Luxman 707 & SQ-700X amplifier

General: 

This amplifier produced in the end of the 1960's & early 1970’s. .

Photos:

 

Special futures:

    The power amp of the SQ700X is more modern than of the 707.

 

Schematic:

     Schematic diagram in PDF format of the 707

 

Owners manual

      Manual & schematics of the SQ-700X 

     

Modifications:

You can modify this amp, to get better results.
Replace broken power transistors with TO-66 transistors 2SC1445 and PNP 2SA765 (Sanken) instead
of 2SA616 and 2SD155 (NEC), or use plastic transistors like 2SB595/2SD525 (Toshiba)
or 2SA1694 & 2SC4467 (Sanken).
The transistors of the pre stages are often noisy. Use BC550/560C or equivialent,
you can get the noise figure below the original specs of Luxman.
On other places in the amp you can use 2SC1775.

 

Sound:

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

© Hans Hilberink - PE1MMK ® - Last update: 30-01-2012, thanks to Marek Łabuda for the schematic of the SQ700X.