Luxman T12 FM tuner

General: 

This Tuner was produced by Luxman in 1980. This is one of the best tuners Luxman ever made,
it has great reception capabilities and sound is excelent. It incorporates great lineair filters in the MF section.
It has some special features, like switchable MF bandwidth.

Photos:

Front

interior view

bottom view - all photos of the unmodified tuner.

Front-end view, 5 gang variable capacitor, input antenna and output to MF section.

 

Special futures:

Switchable MF bandwidth, test tone, Accutouch, anti birdies filter, multipath switch.

 

Schematic:

The Luxman T12 tuner schematic diagram in pdf format, click here.

 

Modifications:

All electrolytic capacitors in the power supply can be replaced.
Some capacitors can be added to the power supply rail through the tuner,
to improve stability.

C193 of 3.3 uF can be replaced. A better quality cap may improve the sound.

The HA11211 discriminator IC can get defective and must be repalced in some cases, one of the
major symtoms in that case is, that there is no centre tuning possible anymore, the centre tuning lamp stays off.
Also the accutouch is often not working properly anymore in the same case. Replacing the IC and adding a coil and
extra capacitor in the IC's power supply line may be appropriate.
I used a capacitor of 0.047 uF and a 1 uF 50V electrolytic in combination with a coil of 0.33 uH.
Also I changed the 22 Ohms resistor in 33 Ohms to get a stable 12V on pin 11 of the IC.
A small heatsink on top of the IC is possible.
Also a anti birdies filter is employed by some local distributors as in the model above. (Audioscript Netherlands)
More simple and also effective anti birdies filters are possible. (Sherwood USA, Denon Japan)
On most of the antie birdies filter boards low grade caps are used, you may replace them with high grade ones.

Users in Europe must consider to change the mains transformer tap used for the mains connection, it is historicaly set to 220V.
But since Europe is increasing main voltage to 240 V over a 20 years time frame, and now being on plus 230 V ~.
So using the 240 V tap is the most sane thing to do now.
Change from the purple or orange (photo above) wire to the red wire of your transformer,
do not wait untill internal voltages of the tuner get too high.
Some transformers may have different coloured wires.

Readjusting the frontend after many years of service may be an option.
Some tuners may suffer unsensitivity because of a worn out front end first mosfet 3SK45,
but most T12's will not have problems in this...

Some T12's have switching problems with the tiny switches on the front panel, most commonly caused by dust and
by wear of the plastics inside the shaft in the front panel of the tuner. Making a little more room solves this.
Sometimes a little silicone spray helps.

 

Sound:

These series of audio components soon got legendary by their outstanding build quality and good sound.

© Hans Hilberink - PE1MMK ® - Last update: 06-01-2012.