This is a review and detailed measurements of the Jeff Rowland 535 stereo (bridgeable) amplifier. It is on kind loan from a member. I believe it costs US $5,900.If you are not familiar with Jeff Rowland, it is a high-end audio company, known for their gorgeous machining of their cases that imparts a 3-D look. You can see that coming through the protective film which I chose to leave on:The unit is incredibly heavy for its small size. The back panel shows the most unusual binding posts I have seen:Those big knobs rotate to tighten bar on two spade terminals. The feel incredibly nice. Alas, they don't mate with banana leads and I had to screw around to connect mine.The amplifier is said to be balanced throughout including input transformer which is made with wire from Cardas (!).Company only states that a switching power supply is used but says nothing about the rest of the functionality. From my testing, it seems to be class D which would explain why the amp stayed completely cool to touch under testing as if it was never on! The massive chunk of chassis aluminum is likely responsible for great thermal performance.As usual we start with our 1 kHz dashboard at 5 watts into 4 ohm:Ah, this is disappointing. Distortion peaks to -80 dB which sets SINAD at an average number of 77:This is way below stated of the art in switching amplifier design. Company specs are similar by the way so this is representative performance as designed.Where specs don't match is in signal to noise ratio:Crosstalk curve usually gets worse with frequency (due to increased effect of stray capacitance) but here it is rather flat:Frequency response is very good with no indication of interaction with the load:Another shortfall from the spec is in power department:Letting distortion peak up to 1% still doesn't give us what the spec says:I don't know how they get to 500 watts unless it is at even higher distortion levels.As a way of comparison, let's see how the power curve looks like relative to noise and distortion of Hypex based NC400 We have slightly more power although the NC400 I tested had a shared power supply. That aside, there is no comparison in noise and distortion department. The 535 way underperforms the Hypex.Finally, here is an unfiltered output of the amplifier at 5 watts:We clearly see the switching waveform. Attenuation is better than 30 dB which is more than a number of other amps I have tested so that is good.The Jeff Rowland 535 amplifier has beautiful fit and finish. And is solidly engineered to run cool and I am sure reliable as a result. It produces good bit of power which should be able to drive many speakers to desired loudness. Alas, it reinvents the wheel and makes it less round. Any amplifier based on Hypex modules will have as much or more power with far less noise and distortion and lower cost.Bottom line, I can't recommend the Jeff Rowland 535 due to its high cost and average noise and distortion.-----------As always, questions, comments, recommendations, etc. are welcome.Every online reviewer begs you for money. What sets me apart is that I spend quality time and energy finding something lame and sarcastic to say about it! So pleaseusing