I picked this unit (two "boxes", a pre-amp box and a power amp box) up with blown right hand channel. The output devices had already been replaced and had blown again, they were not the original types. These amplifiers are fantastic, made with top quality components, well built and stylish cases; this unit is a black one with bronze hammer painted metal top and bottom covers. These amplifiers were made by Jeff Rait in Christchurch, New Zealand. There was also a 60-60 model that looked identical apart from the model number printed on it. I remember seeing these on the shelf in the local Hifi shop beside the Perraux, Fountain & other early New Zealand amplifiers, The power section uses BJT output transistors, in complimentary pairs and with capacitor coupled output. I replaced the output transistors and the power regulator transistor in the power amp, the pre-amplifier was working fine. I carefully tested associated components before powering up using a variable transformer, just in case! It came to life and sounded very nice indeed, no wonder these amps are so revered; in my humble opinion these are well under rated, this is a mid 70's amplifier design by a very, very good designer and appears to be ahead of much of the (NZ) competition of the time, with a well regulated power supply for the power output stages as well as the drivers/pre-drivers and pre-amplifer and build quality second to none for the age. Some may balk at the capacitor coupled output (they are very large and top quality Elna's so should give a good bass response) however some very good designs have used this, the rest of the amplifier uses very few electrolytic capacitors, only two in the pre-amplifier, very unusual. After all that it is the sound that counts and this amplifier has a very detailed, clear mid, bass and treble very nice to listen to, very musical, very smooth; Lee Ritnour's guitar sings and sparkles with life, bass is tight and full, I could easily use this amplifier in a main system and be very happy...more to come it's soak testing at the moment.