Luxman L200/L210 and L200 series

General: 

This amplifier produced in the end of the 1980’s.

 

Photos:

 

Special futures:

This Luxman L200/L210  audio amplifier is a affordable yet high quality amp made by Luxman.
It incorporates Duo-Beta ® feedback and the tone control is not the usual, it is in the feedback line of the power amp.
No traditional tone amp is to be found in this amplifier.
It has "single pcb policy" and has the power transistors directly soldered to the main pcb.
The power supply is simple, but has sufficient capacity to feed a 2x40W basic amp.
The protection circuits are rather simple, so you can easely damage your amp when used improperly.
This amp has a fully symmetric and complementary bipolar transistor power output with
high speed & high current plastic power transistors.

Schematic:

            Click here to see the main schematic diagram

 

Owners manual

            Owners manual of the L200 series in zipformat

 

Modifications:

The power transformer of the L200 is much smaller than in the L230,
but most of the amps of the L200 series are working on the same power rail voltages,
this amp of the L200 series does not have a phono MC/MM switch and has only 1 lamp in the front.

The zener diode D112 needs to be replaced by a 2 Watt type and extra heat sinking to D112 must be applied,
when original light bulbs are applied. Otherwise problems with this circuit will come back again.
The original power design of this circuit part is incorrect, your pcb will probably be burnt like the one
on the photo of the L230 on this website.
When the light bulb is replaced by a led (that I prefer), the zenerdiode D112 is obsolete and can be removed,
the 300 Ohm resistor R153, must be replaced by a 1,5 to 5,6 KOhm 2W type as on the photo, depending on the type led you use,
and then you have the correct power design.

Replace C104 a b, C103 a b, C113 a b, C107, C108 a b, C130, C131, C129, C133, C132, C120 a b, C122 a b, C118 a b and C301 a b.

The power-amp input capacitors need to be replaced: C118, they may be small polyester or
polypropylene 3,3 to 4,7 uF 100V made by Wima, do not use big size caps, keep them small.
The power supply main capacitors C134, C135 of 10000 uF (4700 uF in some L200s) need to be decoupled by small HF capacitors:
add 2x 0,01 uF 100V ceramic or polyester, parallel to C134 and C135.

This amp of the L200 series has smaller sized driver transistors in the power amp section,
replace them with bigger ones as in the L230 or heatsink the small drivers in the L200.

Replacing the power transformer with a type that has approx. same voltages but a bigger iron-pack and a greater current capability,
is a rewarding thing to do, I used a Sansui transformer from the AU-GX series and now power is up from 2x40W to 2x60 Watts RMS.
Only thing to replace also is the drivers as remarked above.

I also did some experiments with different "loudness" switch capacitor values C116a/b, 0.047 uF,
as I found the loudness switching too agressive in the sound image.
I used 0.005 and 0.01 uF, both usable values, this of course depends on the speakers you use,
I used Tannoy HPD315, Sixes 611, 609 and 605 speakers to test.

I found the muting circuit also to be vulnerable to defective parts, so I checked and changed the transistors and some other parts:
Q114, Q114a and Q115, R150,  R151 and D109 / C132, all can be defective in some cases.
Check also working voltages of the caps in this circuit as I found some with incorrect values:
35V caps on a 46 Volt power rail, its certain this is going to be the cause of problems, replace with at least 50V caps.

There may be some other things subject to modification, but this is the main mod. I made.

 

Sound:

These series of "High Quality" audio components soon got legendary of their outstanding quality and excelent sound quality.

© Hans Hilberink - PE1MMK ® - 2003 - Last update: 31-05-2012.