Vacuum tube pre-amplifier GG- PP1


Why HIGH-END?

The valve preamp GG-PP1 by GG Audio Design is aimed for those music connoisseurs. GG-PP1 will reveal the wealth of musical nuances and details of your collection, whose existence you may have never suspected in a marvellous balance between brilliant high frequencies, melodic medium range and massive, well controlled base. With this preamplifier you will never be bored with musical experimenting.

The philosophy of the PP1

The valve preamp GG-PP1 consists of 3 blocks – linear preamplifier; phono RIAA preamplifier and power supply in one box.
( For more details about RIAA - click here. )

The linear preamplifier is realised with the dual triode E88CC in a SRPP (Shunt Regulated Push Pull) circuit. This allows to achieve relatively low output impedance and high linearity. The result is exceptionally even frequency response and very low nonlinear distortions. The low output impedance is necessary to avoid it being affected by the input impedance of the power amplifier. The output impedance of the pre-amplifier should be around 10 times lower than that of the next stage (the power amp in this case). At the same time the lower the output impedance of the preamp, the lower its sensitivity to longer interconnecting cables with higher capacitance.

The RIAA preamplifier is intended to work with both, Moving Coil (MC) and Moving Magnet (MM) phono cartridges, directly, without an impedance transformer. The input load resistance for the MC/MM cartridges, and the nominal input level is adjusted internally. The preamplifier is realised with three active amplifier stages. A passive frequency correction circuit (RIAA standard) is used between the second and the third stages. The first amplifier stage is realised with JFET (transistor) for noise reduction, high overload level and absence of microphony. The second and the third stages are realised with the dual triode E88CC.

A good power supply will have as low as possible output impedance of the power supply unit. The power supply of GG-PP1 is realised as a shunt voltage controller. This circuit has a very low impedance, ensuring high dynamics, solid and stable (hard) base and low nonlinear distortions for the amplifier stages. The mid frequency range is reproduced at high speed, clear and non-contaminated. Colouring in the whole frequency range is avoided, while the high frequencies and the base are recreated naturally. Interferences are also minimised.

The construction of GG-PP1

The box of the device is made of sheet steel with a 10mm aluminium front panel. The chassis for the audio part is made of 2mm aluminium with point-to-point wiring used for the components. This technology allows to achieve the shortest audio-signal paths and simple maintenance. The power supply is mounted on two circuit boards.

The input source selector (Phono, CD, AUX and Tuner) is based on reed-relays, placed close to the gold-plated input connectors. The volume control (high quality potentiometer from ALPS ) is connected in an immediate proximity to the amplifier stage using long axis.

For longer valve life the heater voltage of the valves is applied gradually for about 40 seconds increasing to its operating level, after which the anode voltage is applied through a time delay relay (‘slow turn-on'). For noise reduction the heater voltage is well filtered and stabilised.

Another specific feature is the introduction of a mute function, where a muting relay short circuits the left and right outputs for about 5 seconds after the high anode voltage is applied. The purpose of this function is to limit unwanted and dangerous for speaker systems transients from on/off switching of the preamplifier.

Technicl specifications

 

- frequency response: 1 0 Hz- 1 00KHz ± 0.1 dB
- gain - line stage: 24dB
- gain - mm phono : 60dB
- gain - mc phono: 74dB
- RIAA accuracy: ± 0. 1 dB
- rated output: 2,0 V / THD: <0. 2 %
- maximum output: 30V PP

- input impedance: 50 KOhms
- output impedance: 1.9 K Ohms
- dimensions: 430 mm x 380mm x 95mm
- weight: 7 к g .
- power requirements: 115/230V - 50/60Hz