Preamplfiers

Since we introduced the original M3 pre-amplifier in 1996, based on circuitry developed 1994/95. The M3 and its derivatives have proved quite a success, year on year they have consistently won “Pre-Amplifier of the Year” by Hi-Fi Review in HK starting in 2001 and pretty much every year since then.

The M3 pre-amplifier family were technically the most advanced (and strangely enough, at the same time quite backward looking) line of high quality pre-amplifier available, with its dual mono double choke valve rectified power supplies, optimised output transformers and powerful high gain line stage, it will remain the standard in pre-amplifier topology for years to come and as a result is already widely copied, but our quest for improvement does not stand still, and when our research and development reached its current pinnacle with the patented M10 Galahad power supply, Andy and I decided that it was time to seek to improve the M3 – M8 pre-amplifier’s power supply in line with what we had learned from developing the M10, so in very late 2003 (actually product only really shipped in January 2004) the “Mini”-Galahad supply was born and implemented into the M3, M5, M6 and M8 pre-amplifiers and development work on the M9 started.

The new M3 – M8 supply incorporates what is essentially a simplified M10 configuration where we rather than using the old input choke arrangement, which has now proven to be somewhat dynamically restricting we have a feed-forward supply with a rectifier (the usual trusty 6X5), regulator (ECL82/6BM8) and a voltage stabilizer (OB2) an arrangement that needs much less filtering capacitance and results in a supply that traces the signal stages requirements far more closely than anything else, the result is quite spectacular!

As a result of the greatly increased cost of the above power supply and the fact that Black Gate™ finally decided to call it a day and stop production, we had to “re-jig” the specification of each product to ensure it stayed within the appropriate voicing and off course cost frame. This involved redesigning the output transformers to allow us using newly developed HiB materials, a revised line stage where we changed the first stage valve from the standard 5687WB to an ECC82 type (many versions available here, for example 12AU7, 7316, 5814a, 6189w, 5963, E82CC, CV491 an many others) to reduce the sound of repeating the same valve and circuit coupling in subsequent stages and modified the second stage line valve to either a 5687, 7044 or 6463 depending on the balance we felt appropriate.

A further revision proved necessary in late 2007 when we finally ran out of our stock of Noble volume and balance controls which Noble had stopped making in 1997 (yes we held enough stock to bridge production for 10 years, we do the same with most key Black Gate™ values and 2 watt Audio Note™ tants! It is a key part of our long term commitment to maintain products unchanged for as long as possible), so we had time to prepare for this, and a further revision of the M3 – M8 was instigated which involved removing the tape loop and balance control and replacing it with two handmade Audio Note™ attenuators using ½ watt Audio Note™ tants, another very significant sonic improvement, the new M3 – M8 now had 3 control knobs rather than 4.

See summary table below.

A short general comment on how we “build a better sonic level”!

All Audio Note™ products are placed into levels in a level system which is designed to help customers and dealers build an appropriately sounding Audio Note system, we go to great lengths to ensure that whatever level a product is placed in it has a complementary and synergistic influence on the system sound and represents good value for money in this regard, this is how we design and build our products and our business model is based on offering a very wide product range, end to end and bottom to top, all of which have the same aim, and are designed to ever greater levels of ability to contrast dynamics, timbre and recording quality, see “Are You on the Road to Audio Hell” for further information on our evaluation priorities and system, the three As, Accuracy, Authenticity and Authority to the original recording govern everything we do, rather the misunderstood notion of what ought to be “there”, wishful thinking at best and at worst preventing you from hearing the best of what the artists and their art can provide.

To achieve the improvements available in each level we first design a circuit that is as un-contaminating as possible, inter stage behaviour is calculated with great care, this is an absolute precondition for the component quality to be able to make enough of a difference to be heard clearly, we then apply the standard Audio Note™ procedure of upgrading the parts quality level by level in order to improve and refine the sound. The first step in this direction is presented in the M5, followed by the M6 and finally the M8 pre-amplifier, making up what we call the M3-pre-amplifier family all of whom share the same circuit topology across the range.

Above the M3-M8 family you will find a couple of super quality pre-amplifiers the M9Phono and M10Line (phono version is still in development, in these pre-amplifiers we will take the power supply design, valve choice, materials, circuits and component quality to new heights with a price to match, as anyone who has heard them can testify to!

The improvement in specification, components and materials within the M3 family is shown on the table below.

Power amplifiers

Level Zero to Level Three Power Amplifiers

The Audio Note™ line of power amplifiers is without any doubt the most comprehensive available from a single manufacturer, we cover practically every available power valve available from the small EL84, to the mighty 211 triode, with prices ranging from the fairly modest to the positively immodest, and if combined with a suitable pre-amplifier with provide the highest attainable sound within its price class.

The Conqueror, Quest and the Conquest models are now available with a single stage input using a 6J5, this is to accommodate the need for ultra quiet replay, the standard Quest-Conqueror circuit has very high input sensitivity making it extremely difficult to make the system quiet if very efficient speakers (100dB plus) are used.

It is important to understand that sonically it is desirable to have as much gain available in the circuit as possible, as the wider the dynamic gain window is the better the amplifier/system handles wide dynamic signal levels (contrary to popular belief, dynamics have NOTHING to do with power, it is a function of how much each stage in a circuit’s gain window limits the dynamic peaks), having very high gain and therefore sensitivity in a power amplifier creates problems with background noise levels, in systems where speakers have very high efficiency it is necessary to limit the amount of gain in the amplification, to allow usable attenuation in the volume and to reduce the level of residual circuit noise coming though the speakers.

All Audio Note™ power amplifiers, except the ANKORU/II, have heavily silver plated RCA input and AN-STR speaker terminals with 4 & 8Ohm output impedance. 

Despite the low power output of all out power amplifiers, their ability to drive speakers with even quite low efficiency, there is naturally a limit to how loud it is possible to play, however, even 86dB efficient loudspeakers can be used in smaller rooms.

Level Four & Level Five Power Amplifiers

Building on the same two basic circuit topologies and extending the quality of the componentry used in the Audio Note™ Level Three amplifiers Quest/Conquest and ANKORU/II the Level Four and Five elevate the materials and component quality to levels not often, if at all, seen in commercial amplification regardless of price or reputation, as we move up through the Audio Note™ product range the use of exotic and highly expensive parts and materials proliferate, Audio Note™ thick film tantalum resistors, Cerafine, Silmic and Black Gate™ electrolytic capacitors, silver wire and UHiB and nickel C-cores are not seen in other products, below is a short form breakdown of the components and materials used in each amplifier.