As the previous poster has said, they are not the same. Pioneernut- you are incorrect.
Axel's (TVK) page on the amplifier is also completely wrong- I'll send him an email when I get a chance. He maintains thousands of pages and does a great job, but it is not gospel, especially when piecing together information from all around the world with strange model numbers, confusing pictures and spec sheets that are often wrong.
The M90a is a completely different power amp and was not used in the A-71. The A-71 does not resemble the A-717 at all, apart from the front panel layout. The M90/a is a dual mono amplifier, the A-717 is NOT. Two transformers does NOT a dual mono amplifer make. They merely run the transformers in parallel to lower the output impedance- there is only one set of dual 22,000uF caps. The 858,71 and 91D all had 27,000uF caps whereas the A-717 had 22,000uF caps.
The picks are the A-91D for integrated and the C90/M90 for pre/power.