ICON AUDIO pure triode integrated amplifier 2A3


SKU: ST403-2A3

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For those seeking the ultimate in high definition and smoothness without high power the 2A3 is an ideal valve. The very special 2A3 is a pure triode valve very similar to the WE 300B (1937) but pre dating it by seven years. When designing an amplifier it is not just about using good components but getting the “synergy” right, so music does not sound mechanical or contrived. We consider our ST40-2A3 to be one of the most musical and easy listening amplifiers we have ever made !

A bold statement, but one we are sure you will agree with. Over time customer feedback suggests that most people prefer the “triode sound” over more modern valves.

17 Watts (11.75v@8 Ohms) may not sound a lot, but with average efficiency speakers will fill a normal sized room with power to spare.

The 2A3 is relatively undemanding of the driver stages and power supply, and with valve costs at around half the price of the 300B, means that a true “High End amplifier can be produced for a reasonable price, without any compromise.

What We Have Done:
The basic chassis of our new Stereo 40 series is exactly what we need using specially designed power and output transformers. Again the older, bigger 6SL7 and 6SN7 valves have the exactly the qualities we are looking for, (a more liquid sound than the newer smaller ECC types), also being more rugged and longer lasting.

A 274B Valve Rectifier  (centre valve) helps to give that inky black silence. The generous power supply uses a large “choke” eight large capacitors in a
traditional “Pi” configuration. This gives the required very low source impedance with a huge reserve of power available for large transients. Ripple and hum is very low, with the advantage that it is very resistant to RF noise coming through the mains.

Our  Tertiary Output Transformers has an extra (third) winding which put simply, allows the output transformer to compare both the input and output, and ‘null’ distortion. Thereby dramatically improving the performance, so much so that there is little global feedback used, we believe our expertly hand wound output transformers to be amongst the finest available.

This combination gives a very smooth and detailed sound stage which works well to bring out the colour and texture of older recordings and whilst not over-emphasizing the harshness  of many modern digital recordings. In short an amplifier capable of resolving very high definition that is very easy to live with that has plenty of power to control modern speakers.

The brand new design is finished with a fine metallic paint work that is easy to clean and is wear resistant. A 10 mm solid alloy front panel with polished dark chrome alloy knobs. And our attractive Plexiglas valve cover to create a stunning visual impression. On the scales at 25Kg, most of this weight is the higher than normal grade of iron we use. And our transformers are wound with 4N copper (99.9999% pure).

As each amplifier is prepared to your order here in Leicester. We can offer a range of upgrades including premium and “new old stock” valves, the superb Jensen “oil in paper” capacitors. Ask us for a quote.

Icon Audio is a small company established in 2000. Our speciality is pure  valve amplification, loudspeakers and associated equipment. All our equipment is hand built and hard wired. It is our belief that in many ways valve amplifiers are superior for the reproduction of music.

Total Peace of mind service!

When buy an Icon Audio product, you get:

•  A UK 230-240v specification product. Designed for use in UK and Europe.

•  A full UK guarantee.

•  Free telephone or on-line help

•  A comprehensive manual to tell you everything you need to know, including how to check the performance & how to check and change valves.

•  UK service dept with three skilled engineers that know exactly how your amplifier should sound!

•  Full back up of spares in stock

•  Free valve testing for customers

Specifications and Features

•  Comprehensive manual supplied

•  Full instructions for valve change included

•  All hand wired point to point

•  No printed circuit or tag board to ‘colour’ sound

•  Japanese Blue ALPS volume pot.

•  Class A, all Triode front end

•  Output circuit all pure Triode

•  4x 2A3 precisely matched for best performance

•  1x 6SL7 first stage valve, 2x 6SN7 phase splitter

•  274B valve rectifier for ‘Soft start’ and smooth sound

•  No global feedback used (integrated operation)

•  Standby switch to save valve life and power

•  2x 17 Watts RMS in Triode mode

•  Signal to noise level -90db

•  Freq response better than 20hz-20kHz ±1db

•  Power bandwidth 10hz-30khz -3db

•  Total harmonic distortion 0.10% at 10 watts

•  Suitable for 3 to 16ohm loudspeakers

•  Supplied with attractive safety guard.

•  Audiophile quality metal film resistors

•  Rubicon/Nichichron power caps.

•  Blue LED mains indicator

• Valve rectifier

•  Choke regulated power supply

•  Audiophile quality polypropylene audio caps.

•  Silver PTFE audio cable

•  99.9999% pure copper

•  High grade transformer iron

•  Custom hand wound Tertiary output transformers

•  Ceramic valve holders for minimum noise/leakage

•  Centre tapped heater circuit for minimum hum

•  Gold plated Input & speaker terminals

•  Four line inputs – CD, Tape, Tuner, Aux

•  Tape monitor circuit with ‘Record Out’

•  250mv input sensitivity for full output.

• 230/240volts 76w SB, 140w Min, 240watts max.

•  1.6A AS rear fuse

•  CE, ROHSS and WEEE where applicable.

•  390mmW, 410D, 210H, 25kg (a minimum of 30mm height should be added to allow for ventilation)


(Specifications subject to change, errors & omissions excepted August 2011)


Pure Triode Integrated Amplifier Leaflet




SKU ST403-2A3
Shipping Weight 25.0000kg
Shipping Width 0.540m
Shipping Height 0.400m
Shipping Length 0.540m

1 Year Warranty

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