Leak Sandwich

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The sandwich mid/tweeter is not that bad. Just not up to the task of being both mid and tweeter.It matches the bass unit well in sound and if you use something else it may sound worse.

Although I would not use it in a new design, I would not change it for anything else in an original, just add a tweeter to make a true three way as Leak did.

I suspect the high eBay value is because some are now failing, being old, and owners want to keep their speakers original.

I will try to dig out the 3-way crossover later.
 
frugal-phile™
Joined 2001
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bob_v5 said:
Also a schematics of the XO would be nice.

8 ohm version
 

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I opened up a model 600 three way, Sorry I cannot draw crossover like Dave but will describe. All values are taken off component markings
The drivers had the square ceramic magnets.


Compared to the 8 ohm version drawn by Dave,

Woofer- L=2.25 mH ferrite core
C= increased from 32 to to 50mfd

Mid - Now a two section filter,

-------][-----------XXXXX------
C1 ! L2 !
X !
X L1 = C2
X !
--------------!------------------!----------

First section is C1 L1 as before, C1 16mfd, L1 is 2mH, but bypassed by 290 ohm resistor.
Second section is a series L2, 1mH, with C2 6mfd, across mid.

Tweeter similar to first section of mid, C1 now 6mfd, L1 now 0.3 mH, but bypassed by 12 ohm resistor. Note tweeter is reverse connected.

All coils ferrite cored except 0.3mfd.

Tweeter unmarked except "made in England" on face plate, clear purple dome, possibly Elac?

Hope that makes sense.
 
Interesting thread

I picked up a pair of Leak 2020 speakers last year for free on a freecycle scheme. I'm very impressed with them, coupled with a small T-amp. These have a ceramic sandwich bass and a ceramic tweeter. The cabinets are chip board but the internal sides have thick damping material applied .

The crossover appears to be 3 air cored inductors and a single plastic cap.

The bass is exceptional, but the top end sounds pretty rough. Each tweeter is covered by a piece of cloth , so hard to see them. Any advice on improving the top end ? Maybe I should remove the cloth to check the drivers are not damaged ?
 
Hi!

I've got a pair but the woofer cones are rubbing in both. Some six years back, I tried turning the woofers by 180 degrees, but it did not help. Both are Alnico, magnet woofers and the screws holding the magnet to the frame look like they belong in an aircraft wing (to hold the jet engines on...). Anyway, HAS SOMEONE ever successfully readjusted the voicecoil position on such a powerful magnet assembly, without cutting out the dust cap and shoving plastic strips in there, who could help me through it?

Thanks,


-Steven
 
Hi!

I've got a pair but the woofer cones are rubbing in both. Some six years back, I tried turning the woofers by 180 degrees, but it did not help. Both are Alnico, magnet woofers and the screws holding the magnet to the frame look like they belong in an aircraft wing (to hold the jet engines on...). Anyway, HAS SOMEONE ever successfully readjusted the voicecoil position on such a powerful magnet assembly, without cutting out the dust cap and shoving plastic strips in there, who could help me through it?

Thanks,


-Steven
Long time ago but hey. Place woofer face down, undo four bolts till just free, taking care with vc wires. Move the magnet plate slightly, bounce the cone , when you hear no obvious rasping tighten nuts and refit. This way of centering normally proves adequate for all but the narrowest voice coil gaps.
 
Thanks planet10 and rjb for the factual information here, which helped me repair a pair of 600s I acquired recently. They had been recapped with cheap single polar capacitors for computer/general applications and the values were miles out, this thread helped me pin down the exact values and ensure my crossovers were workable, so this thread was unique and indispensable.

I did listen to them briefly before I did any work and they didn't sound THAT bad!

May I suggest a couple of changes to planet10's schematic in the interests of accuracy. The midrange resistor is 29 ohms, not 290, and the tweeter needs to be shown with reversed polarity.

Now fixed, I quite like them. Not at all the bass monsters those big drivers suggest, bass is accurate and tight, if not lightweight. They excel at midrange, orchestral and jazz, wind instruments especially woodwind. The midrange speakers have fabric surrounds and open edges and seem a bit home made in their plywood square, but work a lot better than they look!

Al
 
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