Yamaha H3000 amplifier (10 available)

The HD3000 is the smallest model in the Series and is rated at 350 Watts per channel into 8 Ohms, 450 Watts per channel into 4 Ohms, or 900 Watts bridged mono into 8 Ohms. This kind of power makes it suitable for medium‑sized studio monitoring systems as well as smaller PA and installation applications, and though the amplifier is fan‑cooled, the fan speed is fairly low which means there isn't a lot of fan noise. The frequency response of the Series range extends from 10Hz to 50kHz within 1dB, and the distortion levels, while not quite in the 'two noughts something' category, are respectably low. The H3000 is a 2U rackmount package, making it the same size as my trusty old Yamaha 2075 (which delivers only 75 Watts per channel). Air is drawn in through vents at either end of the front panel and vented through the rear of the box, which means that suitable ventilation space needs to be left behind the unit. Because the unit is quite deep and heavy, integral rear rack fixing brackets are provided. Two large rotary controls are used to set the left and right channel gains and a comprehensive array of warning LEDs, four for each channel, provide information relating to clipping, the presence of an output signal in excess of 2 Volts, the presence of an input signal in excess of ‑40dBm, and operation of the protection circuitry. When the clip LED lights, a limiter comes into operation, and push‑on knob caps are provided for applications where the amplifier's gain setting needs to be made tamper‑proof. Balanced inputs are provided on both jack and XLR connectors, and further XLRs allow the input signal to be daisy‑chained to a second amplifier. A slide switch allows for Stereo or Bridge operation with a further position providing a parallel input feed, whereby channel A's input feeds both sides of the amplifier. A ground lift switch is also fitted. The speaker outputs are on conventional binding posts, but in acknowledgement of the new EEC regulations (which may be interpreted as: 'a frail old granny, soaked in sea water and fitted with a dicky pacemaker, should be able to poke about in any piece of electrical equipment with a two‑inch steel hatpin, without being able to come into contact with any source of electrical power greater than that required to produce a mild tingle'), a plastic cover is thoughtfully provided, which the majority of users are likely to omit to replace once they've removed it to connect the speakers. A 15‑pin D connector is fitted so that a suitable remote/monitor may be connected, but this is purely for the benefit of installers who can provide such a device, since Yamaha don't manufacture one themselves. The pin‑outs provide tallies for the warning LEDs and provide for remote power‑up and muting. As you'd expect from a modern power amp design, the speakers are disconnected at switch‑on and switch‑off to prevent thumps, and the protection circuit steps in if the heatsinks exceed 95 degrees Centigrade. In real life, this isn't going to happen unless you're either running flat out in Death Valley in the middle of summer, or if you've buried the amp beneath a pile of duffle