Subwoofer connected to Stereo Integrated Amplifier

Hi... i just bought a Onkyo A-9050 Stereo Integrated Amplifier and connected it with my Sunfire SDS12 Subwoofer and my Heco Interior 6000 plus floor standing speakers. However the subwoofer doesnt sound that excellent compared to when i connect it with my Onkyo TX 508 AV Amp. Tried all connections but failed to get a good sound from my A9050 Onkyo which is supposed to be a good amp. Request your advice guys. Thanks, Jan Major

Both the SR508 AV amp and A-9050 stereo amp are rated at about the same output power, i.e. 80W for 508, 75W for 9050, 0.08% distortion, 60 damping factor. But the SR508 has a bigger power supply since it is a multi-channel amp.  The limiter for the stereo amp is its 160W power supply vs 450W for the AV amp.  Also, you get better bass management (for subwoofer crossover) using AV amp.  When using stereo amp, full frequency range is being driven by the stereo amp whereas in AV receiver it depends on speaker setting (large or small).

Thanks Anwar, great advice...

In a stereo system, likely you will get better main-sub integration using the high level speaker input connections to your sub (s). Bass tends to sound slow and weak using line level preout connection even if you crank up the volumes.
Another method is to connect your sub direct to your rec-tape out from your amp but you will need to adjust the sub level every time you dial your amp volume.

It should work the same, have you cancelled the bass management in the int amp?