I have built 3 of the AudioNote kits:

Recently I had a mains transformer go on my Kit1 (plenty bad news) and initially I broke out the Exposure while the Kit 1 was undergoing surgery.  After using valves (tubes to our American cousins) for 4 years the sound of transistors sounded awful - I just couldn't sit and listen to music for a couple of hours or so, as is my wont.  So, I put the Exposure into the dining room system, where its 30watts did a much better job of driving the little JPWs and put the Kit4 into my main system and I have to admit that I immediately preferred the sound of this humble little amp to the Exposure.  You have to understand, if you have not heard of the UK company Exposure, that as trannie amps go this isn't a bad one.  4 years ago when I was looking to upgrade this amp I initially auditioned a number of trannie amps and soundwise much more expensive trannie amps did not sound any better that the Exposure they just had more power.

The problem with the Kit4 is that the high frequency response is a bit "screechy", due I think to polyester coupling caps in the supplied with the kit which are fairly standard components.  Now, AudioNote never did any upgrade kits for the Kit4, which is understandable, there are 10 coupling caps in the amp and a set of paper-in-oils would probably cost more than the original Kit!  So, I had a look around and found some articles on Auricap polyprops and most of these articles were very positive an order was sent to Parts Connexion for the following:

4 x 0.1uF 450v Auricaps to replace C15, C16, C19

6 x 0.47uF 450v Auricaps to replace C6, C7, C8, C10, C17

I also replaced the cathode bypass electrolytics with some Black Gate standards which are relatively cheap. 100uF BG Std @ 50v to replace C11, C12, C13 C14

4 x >220uF BG Std @ 50v to replace C1, C2, C4 C5

The total cost of these components, without sales tax, was $107.10 - not a huge layout.I have now run these in for about 20 hours and can only say that difference is enormous, the Kit4 now sounds absolutely gorgeous and the worrisome high frequency response is now much nicer.The only problem is that the Auricaps have absolutely dreadful leadouts, they are multi stranded and too big to fit through the holes in the pcb.  I ended up drilling the pcb holes to enlarge, but I was worried that I was decreasing the area on the solder pads.  This was worrying, but I knew I could always solder directly to the next component, one side of a coupling cap will almost always be onto a valve base (plate connection).That is the only problem though, as I said above the Kit4 sounds really excellent.  How much is due to the coupling caps and how much to the Black Gate cathode by-pass caps I do not know and I am not really worried.

Pre-Amp

I built the pre-amp kit next, before I built the Kit1 and my initial impression of it was that it had this beautiful expansive, wide sound (sorry I am trying to find words to describe this) but was not brilliant in the high frequencies - a bit ragged - a bit screechy.  Remember, I had not done the Kit4 mod (above) at this time.So what to do? 

After running with the Pre-amp kit for a couple of months I went for the Level 1 upgrade, AN Al paper-in-oil caps, BG cathode bypass caps and the GE6072A valves for the phono section.  This upgrade transforms the pre-amp into a super piece of kit it really does.  I have at this time not gone any further, but I would like to put in two mono switched pots, which would in effect upgrade the balance control as well - if you see what I mean.  I do need a balance control and it always seemed silly to have a balance control - just use two mono pots for left & right.  I suspect that eventually I will go for AN Cu paper-in-oils and Tant resistors - but that's in the future.I say again this pre-amp now sounds beautiful.

KIT1

Enough people have said lots of good and positive things about this amp and my experience with it agrees with them. 

Bill McCormack's upgraded Kit1 with chrome Tx covers, black gates & more!

This is a superb power amp.I have added the level1 upgrade - some Black Gates and Elna's and the large Elna (220uF 500v) on the power supply.Interestingly AN supplies (or did at this time) Al paper-in-oil coupling caps with the kit.I am also now using Electro Harmonix Gold 300Bs, but would love to run with the GEs (well who wouldn't?).I have to say that this is a great way of doing hi-fi.  Go for a good kit and apply upgrades over the years, just make your existing kit sound better.  Do not replace your kit every few years!I would also like to say that you should throw out your CD player and collection, get the best Deck/Arm/Cartridge you can afford - I use a Linn LP12 + Hadcock uni-pivot + A Cartridge Man Music Maker and the sound of this combination is absolutely beautiful.I scour charity shops for old classical (60s and 70s) mainly, when the likes of CBS, Mercury, Decca and EMI were producing some amazing stuff.  I picked up to LPs the other day, both George Szell and the Cleveland, one was Mahler4 and the other was a selection of Wagner overtures.  These were both on CBS (I think) and are just amazing recordings, for fear of making you jealous I won't tell you how much they cost.  Suffice it to say, I am still chuckling.Oh! and one last thing if you follow my advice above the invest in a record cleaner, I have the Moth machine and I tell you, you will not believe the difference it makes.If you wish to ignore me and you still have some vinyl please come to my house and flog it to me for very little money please.

Bill McCormack