Building the ultimate DIY power amp

[AKSA]

K-amps has shown contrition and the thread goes on.

I must say that a brand is very significant. We can thank NP for raising a DIY amp to cult status, and removing any semblance of apology for what it is in the marketplace. A Pass AlephX stands proudly beside a Krell, and this paves the way for the talented DIYer to make something which ranks alongside any of the worlds best.

This is DIY; not consumer hifi, or 'social cachet' high end. We are not so susceptible to the snobbery of owning a high end amp; we are smugly aware that the AlephX probably sounds better.

I suspect we shouldn't even be thinking of Ferrari's or Rolexes. These things are marketing triumphs, certainly, but this does not mean they are best of breed.

Cheers,

Hugh

[dkemppai]

It's rather interesting that the consensus of many is that it is near impossible to beat a 'big name' company, in terms of sound quality. More than interesting, I find it insulting that people assume that what can be done by an 'amateur' will be inferior to what can be done by a 'professional'.

It's not the quality of the tools, or the quality of the lab. It's the quality of the engineer.


LRRockbox,

On a lighter note, I don't think there is a "best amp" There never will be. There can't be. Sound quality is subjective.

The advantage of DIY, is that you can explore amplifier topologies, and parts selections. If offers you the ability to choose and build an amplifier talored to your own taste. You can test the things you couldn't afford, or even find. My advice is try to build a few, and see what you like. Once you find something that you like, improve on it.

I've been designing the 'perfect' amplifier for over a decade. In all that time, I've never listened to a perfect design. However, I do know what I like and know how to build it to my taste. And to me, that's what counts.

-Dan

[Tony]

I've been designing the 'perfect' amplifier for over a decade. In all that time, I've never listened to a perfect design. However, I do know what I like and know how to build it to my taste. And to me, that's what counts.

indeed, this is the way to go!!! me too is looking forward to building my dream giant leach amp that can do 1000watt at 2ohms ..it has taken me over ten years now hampered by lack of funds, but i have quite a stash of parts and maybe in three years i can do it!!!

[K-amps]

Originally posted by dkemppai

On a lighter note, I don't think there is a "best amp" There never will be. There can't be. Sound quality is subjective.

-Dan

Roger that Dan,

The physical being of the amplifier is mechanical in nature like a car, Therein, quality construction (among other things) matters,
The sonic signature of the amp however is the art... Art is subjective hence we will be debating this ad infinium.

On that note, there are People like Nelson and Dan D'agostino (to name but a few) who have successfully married the art AND science of this baby we all love, the power-Amp!

Can you paint better than Picasso... sure you can, will you be as successful? Probably not.



K-

[fab]

Originally posted by tcpip
Great list. How did you make a home-made THD meter? In fact, how does one make a super-low-distortion sine wave generator with a wide freq range? I'd be keen to know any pointers or details you can give me.
D

My home-made THD meter was a design project of mine at school. The distortion resolution of the wave generator and THD meter is not super low, but is 0.005% at 1KHz. It is not built to have the frequency adjusted, but only 2 frequencies: 100 Hz and 1K Hz. For me, I find it sufficient. The THD meter can use 10KHz but my actual generator can not. I may try to have my generator re-designed in the future. I know I have seen very performant THD meter on the internet but I can not remember where.

Fab

[andy_c]

Interesting that Krell keeps coming up as an example of "best". I've had a Krell KSA-100 and PAM-5 since 1984. The power amp arrived with a nasty case of buzzing relays. Around that time, I read a review of Apogee speakers in HFN & RR in which they said that they originally tried them with a Krell amp, but had to return the amp because of buzzing relays. I guess it was a chronic problem with them in those days and they just shipped them anyway. You'd have to be deaf not to hear it. A couple of years later, the amp's power switch (really a breaker) went bad and they sent me a new one. One channel of the phono preamp in the PAM-5 went south too. So I'm not too impressed with them. To top it off, the schematic of this amp was posted in this forum, and I was amazed at how primitive it was. No emitter degeneration in the input diff amp (AC-wise) for example.

My view is that many of the high-end companies are in the business of selling a mystique, an image, just like manufacturers of clothing, expensive watches and so on. It's as if the amplifiers were designed by the audio equivalent of the Keebler elves, mystical creatures with near divine insight into the sonic behavior of audio equipment. Or so they would have you believe. I suspect that a guy like Scott Wurcer knows a lot more about low-distortion design than most high-end audio designers, but that's just my opinion. And figuring out what "sounds best" is highly subjective and depends on the individual anyway.

[macka]

Hugh,

I read with delight your posts and have the greatest respect for you and fond memories of the early days.

Do you remember the Glen Bladderly demonstration at the MAC Gen Meeting and then the infamous comment by Ron just after your demonstration at the Whitehorse town hall?

It takes all kinds in a village doesn't it.

However I can draw a few similarities between your journey and that of Nelson Pass. He is one of the more interesting people I met while travelling the USA and a gentleman like yourself.

I did hear some Pass Diy amps while I was there and tend to subscribe that subjectively amplifers are like wine, its a matter of taste, particularly when you start playing complementry speakers.

What is even more remarkable is that a simple system based on amplifer like the Zen and a basic 2 way diy speaker can beat the pants of mega dollar systems like I heard at the NY Stereophile Show when it comes down to listener enjoyment.

And thats a fact.

Your friend

Ian

[K-amps]

Originally posted by andy_c
Interesting that Krell keeps coming up as an example of "best". I've had a Krell KSA-100 and PAM-5 since 1984. The power amp arrived with a nasty case of buzzing relays. Around that time, I read a review of Apogee speakers in HFN & RR in which they said that they originally tried them with a Krell amp, but had to return the amp because of buzzing relays. I guess it was a chronic problem with them in those days and they just shipped them anyway. You'd have to be deaf not to hear it. A couple of years later, the amp's power switch (really a breaker) went bad and they sent me a new one. One channel of the phono preamp in the PAM-5 went south too. So I'm not too impressed with them. To top it off, the schematic of this amp was posted in this forum, and I was amazed at how primitive it was. No emitter degeneration in the input diff amp (AC-wise) for example.

My view is that many of the high-end companies are in the business of selling a mystique, an image, just like manufacturers of clothing, expensive watches and so on. It's as if the amplifiers were designed by the audio equivalent of the Keebler elves, mystical creatures with near divine insight into the sonic behavior of audio equipment. Or so they would have you believe. I suspect that a guy like Scott Wurcer knows a lot more about low-distortion design than most high-end audio designers, but that's just my opinion. And figuring out what "sounds best" is highly subjective and depends on the individual anyway.

Andy,

I have a KSA-250 and guess what, the relays buzz, lol. I also have a KSA-100 MK.II but that runs very quiet even with the fans running.

Krell has become somewhat of a reference point. I guess some things stick to mind, like the ability of Krells to drive the Scintillas and the ML's to Arc weld. ( not suggesting you use the amp for welding, but just takes things to a different level... clever marketing I guess.) Stereophile and others also help with the mystique aspect. There is still something about these amps that makes people compare them to others.

regards,

K-

[peranders]

Originally posted by andy_c
Interesting that Krell keeps coming up as an example of "best". I've had a Krell KSA-100 and PAM-5 since 1984. The power amp arrived with a nasty case of buzzing relays.

Why did they buzz? Were they driven on unsmoothed DC?

[LRRockBox]

In my original quwestion indeed I have taken Krell and ML as 'reference' . To me, this does not imply they are 'the best'. They are merely that to which other designs are compared.
Others can be bigger, badder noisier, louder, whatever you like. The reference is just a measuring stick. Frequently, you have to measure something that is several times the length of the stick. As often, it will be shorter. Very seldom you will have to measure somethin equal to the sticks length. It doesn't make the stick useless. Merely a reference.
As I'm starting out in amp diy, it's jyst not on to build 10 designs and figure out where I can improve what depending on my listening mood of th day.
I have just selected a few designs who's sound I generally like, and now I will try and build something that is akin to this reference, and then dicide where I want to go from there.