yes you can 'lose signal'
but it's not going to be enough to matter
you also 'lose signal' [it;s degraded slightly]
by going through the DI box...
which doesn;t matter either really, the amount
of change is so slight
what i REALLY wish i had done, and still might do,
is to use a balanced mic element inside
the accordion, wire that to a 3-conductor
1/4" jack, then make or buy a cable
that converts that directly
[no DI box, no transformer] to XLR male,
just like a regular XLR mic.
or - i have seen this too - just have
an XLR male jack on the accordion itself..
the accordion becomes just another mic
connection..
the only problem would be if you wanted to
run some effects, they typically take 1/4"
inputs. so the XLR-on-accordion thing
would be a little clumsy for that..
the 1/4" solution would work better for that
and it takes less square inchage on the
accordion face..