The Quad 44 Pre Amplifier was the bigger brother of the Quad 34 Pre Amplifier and had the addition of an extra input over the Quad 34's four inputs. Ideally partnered with the Quad 405 amplifiers although it is more than happy with any power amplifier, the Quad 44 Pre Amplifier has some nice features to it and clever electronics especially if your main source is vinyl.
The Quad 44 Pre Amplifier has three tone filters, bass, tilt and a high pass filter which allow you to maximise the music from very old or poor recordings by removing a lot of distortion. The Quad 44 Pre Amplifier also is one of the very few home audio pre amplifiers that can cope with high output professional equipment and as well as having swappable modules for disc, radio, cd and tape, Quad were also able to supply a microphone pre-amp card as well meaning this amplifier was well suited to home recording as well as studio recording.
These days people who mainly listen to CD will have dispensed with the Quad 44 Pre Amplifier because the sound quality can be bettered with more modern equipment. Some people have had success upgrading the capacitors in the Quad 44 Pre Amplifier with Black Gate or Elna types and replacing the Op Amps with superior Burr Brown types. No matter the Quad 44 Pre Amplifier is still a popular piece of equipment and given its value second hand is worth considering if you have a lot of old recordings in your collection.
Quad 44 Pre Amplifier Specification
Line Source Frequency Response : 30 Hz - 20 kHz (+/- 1db)
Disc RIAA Frequency Response : 30 Hz - 20 kHz (+/- 0.5db)
Distortion: < 0.05%
Input Impedence: Variable according to modules (Radio & Tape typically 100mV)
Interchannel Balance: +/- 0.5 db
Crosstalk: > 70db
Power consumption: 7 Watts
Mains voltage : 110-120V or 220-240V (interchangeable on PCB)
Dimensions (WxDxH) : 321 x 103 x 207 (mm)
Weight: 4 kg
By J. Gordon Holt Sam Tellig Posted: Aug 1, 1995
This is something we don't see too often: an entirely new approach to power amplifier design. As Quad points out in its literature for the 405, class-A operation of transistors provides the lowest distortion, but drastically limits the amount of power an output transistor can deliver without overheating. (Most transistor amps use class-AB output operation, in which each of a pair of power transistors handles part of each signal cycle and shuts down during the other part. Imperfect synchronism between the two halves causes the familiar "crossover distortion," which accounts for most solid-state sound. In class-A operation, each output transistor draws current though the entirety of each signal cycle, eliminating the crossover transition but doubling the amount of time current is drawn, and thus tending to cause the transistor to heat up more.)
In "current dumping," a low-powered, low-distortion class-A amplifier is used to control the amount of current passing through a pair of heavy-duty "dumping" transistors, and it is the latter which provide the driving power (100Wpc) for the speakers.
The idea is ingenious, and while we cannot fault it on any theoretical basis, we must admit that the first amplifier embodying the principle has proved a bit of a disappointment. Our initial reaction on first hearing was that here was one solid-state amplifier that had neither hardness nor sizzle at the high end. It did not take us long, though, to observe that 405's high end errs in the opposite direction. It dulls the extreme highsthe ones that give air to the sound of strings and crispness t