4
INTRODUCING THE A-6000 300B SET MONOBLOCK
POWER AMPLIFIER
The A-6000 monoblocks are Allnic Audio’s top of the
line power amplifier model. Like all Allnic Audio
products, the A-6000 has Permalloy (iron and nickel
alloy) for its transformer cores. Allnic is grateful to Mr.
G.W. Elmen of Western Electric for inventing Permalloy
for transformer core use, and in so doing, providing an
enormous service to recorded music listeners
everywhere.
The A-6000 has the following features:
50 watts of pure class A high power output. The A-6000 is
a double parallel single ended power amplifier. Almost all
other 300B amplifiers are under, and distortion, driven.
This is a result of the use of conventional "Resister-
Capacitor" circuits, which give only up to around a 70V
swing voltage, with high distortion. This means that an
already distorted signal of a lower than optimum swing
voltage is directed to the deep biased 300B grid. Allnic’s
powerful "Inductor Drive" circuit gives up to a 150V swing
voltage, with very low distortion (about 0.3%). It is this
drive delivered to the A-6000 that allows for a significantly
higher output (50w) than the approximately 27 w output
that could be expected from standard 300B circuits.
Real power drive. The driver tube, a 6GV8, is a very strong
power pentode. We use this power pentode to drive the
300B’s via a choke plate inductor. Our choke inductor
(100% nickel permalloy PC core) has very low power loss
and infinitely high load impedance. This configuration is an
ideal drive stage for 300B SE.
Nickel alloy output transformer. Allnic uses sophisticated
ratio mixed nickel permalloy PB cored output
transformers. Because of their extremely high initial
permeability, it is possible to use lower turns on the
primary winding while retaining very high 'open circuit
inductance”. That means a resulting very wide frequency
range and low distortion bass response. This is another
reason why the A-6000 excels over other 300B power
amplifiers. Allnic also uses a very big nickel core, so as not
to be magnetically saturated at a high current of level of
400mA.
Long life and trouble-free operation. Allnic employs a “soft
start circuit” to protect the tubes and other parts. It applies
the high B+ voltage only after tubes are fully warmed-up.
Fixed bias control grid. Allnic prefers to use low distortion and
high output “fixed bias” rather than the relatively higher
distortion and lower output “self bas” method. That way, it is
possible to eliminate the use of cathode resisters and their
associated heat production.
Natural negative feedback. The A-6000 applies about -6dB of
negative feedback. This is a very complimentary amount of
negative feedback that differentiates the Allnic 300B single
ended amplifier from the standard, which has a very coloured
and weak speaker driving force. With this natural feedback,
the A-6000 has a relatively high “damping factor', very low
distortion, and a higher S/N ratio, without losing the signature
single ended natural sound quality.
Hard wiring. The A-6000 is all hard wired; circuit boards are
not used.
Beautiful 20KHz square wave response. See Figures 1-3.
Fig.1 Square Wave 50Hz Fig.2 Square Wave 1KHz
Fig.3 Square Wave 20KHz
Measured by LEADER LAG-126 Audio Signal Generator
and KENWOOD CS-4125 Oscilloscope
As are all Allnic Audio products, the A-6000 is fully RoHS
(EU Reduction of Hazardous Substances regulation)
compliant in construction and materials.
