July 2010 issue - Page 4

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Having read Tony Bolton’s review of the Icon Audio stereo 40 Mk3 in Hi-Fi World I tend to agree with his findings. Having purchased this amp late last year I have been very happy with it’s musical abilities and my first foray into valves and what they offer. I love it’s organic, detailed sound and fine stereo imaging. I have the KT88 version and the reason for writing concerns my interest in valve rolling. A while back you did a feature regarding this issue and I was intrigued at the time of reading.

If I remember this was more to do with pre amp or first stage valves and I was wondering if you could maybe do a feature on output valves like the KT88.

As the Stereo 40 Mk3 can use several other valves such as the KT66 as used in Quad gear I would like to know what differences or changes would be brought about by such rolling of tubes and costs incurred.

I am happy with the valves fitted at present and am thinking more along the lines of when it comes time to fit new valves.I tend to leave the amp on for several hours of listening, using the stand by facility when not rather than switching on and off.

The rest of my system may seem a bit of a mismatch but gives great pleasure and insight to recordings. For a source I use a Wadia transport with my Apple i-pod Classic, feeding files into a Cambridge Audio Dacmagic (current model). Loudspeaker choice is Bowers & Wilkins 684s wired with Chord Odyssey and Kimber digital interconnect. I had a dem. of the amp with the Monitor Audio RX range you featured recently but found the treble too fatiguing over the long term. The Icon amp marries so well with my final loudspeaker choice.

Any info regarding valve rolling or featuring in the mag would be beneficial. I have been a reader of the mag from day one, many thanks.

Tony Hodgkinson




Shuguang Treasure series 'Black Bottle' carbonised, special edition  premium grade KT88. Expensive!


Hi Tony. It is usual – and safest – to experiment with different brands / grades of the same tube type, in your case the KT88, rather than swap type completely, to say a KT66. The KT88 is specified to run up to 800V on its anode, and has an Ra of 12kOhms. The KT66 is rated at 500V on its anode, and has an Ra of 22kOhms; the KT88 was designed to deliver higher power. You would not normally use a KT66 in place of a KT88; the HT may be excessive which will quickly destroy the valve, and the internal resistance will not match the output transformer primary, and its reflected load.

Take a look at the Shuguang Treasure series ‘Black Bottle’ premium grade KT88 if you want to see what a top tube looks like – and costs! This is where you may want to head. Sweet dreams. NK



I am a long standing regular reader of Hi-Fi World and would very much appreciate some help in fine tuning my system. I am not sure whether this level of system detail is a help or a hindrance for you, but here goes.

My front ends are: Vinyl - Acoustic Signature Challenger, OL Silver and Shelter 5000 cartridge (with Cartridgeman Isolator) into an Audio Innovations 800 MC Transformer and a Missing Link Cryo Reference interconnect.

For CD/SACD - Denon All (with mods for Tricord Clock 4, upgraded power supply and capacitors), and a Missing Link Cryo interconnect.

These sources run into an Audio Note Meishu (Mark 1 with phono stage) with Border Patrol MB power supply and then via Electrofluidics Monolith 20/20 cable into Living Voice Auditoriums (Mark 1 version) with Townsend super tweeters.

The turntable and units sit on two separate Audiophile Star Base stacks. The electric supply is through a dedicated socket from the meter on standard 30amp cable with a dedicated earthing rod and a Russ Andrews PowerBlock and classic PowerKords.

My present focus is on whether to upgrade the MC transformer, speaker cable and perhaps the ‘speakers.

I have restrained from upgrading the ‘speakers to date as the listening room is 18ft x 12ft with the speakers firing down the length of the room.  They are about 12 inches in from the corners and toed in with one of the room’s three sofas situated between them!  There is another sofa at the far end of the room and one in the middle of the side wall opposite the fire place.  This is a far from desirable set up but is the price I have to pay for a minimum level of marital harmony along with my retaining a focus on minimizing the number of units that make up my system, hence the integrated amplifier.

I did previously have Impulse H2 speakers but the size of these really did lead to trouble and strife and were referred to as our ‘coffins’ so, eventually, they had to go. The present Auditoriums seem to work quite well with a respectable level bass presentation despite the room difficulties. However, I recognize that the present bass is hampered with a slightly unnatural and restricted presentation and the level of detail could be improved upon. I am extremely hesitant about whether an upgrade would obtain any significant improvement in sound given the sofa issues and wondered whether I should just focus on a speaker cable upgrade. I have recently added the super tweeters and these do work very well for smoothing off any top end rough edges.

I have a wide collection of music covering heavy rock/metal, soft rock, jazz, blues and classical and, as much as I have tried, I find it difficult to listen comfortably for long periods via solid state amplification. I simply love the single ended 300B sound with the wide and deep sound stage and, in particular, the subtlety of emotion it can convey from a good recording and voice. It really makes music for me, even with CD, and I can forgive quite happily the sound compromises for presentation of poorly recorded rock music. I do not want to spoil what I have and my system upgrades have all been focused on finding a step by step balance for improving on detail and dynamics but without ‘losing the music’ and the warmth and ease of presentation in the valve sound.

Firstly, I would appreciate some guidance on whether upgrading the MC transformer might be worthwhile for the level of my system (I have found myself focusing on either the Pure Sound T10 or jumping up to an Audio Note).

Secondly, is an upgrade of the 'speakers and/or cable worthwhile and, if so, do you have any suggestions that I might explore and, thirdly, whether you have any more general observations on other aspects of the system that I should consider.

Lastly, I have no particular budget for these upgrades as my anticipation is that the level of my system is likely to dictate your responses to a sensible level of upgrade that they deserve and which I should be considering.


Thank you for any help that you can give me.

kind regards

Mike Hannibal




An excellent loudspeaker that works well with valve amps and is not too expensive, the Triangle Antal EX.


Hi Mike. I would not worry about the settees; they damp room bass modes and the one between the loudspeakers will slightly reduce energy from the wall behind. I prefer not to have energy zinging around all over the place (distributed treble energy) in a room and like the better damped, quieter environment lots of soft furnishings impose. Since you like valves and refer to “warmth and ease of presentation” I suspect this is your preference too.

The Living Voice Auditoriums have a good reputation (I do not know them well) but if you want to try an alternative you may well consider the Triangle Antal EX loudspeakers I review in this issue. They matched our Icon Audio MB845 valve power amplifiers well, but they do have some small lift in the treble and are not ‘soft’. It was aurally acceptable though, I felt, and the Antals otherwise delivered a great sound, a notch above much else. I suspect they would suit your room and amplifier.

The Shelter 5000 cartridge on a Cartridgeman Isolator made me wince, and the Isolator may well be compensating for the brighter presentation of the Origin Live Silver, which best complements warmer MM cartridges. My immediate suggestion here is to head for an Ortofon Rondo Bronze budget moving coil, or even a Cadenza Black premium moving coil cartridge. Both have smooth top ends, the Black being almost warm, and both will work in your arm, without Isolator. Stay with Audionote if you can; their products are superb. I hope this helps. NK


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