LUXMAN vintage audio
Luxman T12 FM tuner
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 and lock of the tuning knob.
bottom view - all photos of the unmodified tuner.
Front-end view, 5 gang variable capacitor, input antenna and output to MF section.
Switchable MF bandwidth, test tone, Accutouch, anti birdies filter, multipath switch.
The Luxman T12 tuner schematic diagram in pdf format, click here.
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 replaced 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 to keep this IC up and running.
I used a capacitor of 0.047 uF 50V and a 1 uF 50V electrolytic in combination with a coil.
Also I changed the 22 Ohms resistor in 33 Ohms to get a stable 12V on pin 11 of the IC and reduce max. current.
A small heatsink on top of the IC is possible, I used a common IC heatsink with thermal grease.
Also a anti birdies filter is employed by some local distributors as in the model above,
can be subject to upgrading or modification. (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.
I made a modification to this little additional board, that made the sound even better.
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. Some tuners may need a internal mains filter.
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 and are very sensitive.
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. I use a Würth solvent not avalable in Europe and some USA states.
In some tuners there is the 300 Ohms connection still working, if you do not need that, please disconnect internally to
improve input sensivity and reject reception of very strong stations through the whole FM band.
When you do these upgrades you can get a fantastic sounding T12 tuner that has very good sensivity and good selectivity.
Updated interior of a Luxman T12 tuner, (source: www.tubejack.nl thanks Jack)
These Luxman LSS series of audio components soon got legendary by
their outstanding build quality, good sound and durability.
© Hans Hilberink - PE1MMK ® - Last update: 06-01-2012.