AUDIO FUTURA spa
3. Power Stage
Our purpose was to have a solid state power stage as “transparent” as possible, able to provide/supply 100W in an 8Ohm load. So we have chosen the National Semiconductors LM3886 Power pack as a building block and we have designed a “parallel/bridged” power amplifier. We have decided to use such a component (we are not the first in this, see Jeff Rowland’s Concentra Integrated Amplifier as an example) for its overall electrical characteristics (high power capability, high signal/noise ratio…), its reliability and very good overall
audio performance. The “parallel/bridged” structure we have used requires 4 LM3886 for each channel and allows sharing of the current demanded by the load among the 4 components. It also allows the use of a lower power supply voltage. In such a way we
can obtain more than 100W on an 
8Ohm load and more than 170W on a 4Ohm load. The signal to noise ratio obtained is very good: for a load of 8Ohm with a 100W output power we have 99dB with no filter and 106dB A- weighted (with a noise gate of
4. Protections
Every sensitive part inside the unit has been protected to increase the reliability expecially in respect to the temperature increasing due to the high power capability of the product. As an example the LM3886 used in the power stage is a very reliable component (that’s one of the reasons why we have choosen it!) protected against shortcircuits and overcurrent and it has two different temperature protection systems: one against instantaneous overtemperature and one against average overtemperature. We have introduced a termal protection into the toroidal transformer too to disconnect the primary if the temperature rises too much. And we have even introduced a thermost close to the power stage heathsink to detect the internal overall temperature and disconnect the loudspeakers if the temperature becomes too high, protecting in such way all the components in the unit.
5. Mono/Pre Out
Verdi cento has a Mono/Pre Output. This means the output can be set to be a Mono Out or a Preamplifier output. If you set it as Mono Out you can use it to drive a passive subwoofer. If you set it as preamp out you can use the Verdi Cento preamp Stage to drive a Power Amplifier to realize a “bi amplified” system or just to use the Verdi cento as Preamplifier. The Mono/Pre Out is easily set changing the position of Jumpers on the board with the only simple but essential recommendation of to not do it with the unit on.
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