
The Emperor's New Amplifier (2003) - nkoren
http://www.normankoren.com/Audio/TENA.html
======
JonnieCache
The problem with having an amazingly transparent signal chain (although I
doubt that valves are the way to achieve this but he seems to know what he's
talking about,) is that it pushes all the responsibility onto you the
listener, to choose program material that is well engineered and artistically
resonant enough to justify all that outlay. It's like having special eye
surgery to visit galleries. It doesn't quite add up.

Consider that the gear Miles Davis made all his music through sounded
completely fucked by this guy's standards. For some reason, harmonic
distortion produced before the 80s is art, and harmonic distortion produced
after the 80s is an affront. Its like some kind of analog/digital existential
nostalgia. I blame postmodernism.

The more transparent the amplifier, the better the music has to be, or you
really are wasting your time. If you just want to build high performance
electronic equipment, there are much more interesting areas to work in than
simply applying gain to a pair of AC signals while preserving their phase
relationship.

But yeah, each to his own I guess. I expect these questions are half the fun
if you're into designing your own amplifiers.

~~~
pjc50
The thing is, audiophilia was somewhat justified in the 60s when gear that
_wasn 't_ "high-fidelity" was of objectively lower quality, and also much more
variable between manufacturers and even individual units. When taking your
valves to the the tube tester at Radio Shack was a viable business model.

This built an entire sociology of competitive audio listening, like a much
nerdier version of the car performance tinkering of the same time. People got
very emotionally invested in this kind of quality one-upsmanship.

In the 80s MOSFET amps became viable, cheap and widespread. The baseline
quality was now so much better that non-experts stopped caring much - you
could buy anything in the hifi shop and get reasonable results. But the
culture lives on, lost in the jungle, worshipping at a shrine that almost all
the population has abandoned.

TVs and computer graphics are approaching this tipping point from "more money
buys you noticeably more quality" to "actually I can't see the difference from
the cheap baseline and neither can the people I want to show off to". Notice
how 4k hasn't taken off dramatically.

~~~
AlexandrB
It's funny that you mention TV and computer graphics, because TV and computer
sound has not been a case of "buy anything in the hifi shop and get reasonable
results". When using the audio chain built into modern motherboards I
consistently hear noise from some bus or another polluting the actual audio
output. Poorly-designed, poorly-shielded amps still happen and unlike modern
video output it's not a digital signal that has error correction built in.

~~~
pjc50
Very true. PCs ship with lowest-common-denominator powered speakers and noisy
headphone outs. The average customer and even the gaming customer doesn't seem
to care much. People who do get USB output devices or send SPDIF to their
existing surround system. Maybe Macbooks are less bad at this?

~~~
JonnieCache
Macbooks are indeed great at this. They can output 24 bit 48khz IIRC. And I'm
pretty sure there's even DSP in there to model the resonances of the case and
cancel them out when using the speakers.

And BTW gaming motherboards now commonly have audio interfaces with isolated
power rails and stuff.

~~~
yasth
Almost anything can output that now (or actually much higher) because of
Intel's High Definition Audio (AKA Azalia)

[https://en.wikipedia.org/wiki/Intel_High_Definition_Audio](https://en.wikipedia.org/wiki/Intel_High_Definition_Audio)

The real benefits of a macbook is the 192 kHz (on recent models) tosLink
optical out integrated into the headphone jack, which is just an awesome
feature that I really wish other laptop manufacturers would pick up.

DSPs for resonances/tuning has however been picked up pretty widely (under a
wide variety of brandings/quality)

------
pjc50
This is basically the pinnacle of 1960s audio design. You can tell the author
was trained in this era and knows his stuff by his reference to Bob Pease. On
the other hand, he seems to regard MOSFET power supply regulation with
suspicion.

People in other comments have asked how modern class D amps perform. There are
people doing a similar kind of thing with aggressively purist design
craftsmanship, e.g.
[http://www.hypex.nl/technology/ucd.html](http://www.hypex.nl/technology/ucd.html)
\- producing a similar nice flat Bode plot. The _really_ cheap ones may be
suspect and spew EMI everywhere, but if you're not quite so concerned with
shaving pennies off the price they're perfectly acceptable.

~~~
VLM
Maybe I can help translate the author's EE work into "HN speak" in that what
the author did with this amp design is similar to how programmers do "turing
tarpit" language challenges.

The game rules are usually picked based on how much the player wants to put up
with. His spec for low freq 3dB down is weirdly low to me because I don't own
drivers that run that low (LOL) although the spec for 1dB down is probably
more "audiophile relevant". I suppose as a design goal if a recording has a 5
hz signal I'd want it to be properly amplified for the speakers to turn into
heat instead of sound, rather than clipping and making noisy harmonics every 5
or 10 hz up the band, so there is that justification, but, why not input
filter instead of just making heat in the speaker crossover?

In this story, the game rules were use as little post-1970 components as
possible while maxing out various specs to beyond human hearing. A good
analogy for programmers would be writing a quicksort in BF or intercal. You
don't do that because you need production code, you do that on a dare or to
see if its possible or for the sheer heck of it.

Personally if I needed 50 or so watts I'd use a TI TPA3116 and call it good.
There's kits available on ebay and elsewhere, its a stereotypical more than a
couple watts less than a hundred watts modern class D amp. Simple design one
chip no need for heatsink at lower power out. Does need 24V power and a
heatsink for full power out. The chip costs about a buck. But that breaks the
rules of the game because those didn't ship till maybe two or three years ago,
not 1965.

~~~
mark-r
I think you don't understand the project at all. The point wasn't to play some
game by doing something retro, the point was to create an amp that sounds as
good as reasonably possible. There are many people who believe that tubes are
the best way to do this. I can't say they're wrong; the most realistic sound
I've ever heard came from a tube amp in a shop.

~~~
apalmer
I wonder how literal the parent was being. He seems to be walking the line. I
think from the parents point of view he 'gets' what the original post was
going after. Its just more... busting out the oscilloscope graphs to prove
transparency at sub human audible levels while at the same time picking
components because you can 'hear' the difference is a contradiction. Basic
fundamental point is from a pure amplification of signal without distortion
standpoint there are components that can get you there for a lot less effort
today.

------
bjornsteffanson
This is absolutely fantastic, and thoroughly technical -- particularly the
SPICE simulations. After becoming equally engrossed in designing a "perfect"
microphone capsule, I'm tempted to build one myself.

This was written 12 years ago -- I wonder how the author feels now.
Specifically I'm curious if the author is still contented with the equipment.
Also, apropos of nothing save for sheer curiosity, I'm interested to know what
input media (i.e., specific recordings and formats) and output equipment the
author used (or uses) for both testing and pleasure.

~~~
ableal
Looking at the submitter's id, I'd guess he's still happy.

~~~
nkoren
I'm actually the author's son, but I can confirm that yes, he's still happy
with it. Remarkably, it seems to have resulted in a permanent remission of
what had previously seemed like terminal audiophilia (remodelling the house to
properly dampen its resonance, that kind of thing). He has since channelled
his obsessive tendencies into digital imaging, which is an altogether more
profitable endeavour.

~~~
eitally
Are you Henry, or is Henry Koren your brother? I knew an hkoren way back in
the olden days on the vwvortex forums....

~~~
nkoren
I'm Nathan. Henry is my brother.

------
justinsb
> _I thought about commercializing it, especially when the lab where I worked
> announced it was shutting down, but I soon realized that marketing high-end
> tube amplifiers is not a reliable way to make a living. (I 'm paycheck-
> addicted.) _

It is wonderful that Kickstarter has removed much of the risk for people like
this, that are obviously incredibly talented and have produced something
great, but don't necessarily have the desire/risk-appetite to make it
commercially without a proven market.

------
alricb
Speakers still add orders of magnitude more distortion than your amps, much
like they did in the 1960s, unless you're using something insane like a servo-
controlled Meyer X-10 (with an integrated amp, natch).

~~~
gmarx
Also, more important than amp transparency (which is pretty easy these days)
is how the amplifier reacts to the difficult loads many high end speakers
present

~~~
alricb
For decent, modern amps, not really, as long as you're not getting something
like the interaction between the output filter of a class D amp and the
loudspeaker (as happened with some Crown class D amplifiers and some EAW
speakers)

------
nakedrobot2
Here is another "make your own incredible tube amplifier" from a Dutch
gentleman. I'd be interested to hear from someone who understands this stuff,
how it compares.
[http://www.mennovanderveen.nl/eng/index.html](http://www.mennovanderveen.nl/eng/index.html)

Also, I'd like to hear for myself how they both compare to the $20 solid state
amps.
[http://www.amazon.com/exec/obidos/ASIN/B0049P6OTI/downandout...](http://www.amazon.com/exec/obidos/ASIN/B0049P6OTI/downandoutint-20)

~~~
VLM
As a piece of performance art, they are polar opposites.

One is a craftsmanship project hand built according to some peculiar rules
(pre 1970s tech when possible, etc) and methodically designed to optimize
performance and then tested to verify that performance.

The $30 amazon mass produced amp ships with a 1.5 amp power supply that was
restickered to 2 amps (hope your fire insurance is paid up) and can't provide
marketed power with the supply as provided anyway depending on speaker
impedance connected and no one has any detailed performance stats so who knows
how well it compares in all the parameters that matter. Also it runs about
1/10th the power of the tube amp. Finally it is a class D amp but the chip
mfgr went all closed source on making a "special" D that got patented as "T",
the "T" designator is merely marketing. Its a relatively early class D amp, I
would assume modern class D amps would outperform it.

Note that both amps are antique in their own way, one is a "70s amp" and the
other is a "turn of the century amp".

As a piece of art, one is roughly a highly talented semi-pro artist classic
inspired painting, and the other is a walmart poster copy of a "Dale Earnhardt
on black velvet" memorial mass produced kitsch, should be pretty obvious which
is which.

------
akottas
First time I visited Koren's website and read about his "perfect amp" was
about 10 years ago (around 2006 - when I was designing and building my
"perfect amp"). So this article definitely brings me back to simpler times.

I always found this design waaaay too complex. Some sections seem unnecessary
while others don't make sense (but that's just me - and it doesn't help that
the schematic is drawn a little convoluted). But I suppose it totally depends
on his amp's application (e.g. playing records, studio monitors, live guitar,
bass amp, etc), so it really may be the perfect amp ...for his specific
application.

My thoughts... the power supply is a little too "verbose" for a tube amp --
just unnecessarily complex, and may actually remove some of the imperfections
associated with that crispy "classic tube amp" sound. But I am a strong
advocate of a well-designed power supply, so I can't say anything bad about
it. But there's too much going on between phase-inverter and power amp stages
(output drivers I presume). I would never do that, but to each their own.
However, I do like that he used 6550s. Great tubes!

------
amelius
I am wondering why high-end amplifiers are still so expensive. Amplification
should be a solved problem by now.

Also, what I miss most in the whole sound chain is that I can't change the
volume of the tracks that existed before they were mixed into a single track.
For example, making the volume of that trumpet in the background a little
louder, etc.

~~~
ptaipale
> _I am wondering why high-end amplifiers are still so expensive._

I think it's a bit like why Gucci handbags are still so expensive. Because
they are high end; there are people who are willing to spend that much, even
if what I would call an engineer's assessment "do I get a reasonable bang for
buck ratio" clearly answers NO. People by an experience, they buy a feeling.
And it may be money well spent for them.

------
ape4
Norman, the copyright symbol is broken at the bottom on your photo pages pages
[http://www.normankoren.com/index.html](http://www.normankoren.com/index.html)
Suggest you use &copy;

~~~
mark-r
Lots of stuff broken on other pages as well. The problem is that the meta tag
identifies charset=ISO-8859-1, when it really should be Windows-1252.

------
spiritplumber
[http://arstechnica.com/staff/2015/02/to-the-audiophile-
this-...](http://arstechnica.com/staff/2015/02/to-the-audiophile-
this-10000-ethernet-cable-apparently-makes-sense/) Don't forget that these
things exist because at least some people buy them.

