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Performance Verification Report-Explained The Performance Verification Report (PVR) is your assurance that the item you are purchasing is operating properly. The report is created by our technician and all quoted performance specifications are actual results documented during testing in our audio laboratory. The original report is delivered to you with your equipment.
The following sections explain each test in detail:
PVR-Amplifier:
Rated Power - This is the manufacturer's stated power rating for the unit under test expressed in watts per channel into an 8 ohm resistive load.
THD @ Rated Power - Measured total harmonic distortion at the rated power level expressed in percent. Typical THD for a good quality amplifier will be less than 0.5% (less than 1.0% for tube amplifiers). Test frequency is 1000Hz.
Max Power @ 1% THD - The amplifier is driven to a level producing THD of 1.0%. The power in watts is then measured. This gives a general indication of headroom and build quality. The larger the number from the rated power specification the better. Test frequency is 1000Hz.
Signal to Noise Ratio - The amplifier is driven to it's rated power and the signal removed. A measurement is made to determine the level of residual noise, expressed in dB. This test will reveal any problems with hum or hiss. A good quality amplifier will have a S/N ratio of greater than 70dB. (Note: our noise tests are un-weighted and may appear slightly different from the original manufacturer's specifications.)
Frequency and Balance Check 20Hz - The amplifier is run at a nominal level of 1 watt RMS. A reference level is set and the test frequency changed to 20Hz. Any deviation from the reference level is noted as a +/- change expressed in dB. This test will reveal any frequency response problems or an imbalance in response between channels. A good quality amplifier will have a deviation of less than +/- 3dB.
Frequency and Balance Check 20kHz - The amplifier is run at a nominal level of 1 watt RMS. A reference level is set and the test frequency changed to 20kHz. Any deviation from the reference level is noted as a +/- change expressed in dB. This test will reveal any frequency response problems or an imbalance in response between channels. A good quality amplifier will have a deviation of less than +/- 3dB.
PVR-Preamplifier:
THD @ 1 Volt Output - Measured total harmonic distortion at 1 volt output expressed in percent. Typical THD for a good quality preamplifier will be less than 0.5% (less than 1.0% for tube preamplifiers). Test frequency is 1000Hz.
Signal to Noise Ratio - The preamplifier is driven to 5 volts output and the signal removed. A measurement is made to determine the level of residual noise, expressed in dB. This test will reveal any problems with hum or hiss. A good quality preamplifier will have a S/N ratio of greater than 70dB. (Note: our noise tests are un-weighted and may appear slightly different from the original manufacturer's specifications.)
Frequency and Balance Check 20Hz - The preamplifier is run at a level of 1 volt RMS. A reference level is set and the test frequency changed to 20Hz. Any deviation from the reference level is noted as a +/- change expressed in dB. This test will reveal any frequency response problems or an imbalance in response between channels. A good quality preamplifier will have a deviation of less than +/- 3dB.
Frequency and Balance Check 20kHz - The preamplifier is run at a level of 1 volt RMS. A reference level is set and the test frequency changed to 20kHz. Any deviation from the reference level is noted as a +/- change expressed in dB. This test will reveal any frequency response problems or an imbalance in response between channels. A good quality preamplifier will have a deviation of less than +/- 3dB.
PVR-Tuner:
FM Sensitivity - Measured in micro volts (uV), this is an indication of how well a tuner can pick up distant or weak signals. The RF generator output is reduced so that the tuner produces 3% THD on the distortion analyzer. The RF generator output is noted. The lower the number the better. A good quality tuner will have a sensitivity figure of less than 3uV.
FM THD - Total harmonic distortion that the tuner produces modulated with a 1000Hz tone at 1000uV. 1000uV is considered to be a full strength signal. A good quality tuner will produce less than 1% THD.
FM Stereo Separation - This tests the tuner's ability to separate left and right channels. The larger the number the better. Expressed in dB, a good quality tuner will have a separation figure of greater than 30dB. Test frequency is 1000Hz.
PVR-Receiver:
A combination of the sections above.
Ever wonder why your vintage amplifer is built like a tank?
See the 1974 FTC ruling on power amp specifications shown below. In particular, note section 3(c).
