Losing volume when sub is hooked up


I have an integrated tube amp with pre-outs. when i hook up my sub to the pre-outs i lose some volume. is this normal?
cooch
I wonder if your integrated uses a passive pot or attenuator? If it does and is unbuffered,it will tax the output of your source when used with fairly long ICs connecting a subwoofer. You need a buffer or a integrated with an active preamp section.
not sure about that. i know the ic is about 10 feet long tho. and when i hook the sub up directly to the speaker connections on preamp, there is no volume loss.
Do you mean the main speakers lose volume?
Does the sub have a line/spkr level switch?

Maybe it's in spkr and loading down the pre.
yes, the main speakers lose volume. sub does have seperate line level and speaker level volume controls. it sounds ok but i just have to turn the volume knob up more to get the same volume level i had before hooking up sub to pre-outs. i just don't like losing the power......