Audio Note Kit One amplifier – upgrades

This ‘integrated’ single-ended 300B kit amp was introduced by Audio Note UK in the mid 1990s.  This example was built by me in 1997.

The standard Kit One looks plain and unattractive, so I dressed it up with some Kondo-copper aesthetic!

Not inexpensive (around GBP799 in 1997), this was however a quite good sounding 300B SE amp.

AN Kit 1 OY

Kit One inside a

With ‘entry-level’ but good Audio Note UK output transformers – most important – this sounded a little more ‘modern’ than your ‘traditional’ mellow SET amp.

Good sized OPTs, together with power transformer & PSU smoothing choke, there’s a lot of ‘iron’ on board, so the completed chassis weighs around 18kgs.

Some years ago, the standard volume pot had been changed for a much better sounding Noble plastic film pot. (Noble AP25, USD25 from Percy Audio, an excellent sounding pot.)

IMG_3301 a

The input-driver PCB

Now for some simple & obvious upgrades – the ‘cathode bypass’ capacitors on all 5 signal valves – just 6 caps in total.

The standard Kit One comes supplied with Audio Note aluminium foil, paper-in-oil signal coupling caps (good), but the Cathode Bypass caps are standard Japanese Rubycon electrolytic caps, nothing special sonically.

Our plan is to install Elna Silmic II electrolytics – which are the best sounding electrolytics that I know of.  Produced for ‘audio’ but not costly (from Hifi Collective UK).


The Rubycons removed and the Silmics can be seen under, between the 300B valve/tube bases.

The Silmics have lovely tone for an electrolytic, wide tonal bandwidth, with harmonic ‘decay’ and openness.

(Black Gates caps are popular audiophile upgrades, but these (no longer in production) caps do not sound natural to me – ‘lively’ but ‘hard’, forward and ‘hifi’ sounding to my ear.)


Lifting the input-driver board.

Unlike the 300B cathode caps above, which are conveniently attached to a solder-tag strip, the input and driver cathode caps are soldered through a double-sided PCB, requiring lifting the input-driver board to unsolder them, followed by sucking clean the PCB holes ready for re-installation.

The completed job:



Sound:   (Comments from the present owner of this amp.)

” The Silmics have ‘tamed’ the amp a lot….. I can immediately tell it’s changed.  My Technics SL120/sme3009/DL103…. sounds much more modern and listenable…. CD/file playing…. the output of the DAC-AH is transformed and I’m able to listen to CDs at a lot lower volume and enjoy them….. a lot more coherent.




3 thoughts on “Audio Note Kit One amplifier – upgrades

  1. Just discovered your site, absolutely enthralled, in case I missed it, do you have info on your site somewhere on the dimensions/angles/etc for various typical tonearm sizes/makes (7″/12″/etc?) Absolutely love your work.

    • Hi Brian – you’ll find commercial tonearm data on various sites like Vinyl Engine.
      Otherwise, I use John Elison’s spreadsheet to calc null point, angular offset, etc. for any Effective Length tonearm for different alignments, Baerwald, Lofgren etc.

      Thanks for visiting – Owen

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