Quad 606 Power Amplifier
The Quad 606 Power Amplifier is another classic amplifier design from Quad utilising their patented current dumping technology. Essentially a current dumping circuit like the Quad 606 Power Amplifier consists of a very high quality low power class A amplifier feeding a high power low quality amplifier which is used when required.
The Quad 606 Power Amplifier was originally launched in 1987 and essentially was a new improved version of Quad’s 405 amplifier with extra oomph and a whopping 140 watts per channel into 8 ohms whose sonic improvement compared to original Quad 405-2 was significant.
The Quad 606 Power Amplifier was also very popular with professional audio people as well as audiophiles possibly because of the sheer power of this amplifier coupled with Quad’s reputation for producing solid well built amplifiers.
The Quad 606 Power Amplifier was discontinued in 1997 to make way for the Quad 707 power amplifier which was another current dumping design that improved slightly on the Quad 606 and was one of Hi-Fi World’s recommended amplifiers at that time.
If any current owners of the Quad 606 Power Amplifier are interested, Fidele Audio offer an upgrade service which improves the original sound by replacing the class A circuits op amp (Texas Instruments TLC271) with a much a higher quality one - a Burr Brown OPA627AP and upgrading some capacitors with Black Gate (just about the best you can buy - if you can find someone who stocks them). I can certainly vouch for this upgrade as I use a Net Audio modified Quad 405-2 whose upgrade is very similar.
Quad 606 Power Amplifier Specification
Power Output: 140 watts per channel (8 ohms)
Distortion: < 0.01%
Input Sensitivity: 500mV
Input Impedence: 20Kohm
Crosstalk: -100db (100hz), -85db (1 khz) and -65db (10khz)
Hum and Noise: 105db
Voltage Rating : 220-200V AC (110-120V via simple power board modification)
Dimensions (WxHxD): 321 x 140 x238 (mm)
Weight: 12kg
October 13th, 2007 at 11:40 am
Any idea how many 606’s were made please? I have a 606mk2 that has red writing on the label instead of the usual green to display the serial number. Also instead of a U ****** It starts with a number and then ends with an S. Any ideas? Thanks
October 15th, 2007 at 8:44 am
The Quad 606 was in production from 1986 to 1997. 27,700 units were made and after serial number 21600, the amplifier underwent some major changes to improve reliability and stability which I assume is the version you have.
October 27th, 2007 at 4:00 pm
i want quad power 606 what is this prise
December 28th, 2007 at 1:10 pm
Hi - I have a Quad 606 power amp and am using it with a Quad 34 pre amp. I would like to change the pre amp. Any ideas?
Thanks
April 3rd, 2008 at 9:14 am
I also have a 606 power amp and am using it with a 34 pre-amp. The 34 failed on me about 18mths ago, and I had it repaired by Quad (at a reasonable expense) and it has since failed again. I am keen to keep the power amp, but am looking to use another pre-amp. Like Kim, I would welcome any ideas you have. Many thanks.