OPTs are available on Request, please contact for details, model-by-model.
Audio Note™ valve output transformers are arranged into three catagories in order to offer the best possible outputs at different price points, fall into the following:
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.
Single 300B Output Transformers - TRANS-300
Bifilar and Trifilar wound double C-core output transformers designed for the 300B or single 2A3 with 2K7 primary impedance and 4 & 8 Ohm secondaries for single ended operation, 90mA Standing Current, 50 Watts.
Size 115 mm x 102 mm x 136 mm, mounting holes centre to centre 87 mm to 84 mm both sides.
The standard version of the TRANS-300 (E/I) type output transformers comes with steel frames. All group C transformer come with copper frames as standard. However, as a higher quality option we do offer them with solid copper shrouds, as shown in the top right picture, for an additional £ 72.00 per transformer. The copper shroud being non-magnetic improves not only RF influx, but also low level behaviour as it does not short out the airgap on the higher permeable cores like the AN Ultra HiB and the nickel cores this is essential for optimal performance.
All Copper – Copper transformers have copper lead out wires, Copper – Silver have copper wire on the primary and Audio Note silver leadout wires on the secondary and silver naturally silver wire all round.
Parallel Single-Ended 300B output Transformers - TRANS-305
Group C, bifilar wound double C-core output transformer with 1K25 primary impedance and 4 & 8 Ohm secondaries for 300B or 2A3 in parallel single-ended operation, 180mA standing current, 50 watt, , Size 115 mm x 102 mm x 136 mm, mounting holes centre to centre 87 mm to 84 mm both sides. Price is for ONE transformer!
Single Ended 211, VT4-C & 845 Output Transformers - TRANS-310
Group C, bifilar wound double C-core output transformer with 10K primary impedance and 4 & 8 Ohm secondaries for 211/VT4-C or 845 in single-ended operation, 240mA standing current, 50 watt, flash tested to 5,000 volts, Size 115 mm x 102 mm x 136 mm, mounting holes centre to centre 87 mm to 84 mm both sides. Prices are for ONE transformer.
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.
We shall shortly be adding a range of parallel single-ended 211/845 output transformers, so keep a look out for them.
As a rule delivery of the above output transformers is from stock, but dependent on internal usage delivery time can occasionally occur, especially the new custom made AN Perma Nickel cores may be on very long delivery, which can be as long as 16 – 18 weeks, we will normally try to tell you if a transformer is not in stock how long the delivery is likely to be, but in the case of the permeable materials production processes are very complex and problematic, so just beware.
Pre-amplifier Output Transformers
Audio Note have always be advocates of the pre-amplifier output transformer. Instead of using an anode resistor / signal capacitor on the pre-amp output valve, they position a high quality transformer on the anode. The result is an esquisite highly detailed sound.
The TRANS-027 range is used in all their finished products such as the M3, M5, M6 and M8 pre-amplifiers. There are various options on the TRANS-027 as the range has now expanded to include not only copper (primary winding) / copper (secondary winding) but also copper / Audio Note™ silver and all Audio Note™ silver wired versions. There are also the I/E or double C-core versions with different core materials available too.
All Copper – Copper transformers have copper lead out wires, Copper – Silver have copper on the primary and Audio Note silver leadout wires on the secondary and silver naturally silver all round.
The TRANS-011 which has the same options as the TRANS-027 is a pre-amplifier output transformers that can be used pretty much anywhere and are especially used in simple line pre-amplifier circuits like the M1 and M2.
All the above pre-amplifier output transformers are the same size, whereby copper frames come as standard, 78mm wide by 67mm high by 67mm deep, with mounting holes centre to centre at 54mm by 54 mm both with transformer standing up or lying down. However, as a higher quality option we do offer them with solid copper shrouds, as shown in the top right picture, for an additional £ 72.00 per transformer. The copper shroud being non-magnetic improves not only RF influx, but also low level behaviour as it does not short out the airgap on the higher permeable cores like the AN Ultra HiB and the nickel cores this is essential for optimal performance.