Like the earlier poster said, impedance.
I can't comment on the sound -- its often a matter of personal taste -- but some of the bogus speakers I mentioned (labelled with names designed to sound like existing brands) are "designed" by people who have no electrical knowledge, using the cheapest drivers they could find.
Result the speaker presents something close to a short circuit to the amp.
Of course it's possible that you have a perfectly sensible pair of speakers and I've just never heard of that brand. But the only reference I could find on Google was to the conmen I mentioned earlier.
In which case I would invest in a multimeter and set it to the range around 200 Ohms and measure the speaker's terminals with the amp disconnected. The reading should be between 4 and 12 ohms -- anything less and you could have problems.
This isn't a definitive test because impedance can vary with frequency but every decent speaker I've ever measured was around 8ohms.
If the speaker's aren't the issue, then you have a different problem with the amplifier.