[kyrill]

Hi

I will say goodbye to my Klyne system 7 preamp, Melos 400 triode amp and my Martin Logan's Quest  electrostatic speaker. It involved me for years and it is time to move on.

Then I discovered the DIY camp.

I start with first,  new speakers and God knows why I fell in love with the Accuton ceramic drivers (accuton.com). They have a rare low K2/K3distortion of under 0.5% for most of their range at 5 watts (!)Since very short they have a 93 db version (not on their website yet).
Never heard them, don't need to. Like I never heard the Klyne, the Aspen the decware or even Martin Logan, before I buy or bought them. It sounds odd, but listening only works if you can have the complete chain in your own listening room after fully breaking in. In Holland for some reason there is not one shop that has the gear I want as a complete chain or even the brand I  like, like  Klyne,  and Melos.

Well, i already bought the digital preamp from my most favourite country to live in: Australia.
It is the DEQX pdc-2.6. If all my information is correct the (little) flaws will be buried in the enormous advantages, like phase and frequency correction of speakers and DRC (digital room correction) This is my base unit (http://www.deqx.com/index.html) plus I can stil tweak/mod the preamp

Now I can build speakers and not worry about crossovers.( 3 way cross overs are part of the DEQX)

My amp choice was (is?) Decware  SET  amp kit (4x mono for a two speakers active x-over) But tubes need to be replaced but I really like Steve Deckert's  simple design. The love for his amplifiers equals the love of Hugh for his babies.

But LCaudio.dk (which has the most stable clock mods in the world for any digital gear, I modded my Copland 288 cd player with it) got a very favourable high endish review of their digital poweramps that they also sell as a kit.. I know SET will sound more natural and real but 100 or 200 watts that does not need replacement and sound almost as good as the best tubes IS very tempting.

And then I stumbled upon another Australian company: Aspen.  with such high praise all over the world, but mostly (not all from the people that already bought them, except  the enthousiasm of Hugh is so real, and he does participate in different forums, showing his clevererness like other designers do in those forums, but also  his kindness to the end users, which is second to none  on the web.

Now the choices narrow down to Decware -providing a true SET tube amp of a very low 5 to 6 watts, so with my choice of Accuton I will not get more than say  102 db, but very clean,  perfect phase and room correction, it will sound more loud because of this- OR the Aspen 100 (4x mono) under the same circumstances.
I love Mahler, Rachmaninoff  but also Tool and David Byrne.

I might question the chain: digital preamp with Burr Brown audiophile opamps and a sweet pure SET tube amp .

Will the Aspen 100 need  the no gain TLP for being a good alternative ?

So is it only a choice between the last drop of transparency and refine ment and low watts against some less and  more power, or is there more that I overlook?

It is impossible (again..) to organise a listening session first and then decide.
What would you do?

[blizzard]

Hi kyrill,
  Would you know if The DEQX products are available in the US?

           Thanks,
               Steve

[kyrill]

blizzard:You can't make it from their website. But I stumbled upon:
http://www.e-speakers.com/products/deqx-new.htm with good 'old' Google.
I ordered direct from DEQX.  It is easy to see that this will be the (nearby) future.

[blizzard]

Hi kyrill,
  I totally agree with you.  It's too pricey for me at this point.  But, this is definately the way to go.  I envy you at this point in time.  Good luck with the project and thanks for the link.

              Steve

[AKSA]

Hi Kyrill,

A very interesting post;  almost surreal.  Thank you.....

There are some very difficult issues here.

First, we know about CD players, and the best ways to achieve best sound with them.  For my money, it's something like a tube preamp between the CDP and the amplifier, IF the amp is SS.  This was the reasoning behind the development of the GK-1.

The digital preamp is something new I've not yet heard.  However, with all the parametric adjustment, I'd guess it is really a very flexible digital source, so the 'sonic' qualities will be not unlike the CDP itself.

As I see it, with your CDP and Digital Preamp you have two choices for full range.

1.  Steve Deckert's SET.  (A very good, low cost entry into SET, I thoroughly agree with you and if I had not recently designed and built a little SET of my own, I would have bought one myself.)  Its power is 6W.

2.  The AKSA 55N or 100N.  This choice gives you power aplenty for full range, and either amplifier would likely be good  But there is no tube in the chain and you and I know that tubes do something special to the sound which is probably worth having.  Not everyone's cup of tea, but very likely yours since you've owned and loved Triode amps.  For best results with a full range system, I'd recommend the GK-1 between preamp and power amp, and this raises issues of redundancy.

Let me explain.  Your taste runs to Mahler, Rachmaninoff, Tool and David Byrne.  The last two are not too difficult to reproduce, but Mahler is ritual Murder on Hifi.  Huge orchestras.  Stunning detail.  Cacophonous percussion.  Let me assure you that a 6W SET will not satisfy this requirement with any kind of speaker less than about 96dB/watt/metre.  Of course, I do not know your speakers, so should not comment further.


Next, we look at your active crossover options.  Here it gets interesting.

For power, and assuming roughly equal speaker sensitivity around 88dB/watt/metre, you might need around 100W for bass, 40W for midrange, and 10W for treble.  This would give you a huge sound on just about anything, up around 110dbA.  Deafening.  However, these are typical figures, and opinions differ on precisely what is required.  I have a pro-audio friend who scoffs at anything less than 1200W for an average size room!  I am astonished how loud my little 1.5W SET goes on my AKSonics, and there is no way I consider 1200W necessary, even for Mahler!!

Most 100W SS amps will handle the bass requirement without problem.  The AKSA is better than most because it does bass so musically, according to one CARY 805  (SET 845) owner who uses ProAc Towers and the 100W AKSA for the bass drivers.  The midrange amplifier does need appreciable power to cope with orchestral works, and a SET of 6W would not be enough.  You can build AKSAs at precisely this power, so all is not lost there.  The AKSA can also be built down to 15W (20V rails), and is eminently suitable for the top end amplifier, but my own feeling would be to take the bull by the horns (metaphorically, of course, no horns please, we're direct radiators here!) and use the Deckert SET amp for the top end.

This gives you the benefits of complete parametric adjustment of your crossover points and phase/room alignment from the digital pre, the power and musicality of the AKSA in the bass, the clarity and transient response of the 40W AKSA for midrange, and the sweetness and romance of a silky tube top end.  I would suggest Nirvana upgrades for all of these;  this is a premium system and we should go all out for the very best sound achievable.

This would be a killer system, and I believe you would be endlessly satisfied and fascinated with its performance.  And you could tweak it to your heart's content......

In closing, the 40W AKSA is slightly different to the 55W, and runs off 30V rails.  Sound quality is slightly better, in my view.  I have one customer who believes the 25W AKSA, an even lower power variant of the 55W AKSA, sounds like 'a powerful, slightly cleaner 2A3 SET'.  I mention this because it demonstrates the compatibility with tube amplifiers, and I do suggest you follow your instincts and use the Deckert for the top end.  Incidentally, I think the Decware 6W SET is a brilliant piece of production engineering.

I hope this helps, sorry about the long rant.

Cheers,

Hugh

[kyrill]

away from her eyes.
I thought it was there for good,
So I never really tried..

Only the first sentence, Hugh  
the rest is my association to a beautiful poemlike song of.. I bet you know.

I did not think of a combi with the Decware. I thought your amps were not up to it.
But listening to yr own SET with the Aspen amps deeply wired into your inner reference for sound, produced your advice as is.

I was not thinking of your total pre amp, not only of its redundancy, but also I like to keep the audio signal path as simple as possible. That is why I regard the TLP as more appropriate (and also costs play a role).

I have a question. I have read before (years ago from Harry Pearson of TAS) that a 30 watt ss amp will sound better than a 100 watt amp. Now you remind me to this again. Why is this so?

Your remark on your website pointing to the possibility to order lower wattages than 50 watts, almost made no sense to me, except that the customer can choose less powerful transformers and so lower the cost relatively and loose watts with it. But now there is a better reason for this?

I really like your advice it opens a lot of space to experiment, to compare  and to tweak and tweak...

[AKSA]

Hi Kyrill,

One more before I retire.....

I was not thinking of your total pre amp, not only of its redundancy, but also I like to keep the audio signal path as simple as possible. That is why I regard the TLP as more appropriate (and also costs play a role).  

You should tell that to the sound recordists who put together our music!!  with modern mixers, there can be up to 100 opamps in the signal path!  Makes nonsense of minimalist hifi, doesn't it?

I too thought this once, until I designed and tested the GK-1.  It adds complexity to the signal path, no doubt, but it increases image width, depth and even enhances height, and it adds that 'organic' sense of the performer being in the room.  Very strange......  Ask the people in this forum what they think!

 

I have a question. I have read before (years ago from Harry Pearson of TAS) that a 30 watt ss amp will sound better than a 100 watt amp. Now you remind me to this again. Why is this so?

This is actually a very difficult question.  It relates to the problem of stability in a global feedback amplifier.  This is guaranteed by using 'lag compensation' (LC), which pulls the gain of the amplifier back to below one by a frequency called the 'pole' frequency at which negative feedback turns abruptly to positive feedback.  LC is very bad for sonics, and is strongly influenced by rail voltage.  If we have a high power amp, rail voltage is high, and we need lots of LC.  This sounds a little 'slow'.  If we have a low power amp, with low rail voltage, there is less LC and the sonics are superior.

Of course, the usual disclaimers, YMMV, this all depends, all things being equal, and so on.....  There is also the matter of multiple output pairs, which degrade the sound unless the match is perfect.  But by and large, Harry Pearson is right.

Your remark on your website pointing to the possibility to order lower wattages than 50 watts, almost made no sense to me, except that the customer can choose less powerful transformers and so lower the cost relatively and loose watts with it. But now there is a better reason for this?

So many phenomenon in life trade quantity for quality.  Books have been written on this topic.  Something similar happens in the auto world;  people want more power, no problem, bigger engines, more cylinders.  But so often the engine is not so smooth - you always pay for feral performance.

Much is made of how much power the domestic hifi really needs.  I'm always surprised when I listen to my 1.5 watt SET how adequate it is for most music, though not for Mahler, I must admit.

I really like your advice it opens a lot of space to experiment, to compare and to tweak and tweak...

My advice is just that, as I can't get into your head and tell you what you need.  But I'm reasonably sure I have it right, all the same, no guarantees!

Certainly active crossovers open up both more possibilities - and a few cans of worms!

Cheers,

Hugh

[Brad]

So, Hugh, when is your 1.5 watt SET going to be available?

What tube does it use?
What price point are you going to hit?

[kyrill]

Beste* Hugh

As I have not received my DEQX yet (backorder, but they promised me  to send it this month) and as I can imagine that I, being you, would be curious, I can ask DEQX to send the unit to you, if you have the time to audition it.
They are in Sydney.. (One Australian brother to another..

After a week or two you send it to me. Yr only cost would be the freight. To be honest they would have send it by airfreight to me, so no seashipping and waiting 4 weeks at the best.
They also would "pay" for the insurance, but I am willing to share the insurance cost if its reroute thru you.

I would not mind it, since I am still saving for the discrete channel amps and it would be fun to hear yr  impressions of the good and the bad, not necessarily, but especially if you share yr findings in this forum. There is a  less expensive DEQX version, with all the attributes, but without the preamp/volume function, which will make it more compatible, no more redundancy with the GK-1.
* is Dutch

[AKSA]

Kyrill,

This uncommonly decent of you, but I should decline your kind offer.

First up, I try to avoid 'borrowing' other people's equipment because I'm running a business and I'm in a very vulnerable position.  I can't mix business and friendship, and must be fully professional.  It's a pain, but there it is....

Secondly, Ben Williams, the Aspen digital design genius, is presently in the UK visiting relatives and won't be back for another three weeks.  He is the one who would be particularly interested in assessing it thoroughly.  Recently Aspen bought a Behringer digital EQ (not sure of the model, 2496 something) and Ben is presently putting it through it's paces.  We are striving to copy the copiers!  We too are very interested in digital filtering and crossover design!

Finally, I'm 'flat out like a lizard drinking', as we say in Oz, working on numerous projects all at once, despatching parcels, trying to be a reasonable family man (failing on that score..), organizing admin, customer inquiries, troubleshooting by email, etc.  I'm not complaining, because I do enjoy it, but I'm so busy I can't possibly take on an equipment review.

Brad, let me answer your question on the SET.

With people like Steve Deckert doing a brilliant SET at a bedrock price at decware.com, I made a decision some time back NOT to enter this market.  The killer is weight, and cost of parts.  The cost of the transformers and chokes alone for my tiny little SET was a tad under $US300, and no-one in the DIY world would be prepared to pay double these figures and more for 1.5 watts.  Bang for the buck is dismal.  This was the reason I gravitated to SS, and of course the prospect of the high voltages of tube circuitry is balking, both to the constructor and the responsible designer.

I designed and built an SET because I wanted to pick up the skills and learn the 'sound'.  Actually, I rather like it, so I'm about to do another one, with the 6C33B, the big Rusky tube with 60W plate dissipation.  SET is very good for jazz and acoustic, but not marvellous for large orchestral works, at least in my view.  It requires efficient speakers - power is very limited - and delivers a highly processed, musically distorted sound.  It is an acquired taste, like certain fermented cheeses.

In closing, a few points on what the AKSA will and will not do.  First up, the NAD3020 has a phono section designed by Tomlan Holminson, who worked with George Lucas some years back to produce the THX standard.  I have a copy of the schematic, and whenever I feel I understand audio electronics I take up this circuit and realize I know very little....  This phono is one of the legends of the design world, and it's difficult to imagine anything better.  Holminson designed it as a young engineer fresh out of college.  Now that's chutzpah!!

So, if you use that NAD phono section, and couple it direct to the AKSA (at pre-out), it will be marvellous.  And from all reports, the power amp section of the 3020 was pretty good, too.

The AKSA is a classic topology with a couple of modern twists and an obsessive fanaticism about layout and component selection.  This is not to downplay the design, but most engineers who see the schematic dismiss it as being 'trivial, nothing groundbreaking, ho hum'.  The truth is, those who hear it play are astonished that it can be this good, but the clear message is that audio is as much about the detail as it is about the topology and circuit dimensioning.  Many manufacturers know this, in fact, like Gordon Rankin of Wavelength, and Ken Ishiwata of Marantz.  Of course, why should this technology be any different to others?  Everything else is about detail too...

Cheers,

Hugh

[kyrill]

Well I understand yr position and yr busy schedule

The nad 2030 plays n the kitchen, it is unmodified and cannot stand a real comparison to the Klyne and the Melos, . which are together 30 times more expensive. I use the Klyne separate phono preamp as the phono preamp.

However it must be very late or very early in the morning at yr place ...
I thought you were sleeping by now