Denon AVR-5805 Measurements Continued

When the analog preamp was driven at 1Vrms (typically ½ signal strength to achieve ½ of max power of most power amps with voltage gain of 29dB) distortion levels were (+.0219 + 107.997)dBv = 108.216dBv (about 7dB better than what I measured on the Integra Research RDC-7.1 Processor ) or 100*alog(-108.216/20) = .000388%! The yellow trace represents "Pure Direct" mode, while the red trace represents normal stereo. As you can see they are virtually identical in performance which is testament to the excellent noise mitigation and layout of the receiver even when all functions are active.

When I drove the analog preamp to over double the voltage required to achieve max gain of most power amps (4Vrms) distortion levels were very commendable (+12.096 + 84.466)dBv = 96.562dBv or 100*alog(-96.562/20) = .00149%!

Note: The preamp section of the AVR-5805 is benchmark regardless of receivers or processors. The Inputs can handle 10Vrms unclipped while the outputs can deliver 8Vrms unclipped! The preamp gain is (Av = 5.78) or 15.2dB. M ost consumer equipment (i.e. CD players, VCRs, etc) drive 1-2Vrms max via their analog outputs so there shouldn't be any compatibility problems here. If for some reason you find the input levels too high, causing clipping, the AVR-5805's independent level trims for each input will come in quite handy.

This is great foresight on their part, though in all likelihood the expected use of this feature is more for level matching sources than eliminating preamp clipping given the awesome headroom of the Denon preamp section.

Ch-A SIGNAL to NOISE RATIO

• -116.62 dB below 18.49 dBV Reference Level (at 1.04 % THD+N)
• < 10 Hz - 22k Hz bandwidth , no option filter.
• This is out of the preamp out. Thus at 8.4Vrms -116.6dB SNR

With a 200mV Input Signal, I adjusted master volume for 1Vrms out, preamp gain (Av=5 or 14dB), and measured as follows:

• -20.452 dBrA with signal
• -116.419dBrA with signal

Thus the SNR was 96dBrA which is phenomenal performance and rarely achieved by high end preamps let alone receivers! Typically we see #'s at 90dBra or less.

Power Amplifier Section

The AVR-5805 amp section delivered a whopping 195wpc into 8 ohms at .97% THD and 340wpc into 4 ohms at 1% THD with two-channels driven and about 170wpc into 8 ohms at 0.1% THD for four channels driven (mains limited, see notes)! This is definitely the most powerful amp section we have seen in a receiver and appears to keep up with many of today's multi-channel dedicated amps in the $2k and up price range.

Ch-A SIGNAL to NOISE RATIO 8 ohm test

• -110.87 dB below 31.94 dBV Reference Level (at 0.97 % THD+N)
• < 10 Hz - 22k Hz bandwidth , no option filter.
• This equates to 39.54V or 195 watts at .97% THD (onset of clipping)
• 110.87 - 22.93 = 87.9dB @ 1 watt (calculated from full power)

Ch-A SIGNAL to NOISE RATIO 4 ohm test

• -110.08 dB below 31.31 dBV Reference Level (at 0.98 % THD+N)
• < 10 Hz - 22k Hz bandwidth , no option filter.
• This equates to 36.77V or 338 watts at .98%THD (onset of clipping)
• 110.08 - 22.30 = 87.8dB @ 1 watt (calculated from full power)

Measured at 1 watt: 200mV input: Master Volume: -3.0dB

• At 1 watt: - 24.566 dBrA
• At idle: -112.482 dBrA
• SNR: 87.92dB @ 1 watt (actual measurement)

This is excellent performance especially since the preamp section is also included here! These SNR measurements certainly demonstrate this receiver delivered more than spec'ed power, and more importantly, had an extremely low noise floor which is critical when listening at low power levels to preserve detail ensuring all of the musical nuances maybe heard.