Recent content by Armand

There seems to be some movement regarding this now. I'll keep you posted when I know more.

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.

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

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...