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    Adam ‘Tensor’ actives repair needed

    There seems to be some movement regarding this now. I'll keep you posted when I know more.
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    Adam ‘Tensor’ actives repair needed

    Thank you for the info. I'll ask KSTR if he'll be so kind as to help me with some information after looking a bit more into it.
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    Adam ‘Tensor’ actives repair needed

    Hi. A customer came in with two of these plate amplifiers today in my electronics workshop. One has an amplifier fault in the bass section. Did you have any success in finding schematics for these? Best Armand
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    Let's stop calling Class D amplifiers "efficient" when they are not.

    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...
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    Noisy Purifi amplifiers

    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...
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    Noisy Purifi amplifiers

    The noise from the modules themselves are about 20uV. That is dead silent. Even with the ear just next to the tweeter.
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    Vera Audio P400/1000 Review (Amplifier)

    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...
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    Vera Audio P400/1000 Review (Amplifier)

    Only 0,5dB lower than a pure sine wave at full scale.... "music"??? ;)
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    Vera Audio P400/1000 Review (Amplifier)

    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...
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    Vera Audio P400/1000 Review (Amplifier)

    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...
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    Vera Audio P400/1000 Review (Amplifier)

    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...
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    Vera Audio P400/1000 Review (Amplifier)

    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...
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    Vera Audio P400/1000 Review (Amplifier)

    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...
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    Vera Audio P400/1000 Review (Amplifier)

    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...
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    Vera Audio P400/1000 Review (Amplifier)

    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...
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    Noisy Purifi amplifiers

    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 :)
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    Noisy Purifi amplifiers

    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...
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    Vera Audio Class-D Amp Build Quality

    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...
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    Vera Audio Class-D Amp Build Quality

    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...
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