It was in 1976 or 1977, when I got to listen to her at Hubli and while I have no recollection of the details of the concert, there is no question that it was a fantastic concert. I later got to listen to her concerts in Hyderabad and Mumbai. It is/was always such a delight to listen to her, with her individual style and techniques, that we now see in her daughter and grand daughters.
It is not common knowledge that she started out as a carnatic violinist first (her brother T N Krishnan is one of the great ones from the CM genre) as quite an accomplished one and then dived into the hindustani genre with Omkarnath Thakur as her guru.
Here are some recordings for your listening pleasure starting with Omkarnath Thakur with N Rajam playing (I hope that is accurate):
The recordings are sorted alphabetically by the raga name for no particular reason.
bAgesri
bAgesri kAnaDa
bahAr
bhairavi
chAyA naT
darbAri kAnaDA
dEsh
durgA
gOrakh kalyAn
hameer
jinjOTi
mAlkauns
misra kamAj
miyA ki sArang
miyA malhAr
nilAmbari
piloo
tilang
tumris in bhairavi & kamAj