Kronos AV
Kronos AV

Icon Audio Stereo 40 MkIV Integrated KT88 Amplifier
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  • Regular price £2,499.00
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Exceptional all-round performance at a modest price!
The Stereo MKI was our first model in 2001 and has always been a special product to us. Since that time we have substantially improved it over the years. 
In its latest guise, the MK IV has several upgrades making it exceptional value.

Headphone Socket.
Following customer feedback the new model now has this feature. Giving greater flexibility of use.

Improved Power Supply.
In conjunction with our re-designed output transformers, the Ultralinear Power is now over 50 Watts. This gives greater instantaneous power available for heavy transients, and a more solid bass.

More Triode Power.
We know that majority of customers use the Triode Facility most of the time. The Triode power is now 30 Watts enabling use of all but the most inefficient speakers.

Re designed driver circuit.
Using a “cascode” configuration for the first stage enables us to use the venerable 6SN7 valve for all the driver circuit functions. This gives better definition whilst improving the frequency response at lower volumes. This also simplifies valve replacement as the amplifier only uses two valve types.

The Stereo 40 MK IV is packed with high end features:

Choke Regulated Power Supply
Working in conjunction with the smoothing capacitors the large choke gives super-smooth power regulation for a silent background.
Tertiary Transformers have an extra (third) winding which reduces distortion, using less global feedback. We believe our large handmade output transformers to be amongst the finest available. They are more expensive and difficult to make, but worth the effort.
Low Feedback Too much feedback can spoil the sound of an amplifier. We only use a small amount in the Stereo 40 MK IV.
GEC KT88 and U.S. 6550 valves
Considered by many to be the finest Beam Pentode valve ever created, efficient, easy to drive with low distortion the Stereo 40 MK IV is designed to get the best out of this valve in big dynamics and micro detail. The American 6550 is a similar alternative.

Ultralinear or Triode?

For sixty years hi fi fans have argued which sound is better. With the Stereo 40 IV you have the choice of both at the flick of a switch. It is like having two amplifiers in one! Most hi fi fans prefer the sound of triode operation.
6SN7 (CV181)
This vintage 1941 forerunner of the miniature ECC series has a more “vivid” sound and balances well with the modern KT88. Our CV181 version comes as standard.
Remote Control
Useful to get exactly the right volume in your listening chair position. Allows fine adjustment of the right sound level.
Plenty of Power
50 watts of power is enough to fill a medium to large room with a high volume of musical excellence.
We can offer a range of upgrades including Shuguang “Treasure” valves and Russian types. As well as the superb Mundorf “silver/gold in oil” capacitors. Ask us for a quote.
All hand wired point to point, no printed circuit board
• Class A, all Triode front end
• Output circuit Ultralinear or Triode switchable
• 4x KT88 matched for best performance
• 4x 6SN7/CV181 first stage valve and phase splitter
• Standby switch to save valve life and power 
• 2x 50w per channel Ultralinear output continuous
• 2x 30 Watts in Triode mode continuous
• Remote control with high quality ALPS motorised pot
• Signal to noise level -90db
• Freq response better than 20hz-20kHz +0 – 1db
• Power bandwidth 30Hz-30kHz -3 dB
• Total harmonic distortion 0.2% at full output
• Suitable for 4, 8, and 16ohm loudspeakers
• Supplied with valve cover.
• Choke regulated power supply
• SCR audio caps, or Mundorf silver/gold in oil upgrade option
• Silver plated copper PTFE audio cable 
• Custom hand wound Tertiary output transformers
• Audiophile Gold plated Input & speaker terminals 
• Four line inputs: CD, Tuner, Aux plus Tape
• Tape monitor circuit with ‘Record Out’
• Input sensitivity 250mv.(high). 800mv (low).
• Comprehensive manual supplied
• Power requirement 230-240volts (117v adjustable)
• 76 Watts standby, 140 W Min, 240 W max. 
• 39cmW, 41D, 23H, 23kg (allow for ventilation)
(Specifications subject to change) *(Root Mean Square = continuous output)

We are still delivering orders as normal. When your order ships you will still receive tracking details. For UK shipments, Our couriers have procedures in place to ensure deliveries are arriving as quickly & safely as possible. Drivers can now sign for your parcels, however will notify you that they have arrived, in order to ensure you receive your parcel. Signing for the parcel has now been stopped temporally for hygiene reasons. Drivers are also working with customer instructions, so you can ask them to leave the parcel in a safe place (doorstep etc...) if you prefer not to come into direct contact with the driver.

Express Deliveries

Express Delivery is FREE on all orders over £50. Express Delivery offers delivery in 24-72 hours from time of purchase. We use premium couriers for this service, mainly DPD & Royal Mail. DPD will offer you a one hour window for delivery to make sure someone is at home, or you can reschedule the delivery if no one is around. 

Standard Deliveries

Here at Kronos AV, we have vast experience with e-commerce sales. Making sure that your parcel arrives undamaged is a huge priority for us. That’s why at Kronos AV, we only use premium couriers for all our orders. All our parcels are shipped with DPD or Royal Mail and are always sent Signed For to make sure it gets to the right person. 

If for any reason your parcel does arrived damaged, please get in touch, and we will be happy to get everything resolved for you. We are always on hand to help!


Delivery is FREE on all orders over £50. In order to offer FREE delivery to UK customers, we use several premium couriers to ensure your delivery arrives safe.

Most large orders (over 2kg) ship using DPD or DHL courier and smaller orders (under 2kg) by Royal Mail signed for services.

The most appropriate courier will be chosen for the items ordered to ensure the quickest possible delivery.

We can offer very generous trade in offers across the majority of our product range. 

Why not ask and see how much you HiFi is worth!

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If you have any question, please feel free to call us on 03435236169 or email