Quad 405/306/520/606/707/909

405306520606707909 These are the famous Quad 'current dumping' amplifiers. We can adjust the sensitivity of 405s, 606s, 707s, and 909s at no extra charge. Many users find these too sensitive: a 2x or 3x gain reduction makes them more usable. The selected Berndt Ludwig 405 modifications we perform are sufficient to more or less transform a 405-1 into a 405-2.