Yah. Try it. To simulate, put a 10k resistor in parallel with the output from your deck. That's the best you'll get out of it, turn it down to less resistance and you'll lose more highs. If you have a deck that puts out 5 volts, it won't matter(as much) but if you are like us regular shlubs with typical outputs of less than 1 vdc it makes a big difference.
You will also notice that the dumbasses that design that stuff use parts that are not suitable for audio. For instance, I bought a David Navone device supposed to do the same thing, he used a linear pot instead of an analog, no bypass caps. There is a big difference in the way they work, I won't bore you guys with details. If the LC1 is different, that's great but if it is a passive device (no +- vdc sourced to it) then it is sucking your highs and tone to ground. It is a fact, physics at work.
Buy a good preamp, don't waste your money on the low level stuff. If you do you level control from the preamp you will have a lot less grief with noise problems. Just my .02