Peters thread on AK is a great one. There's very little info on these, his documentation, and restoration work was outstanding. Geoff, I've had 4 pairs of KLH's, still have three. The Five, Six, and Twenty Three. Of these, which are the most easily found, I rank them in this order, Five, Twenty Three, Six. The Fives are outstanding, period. They give my AR3's a real run for the money, and a performance bargain, though prices are creeping up. The Twenty Threes are Sixs on steroids, the cabs are bigger and they share the woofer with the Five which can handle a lot more power than the Sixs. Ahh, the Sixs. Absolutely love them. Mine are 1963 models, with the glued woofers, and one glued tweeter. The other tweeter is screw mounted. This is the year the screw mounted tweeter was phased in. I believe 1965 the screw mount woofers came. My other pair were 1972's, end of the production run with vinyl clad cabs. Both Sixs sounded virtually identicle, except, the 1963's go a tad deeper due to the epoxy mounted woofers longer excursion. I have them hooked up to my Scott LK-72, and it's a sublime mating. Hopes this helps you a bit, but any of these I'm sure you would be very happy with. Glenn