The Integrated that I already own does not have amp-in jacks nor the sort of u-shaped connector you describe.
However, generally I will just pretend that one of the 'in' jacks (such as tape or CD or tuner) is from a pre-amp. Voila, I have my pre-amp in. One could do this with virtually any integrated, so the question arises... will this hurt anything (except the sound quality)?
Now, on other amps I am considering, they may have these amp-in jacks, so they may be more accomodating to this sort of abuse.
jl
However, generally I will just pretend that one of the 'in' jacks (such as tape or CD or tuner) is from a pre-amp. Voila, I have my pre-amp in. One could do this with virtually any integrated, so the question arises... will this hurt anything (except the sound quality)?
Now, on other amps I am considering, they may have these amp-in jacks, so they may be more accomodating to this sort of abuse.
jl