New Stereo 300 MkII

300B DHT* Amplifier

Beautifully Simple

High Definition

30+30 Watts Triode*

Remote Control

Choke Power Supply

Some things are hard to improve on and that is especially true of the 1930s 300B valve. *Directly Heated Triodes are considered by many to be the pinnacle of audio quality. At Icon Audio we have used all our skills in order to build an amplifier that gets the best out of this venerable tube. Warm, transparent, satisfying. With 30 + 30 Watts of power available from 20 Hz to 20kHz this amplifier is sure to please the most demanding listener.

Western Electric designed the 300B to give a high quality, good output in cinema sound. In doing so they created a valve which in audio quality has never been bettered. Although primitive by today’s standards it has very low distortion and has very linear, properties which make ideal for the finest amplifiers. Because of this more care is need in designing the associated circuitry in order to remain sympathetic to its genre (don’t expect to see 300Bs in a budget or guitar amp).

The all-important high definition drive circuit for the 300B output valve is achieved by using the superb 6SN7 valves in “Cascode” mode. 6SN7s date from 1940 so fit in well the overall sonics. We feel the 6SN7 (CV181) has a more relaxed presentation than their miniature cousins, these larger driver valves are the best in their class for their musical sound and longer life. Try our new David Shaw types or choose from TJ/Full Music, SG Treasure, Psvane, Vintage USA/Russian types.

Good sensitivity from the built in “passive” pre-amp ensures good results from virtually any type of input.

The “easy bias” meter enables simple checking that the 300Bs are at optimum performance, the meter also gives an indication of the output power. Very useful when you may need to know if you are likely approach the maximum available power.

Input sensitivity is varied by changing the feedback this enables use of the amplifier without any feedback or using low sensitivity ideal for use with a separate pre-amplifier.

Partnering loudspeakers and source equipment needs to be done carefully. If there is a down side to 300B amplifiers it is that they are more revealing and will not “mask” deficiencies as much as other amplifiers.

The standard valves give excellent performance. But for those who may wish to use “premium” or the new Western Electric 300Bs and want to maximise the life of these valves, therefore on request we can supply the amplifier with a lower HT which will give a maximum of 21w per channel output.

Specifications and Features

• Comprehensive manual supplied
• Remote control: HQ ALPS motorised volume pot
• All hand wired point to point
• Pure Class A CV181/6SN7 driver stage
• Output power 30W 8Ω
• Large Choke regulated power supply
• 4x 300B output valve (AC heated)
• 4x 6SN7 (CV181) double triode
• Signal to noise level -85db
• Freq resp 20 – 20kHz -0.2 to –0.5dB (8w 6.25dB FB)
• THD typically less than 0.05% 1khz (1w)
• THD typically less than 0.2% 1khz (8w)
• 4 & 8 ohm loudspeaker taps
• Low feedback design (0, 6.25, 15.2dB)
• Switchable gain control giving 140, 300, 790mV input sensitivity
• SCR audiophile caps, Jensen upgrade option
• Silver plated copper PTFE audio cable
• Tertiary winding output transformers
• Gold plated Input & speaker terminals
• Channel balance typically within 0.2dB
• 117/235 Volts 150W – 235W
• C E, ROHS WEEE, FCC
• Size 380mm wide 330mm deep 230mm high
• Unpacked weight 26 kg

Typical values @ 240v AC (Specifications subject to change)

Summary:

Ideal for: Situations where the very highest fidelity is required from a medium powered amplifier. Well suited to larger more efficient speakers. Very detailed sound stage with a mid range to die for. Delightful listening quality.

REVIEW

Hi-Fi World March 2019