Quad 405 405-2 specifications

Brand : Quad

Brand: Quad

Model: 405-2

Other models of the same series:

Quad 405 Power amplifier : The "current discharger" 405 is based on the "feed forward error correction" principle of 1928. This principle is based on the requirement that the output signal may only differ in size from the input signal. Deviations from the original, such as those caused by the usual negative feedback, are undesirable distortions. The "current discharge principle" avoids this problem by subtractively comparing the input signal with a matching part of the output signal. This results in a correction signal which is added to the "distorted" output signal and erases its distortions. The amplifier inverts the signal, a positive input signal is opposed to a negative output signal. With a quad preamplifier, which also inverts, this behavior is compensated.

about the device:

The device has no power switch and is connected by the quad preamplifier 33 via a special power cord. If you use a common cold device power cord, you have to turn the power amplifier on and off on the power strip. The input socket is a 4-pin Din socket, the assignment of which is printed on the rear wall of the device. If you want to connect a "foreign" preamp, you need a DIN / RCA adapter, or you have to install 2 RCA sockets (which is quite simple, because there is enough space, there are 2 holes and the DIN socket is right next to it). The LSP sockets are simple clamping mechanisms and difficult to access with thick cables, since the DIN socket is unfavorably located next to it and the clamping mechanism also only allows cables up to 4 mm2. The actual power of the Quad 405 was measured by well-known Hifi magazines with 120 watts at 8 ohms. The bandwidth of the transmission is only 20-20000 hz. This "limited" transmission range was deliberately carried out on the quad devices in order to be able to reliably exclude interference below and above the range. The rise time is only 0.1 µs. The input sensitivity at 0.5 V.

In terms of sound, I can really recommend the power amplifier with the corresponding preamp, but the operation, especially of the preamp, is English "split", as well as the unusual wiring of the devices with each other. In order to prove that this concept behaves sound-neutral, the then importer Thomas Wegner (Scope, Hamburg, later Schaulandt)connected 10 devices in a row and demonstrated them publicly. The QUAD's own DIN cabling "forces" the user to combine with QUAD to a certain extent. If you connect to other manufacturers via adapter cables, the inversion should be taken into account.

Sine power: 2 x 100 W at 8 ohms
Harmonic distortion at 1 kHz: < 0.001%
Intermodulation at rated power: < 0.01%
Signal-to-noise ratio: >95dB
Overall frequency response: 20 Hz - 1 dB to 20000 Hz - 0.5 dB
Outputs: 4 - 16 ohms
Dimensions: 341 x 115 x 195 mm
100-120V or 200-240V
Weight: 9 kg