LUXMAN   vintage audio

Luxman L30 & L31 integrated amplifier

General:

This is the very nice sounding ~2x35 Watts L30 integrated amplifier from Luxman.
Its looks nice, it sounds good and it was relatively cheap and very well constructed.
After a few years it was replaced by the L31, that was basicly the same amp with a little more Watts in the output.


 

User Manual:

not yet available

Special futures:

On higher efficiency speakers it was clear that this relatively simple amp was capable of delivering very good sound.
It has no major flaws in the design and construction. It has channel separated tone controls, like its bigger brothers.
Its very rewarding to extend the life of this amp by repairing and upgrading it to modern standards.

 

Specifications:

Schematic:

 

Service Manual: 

The Service manual of the Luxman L30 amp, click here to download in Zip format.

 

 

Modifications:

Of course you can modify this amp to modern standards. After alignment, one starts with the capacitors of the complete amp.
Replace them for modern ones.
The power supply can also be upgraded with better capacitors. use 2x 10.000 uF and better (faster or higher current) diodes if nessecary.
Check and adjust zero voltage and idle currents in the power section. Hardwire the speaker switch if you like.

Further modifications of the Luxman L30 can be the below parts that may be upgraded:

Only parts of LEFT channel are marked here, upgrade the RIGHT channel-amplifier as well.

Power amp section: You may:

Change C211 and 213 into 100 uF same voltage, or higher.
Change C203 and 207 into 100 uF SQ (or LL or LN quality) same voltage or ^.
R201 to 206 can be metalfilm same wattage.
Add to C203 and 207 a capacitor of approx 0.047 uF 100V, (parallel to these electrolytic caps).
C201 can be polypropylene 100V.

Power supply section:

Change C219 and C220 to 1000 uF same voltage.
Add to these C219 and C220 caps parallel a capacitor of approx 0.047 uF 100V, same procedure as above.

Pre-amp section:

C130 can be polypropylene.
C124 can change into 1000 uF SQ same voltage or ^.
C135 can change into 1000 uF SQ same voltage or ^.
C113 can be 1000 uF SQ same voltage or ^.
C119 can be polypropylene 100V.

In the riaa pre-amp are already LN resistors placed by Lux, some R's in the signal path can be changed to metalfilm R's as well.

Thats all for the passive parts.

Replace all Hitachi small signal transistors, as they suffer from the notorious silver-oxide creeping disease.
The 2SA836 and 2SC1345 made by Hitachi will sooner or later add a lot of noise and even storm and thunder to your RIAA amp.
The Hitachi transistors will not survive, so you better start replaceing now.
Replace with modern BC550C/BC560C and all noise problems are history.
Remember that the Luxman PCB's are delicate when you start desoldering.
Small signal transistors that are in this amp of other brands do not need replacement as they do not have silvered but tinned leads.

The power transistors of this amp are very good ones made by Toshiba, if you have to change a set of these
use the original 2SB531 & 2SD371 or may be equivalents or for instance Sanken 2SC4466 or 2SC5100 and its complementary,
There are more equivalents of other brands like NEC also on the market NOS or new.
If you can find NOS TO-3 transistors thats even better, as TO-3 transistors have better heatsink characteristics and
a better power transfer graph, if you want to use the faster RET or LAPT by Sanken, remember to insert extra
anti-oscilation C's in the power-amp section, as these transistors have Ft's up to 60 MHz.

http://www.sanken-ele.co.jp


 

Sound:

Very good for such a cheap amp. The combination with Tannoy HPD 295A or HPD315 is excelent.
Take a look at the Tannoy Monitor Gold website for more info on Tannoy speakers.
 

 

 

 

 

Hans Hilberink - PE1MMK & Ruud 2003 - Last update: 10-08-2015.