Having had an opportunity to test Onkyo TX-SR383 vs Pioneer VSX-933, I’d like to share my impression here to facilitate your choice of a new AV receiver.
AV receivers under review have the same number of channels. In terms of power, there are differences, the TX-SR383 has such a ratio W/Ohm - 100/8, 135/6, while the VSX-933 has a power of 80/8, 165/6. The value of total harmonic distortion is also different, and for the TX-SR383 it is 0.09%, but for the VSX-933 it is 0.08%.
The manufacturer installed different DACs, the TX-SR383 received the model 192 KHz/24-bit, but the VSX-933 is equipped with AK4458 384 KHz/32-bit. The Bi-amping function is implemented only in the Pioneer VSX-933. The model VSX-933 can transmit an audio signal directly to the amplifier and bypasses any DSP processing. Each of the receivers has a Bluetooth connector. The VSX-933 has access to the Spotify service. The quality of 4K/60Hz signal remains unchanged when transmitting from a source to a TV or projector via HDMI for both receivers. Signaling over HDMI in standby mode can provide the TX-SR383 and the VSX-933. Video scaling is only possible with the VSX-933. Operation with the Dolby Vision is only possible with the VSX-933.
The number of HDMI inputs/outputs varies depending on the receiver, the TX-SR383 has 4/1, and the VSX-933 has 6/1. HDMI Audio Return Channel is implemented in both devices. HDMI eARC is not supported by the TX-SR383 and the VSX-933. When comparing receivers, it becomes clear that each of the rivals can work with HDMI CEC. TX-SR383 and VSX-933 support the standard HDCP 2.2. In the presence of a built-in phono stage for connecting a vinyl player only at Pioneer VSX-933.
Ability to create 2 Multi zones inherent in both AV receivers. There is an ECO mode in neither AV receiver. The Pioneer VSX-933 can be properly configured using the setup assistant.
A Dolby Atmos multichannel audio format is available only in the VSX-933. Only in the VSX-933 realized a DTS:X surround technology.