JVC TT 71: buy now for spare for my or TT81?

I've been using a QL-7 with the TT-71 while I mount a second tonearm on my TT-81 in the two arm JVC plinth. While the specs of both motors are similar, the TT-71 has noticeably less torque. Of course, it's possible my TT-71 is less than optimal; both decks are pretty old. I also prefer the mechanical switches of the TT-81 versus the touch controls on the TT-71.

But to answer your question, there's no reason not to get a TT-71 for backup, as it's perfectly adequate, but I believe the TT-81 is better in just about every way.

I own 3 JVCs, a TT101 (which is dead) an 801 that runs like a clock, and a QL 7 with a TT 71 engine that I just did a full restoration; all my turntables I restore and overhaul by myself.
I think TT 71 and 81 are better than Technics SP 15 and 25 at least in terms of engine.
The TT series engines are big and sturdy as breakfast cups and there is a lot of substance, those in the SP 15 and 25 or SL 10 are the same as the small and compact Technics 1200s.
It doesn’t mean much but I like fat.

The motor TT 71
https://i.postimg.cc/J0pSMJ3z/DSCN6089.jpg
https://i.postimg.cc/zvyFHgZB/DSCN6093.jpg
https://i.postimg.cc/bJBQPwDj/DSCN6100.jpg

In the TT 101 I made a complete recap and replaced all the pcb trimmers but it still didn’t work well .... I have to give up for some time ... it totally stressed me out!

Elliot, I am not sure what you meant, but if your interest in a TT71 is based on its fitting your TT81 plinth, I do believe a TT101 would also fit a plinth made for TT81.  Of course, the factory plinth for TT101 (to be found included with a TT101, along with a Victor tonearm, in the package known as QL10) might be a bit better than an OEM TT81 plinth, but I really don't know that for sure.  Anyway, if what you want is an inexpensive back-up turntable for your TT81, sure, the TT71 would be fine.  You either want it or you don't.  It's not a matter of anyone's opinion.

best-groove, I feel the same way as you regarding the build quality and really like that substantial motor. I'm not sure but I think the TT71 and the TT81 use the same motor. I think the TT81 has upgraded electronics.
As far as the switches go, I'm fond of the touch switches. The TT61 that I had for a short time used the mechanical switches and I just thought they were OK but the touch switches seemed to be a step up. Plus there are no contacts to get dirty.
BillWojo