't open them. Maybe it is not correct because the last customer take the mid and bass speakers to make them as new (I don't know the word "remembraner" in english). I must show inside I think.
BR
Boudu

Mr. Widget
08-08-2003, 11:53 AM
"(I don't know the word "remembraner" in english)"

Do you me he reconed the drivers? Recone is not in the dictionary, but it means to replace the cone, voice coil, surround, and spider. At least this is the proper way to do it. For the mid horn it would mean a diaphragm replacement.

In any event, if you think that it is likely the speakers are working properly, pull them out of the corners and give them a listen. It is very rare that a corner is an ideal location for imaging and the proper creation of the stereo effect. This is one of the problems faced by all corner horns and in fact why Klipsch encouraged the use of a center speaker 40 years ago.

boudu
08-08-2003, 01:43 PM
Yes the speakers were reconed but the only place I have is on the corner for the moment.
I had many speakers brands before L300 and it's the first one with this horrible boomy bass.
Somebody knows exactly how are speakers inside (I mean for LS + on + on the x-over, MS + on - or + on + etc....), with these informations I will be shure.
I think there is a problem because a friend of mine had JBL Olympus and bass are not so loud. I must find a solution to not sell them too fast.

Mr. Widget
08-08-2003, 02:01 PM
Well if you think there is a problem, the most likely culprits are the L-pads.

Do both speakers sound the same?

Here is the link to the pro version of the L-300 crossover. I am not sure if they would have the same color code or not. They are identical electrically, but with JBL you never know what they are thinking.

There are many on the forum with your speakers, hopefully someone will chime in with the proper wiring info for the L-300.

In the meantime try rotating the L-pads fully back and forth several times to see if it helps.

http://www.jblproservice.com/pdf/Network%20Schematics/3133A%20Network.pdf

boudu
08-08-2003, 02:27 PM
both speakers sound the same and I do play with Lpad when I buy them because I heard that they need a little it.
Thanks for the x-over but mine are the same of the 4333 with bi-amp possibilities. The same of this picture : http://www.retroaudio.ru/speakers/4333AWX.shtml
I hope it's possible (wich version ,) and not fantasy.

Mr. Widget
08-08-2003, 02:52 PM
The 4333A with bi-amp switches is the crossover I posted. It is called the 3133A.

The 4333 does not have the bi-amp switch.

Here is it's crossover.

http://www.jblproservice.com/pdf/Network%20Schematics/3133%20Network.pdf

Tom Loizeaux
08-08-2003, 03:01 PM
If you can be a little more clear about what problems you are hearing, maybe we can help you find the problem and get these working properly. Explain in more detail what you mean by "boomy bass", etc. The more detail you give us the better able we will be to help.
Please keep giving us information.

Tom Loizeaux

boputnam
08-08-2003, 03:07 PM
Hey, Widget....

Now I'm confused :spin: !!

If this is the 4333A, maybe the bi-amp switch is IN, and needs be OUT to use the internal crossover?

Hey, bondu !!

Rotate that little screw at the base of the crossover to the left (<-- ) to "INTERNAL CROSSOVER".

scott fitlin
08-08-2003, 03:08 PM
can it be that the L300 is an impedance mismatch for those OTL tube amps? Tube amps were known to be finnicky and load sensitive. If it is an impedance mismatch it would cause the frequency abberations described! Especially if the OTL amp has a high output impedance.

Just a thought!

Mr. Widget
08-08-2003, 03:19 PM
Tom is right we need more info.

Bo, you have a point, it could be operator error with the crossover.

Scott brings up a good point. It could be an amp issue.

boputnam
08-08-2003, 05:06 PM
boudu...


"mine are the same of the 4333 with bi-amp possibilities" and your first description got me to thinking - you may have the crossover set to EXTERNAL CROSSOVER, and for your set-up it needs be INTERNAL CROSSOVER.

Here's a picture that looks set to INTERNAL CROSSOVER.

You should connect to only the lower binding posts.

Any luck??

Ha! Maybe you can't hear us anymore - you're dancing!! :dancin: :dancin: :dancin: :dancin:

lpd
08-08-2003, 05:47 PM
Yes, I have made the mistake of having the bi-amp switch on external crossover, and fortunately didn't damage anything because the horns were not wired :eek: Make sure the switch is set to internal crossover.

Do you have any sound from the horns/tweeters? How is the output matched to the bass drivers? Perhaps the l-pads need cleaning.. I replaced both the tweeter and horn l-pad and it made a huge difference in both the tweeter and horn its like they came alive.

I run my JBL's on an Acoustat TNT200 and a Dynaco 70 sometimes. Sounds great on the tubes. Not as much headroom but the midrange is to die for (can't wait to listen to the 4343's)!!!

Good luck and keep us posted!!

scott fitlin
08-08-2003, 07:20 PM
i could see JBL midrange drivers sounding fantastic on a low power tube amp. JBL drivers for mids are very efficient!

A bi amp combo of SS for the lows and tube for the mid/high should really knock someones socks off!

MikeM
08-08-2003, 10:07 PM
Afyer being used to the klipchkorn the L300 will ne a major change in sensitivity! What cond are your output tubes Good you say?.Well the L300 has a nice current hungry woofer. Not ineffecient but still you will benifit from lowend grip ot solid state for lows Bring the L300 about 4 foot from the rear wall. You want to isolate this speaker from the room as much as possible. Why didnt you like the corner horns? Enjoy you L300 they are FANTASTIC speakers. 116Degrees in las vegas today

Norbert
08-09-2003, 05:13 AM
I had a look on the Silvaweld Tube Reference OTL amplifier's datasheet (http://www.silvaweld.com/e-7.htm) and it states a damping factor of only 10! I don't think that this is a good match for a woofer like the 2231.
I definitely think that your boomy bass problem is linked to this thread: http://www.audioheritage.org/vbulletin/showthread.php?s=&threadid=558
Another fact which probably worsen things is the corner placement.

Best regards,

Norbert

boudu
08-10-2003, 01:31 AM
maybe you 're right for the amplifier, I have the possiblility to test them with an MC 275 CE, do you think it will be better ?
Regards
Boudu

IDF
08-10-2003, 01:43 AM
I have the possiblility to test them with an MC 275 CE, do you think it will be better ?

-------------------------------------------------------------------------------
Boudu,
McIntosh amps are very well suited for JBL. The Mc 275 Commemorative should work fine. You could also try some solid state versions.
Regards

IDF
08-10-2003, 02:05 AM
Boudu
In addition.
Norbert is right, you must absolutely avoid corner placement because it will enhances bass response. Let corners to KHorns ;-)
JBL literature says that the monitor "should be mounted against the wall, and not away from it". For example my 4343s are also nearly touching rear wall by one corner and +/- 10 cm on the other rear corner.
Hope this helps.

Norbert
08-10-2003, 04:39 AM
I think the McIntosh MC275 will do the job. Apart from other amplifiers I'm runing a Cayin 788 (KT88 Push-Pull) on my 4430 monitors. The 788's circuit is based on the MC275's circuit especially the output configuration including the trannies. So I think they will behave quite similar. At least it's worth a try.
But do not forget, this sort of amplifier isn't the last word in bass definition and performance on large-size JBL monitors but it's more than acceptable.

Best regards,

Norbert

MikeM
08-10-2003, 12:28 PM
The manual that says to place the monitors against the wall is now 30 years old. Amplifiers have progressed enough to have enough grip to controll the loend with out adding the rear wall room gain thing. Sound like maybe you ARE AGGREVATING A ROOM MODE by driving the system to compete with the corner horn. Again try diffrent room placement. With the L300 I found the best position was 4 foot out from the back and side and move your listening chair Farther away.I dont know you decor but try placing a large tapestry on the rear wall to adsorb some of the refection and boom. and good amp with conrtol for the lows will be wise. Mark levinson make some great lowend amps for biamping. And equalization is another bumpy road.
:banghead: Have fun and good luck. Just relax and maybe that boom want be as bad as you think.

IDF
08-11-2003, 02:23 AM
"The manual that says to place the monitors against the wall is now 30 years old. Amplifiers have progressed enough to have enough grip to controll the loend with out adding the rear wall room gain thing".
------------------------------------------------------------------------
I don't agree.
I'm currently running an amplifier whose damping factor is 200. But if I don't have the rear wall load, I don't have the soundstage.
:confused:

johnhb
08-12-2003, 08:28 AM
Get a carpet! I removed a rug from in front of my Hartsfields for cleaning and the sound quality declined. I'm listening to a pair of L-300s right now in a carpeted room and they sound perfect.

boudu
09-14-2003, 11:15 AM
This week I find a moment to open my L300s and what a bad surprise to find a boomer JBL n2135 (8ohm)!!! ,no 2231A or Le15, for mid 2420 (16ohm), for high 077 (8ohm). I think that I've found this big problem but now I have another one : Wich bass speaker must I buy , 2231A or LE15 ? and are the other speakers the good one ?
Waiting yours answers
Boudu

Mr. Widget
09-14-2003, 12:05 PM
The fact that you have a 2420 in there along with that woofer puts the entire system in the suspect category. You obviously are way beyond the niceties of sequential serial numbers... you have a pair of L-300s that have been resurrected from the dead using the Frankenstein method.

The 077 is correct. A 16 ohm 2420 is perfectly fine too, electrically and acoustically equivalent to the 8 ohm LE85 that should be there. (There are many threads explaining this elsewhere on this forum.)

The proper woofer is the 136A. An equivalent woofer is the 2231A, if you can't find either of these, a 2235H will also work well.

Due to the other changes, you should look at the crossover to make sure it is correct, and I would want to make sure the diaphragms in both the 2420 and 077 are correct.

boudu
09-14-2003, 12:33 PM
I like your explanation , tomorrow I will call Frankenstein. I will buy new woofer but I'm not able to test the others speakers and I don't know how verify the network ?
BR
Boudu

4313B
09-14-2003, 12:55 PM
The 2135 (D130) should be able to take a C8R2235 kit.
Is there a number written in chalk on the back of the 2135 cone?
Are both low frequency transducers 2135's?

boudu
09-14-2003, 01:41 PM
I have two 2135 and there is something write in chalk on the back of the cone.
BR
Boudu

Mr. Widget
09-14-2003, 01:54 PM
Originally posted by Giskard
The 2135 (D130) should be able to take a C8R2235 kit.
Is there a number written in chalk on the back of the 2135 cone?
Are both low frequency transducers 2135's?

I forgot about the 2135:o You might have something there, Giskard. I bet they did recone them. Still a Frankenstein though.:D

Hopefully a well done Frankenstein, however it is only a success if the end user likes them.

4313B
09-14-2003, 02:51 PM
Originally posted by Mr. Widget
I forgot about the 2135:o You might have something there, Giskard. I bet they did recone them. Still a Frankenstein though.:D

Hopefully a well done Frankenstein, however it is only a success if the end user likes them.
Who knows what kit though. It could be a real hack job. What does the dust cap look like? What does the surround and cone look like? Obviously something is quite wrong if he doesn't like the sound. A 2235H sounds great in an L300 or 4333. In any case, he has two decent cores if the mags are still strong.

Mr. Widget
09-14-2003, 03:01 PM
"Obviously something is quite wrong if he doesn't like the sound."

Well, sorta... not everyone likes the L-300. There are those that prefer, say a Klipschorn, or a whack on the head:banghead:

boudu
10-20-2003, 11:27 AM
Finnaly, I sell them yesterday. Now I will buy maybe a beautiful pair of 4350 A in mint condition. I post a new thread about this subject.
BR
Boudu