General:

Nice early Luxman tuner with good performance, made by Lux Japan in 1964.

The WZ70 was conceived to appear as a kit also.

 

 

^ Front pictures

 

Special futures:

Stereo FM tuner with tubes and AFC switch, dubble dial, tuning tube and stereo lamp, 110 or 117 Volt mains.

Range FM: Japan, from 76-90 MHz.  Range AM: standard MW.

Full metal cabinet.

 

User Manual:

Click here to download the service manual PDF format 

construction

All Tubes ^

 

Schematic:

Click here to download the schematic diagram. (construction)

 

^ Inside the WZ70: top view, all tubes, no pcb's, restore ready.

 

^ Inside the WZ70: bottom view, no pcb's, restore starting.

 

Specifications:

 

Model: Luxman WZ70

Type: FM stereo / AM tuner

Reception frequency FM: 76MHz ~ 90MHz / AM: 535kHz ~ 1605kHz

Usable sensitivity FM: 3μV (S / N 30dB)  mono / AM: 25 μV (S / N 30 dB)

Image ratio FM: 45dB  /  AM: 60dB

Frequency characteristics FM:  30Hz~20kHz / FM Stereo: 30Hz~15kHz

Channel separation:  30dB or more (80Hz-10kHz) / 42dB or more (1kHz)

Leak carrier:  40 dB or better

Distortion: 1% or better

Output: 500mV RMS (100% mod) up to 1 Volt.

Vacuum tubes: (12 pcs)

6BA6: 2 (EF93)

6BE6: 1 (EK90)

6CB6: 1 (~EF9x)

12AU7: 1 (ECC82)

6AU6: 2 (EF94)

6DT8: 3 (~ECC85)

6U8: 1 (ECF82)

6RE13: 1 (~EM84)

Diodes: 11

Dimensions: Width 348 x Height 130 x Depth 215 mm

Weight: 6kg

 

 

^ Stereo reception after the restore, excellent reception and sound.

 

Modifications:

I made some modifications after the restoration of the WZ70. I exchanged the 2 power supply diodes,
and added some capacitors to the power supply. Also exchanged some capacitors in the signal path.

Very strange was this:
Usually the electrolytic capacitors are worn out and far beyond their specifications after ~50/60 years.
The blue Nichicon electrolytics appeared to be in good condition and within the specified values.
However the gray Nichicon foil capacitors were in very bad condition: approx. 2x the value specified.
So I had to exchange all the gray ones, specially in the audio-out section.

The 6RE13 (~6HU6) "Magic Eye" was broken and hardly any usable data or replacement to be found.
So I changed the schematic for the use of a EM84 or EM85.
The new EM84 works fine, you may change the 1 meg Ohm resistor to 100k in the g1 drive circuit
if the sensivity of the EM84 is not sufficient:  yellow wire to pin 1 of the EM84 socket.

Most of the tubes are replaceable by European equivalents, only the 6DT8, 6CB6 and the 6RE13
have no direct equivalent, but can be replaced by USA or European tubes with small modifications.

 

 

New dial-lamps fitted ^

 

 

^ FM reception with 6RE13

 

 

^ FM mono reception with EM84 and stereo lamp off.

EM84 data ^

 

^ Luxman serial # ^

 

Traditional Luxman power transformer ^

 

Sound:

The sound on FM is good, stereo is ok, AFC is ok, the AM is very sensitive.

Construction.

^ Switched off

LUXMAN
Electronics

 

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