At Mac clinics that Davie was conducting he would take the time to show Mac owners of MC 60's MC 75's and MC 275's that the KT 88 had lower distortion, with better signal to noise and better linearity and how the amplifier would put out more power above its rating with KT 88. Of course the factory only used hand picked Gold Lions at the time. One of the reasons I switched from 240's to 275's was by the KT 88 having a much larger envelope the amps ran cooler as did the Power transformer easily doubling the life of all the out put tubes and the tubes near buy. The 275 always sounded a little mellower to me though the 240's and the 275's basically measured the same at lower power levels
For folks who thought 275's were inferior in the bass, we would hook up a C-24 and play a record noted for bass, The issue was not the 275. A C-24 could wipe a C-22's any time any place. It was scary. After I heard a C-28 driving 3500's compared against my C-22 I was immediately sold on SS. The next move was a horizontal one and one of my two regrets I made buying Mcintosh. I traded my 275's for 2100's. I should have bought the 3500's while I had the chance. Even if they were a maintenance night mare at first. But I knew I was going to bi-amp, and having to purchase two more 3500's eventually was almost financially impossible and the amps would soon be discontinued.
I'm way off subject now:
The other regret wasn't as severe. I should have bought MC 7200's when they came along. I knew they sounded better, but I didn't. I kept my Crowns fore close to 30 years, before I bought my 207's and 206. . The 207is a great amp. Not as warm as Mac tube amps and SS amps like the 2200 with low damping factor and not as dry as Crown amps. A nice pleasant, easy to listen to amp. But its not laid back either and little noises and distortion are easily revealed. But you don't feel like you have been smacked in the face either, like the Crown amps often would. Back in the day Crown amps could be 20 db quieter than Mac tube amps and 15 to 20 db quieter than Mac ss amps and that was a bunch. That's the difference between buying a Quad balanced amp recently and unbalanced amps like my 207's MC 252 and MC 300. Its something you can hear but not all the time. When you are listening to quiet passages with semi efficient speakers you only have about 50 db below the signal where the noise lies. Thats marginal for sure. 70 db would be better for sure. Thats what quad amps give. Where would I put 8 MC 301's and one 207?. I'll stick with my two 207's.
May I make a suggestion ' a fully balanced MC 2507 or a MC 307. That's a challenge . How do you combine the quad sections without an auto former, Accuphase does. Who had Quad balanced first Mac or Accuphase?