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Hibuckhobby
03-07-2010, 08:02 PM
I recently got a pair of L-200's in nice conditions.
Ever since I got them, I've noticed that the sound
from one speaker sounded a bit thinner and brighter
when I set both speakers to "laboratory standard".
As soon as I put that speaker on any other setting,
the highs are severely rolled off. Put some pink noise
through them and the two speakers sound quite a bit
different from one another.

Where do I start in tracking this down. The woofers
and horns both work...just different tonal qualities.
Crossover??? Or????
thanks,
Hibuck....

BMWCCA
03-07-2010, 09:09 PM
Once you're sure it's not your electronics (swap speaker leads right-to-left), try running both L-pad (HF level) controls through their full range (5) positions many times (electronics turned off!) and see if that helps at all. :dont-know

Hibuckhobby
03-08-2010, 05:17 AM
Have done that...even tried different amps. Results the same.
Hate to open them up if it's not necessary.
Hibuck...

Mr. Widget
03-08-2010, 07:56 AM
...try running both L-pad (HF level) controls through their full range (5) positions many times...

Have done that....It does sound like a dirty or possibly burned out L-pad. You might try spraying contact cleaner into the pot if it is one with open vents...

To do this without wrecking the foilcal (name badge) pull the woofer and look at the back of the L-pad with a mirror.

If the L-pad is burned or otherwise damaged, it must be replaced. This can be done but even with a heat gun and great care it is unlikely you can remove the foilcal that covers the nut without some degree of damage. There are folks who make replacements though.


Widget

jcrobso
03-09-2010, 07:59 AM
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=260-255

BMWCCA
03-09-2010, 10:06 AM
If you have to replace the L pad this will work.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=260-255


Again, I'm far from the expert but isn't the control on the L200 Studio Master a six-pole switch rather than a variable L-pad? Sure appears that way in the schematic.

Robh3606
03-09-2010, 03:28 PM
L200 Studio Master a six-pole switch rather than a variable L-pad?

Depends on if it's an A or a B. The older version with an LE-15B used a stepped switch attenuator where the newer 136A version used an L pad

"so it's desert topping and a floor wax"


Rob:)

BMWCCA
03-09-2010, 03:36 PM
Depends on if it's an A or a B.Or just an L200 with no letter, right? Silly me! When the original poster said "L-200" I figured that's what he had! :banghead:

Robh3606
03-09-2010, 04:16 PM
Or just an L200 with no letter, right? Silly me!

Not really I don't see where he tells us??

Rob:)

BMWCCA
03-09-2010, 08:23 PM
Not really I don't see where he tells us??
Umm, in the subject line, and the first line of his first post...

I never refer to my L150As as "L150". Just figured everyone used clear references. My point was there are three versions; L200, L200A, and L200B. All but the latter use the six-pole switch. But you're right, we'll never know the truth...unless the original poster comes back to illuminate this thread. :D

Robh3606
03-09-2010, 08:45 PM
I never refer to my L150As as "L150".

Well the Devils in the details. I think they are L200's because he says Laboratory Standard. That's on the foil cal of the L200. I thinks it's just a "0" on a 200B. Your right though pictures sure would be nice. Oh Well just keep us guessing.

Rob:)

Hibuckhobby
03-10-2010, 05:44 AM
To the best of my knowledge these are L-200's. The switch is a stepped switch that has "lab standard, -6db, -4db, -2db and lab standard" in that order as you turn clockwise. I have them both on -4 right now because that's where the speakers sound the most similar.
regards,
Hibuck....

Mr. Widget
03-10-2010, 08:58 AM
So then it would appear you do have the "original" L-200 with LE15B woofer and a rotary switch with various resistors as a pad. Sounds like someone was playing those speakers very loudly and burned up a few of the resistors. They can be replaced.

The diaphragms in your compression drivers may be a bit used up too... when used in pro applications, or simply driven hard at home for an extended time the aluminum diaphragms can "wear out" through a process known as work hardening. They will still play, but may not sound quite as they should.


Widget

jcrobso
03-10-2010, 08:58 AM
I recently got a pair of L-200's in nice conditions.
Ever since I got them, I've noticed that the sound
from one speaker sounded a bit thinner and brighter
when I set both speakers to "laboratory standard".
As soon as I put that speaker on any other setting,
the highs are severely rolled off. Put some pink noise
through them and the two speakers sound quite a bit
different from one another.

Where do I start in tracking this down. The woofers
and horns both work...just different tonal qualities.
Crossover??? Or????
thanks,
Hibuck....
The easiest way is to start swapping things one at a time.