Visitors to my website will know how much I enjoy working on classic and vintage electronics. One category of gear I love is monster receivers from the 70’s and 80’s. The Sansui G-8000 Pure Power DC Stereo Receiver is one of the biggest and baddest monster receivers, read on to take a look!
The Sansui G-8000 receiver was created at a time when Japanese manufacturers were competing to produce the meanest hifi beasts, like this Pioneer SX-1250 I restored. The G-8000 is not quite as mean as the SX-1250, but make no mistake, the big Sansui is a real monster. A quick look at the specs over at Hifi Engine shows that this receiver puts out 120 watts per channel into 8 ohms. More information can be found at Classic Receivers.
The Sansui G-8000 features great build quality, something we normally associate with gear of this vintage and price, no surprises so far. All major circuit blocks are located on their own boards and some are fitted inside shielded boxes, as is Sansui tradition. This is a nice touch that appears a lot in gear of the period. Sadly, we rarely see it now.
One thing worth noting with this design is that Sansui used a lot of board-to-board interconnects. These are nicely executed with gold-plated pins in most cases, but the connectors were quite loose in this receiver. Also worth noting is the incredible complexity of a piece of analogue engineering such as this. There are so many switches, rotary controls and wiring, all of which accumulates dust and dirt over time and can cause problems.
The issues with this Sansui G-8000 related to these connectors, controls and dirt, as well as some not very clever previous repair work. According to its owner, one channel was cutting out intermittently and the controls were noisy. I found loads of dirt, excessively high DC offsets in both channels and idle currents set to almost zero in both channels.
Servicing the big Sansui involved cleaning and lubricating all of the switches and controls. It’s important to use a quality cleaner and lubricant for this. I tend to use isopropyl alcohol to clean controls like these at it whisks away oily residues that can accumulate inside switches and potentiometers. I then sparingly apply a premium lubricant like Caig or Contact Chemi.
I systematically remade every board-to-board interconnect i could physically get to and some of these were clearly very loose. I then power the receiver up and let her idle for an hour or so, before adjusting DC offsets to zero in each channel and setting bias to 16mV. The intermittent channel issues are fixed, which is great news for this lovely old receiver and she certainly will sound much better than she did, with bias current correctly set and no DC biasing the speaker voice coils as it was.