PRODUCTS | LP-1

LINEAR VALVE AMPLIFIER GG-LP1

Why HIGH-END?

 

Every High End audio system needs a preamplifier that has not only high technical parameters, but also contributes to the deep emotional impact on the audience. Without substantial attention to the concept of the circuit design and the construction, the transparency and the natural reproduction of the sound picture would be lost.

This preamplifier is developed to satisfy even the most stringent requirements of any audiophile, as well as for professional studio applications. With its classic design, uncluttered circuitry and the use of selected high quality materials, GG-LP1 will give its owner incredible music experience and satisfaction.

The GG-LP1 philosophy

The valve preamplifier GG-LP1 consists of two units: a linear preamplifier and a power supply unit, housed in a single box. It also offers significant flexibility with its 5 linear inputs and 2 outputs.

Equal attention needs to be given to absolutely everything – from the circuit design and the materials for the box and the chassis, even down to the temperature of the solder joints.

The amplifier part is realised as a common cathode and an active load circuit. The active load has some advantages over the resistive anode load – full use of the valve amplification, low distortions and very good suppression of power supply noise. However, a global negative feedback is used. The valve 6H30П – dual triode (Russian military grade produce) is used as an amplification component. It features high operational anode current, and very low output impedance, medium gain factor, low microphony and low noise. With such specifications this valve is perfect as an preamplifier, without the use of a cathode repeater. GG-LP1 can be used as a preamplifier to a transistor output amplifier, with a relatively low input impedance of 10KOhm.

Particular attention is given to the power supply unit. The anode voltage is provided through a valve rectifier (EZ81) with a choke based filtering and a separate valve voltage control for each channel (two valves ECL 82). The heating for the two valves is stabilised DC (LM 317). This way the hum is practically eliminated, the noise is minimised and the life of the valve is extended. The stabilised heating allows a faster, well defined and natural bass.

The special selection of audiophile materials – capacitors by Mundorf and Rubycon, resistors by Allen Bradley, Holko and Riken and cables by the well known Van den Hul – contribute to the high quality of the sound.

Every amplifier is accurately handmade, with selected high quality components. The wiring is point to point and the components are hand-soldered. The preamplifier is made in two versions: standard and deluxe. The difference is in the quality of the resistors and the capacitors. The chasses of the deluxe version are made of copper, the joints are with silver soldered and there are separate mains transformers for the anode voltage and the valve heaters in standby mode of operation.

Construction specifics of GG-LP1

The preamplifier is made in a classic streamlined design and 17’’ width. On the front panel there are two buttons (power and mute), a volume control and an input-signal selector switch (aux1, tuner, CD, tape and aux2). The level control is a stepped 24-position attenuator by Danish Audio Connect (DACT) – model CT2, with 2db steps at 0.05db precision (for comparison potentiometers with 10% accuracy are used in standard designs). The CT2 is developed for maximum sound quality, precision and reliability. This makes it equally suitable for audiophile as well as professional applications. All contact points and PCB tracks are gold-plated. The input source selector switch is by the same company (http://www.dact.com) – model CT3. Specific for this input selector is that it switches both the signal and the ground contacts, which minimises the cross-input interference.

The volume control and the signal source selector switch are mounted adjacent to the RCA inputs and the control is achieved with long axes. The meticulous PCB design ensures the shortest signal path.

The stability of the construction and the use of sound absorbing (deemphasising) materials, ensures the necessary protection of the preamplifier from external sound waves as well as internal vibrations, caused by currents in the electrical circuits. The preamplifier rests on special three point supports by Soundcare (http://www.soundcare.no/). These help to minimise the mechanical-acoustic feedback, which appears in a closed listening environment. The supports are made of special materials selected through long times of listening, tests and measurements.

The result is improved control over the low frequencies and clarity of the musical landscape

Another specific feature is the introduction of an auto-mute function (muting relay – a micro relay short-circuiting the outputs), at power on/off switching. The purpose is to eliminate unwanted, dangerous (particularly for loudspeakers) transients associated with capacitor charging and discharging. This automatic functionality operates also in cases of disconnection and power supply failure.

The construction and circuit design solutions doubtlessly are very important. However, most important is the end result – the sound. A clarification is needed here: the term ‘valve sound’ is not precisely defined – valve preamps and amplifiers sound differently. The experienced audiophile can instantly determine the difference in the sound ‘signature’, even for amplifiers with the same circuit designs and valves, but made by different manufacturers. This is why every piece of valve equipment is strictly individual with respect to its sound. Here we talk about individuality in positive sense. The sounding differences are detected not only by ear, but also on emotional and even subconscious level.

Although GG-LP1 is more of a ‘budget’ preamplifier, priced much below the top High-End models, its sound is surprisingly neutral and balanced, even by ‘non-valve’ standards. Present in it is a lot of warmth and something elusive, characteristic only of the valve audio technology. The preamp does not introduce distortions and changes to the sound, which can be caught by ear. These are perceived more at subconscious level as own individual sounding, which being far from disagreeable, can in fact win the hearts of many audiophiles.

Technical specifications GG-LP1

All measurements are made with load resistance Rload = 47Kohm

 

-Gain                                                                     21,5 db (1 KHz)

- Frequency response

  Input attenuator at position 12h                           12Hz-85KHz( +0/-0.5 dB)

-Total Harmonic Distortion,

  1 kHz / 2.0V                                                          57db(0,15%)

- Maximum output

  (1KHz, 1% THD)                                                  18 Vrms

-Signal-to-noise ratio  (CCIR 468-2)                     

 unweighted (15Hz-30kHz)                                     81db rms
                    (30Hz-16KHz)                                     93db rms
 weighted                                                                92db rms

- Input impedance                                                      100 Kома

-Output impedance                                                850 ома (1 KHz)

-Absolute phase                                                     inverting

-Tube complement                                           6Н30П х 2-amplification stage                  
                                                                                 ЕСL82 х 2-voltage regulator tube
                                                                                 ЕZ81 х 1-voltage rectifier

- Power requirements                                            230V

-Power Consumption                                             45 W

-Dimensions:                                                            90 мм- high
                                                                                 440 мм -wide
                                                                                 340 мм -deep

- Weight:                                                                  7,5 Kg

 -Shipping Weight                                                  12,5Kg