Holfi Power NB250 + Papu 250 vejl. pris 90.000 dkk - sælges nu for 45.000 dkr inkl. fragt

Power NB250 DC is a battery powered power amplifier with a 2X250W/8ohm output rating – simply the biggest amp available with battery power in the world. The electronic design honors the principle: “Simple is beautiful”. The basic design features are normally connected with tube amps – single ended/non feedback – but actually this is a solid state amp. The intention was to build the ultimate power amp to drive the best speakers on the planet to the most of their ability….and to do it with ease.

BATTERY POWER
Batteries offer - at the same time- the cleanest and the most powerful supply. In plain figures a battery power supply has more than 30 times less noise than a conventional supply. That is the figures when you are not playing music on the amp – when you load the amp heavily the difference gets even bigger (300-1000 times less noise). At the same time the batteries delivers far more current than a conventional supply. The batteries in the PAPU (Power Amplifier Power Unit) delivers more than 300 Amperes. You can obtain that amount of power from a conventional supply for 10 milliseconds – the batteries can do it for periods of more than 10 seconds (a thousand times longer period). Given the near perfect DC-source that the battery is, we find it difficult to understand that it is so rarely seen in high end audio – to us it seems natural that most high end designs should include batteries.

2X250 WATTS/8 OHM
Holfi amplifiers used to be built with one pair of output transistors as we found through listening tests that having more transistors in parallel increased the output current capability but also compromised the tonal balance. In our listening tests we always found that the loss of integration between the fundamentals and the high frequencies were an unavoidable - and unacceptable - compromise with multiple transistors in parallel. As such we were always limited to around 130 Watts per channel as we did not want to use slow, rough sounding industrial semiconductors. The way to the 250 Watts came through a special serial coupling of the output transistors, maintaining only one set in the signal path and having one set basically as “slaves” to take half of the heat. The new design adds one important feature to the output stage that actually gave a - to us - surprising improvement in dynamics especially in the low end: The “slaves” keeps the voltage across  the output transistor much more stable and actually completely stable up until around 130 W/4 ohm.

BATTERY MAINTENANCE
There must be a downside to batteries you might think and of course you are right. As a designer you need to take care of the batteries to have the longest possible lifetime, but in the end they will have to be changed. Battery lifetime is 5 to 8 years – we recommend changing batteries every 5 years, as we cannot see the point in having the ultimate power amp with 8 year old batteries performing at 60-80 % of what´s possible!? A battery change in a HOLFI product will cost between 5 and 10 % of the original sales price. The Power 250 DC contains many batteries and therefore it will cost you the 10 %. Pre-amps and CD-players is closer to the 5%.