So i guess what is the problem? Are they putting much cheaper amps in current AVRs? I did notice a major weight difference with the new one being much lighter.
There is no way the new one is much lighter, unless you have a typo in your post.
AVR-2310CI......................24 lbs
AVR-X3800H.....................27.6 lbs
As Eppie mentioned, aside from the features, you old and new AVRs should be very comparable in terms of power output. So, all else being equal, if the old one does not distort for your application, then the new one should not distort either.
Having said that, neither AVRs are considered suitable for your 4 ohm speakers, let alone the crossover issues TLGGuy and Verdinut pointed out. You have been fine with the little 24 lbs AVR-2310CI, likely because you don't listen very loud, and/or sits not too far, such as only 7 to 10 ft from those tower speakers.
Other than that, either you unit is detective, or you are doing something wrong. To help narrow down the caused, more information are needed, such as the following:
- Did it distort in direct mode, and pure direct mode?
- How many channels was it driving, or it would distort regardless, even just 2 channel stereo?
- Are you doing anything different than when using the old AVR?
- Does it distort only when you crank the volume pass a certain point, if so, at what point, example: 0, -15, -10 etc.?
- Do you still have the AVR-2310CI? If so, have you put it back on and see if it is still fine without distortion, that's just to find out if anything else might have changed.
What about the other channels, do they sound distorted too?
Edit: One other thing, did you have the impedance setting set to 4 ohms?
If you did, that could also be a contributor, as it would limit current to your 4 ohm speakers and could result in distorted sound at volume setting lower than if you had it set to 8 ohms.