This is a review and detailed measurements of the NAD C 320BEE power (speaker) amplifier. It is on kind loan. The C 320BEE is a vintage product, dating back to 2003 I think. The BEE designation is apparently a reference to Bjorn Erik Edvardsen who was one of their designers. Can't tell if he designed this version or this is based on work he did years earlier. Either way, I am told it is a "classic." I don't keep up with such things but I am sure some of you will set me straight if that is, or isn't so.From what I can tell the original cost was US $399. So quite a budget piece for a mid-tier brand like NAD.The C 320BEE is typical of NAD design language which is maintained to this day:There are set of tone controls and balance which I appreciate in this day and age when it is removed from most gear.I did not seek out the manual and remain unsure how this thing powers on. You hit the power button but nothing happens until you press one of the input buttons???Here is the back panel:It is an old school layout with non-removable power cord, jumper set for pre to power map. And a set of RCA jacks lined up.The unit appears to run cool but there are large holes on the bottom where the amplifier heatsink is and if you touch that heatsink, it gets quite hot.In testing, without undue stress, the unit went into protection and would not reset until I cooled it off with a fan and left it off for a few minutes. Most amps survive my testing without going into protection mode since I only push them to max power for seconds.Also, in the process of changing my setup for 4 to 8 ohm, the unit went into oscillation, producing 107 watts on its own with no signal. So there is some instability in the design. This happened when I changed my load impedance to 8 ohm so perhaps you won't see it if you don't mess with speaker output while the unit is on.To be on the safe side, for the last few tests I put a fan on top to keep it cool and that got it to run very reliably.Let's start with our usual 5 watt dashboard into 4 ohm:The highest distortion product is at -100 dB. Since out SINAD (signal to noise and distortion), is only 90 dB, it means there is 10 dB of noise that is degrading that. All else being equal, noise is less of an audible problem than distortion so that is good. Take at its value, the C 320BEE clocks much better than many other amplifiers we have measured in this regard:Drilling into the 1 kHz tone spectrum we see the nice clean output of classic AB amplifier:Those of you who hate class-D spectra in ultrasonics, can rejoice now.Signal to noise ratio is good but is power dependent:I think the spec is a few dBs better than this but I am sure you can mess with levels and volume control position to get there. Either way, this is plenty clean for CD/16-bit playback.Crosstalk is unremarkable compared to state-of-the-art:Fortunately, this should not be an audible issue as there is plenty of separation between channels here.Frequency response is broad and quite flat in audible band:Even at 100 kHz, the response is only down 1 dB. So your high-resolution music can sing without the amplifier truncating their bandwidth.Let's look at intermodulation distortion (two tones at 60 and 7 kHz) versus power output:This is a well-behaved amplifier until it gets to its limit and then clips hard as amplifiers tend to do. Of note, there is a "soft clip" light but I did not see it come on in any of my tests.We can run the same test but with two high frequency tones of 19 and 20 kHz:Forgetting about the ultrasonic ones around 38 kHz, the distortion sidebands remain at -100 dB which is very nice. You can play your 16 bit content without worrying about any distortion above its noise floor.Most important test is power versus distortion. Let's start with 4 ohm load:This is very modest level of power but no strangeness in its response. We can run the test again but compare to modern "streaming" amplifiers of today:We have very clean power compared to them but less power as compared to either SONOS or Amazon Link Amp. The NAD does outperform the NuForce STA-200 though in every respect.Switching to 8 ohm gets us this:I am puzzled that power output remains identical in both cases. Something must be controlling that.The graph of distortion versus frequency at power levels is quite messy as it typically is:Putting aside the light pink which is at or near clipping, the amp if well behaved with only a modest rise in distortion as power levels increase.To keep things exciting, I added a new measurement to this test. It is the "dynamic" power according to CEA-2006/490A designed to keep car audio amplifier companies honest with peak power:These are burst power measurements. Let me know if you like them and I will run them in future reviews. I think there is some merit to measuring this way as music is not continuous sine wave.Nice to go back in time and test amplifiers which were simple to understand and simple to measure. The NAD C 320BEE seems to have been competently designed for modest power delivery at a budget price. In that regard, it completely succeeds in its mission.Personally, I think 67 watts is not enough for home listening. Today's speakers have become smaller in size and shrunk in efficiency, needing fair bit of power to get them to produce proper dynamics. If you disagree otherwise, or have sensitive speakers, the NAD C 320BEE seems to be a good unit to buy. It certainly does away with any anxiety you may have with using class-D amplification.------------As always, questions, comments, recommendations, etc. are welcome.My wife is leaving town this weekend so I planagain. Only panthers are invited this time so you can't attend. But you can helppurchase of ton of meat with need for the even using: