sh ICON AUDIO Stereo 40 integrated amplifier 6AS7
A pure triode good all rounder
This secondhand unit is about 4 years old and has a new set of valves.
"It is ten years since we made our first amplifier the “Stereo 40”. Since then we have made many other designs exploring the wonderful world of valves. In this time Icon Audio has gained an enviable reputation for quality, innovation and value. To celebrate this we decided to embody
these qualities in an amplifier that is of very high quality, a little bit different and at a very affordable price.
A triode amplifier is the obvious choice, but the high cost of the vintage type triodes would make the amplifier expensive, so we cast our net a little bit wider and found a more modern “military” valve that has often been overlooked….
The 6AS7 started life as a triode power regulator in the early 1950’s, but it has such excellent audio qualities that it quickly became a “hi fi” valve. Its low voltage and high current means that we can make excellent output transformers, it also is “indirectly heated” giving lower noise and its low price means that re-valving will not be painful to your pocket. Its heater current is a little high but causes no problem. If we were going to design a modern triode, we would be looking for exactly these qualities.
Giving 33+33 Watts Push-pull it makes an amplifier that will drive almost any sensitivity of speaker. Its biggest drawback is its low gain, but again this is no problem using our expertise gained in designing our MB845/805 and 2A3 amplifiers. We used our favourite driver valves the 6SN7 and 6SL7 which are of a similar vintage so are sonically well suited and provide an excellent voltage drive. Our existing Stereo 40 series chassis is ideal, and keeps costs down. We designed special transformers for the 6AS7 output and different power requirements. Our
LDT Tertiary Output Transformers** has an extra (third) winding which put simply, allows the output transformer to compare both the input and output, and ‘nulls’ distortion, thereby dramatically improving the performance, so much so that there is no global feedback (integrated).
We believe our expertly hand wound output transformers to be amongst the finest available.
A 274B Valve Rectifier (centre valve) helps to give that inky black silence. The generous power supply uses a large “choke” and 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.
From the first prototype audition we knew this amplifier was something special. Sonically the amplifiers signature is typically warm, very much a triode, being smooth and creamy without being “lush”. The dynamics and macro dynamics are
exceptionally well detailed and whilst are very well suited to orchestral and Jazz works, but with the ability to give good speed and attack for interpreting rock music. The 6AS7s distortion is mainly 2nd harmonic which is cancelled out by the push-pull output stage.
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 that we use. And our transformers are wound with pure 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).
Total Peace of mind service!
When you buy an Icon Audio product, you get:
• A UK 220-240v specification product. Designed for use in UK and Europe. (117v by internal adjustment)
• A full 12 months parts & labour guarantee (excluding valves)
• Free telephone or on-line help by our engineers indefinately
• A comprehensive manual to tell you all you need to know, including how to change and check the performance of valves
• UK service dept with four 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 and bias meter
• All hand wired point to point
• No printed circuit or tag board to ‘colour’ sound
• Blue ALPS volume pot (Japan)
• Class A, all Triode front end
• Output circuit all pure Triode
• 4x 6SA7 precisely matched for best performance
• 1x 6SL7 first stage valve, 2x 6SN7 phase inverter
• 274B valve rectifier for smooth sound
• No global feedback used (integrated operation)
• Standby switch to save valve life and power
• 35 Watts per channel, 33+33W both channels driven
• Signal to noise level -95dB
• Freq response (L) 20Hz – 20kHz +/- 0dB 15W
• Freq response (H) 20Hz – 20kHz +/- 1dB 15W
• Min bass frequency for full power 15Hz
• THD 0.56% (L) 1.3% (H) both @ 15 W
• Suitable for 3 to 16ohm speakers (8 & 4 Ω taps)
• Damping Factor 5.00
• Supplied with attractive safety guard.
• Audiophile quality metal film resistors (Taiwan)
• Rubicon/Nichichron power caps.
• Purple LED mains indicator
• Choke regulated power supply
• Audiophile SCR/Solen Polypropylene audio caps.
• Optional Jensen Copper foil paper in oil upgrade
• Silver PTFE audio cable
• 99.9999% pure transformer copper
• High grade long grain transformer iron (Japan)
• Custom hand wound Tertiary output transformers
• Ceramic valve holders for minimum noise/leakage
• Gold plated Input & speaker terminals
• Four line inputs – CD, Tape, Tuner, Aux
• Tape monitor circuit with ‘Record Out’
• 280mv input sensitivity (H) Integrated
• 680mv input sensitivity (l) power amplifier
• 230/240volts 180w Min, 250watts max signal.
• 2A AS rear fuse
• CE, ROHSS and WEEE where applicable.
• 390mmW, 390D, 230H, 20kg (a minimum of 30mm height should be added to allow for ventilation)
(Specifications subject to change, errors & omissions excepted August 2011)"
1 Year Warranty
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