Double down, good or bad?

We are not here to argue, we are here to learn from each other's knowledge.

Magfan, glad to see another fab guy. I am a yield guy because of my EE/device physic background, but know process well enough to do my job. As we shrank from 0.5um, we added LDD, halo, and now HKMG to deal with leakage. On top, both N & P stress are going wild and we have far exceeded Moore's law prediction in transistor drive current from linear scaling! All thanks to brilliant minds that work endlessly to produce faster and smaller chips :)

I think amplifier & speaker interaction is still an area that's not well understood when coupled with psycho-acoustic, human do not hear like machine for sure. If there is a perfect amp, Nelson Pass would not have changed and optimized his design constantly. Didn't he think X series amp was perfect when it was introduced several years back, why the X.5 update?

Ralph, As much as I respect your opinions, I don't agree with the suggestion that amps that measure well don't sound good, and amps that sound good don't measure well. While I'm not suggesting that we have all the neccesary measurements to guarantee terrific sounding amps yet, I do suggest that we currently have the neccesary measurements measurements to guarantee that we don't make terrible sounding amps. Obviously the same token that keeps tube amps a marketable comodity, does the same thing for solid state amps.

Semi, I worked in a FAB for 30+ yrs. Yep, moore's law SEEMS to apply. Any new technology will make such rapid progress at the beginning. I've worked from submicron to power devices, many places in between, started with evaporation and saw the start of semiconductor sputtering. Etch from all wet to dry. You name it.
As I'm sure you well know, there are theoretical limits to speed, density and even memory limits. What do you do after you have junctions a few angrstroms thick with linewidths to match? How do you implant that and not either overdrive and still have l effective?
Certainly there will be opportunities in the future. nano devices, and even superconductors may play a part, but once the 'low hanging fruit' is gone, the pace of density increase must slow, if not reach saturation.

To help you close your 'amp/speaker impedance interaction' problem, please look up Power Factor on google. The Wiki article will explain much.
\
Also, since you are a semiconductor process (I hope) guy, you should be able to adapt over to the Smith Chart.


http://www.hometheaterhifi.com/component/content/article/228.html

Swanny definitely has too much faith in 1 person. I work in leading edge semiconductor industry and over 10 years ago people thought we could not follow Moore's law any more, guess what? If we stop researching and understanding the technology, we will not progress. Still think it's nuff said?

I am curious about amp/speaker impedance interaction, I have owned numerous speakers and amps in my life, in fact I also owned several Pass amps. Nothing is perfect and there is not one amp or speaker that is superior than others, it's always a compromise game. But learning where to compromise is the fun part of this game.

I'll take it a step further- there aren't **any** tube amps that double power, yet the tubes vs transistors debate has been here for 40 years... what does that tell you? The tubes failed to be the 'obsolete' technology that they were supposed to be- people keep listening to them.

The simple answer is that they must be doing something right!

The ability to double power as impedance is halved has been entirely a solid state thing. The idea behind it is that the amp is considered 'load impervious' if it can make constant voltage output into all loads, IOW double power as impedance is halved (conversely halve the power as impedance is doubled), so you can get flat frequency response from a speaker that has a box resonance. But what if the impedance curve of your speaker isn't based on a box resonance, like an ESL, magnetic planar or horn system? The model starts to fall apart.

So here's where that leads:

http://www.atma-sphere.com/papers/paradigm_paper2.htm

Its not really a tube vs transistor thing after all- its a bit bigger than that, just as it is not about objectivist vs subjectivist, and we are talking about equipment matching too. Its all those things, but also about the fact that the industry has a dilemma: make it look good on paper to make lots of dollars, or make it to sound good to the ear to make lots of good sound?

Its my contention that this has been going on a long time and the industry does not like to talk about it (doing so reveals the purely monetary angle), resulting in a ton of confusion (and often bad sound) in the audio community.

Read Nelson Pass's discussions-see passlabs.com. Nuff said.

I always thought that doubling down was the sign of a technically correct amp that could handle the "WICKED LOADS" (without oscillating or otherwise becoming unstable) rather than a requirement.
I would never go so far to say it should be avoided. Ralph knows a lot about amps. By his own admission he pushes the technical envelope and is quite a design radical. His amps don't double down. I am sure he has had to explain that to a lot of potential cutomers.