VAT219 2-channel Vacuum Tube Power Amplifier by GRA & AFCH

It is a stereo Amplifier designed for home audio and home music systems that produces 5 Watts per channel

Designed to work with any home audio source: CD player, laptop, smartphone, PC/Mac, etc.

LISTING INCLUDES:

• VAT219 2-channel Vacuum Tube Power Amplifier
• Full set of supporting Nixie Tubes

FEATURES:

This Amplifier built on SRPP scheme and in fact is a push-pull power amplifier, not a single-ended gain stage
The peculiarity of the SRPP circuit is that there is no direct current flown through the audio output transformer and therefore it does not magnetize its core
This allows the use of toroidal audio output transformers

The use of toroidal audio output transformers results in a number of advantages:
– lower output frequency – up to 10 Hz (due to higher inductance)
– better flux linkage between the primary and secondary windings, this allows to obtain a higher frequency at the output, right up to 50 kHz
– lower output impedance (due to fewer turns), resulting in increased damping factor
– higher power-to-weight ratio

Our output transformers use layer-by-layer sectioning for winding
Thanks to that it was possible to achieve simultaneously two opposite parameters
These are good inductive coupling and low capacitive coupling between the primary and secondary windings
This in turn made it possible to obtain an absolutely linear characteristic of the frequency response from 10 Hz to 50 kHz
(see below in the description of the measurement graph)

The amplifier does not use feedback and dynamic distortion is minimized
Therefore, the amplifier has the highest HI-END sound while retaining the true tube sound

UNIQUE FEATURES:

• Nixie Tubes meters display the current volume level, and countdown timer when the amplifier is turned ON or OFF.
• Amplifier Tubes require heating of the cathode for the appearance of electron emission and the start of operation.
• And, accordingly, there is time before reaching the operating mode, therefore, the indication of this delay is very useful.
• The countdown shows the delay before applying or removing high voltage to the radio Tubes, this is necessary to extend the life of the Tubes.

SPECIFICATIONS:

• Output Power: 2×5 Watt
• Output impedance: 8 Ohm
• Frequency range: 10-50000Hz
• Distortion THD: 0.3% (at 90% volume)
• Supply voltage: 100/110/230 V 50/60 Hz (selected by switch)
• Amplifier dimensions: L: 33,5 cm x W: 24 cm x H: 13 cm (without Tubes)

SRPP is fundamentally a push-pull power amplifier, not a single-ended gain stage

MAIN COMPONENTS:

The input stages of the preamplifiers are built on 6H23P tubes and the output stages use 6C19P tubes.
The display unit consists of two IN-14 nixie tube and one IN-19 nixie tube.
The circuit uses only high quality capacitors.
The amplifier has 4 transformers: 2 output toroidal audio transformers and 2 supply toroidal transformers.

MATERIALS:

The Amplifier is made of noble materials:
– the case is made of 100% natural solid ash made on a CNC machine and finished to perfection by hand by a high-class craftsman with over 40 years of experience
the wooden surfaces of the case are covered with 7 layers of piano lacquer
– the top cover is made of stainless steel
– the volume knob is lathe-made from a solid brass billet and anodized to prevent oxidation

Frequency response measurements were carried out on a spectrum analyzer with an HP 3563A tracking generator
THD distortion measurements were carried out on an HP 8903A