Audio Note™ output transformers

Group A.
Economy range, where the price/quality relationship is carefully calculated to ensure audio quality in a compact package. The quality criteria for group A are 20Hz to 20KHz -1 to -1.5dB, they are IE cored with silicon steel laminations and are supplied with frames and solder tags, which will allow good audio quality at the cost. The main cost saving being the use of a smaller core, specified to the exact power level required, rather than overspecifying by 50 or 100%, as we do on Group B, the winding quality and copper wire is the same.

Group B.
Mid-price range, these are typically 20Hz to 40KHz minus 1.5dB, IE cored with high quality silicon steel laminations, wound with oxygen-free copper wire and supplied with either bell-ends or frames always with flying leads. Andy Grove is designing a small range of push-pull transformers over the next 3 month to compliment those listed. I shall announce these as they become available.

Group C.
The higher categories offer a choice of either copper primary and secondary, copper primary with Audio Note™ pure silver secondary or fully Audio Note™ silver wired bobbins with a choice of different core materials, all the transformers are wound in-house and can be fitted with any type of core listed below, no push-pull outputs will be offered, unless demand requires it and even then I think it is a waste of time.

Other info.
All primary impedances are calculated for Class A operation, with the main consideration given to maximum dynamic power transfer ability and minimum distortion, rather than meaningless steady state sine- or squarewave conditions.

All Audio Note™ single-ended output transformers are airgapped.

All are tested to insulation levels of minimum 3,000 volts, all 211/845 outputs are insulated to 5Kv flash, every transformer is tested to this level of insulation.

We generally overspecify our transformers by 50% power in Push-Pull (which means that a transformer stated as 25 watts will not saturate at stated power but will allow about 35-38 watt peaks, our single-ended outputs are generally over specified by 100%, which means that they will instantaneously allow peaks of double the given maximum power through undistorted, this is necessary due to the better clipping behaviour of the single-ended stage.

Additional information from Peter Qvortrup:
Up to now the recommendation has been that all Audio Note™ silver wired bobbins should only be used with Nickel C-cores as the performance improvement is tremendous, however, with the emergence of the new AN Ultra HiB the sands have shifted, so whilst in general it is still my view that the nickel cores are the best sonic investment one can make, the Ultra HiB has changed the position to the point where the Nickel is really only a good investment, if there is silver in one or both windings, the AN Ultra HiB should be considered as it provides a slightly gentler character with a better/deeper bass character than the nickel irons, bear this in mind when you plan your project.

Believe it or not, I have tried to keep the prices of the above transformers as low as possible, and I would like to remind all of you reading this, that when you consider the fact that a Japanese made ONGAKU™ output transformer would cost at least 3 times as much as the best version of one of the new Audio Note™ silver wired 211SE output we offer above, and that in addition to this our output transformer has not only a better C-core and general specification than the original ONGAKU output transformer, so whilst these prices may seem expensive, the product offered is incomparable to anything on the market both in terms of both sonic and technical quality.

The Audio Note™ output transformers offered above differ from the ones used in production amplifiers in two key areas,

1. Output transformers in such amplifiers as the ONGAKU™, KEGON™ or BARANSU are carefully matched to three different parameters (I am not at liberty to tell you more than one, frequency response, the other parameters are proprietary, as I do not want our competition stealing more of our technology and ideas than strictly necessary).

2. We use the C-cores with the best/neatest lamination alignment in production, and whilst this makes little difference to the sound, it is important to appreciate this fact.

All the above transformers are supplied raw in the sense that they are unpotted and with flying leads.