I have had an interest in current dumping amplifiers for many years having built a Quad 450 clone more than 20 years ago. The current dumping principal seems to offer many advantages with no bias adjustment excellent stability etc and there has been much discussion in the past over how and whether it works as Quad claimed. The later Quad amplifiers such as the 606 aka 707 and 909 are often well reviewed and I think would make the basis for a very good amplifier. Many of the Quad designs are compromised by commercial necessity yet still offer excellent performance. All of these amplifiers were designed before modelling was possible. Would anyone be interested in modelling the Quad 606 to try to further understand how it works and to better realise its potential. I have a few spare 707 clone PCBs but I have not yet had the chance to build one.