[MikeC]

Where no-one notices the contrast of white on white. - Counting Crows, Round Here

Alternatively, "impressions of the AKSA 55 Nirvana Plus".

I did promise Hugh I would write up some of my impressions of the amp, having been one of the first fifteen to snatch the upgrade kit from him. I was listening to the Counting Crows - August and Everything After, last night, and the opening verse of Round Here struck me as pretty accurately describing the strengths of the amp. For the non-cryptic among us, the key strength of the upgrade is the nailing of the musical subtelties that are normally lost in reproduced music.

I promised Hugh in an earlier private e-mail that I would not reveal details of the upgrade component and circuit changes, as he makes a living selling the kits. If anyone was really desperate to bypass Hugh, most of the upgraded components and some circuit enhancement have been discussed here previously, and have in fact been collaborations with some of the forum members. I won’t go to the extent of summarising any of the changes, so if anyone wants to cheat, be prepared to experiment with all the options, as Hugh has done. It is not a secret that some of the changes involve Black Gate caps. The #$%^&#@ things took forever to break in , and I am still not sure that they have done so completely. I am still amazed that anyone had the initial patience to persevere with these things until they sounded good. I can’t comment on their overall contribution to the improvements wrought, but I am sure they contributed enormously to the extended break-in time.

Initially, after resetting the bias and checking DC offset, the overriding impression was of a sense of calm to the music. Notes and small details seemed to come from a blacker background, to use an audio cliché. There was a lack of bass and body to the sound, however, and this arrived after 10 – 20 hours running in. At this time, I thought there was something wrong with the amp, as the sound had now homogenised, and become bloated. Once this stage passed, the sound has been getting sweeter, with a bright edge to the sound slowly diminishing. It took running a CD on repeat at reasonable volume all day while at work, and checking for a change in sound when returning home, to get through the burn-in. As I have not listened to the amp for the bulk of the time it has been running, I am sure I have not acclimatised myself to the sound.

The initial sense of calm to the sound has remained, the bass extension and tunefulness has returned, and small musical details are readily apparent as separate components of the mix. I am now hearing things in familiar recordings that must always have been there, but are just more apparent now. Most importantly, really poorly recorded stuff (like most commercial recordings) now sounds a lot more enjoyable than previously. This has to be as a result of letting more low level detail through due to the lowering of the subliminal noise floor. Well recorded material sounds spectacularly "right", with ambience, instrument decay and small vocal inflections clearly delineated and contributing to the emotional experience of the music.

Before anyone accuses me of being Hugh in disguise (I'm not, he even forgot my continent   ), I had better finish off. Hugh, thank you for a great amp, I hope you sell many more.

Cheers

Mike


PS: Please may I finish with two words - Eleanor McEvoy. If you don't know her, look her up on http://www.amazon.co.uk. Yola is superb, and I have just received Early Hours, her latest album. Real music and emotion, not the top 40 bubblegum which is all our local shops here seem to stock.

[AKSA]

Mike,

At the risk of sounding a little ingenuous, I'm lost for words.....

Thank you, Sir, of the Dark Continent...

Cheers,

Hugh

[Rhythm Willie]

What a great descriptive & detailed post. Mike, you would make a superb  hifi journalist, you gave me an excellent visual & aural impression of what you experience with your music, and the running in process.

Eleanor McEvoy? - Will have to investigate her when spending with my CD vouchers I got for my birthday on the 22nd June.

I am looking forward to the release of the 100N+. I can't imagine how it will improve on the 100N which is the best sounding amp I have ever had in my lounge room(including a listen to all the Naim's,Metaxas,some Krell's, high end valve amps & (am I biased) I actually preferred the Aksa 100N sound to the Halcro DM 58's.

[DSK]

I actually preferred the Aksa 100N sound to the Halcro DM 58's....

Well, if that ain't throwin' the cat amongst the pigeons!  

I realise this is extremely subjective and that your comment may even have been somewhat tongue in cheek, but how about a brief description of the areas in which you felt the AKSA sounded better than the Halcros?

[ginger]

I have just come across this post having been missing in action for a while building a 120W per channel valve amp.

My reference amp remains the AKSA 55NPlus. I also read the news at aksaonline and note that Hugh has given me some of the credit for this development. Thanks Hugh.

I few points for those of you wondering about upgrading from the Nivarna to the Nivarna Plus (blatent unsolicited advertising).

Being a Professional Electronic Design Engineer with 30 years experience, I started by doing a circuit design review, I was convinced that a current source loaded VAS would be an improvement over the bootstrapped resistive load and that I could improve the amp by making design changes. 3 months of effort convinced me I was WRONG and that the basic circuit was best as is.

I then started tinkering with component values and types - particularly capacitor types. After achieving significant improvements by changing componenets here and there, I wondered if I did a blanket change of all of the electrolytic caps to the best possible (Super 'E' connected Blackgate Ns and NXs) might be the go. This quickly established that it was possible to over finess the amp and I started backing out these very expensive options. The eventual selections are a result of a further 3 months cycle of make a change, wait for it to settle in, listen critically, get a second opinion etc.

For those of you with the 55 Nivarna you may be wondering how much more can be squeezed out of this already stunning amp. The surprising answer is quite a bit, particularly in the area of a "dead black background", fine detail, stereo image definition and size and subjective power (bottom end especially). The AKSA has always had a very strong bass but I knew we had got the upgrade just right when the mids, highs, detail and imaging started to leave my 845 Single Ended Triode Amp for dead. This was cetainly NOT the case when I started with just the standard Nivarna Upgrade.

The Nivarna Plus upgrade is a carefully considered set of minor mods and component upgrades which screws the last little bit out the amp without going overboard on very expensive components with no added benefit. Believe me, I tried the lot.

Is the 55 Nivarna Plus exactly the same as my amp - no but its 95% the same, which is what you would expect, given different tastes. That is to say Hugh did'nt take my word for everything, he auditioned all the changes I made for himself, suggested changes I might try etc.. Where we had differing views I cetainly tried his recommendations and our preferences gradually converged.

Conclusion: The AKSA 55 Nivarna Plus is quite possibly the most mature design of any amplifier around in terms of circuit design, operating points and component selection.

I RECOMMEND this upgrade to all.

I would add, be patient, some of the caps in the upgrade DO take time to settle in - a minimum of 40 hours BUT you will notice further improvement past this time. If you want to speed up the settle in process leave the amp powered up even when your not listening for a couple of days.

Cheers,
Ginger

[Rhythm Willie]

DSK - Yes very subjective, but :-

The Aksa 100n's have IMO huge reserves of power running my Vaf I-93's in my reasonably sized lounge room,they are only idling at large DB's so firstly I would never need the 220 watts plus power of the Halcro's.

The sound of the 2 amps is fairly similar in some areas(thanks Philip Vafiadis for the opportunity to hear the Halcros).I have done some minor mods to the Aksa(built in monoblock form with shielded power supplies,silver micr cap at C6, some black gates)

Similar control, quietness,crispy tingling highs,bass control speed & slam, I just felt the Aksa's had a bit more natural warmth to female vocals,cello & accoustic guitars. The problem with this very subjective test, was that I did'nt have the luxury or time to continually switch back between the 2 amps, which I was able to do numerous times with the other amps I have borrowed. Two of my audiophile friends however were also present and confirmed there was little to pick between them in my set up(I used the direct variable output of my Sony XA7 ES CD Player for the listenning test i.e. I did'nt want a pre amp to confuse things ).

I suppose it just goes to prove that specs(as Hugh describes) do not always convert to a better emotional listenning experience.

[DSK]

Rhythm Willie,
Thanks for sharing your experience with us on the AKSA 100N vs the Halcro DM58's.

Given that the upgrade from Nirvana to Nirvana Plus is approx twice the improvement of the upgrade from stock amp to Nirvana, I think you'll be laughing all the way to the bank.      

[MikeC]

Rythm Willie said:

Mike, you would make a superb hifi journalist

Now my cover is blown.    Actually, writing for a living is the furthest from the truth, and I tried very hard not to use audiospeak in my comments. Thanks for the kind words, though. I'm an engineer, and we are not normally appreciated.

You will not be dissapointed with the sound of the 100W N+, if the 55W is anything to go by. Mine is only compared to a Proceed Amp-2, and pre-upgrade, to a big Marantz AV receiver. I have heard mega systems, including full Mark Levinson and Krell sources and amps, but only 2 complete systems came close to the emotional communication that I achieve now with the AKSA. I haven't heard anything really high end for a few years now, but my lasting impressions are (generally) of a superficiality and sterility to the sound. This is absent in my system now.

Cheers

Mike

[kyrill]

Hi

May I throw in my 2 cts?
I have lived 10 years with very expensive* gear. Martin Logan Quest speakers
Melos triode tubed poweramps and Klyne LX7 preamp, TEAC transport and Counterpoint DAC (who is build like a Rolls Royce when you open it.  The sound was so lifelike and warmth and precise that I became famous along my friends who auditioned it. The evenings, when friends were over for dinner or just for an social vist, ended with listening to music in the music room. A room with a pentagram form (only 2 of the 5 walls are paralell to each other) professionally damped, dedicated to listening only and "bilateral talks"

That was my reference. The new reference is gradually evolving around the DEQX powered by the AKSA's and GK-1s
The difference is already astounding. My old setup sounds less lifelike, less speed of transients and the AKSA's alone very closely resemble the musical warmth  but are moch more refined sounding than the beyond 7000 US* old dollars costing MELOS who weights each 27 kilo's . The Melos blew away the Audio Research, the Krells and the Mark Levinsons I listened to, before making a choice.
Now,  I anticipate the effects of the GK-1(not finished yet)  to the AKSA's to exceed the Melos in all its properties by a large, maybe Hugh margin  

*I put this in to contrast these to the price of the Aspen amplifiers

But also
I use now much more refined power conditioning. Wow what a diiference.
The most precise CD player clock in the market under 300 US dollar (there is a better one for over 10,000 Euro's !! ) Wow what a difference
The 20 dollar costing Herbies grungebuster cd mat Wow what a difference
and teh DEQX room and speaker correction wow what a difference, especially the speaker phase correction plus the omitting of the external crossovers. In the end it are the speakers who transform electrical energy into music.
To be short the sound becomes sometimes so real that my brain, unasked,  warns me that there are people in the room and fear (!) opens my eyes. I thought I was alone, eyes closed emerged in the music and suddenly unexpected there is/are  a real presence in the room. Spooky if unexpected

[andyr]

Hi ...
To be short the sound becomes sometimes so real that my brain, unasked, warns me that there are people in the room and fear (!) opens my eyes. I thought I was alone, eyes closed emerged in the music and suddenly unexpected there is/are a real presence in the room. Spooky if unexpected ...

Kyrill,

U need to stop that LSD intake, mate!  

Regards,

Andy