Comparing Krell KSA50 Class A with AKSA 100W Nirvana Plus

ctviggen · « **on:** 15 Dec 2005, 12:49 pm »

I'm thinking of building my own amp. I've been following this DIY forum:
http://www.diyaudio.com/forums/showthread.php?s=cab2b115f1e8e93ec8fa34b68c3ac937&threadid=31077&perpage=10&pagenumber=514

(There's also:
http://www.diyaudio.com/wiki/index.php?page=Building+guide)

I've also been thinking of building an AKSA 100W Nirvana Plus amp. In short, my question is Which one to choose?

The Aksa materials say: "All AKSA amplifiers run very efficiently in Class AB with a quiescent current of 58mA per complementary pair, and deliver imaging, slam and clarity rivalling the best Class A designs but with none of the troublesome thermal problems."

I'm under the impression that a new AB design would have to be better than an older (though they've updated it somewhat) A design. From that perspective, I'm thinking I'd like to go with Aksa. However, building an amplifier almost from scratch and having the result be class A intrigues me. On the other hand, I've not ever built anything from scratch, and although I have an enginerding degree (EE), I haven't used my EE skills in a while.

So, for a first amp, do I build an older A design where I have to specify and order basically every single part, or do I go easier this time and build (what's likely a much better amp anyway) the Aksa?

Thanks for any resonses!

DSK · « **Reply #1 on:** 15 Dec 2005, 12:55 pm »

Hi Bob, FWIW my AKSA 100N+ replaced (outperformed) my well respected Class A amp (Plinius SA100 mk3).

rabbitz · « **Reply #2 on:** 15 Dec 2005, 01:30 pm »

Even though I only built the AKSA 55N+, the attraction over another high quality DIY amp is all the components are supplied as designed to make the amp perform at it's best, so the hard choices are made, plus a great set of instructions as well as Hugh's support.

I've built several other amps and sourcing of components can be a pain as well as selecting the best for the job is, well, a bit hit and miss..... sends you nuts.

My thoughts on the subject anyway.

CButterworth · « **Reply #3 on:** 15 Dec 2005, 01:54 pm »

Bob,

After building only a couple of battery powerede headphone amps, I approached the building of an AKSA 55N with some trepidation. However, Hugh's instructions are great, as is the extremely prompt answers to all questions that I posted to the forum.

The hardest part of the project (for me) was drilling holes and slots in the chassis to house everything, and (psychologically) attaching my multimeter to a completed amp while knowing that 110 V was entering the system - of course Hugh reminded me that the Aussie and UK folks had to deal with 240 volts!

As for sound, well what do I know about expensive Class A amps? My AKSA 55N sounds beautiful to my ears. It certainly was not horrendous to construct, in fact it was fun.

Regards,
Charlie

PSP · « **Reply #4 on:** 15 Dec 2005, 03:17 pm »

I'll second Charlie's comments. Assembling the amp and power supply boards are well-described in Hugh's outstanding instructions. Hugh and others have agonized over each component choice, so you are guaranteed to get extraordinary sound as soon as the electrons flow.

The hard part for me is always the chassis work. If you want drop-dead gorgeous metal work, I hope you have the skills or a friend with a machine shop. If you want a nice-looking amp built into a Par-Metal box, I would be happy to share pictures and my "pretty good, but far from perfect" approach to building an amp. In fact, since I'm getting ready to build a 100 N+ (probably with a reduced rail voltage for added stability into low impedance loads) to drive the bass in the Orions I plan to build... I could take a lot of pictures and post my assembly methods as I go.

I do not pretend to be an expert on chassis work. All I can say is that I have built 5 AKSA amps (3 55's and two 100's), a TLP, and a GK-1R that all look very nice on the rack. I will be happy to show you and others how I have approached this part of the problem.

If you build a 100N+ (by the way, I very much recommend both the N and the +), you will be a very happy camper.

Peter

lonewolfny42 · « **Reply #5 on:** 15 Dec 2005, 03:39 pm »

Quote from: PSP

If you build a 100N+ (by the way, I very much recommend both the N and the +), you will be a very happy camper.

Peter

Late edition....Tour Thread.....

http://www.audiocircle.com/index.php?topic=14552[/list:u]

ctviggen · « **Reply #6 on:** 15 Dec 2005, 04:25 pm »

Well, lack of time has prevented me from doing anything like this. This weekend, I'm climbing into my attic for the umpteenth time to finally install insulation -- the rest of the many weekends was given up to routing wires for a network/cable/phone system and building a platform to be able to have the area underneath the platform with insulation so that I can store boxes/crap up there yet still add to the insulation. I do have a list of things I'd still like to do to my house, but right now I'm burnt out on the house, having spent every weekend for the last 5-6 (or more?) weekend working on it. And a lot of the stuff I still want to do (add recessed lighting in the kitchen and closets) requires attic work. It's cold up there! Also, I'm engaged and spending a ton of money on a house doesn't exactly help pay for the wedding. Of course, neither does buying an amp, but at least with an amp there are few hidden costs -- my last housing project went way, way, way beyond what I expected for costs (and time).

So, I hope to have some time in the near future to build something like the AKSA. I also agree that instructions are very helpful, as the KSA comes basically with none, although there is a ton of material on the DIY site about the KSA -- which is one of the problems, wading through all that material. And, it's good to know that others have compared class A amps to the AKSA. As for machining skills, I have none. I'll likely be asking a lot of questions about that. On the other hand, I have a friend who may be moving back to CT, and he has more machining skills in his pinky than I have in my entire body. He should be able to help me, and may have access to equipment. I'll read the sticky this week about the tour. This amp is mainly for my second system, but if I do build it, I'll compare it with my Jeff Rowland to see which one I like better. That should be an interesting test!

Carlman · « **Reply #7 on:** 15 Dec 2005, 04:36 pm »

The only kit amp I've built has been the AKSA 100wN and 100wN+. Actually, I had Hugh solder the boards at a reasonable fee, and then I assembled the amps and connected things together...

Hugh has a case that works well with the amp, is strong as a tank, and looks nice.

I've compared the AKSA to a good many amps and can't really fault the N+ version in any way. I found it accurate, alive, detailed, but smooth and musical also. I haven't found an amp I'd call significantly better, just found amps that sound different. I've gotten into digital room correction lately and will eventually try the AKSA again with room correction engaged. That should be very interesting and entertaining.

You can choose what level of kit-building you want to do... if you want to do the soldering, you certainly can... but if you're a little worried about it, let Hugh do it! If you don't like case-work, build it in CAD and send it to Par-Metal... or a good machine-shop. Ask them to blast the face plate with walnut shells, sand, or whatever you like..

The connectors are all your choice also...

Anyway, with the AKSA you have a set of known instructions, and you can customize it. With other kits it seems you have options from the start and a lot of uncertainty.... but a different set of choices, and more customizable options...

Choose wisely and enjoy!

Sintz · « **Reply #8 on:** 15 Dec 2005, 05:08 pm »

ctviggen:

Don't worry about the difficulty of this project. This was my 1st DIY and wansn't bad/difficult to complete. I had basic soldering skills and only minimal fabrication experience (pretty much none, to be honest). Although I have and EE degree, I haven't used it in 5+ years, but it didn't matter.

All you need to do for fabrication is choose a case, cut a few slots in it for the heatsinks, drill a few holes to mount the torriods and mount the PCBs. Other than that, it's step-by-step instructions. Take your time, don't rush to get it done and you'll be fine. Of course, if you have any questions along the way we're here to help and Hugh is excellent at diagnosing/troubleshooting any issues along the way.

I've found that by building it myself, I developed a 'bond'

with it as well as a level of 'pride of ownership' I've never had with any CE before.

Hope this helps.

JoshK · « **Reply #9 on:** 15 Dec 2005, 05:12 pm »

I'd recommend the AKSA over the KSA for a first amp project, from what I can gather about the two. You already have Chris's opinion about which is better between the 100N+ and a similar Krell. As a former EE, you will not have a difficult time following instructions, schematics and part selection, but a scratch project can be more difficult than it looks on paper sometimes. Never underestimate the difficulty (and frustration) that layout and grounding can be when you are learning!

I very quickly caught on to reading schematics and figuring out what was going on, but building it requires a whole new set of skills to develop. Doing a couple of well thought out projects with good instructions helps you understand the basics of good layout and grounding.

P.S. if you really get stuck, which you won't, I am not that far away and you can always bring it down and I'll try my best to help you figure it out.

ctviggen · « **Reply #10 on:** 15 Dec 2005, 06:14 pm »

One of the reasons I'd like to try the DIY route is for the satisfaction of building something. And, I'm reading two books on amp design (both of which, by the way, ridicule audiophiles), so I'd like to take a look at schematics and see how things work and what could be "improved" (based on my short experience with repairing my Creek integrated, I already have some options in mind for the power supply design for whatever amp I decide to build). I am leaning toward the AKSA, though, as it would be hard to spec out a complete amp without burning something up.

As for being an EE, that just allows you to get into more trouble! We're less afraid of current/voltage! In enginerding, you learn theory. When I went to work for Honeywell way back when, I had no idea that resistors had wattage ratings. That was never discussed at all in school. I had no idea that "-" on a terminal could mean negative voltage (not ground), but I do now that I burnt up an oscilloscope probe! Being an EE gives me the fundamentals; show me a filter circuit, and I can write down (with some review) the transfer equation for it. But there's a chasm between theory and reality: it's one thing to be able to look at a circuit and tell what it does, but it's entirely different thing to design the circuit. One does not imply the other, and the ability to design is a skill that takes experience.

Anyway, should I go the AKSA route (and can convince my fiancee to let me buy yet another piece of equipment), I would more than welcome any help.

Marbles · « **Reply #11 on:** 15 Dec 2005, 06:19 pm »

Quote from: ctviggen

and can convince my fiancee to let me buy yet another piece of equipment....

Your relationship is getting off on the wrong foot

It is better to ask for forgiveness than permission!!!

ctviggen · « **Reply #12 on:** 15 Dec 2005, 08:44 pm »

Tis true! But she didn't complain when I got the RM40s and actually likes the sound (and didn't complain when I purchased the modified SB2, etc.), so I don't think she'll too hard on be about something like an amp. You see, I'm trying to get all my toys before we have kids -- the money is gone once that starts!

woodsyi · « **Reply #13 on:** 15 Dec 2005, 08:58 pm »

Quote from: ctviggen

Tis true! But she didn't complain when I got the RM40s and actually likes the sound (and didn't complain when I purchased the modified SB2, etc.), so I don't think she'll too hard on be about something like an amp. You see, I'm trying to get all my toys before we have kids -- the money is gone once that starts!

Bob,
More than the money it's time that you won't have. Get all your DIY project done BEFORE you have kids. Or wait 18 years like I may be doing with the UCD 400 kit just sitting around......

AKSA · « **Reply #14 on:** 15 Dec 2005, 11:39 pm »

Bob,

It's the journey as well as the destination. You learn so much, and if you have the audio tinkering bug, the dreaded ATB, then it's a huge buzz.

There is a lot of pleasure in the ownership of the construction, too. There are countless thousands of hours of development in something like the N+, so you can be assured that when you've finished it the sound will be up there with the best in the commercial marketplace. The differentiator is the knowledge you built it yourself; you can take great pride in doing this properly because you know from a wide sweep of opinions out there that the product is good.

I've come under a lot of criticism lately for 'stone age topologies and old, tired ideas' but in all honesty the crux of the AKSA is technological convergence, and I've simply taken a tried and true approach and refined it to very high levels along musical lines which by and large has been rare across the decades.

And yes, once you have children, you have no time........ Do it now!

Cheers,

Hugh

ctviggen · « **Reply #15 on:** 16 Dec 2005, 12:16 am »

Hugh and Woodsyi, I've seen the light about kids, which is why I'm attempting to get my house situated and some DIY stuff done before then. I realize that once kids come, all the time goes at least until they're a certain age. One problem I'm having is that my house projects are taking up too much time. However, now that it's cold outside, those have mellowed off. I still have one or two projects to complete while it's cold, but I think I could work in some "fun" soldering projects in the interim! I do think that I've started down a dangerous road -- go DIY and I may never come back! I think I will be ordering an Aksa, then. It's just up to me to decide when, which will probably after the holidays and the presents! While I think the Krell KSA 50 would be an interesting project, it's also going to be a lot more work than I would like at this time.

Thanks for the input!