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A good question. And as always, -I guess it depends. Modern circuit boards with small and light components can withstand a lot of vibration. The output coil is however fairly heavy and it could cause problems if subjected to too much vibration. That being said, these are soldered to the circuit...

It's safe

With "dead silent" I mean that both 11,5uV and 20uV will be impossible to hear even with the ear very close to a standard dome tweeter. Our purifibased amplifiers Vera P150/600 has a noise floor of 18uV measured on the speaker terminals. On my 92dB/W speakers it is below my hearing threshold...

The noise from the modules themselves are about 20uV. That is dead silent. Even with the ear just next to the tweeter.

I digged out some measurements of this from earlier and the crosstalk looks correct. Crosstalk can have many sources. It can be the high voltage power supply, it can be the low voltage power supply, it can be from the speaker cables inside the cabinet radiating electromagnetic fields or it can...

Only 0,5dB lower than a pure sine wave at full scale.... "music"??? ;)

Yes. Here is a test I ran with a continous sine signal of 600W into 8 Ohm (69V RMS). That is just 4dB lower than the clipping limit at 1.5kW (110V). The crest factor of a sine wave is 3dB, and no music has a crest factor of less than 7dB so this should be a more than good enough test. The...

In high power class D amplifiers like the Vera P400/1000 the output coils of the NC500 gets quite hot at high power levels. Since these are located close to the surrounding capacitors it will heat them up as well. 90 degrees celcius (194F) is not uncommon, and I have in fact managed to push the...

The two internal amplifier modules works out of phase, so the colour choice is intentional. One can argue that it would be better to connect red/back differently on the PCB on the left channel but then this would be confusing when looking at this when the amp is in bridged mode. I find it more...

The test I did was not very scientific. I just tested different types by soldering them on the PCB in our buffer and measure distortion with an Audio Analyzer. (R&S UPV). The test was done with a somewhat high voltage of 10V RMS to better resolve the temperature coefficient. My initial though...

I can see your argument. It is not easy to reach back and remember where the gain and bridge knobs are. On the other hand, we see the gain switches as an installation "set and forget" feature much as the bridged knob. In addition, there is no harm if you accidentally use the bridge knob while...

Accuracy in the variable gain is something we have paid attention to. Personally I hate it if the left/right gain balance is altered when changing gain settings. Potentiometers are the worst! We use dual Susumu 0,1% precicion metal film resistors for all gain settings per channel. (A total of...

Gain setting does not impact maximum power. Other than of course that lower gain setting requiers higher input voltage. Our experience is that the industry standard of 27dB gain is too much in many systems. The result is that noise from the sources are amplified too much, causing hiss in the...

To short the XLR you can simply use any short length of bare copper wire and insert it into pin2 and pin 3. Totally safe. I am 99% sure it will be silent on XLR also. The conclusion is that the noise comes from the source. Buy a better source :)

Disconnecting the source leaves the input open and it is just the amps internal ground reference that keeps the signal to ground. Depending on the implementation of the input buffer and the ground reference this will give various results and most certantly increased noise. The only way to really...

Is is a 20kHz 3,1V sine wave mixed with a 440kHz 0,3V sine wave. There are small amounts of unavoiadable remaints of the switching frequency left on the output on class D amplifiers. It cannot be heard and it does not affect tweeters. Let me explain why. The switching frequency current and...

It seems you have understood that even if the the second harmonic of a 10kHz signal falls outside the hearing range it will show up on the graphs at 10kHz. See below picture from Amirs test that many people misunderstand. They interpret this in a way that they think there is "distortion" at...

I have done the 19-20kHz test, but only at 5W average power. We can see thet the in band distortion is at maximum -115dB at 1kHz. This is at (or close to) the limits of my analyzer. No high frequency noise. Will do a full power test later. I can do a THD measurtement also, but it will be the...

With 875W continous sine wave into 5 Ohms I guess the P150 will give up after 2-3 minutes or thereabouts. The front LED will issue a warning with yellow light when the temperature is close to shutdown. If the temperature continues to increase, the amplifier will shut down and the button on the...

I have experienced problems with increased THD at high power (above ~200W) when using cheap bananas. I then switched to connect bare wire to the screw terminals which in my book is the safest way. However, -for convenience, I have now switched to more expenside lockable rhodium bananas and have...