a report about a modification of a VAIC 300B-SE Amplifier
This model is one of the most versatile ever made. It is an "integrated" amplifier, meaning you have a normal SE tube amplifier, and a pre-amplifier
integrated. These are separate circuits.
When you use the internal preamplifier, you have a volume control and
a selector for CD, Tuner, etc.
When you use the "direct" option, you enter the signal directly to the
driver tubes (larger tubes in the middle) and the pre-amp is taken out
of the circuit by means of relays. Of course you need your own pre-amp
in this case!
Some great tuning has been done to this amplifier
All Yamamoto Teflon/Gold sockets. The special suspension construction of
the original sockets was kept.
made fixture, to replace the chinese sockets by Yamamoto
x Noval sockets used for Pre-amp board.
All Capacitors on the Audio PCB Board have been upgraded to AURICAP
High resolution Capacitors
All resistors in the signal path have been upgraded to the gold plated
Japanese RIKEN Carbon resistors
All input connectors (and these are many with this amp....!) have been
upgraded to nickel-free Yamamoto Gold/Teflon parts
Bias Setting of the 300B tubes can be done through the front plate, as
with the later AYON models.
Measuring of the bias level can be done through a high Quality BNC plug,
at the back. A cable is supplied with it. All you need is a Volt meter
to do the setting yourself. No need any more to have a service technician
visit you. No need to open the amplifier any more.
Signal wiring of the potentiometer done with silver plated Teflon cable.
Pre-amp tubes can be AC heated as original, or DC heated with an external
power supply. DC or AC heating can be selected from the back with a locking
switch. The external DC power supply belongs to the amplifier. The DC heating
removes last fraction of hum, and also increases the types of pre-amp tubes
that can be used.
Belonging to the amplifier are following items:
NEW, unused Emission Labs 302B tubes.
NOS, unused Mullard E182CC driver tubes.
NOS, very little hours "CIFTE" 6189WA pr-amp tubes.
Volume control can be done by hand, or by using the remote motor control.
(An electric motor moves the volume control). This part has cost 175 Euro
new. It is included with the amplifier. It is made of piano lacquered wood.
<-- Click image
Original box + wooden shipment crate (for getting insurance on the shipment)
Important features of this amplifier:
Tube filament voltage and bias voltage is adjustable. A wide variety for
power tubes can be used, like 300B, TJ 300B/n, AD100, 320B-XLS, and even
the wonderful 520B tube!
- ALPS Volume Potentiometer, conductive plastic - noiseless.
All signal functions switched by relay board, operated with stabilized
- Very well controlled start of power tubes:
Litz wire SE transformers, double potted.
Internal fuse + external fused. / Mains
fuse can be replaced by user.
Electronically stabilized DC Power Supply for:
Step: Slow start of Filament voltage
- Step: After 10 seconds pre-glow, HV will switch-on of the power tubes.
- Step: Analog electronic circuit will provide Slow ramp-up of the plate
current (5 seconds) after applying high voltage.
Deck plate and front plate are Rhodium plated.
This gives a beautiful shine, and will not scratch.
Wooden sides are piano laquered.
Bottom has spikes attached to it.
DC Motor Control / Remote Volume
- Signal Relay Board
2x 15Watt Single Ended, Class A
Output 4 Ohm, 8 Ohm
Input selector 3x. Tape 1x. Direct 1x (direct bypasses the pre-amp)
Size: 52 x 25 x 42 cm
Weight 30 kg
The amplifier is in
excellent overall condition, and was recently completely serviced. All
you need to do is plug it in, and play. This is a wonderfull piece of heavy
metal, and VAIC amplifiers are not made like this any more!
Optional, several NOS and new tubes,
belonging to this amplifier could be purchased from the current owner.
Test report (in German) about this amplifier as published in "Image HiFi" can be send to you by email. Please ask when you want to receive a copy.