I've read Rod's articles. Remember, I'm an old guy, too. 
In any case, as I've told you about a million times, there's lots of different ways to to controlled subjective evaluation. ABX is just one. If you're allergic to that format (or Charles is), there are quite a few others. See my upcoming article in Linear Audio Vol 2 for a brief survey- I'm sure Jan will send you a copy when it's out.
The one and only non-negotiable point is that it's done by ear alone. Everything else is flexible.
In any case, as I've told you about a million times, there's lots of different ways to to controlled subjective evaluation. ABX is just one. If you're allergic to that format (or Charles is), there are quite a few others. See my upcoming article in Linear Audio Vol 2 for a brief survey- I'm sure Jan will send you a copy when it's out.
The one and only non-negotiable point is that it's done by ear alone. Everything else is flexible.
Charles,
Thanks for the detailed answer. First forgive me if I mis-read or am mistaken about you and the capacitor size... but that is keeping with the style of this thread
Please don't confuse my measurements intent. It usually starts because I hear something and want to identify it. Then it is easier to check similar issues.
The meaning people derived from the resistor tests I found most interesting. The most common improvement offered was to use three control resistors and only one test specimen, ignoring the ability to do the test without a standard. The second as you mention is that temperature coefficient was the only item measured. Someone actually suggested using a filter to remove the test frequency. What I have noted is that the third harmonic which does change with frequency is most tied to the thermal properties. However the base spreading of the test signal was due to self noise. Even more interesting were the 2nd and 4th harmonic distortion on some resistors that many prefer for audio use. I have seen at least one noteworthy amplifier that uses such a resistor near full power as the feedback resistor.
As to smaller resistors sound better, I am curious as to if that is anywhere near full power ratting or well below it.
I don't think my article has come out yet where I show how the "DC" offset in an AC line exists and slowly shifts the operating point of a transformer.
Along the same lines is the low frequency modulation of the AC line voltage which I know John has addressed and I assume you also.
On the non-ferrous filter, I don't know if you have seen my "Macrame" (Named by SY) filter. I am planning on an article showing how to implement this into an AC line cord. That article will also include other details such as transformer phasing for minimum leakage current, DC offset protection, and a few other "Tweak" issues that seem subtle but are easily measured and some can even hear them.
A side note on what can be heard. When we do listening tests, one of the fellows (Who has moved on) often would not hear the issue. He would then take over the testing and was often surprised when others including my secretary (A Navy vet with no real interest!) could pick out the issue.
Have a fun day.
ES
Charles,
The problem I have is when you or John issue statements based upon what you hear.
For example:
Both John and you mention using Resista resistors which measured the best of any very low cost carbon film resistors I tested. But of course the difference between the best and worst is at levels some seem to think doesn't matter.
You recommended larger cans for the same value of capacitor to sound better, it turns out they have much better vibration and leakage characteristics.
You mention using power line filters slowly changes the nature of power amplifiers sound. I record that inductors and transformers on normal AC lines do very slowly change.
John uses "flatpak" transformers, they have the lowest RF passing of any I have tried.
John does a number of extraordinary steps in the Blowtorch power supply, all of which have measurable results although at a very low level.
Now someone comes along and lets me know that the 5534 op amp is just as good as others. I didn't like the sound of it in many applications, Sam Groner using Walt Jung's techniques finds it not as good as many and You and John suggest not using it.
So the great question is will you and John continue to give us this obviously opinionated advice? And do you do all this by ear?
ES
We've been here before, coincidental connections between some measurements and anecdotal listening tests done out of your control. In any case the higher power resistors would measure better in your tests and Charles claims they don't sound better.
And guys, I don't need you and a 100% of a room full of your buddies telling the difference in "seconds". We could do this stuff without the exaggerations. I still can't hear the difference with my cables on wood supports.
John,
I have to side with SY on this. He did his best measurements on what he believed the device would do. There may be valid issues with some tests he did not run and If I ever get the inclination I may try them. But there was no dishonesty involved.
As to Parasound, SY would not be the appropriate reviewer for these products. Niche products are designed for a niche and should be reviewed by a member of the niche group.
The goal is to have fun. Ego contests are a waste of time, mine is the biggest! That is why the basic unit of measurement of Ego is the millisimon! None are larger!
ES
Richard Feynman is (was) one of the most honest scientists, with the most integrity that I know of. His Cargo Cult concept is a very powerfull argument for the scientific method.
I read a letter he wrote to his daughter on the occasion of her 10th birthday. He thought it important to instill in her, at that age, honesty and integrity, self-criticism and really doing your own thinking.
He told his daughter three reasons NOT to believe something: authority, religion, tradition. The three reasons why progress in any field is stagnated.
A great man!
jan didden
Why bother, the implication is that it works "dramatically" with any amplifier. Don't change the subject.
Most production houses use CNC, laser, or water jet cutting these days. Have they hit up Norm yet?
You are kidding though, this thing triggers and it's 100% down, few businesses would tolerate this. I have yet to see one.
That is why you have a backup cartridge to install if it triggers and also a backup saw blade. Wouldn't be down maybe 10 minutes max and no surgery, rehab, lost man power and workman's comp issues
Still a serious need for table saws last I looked at the woodworking industry, but hey I just work in this industry. SawStop are the the defacto these days unless you are talking sliding table saws then the Europeans (Martin and Altendorf) are still the Mercedes of that class of table saws for production shops.
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Nice sentiments but LG and Samsung in particular make this a fantacy senario. The BOM on a $39 DVD has no room for it. You probably would not be able to show a single high volume socket in an asian consumer product that uses any one of those National amps. Analog video decoders???? you must be mistaken, we have never had a high runner in mainstream DVD business. Those were for computer video out, originally developed for Apple. Digital delivery of video was inevitable, but maybe you can explain why the YPrPb on my TIVO looks better (or at least as good as) the HDMI.
EDIT- BTW the AD712 probably remains high in the audio sales list. The "op-amps for audio" babble on many data sheets is just that, I think half of it is from all the engineers that envision themselves as the ultimate DIY'er.
I can confirm the BOM cost thing first hand. The engineers are driven to extract every penny out of the cost, and even a penny will make them do it. For reference, an entire TV SMPS (LIPS so it also includes a CFL backlight drver) for a 42 inch system costs <$10. Don't ask me how they do it, but certainly the semi industry get screwed along the way in my view. OT I know, but that's the nature of business today. High end is a niche activity, whether we like it or not.
That is why you have a backup cartridge to install if it triggers and also a backup saw blade. Wouldn't be down maybe 10 minutes max and no surgery, rehab, lost man power and workman's comp issues
Still a serious need for table saws last I looked at the woodworking industry, but hey I just work in this industry. SawStop are the the defacto these days unless you are talking sliding table saws then the Europeans (Martin and Altendorf) are still the Mercedes of that class of table saws for production shops.
Probably 90% of the table sawing is on site with those little portable units. It's nice, I just don't see them. Stick your arm in a portable planer, a French shaper, band saw, or any number of other tools. No accounting for idiots.
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Hi,
I seem to have missed most of the posts that explicitly advocate VAS loading as methode of broadbanding. It seems a little counter intuitive to do so in a feedback amplifier.
It is of course absolutely necessary to load the amplification stages resistively in zero feedback circuits (Charles Hansen's designs are good examples).
The biggest issue in our amplifiers remains the output stage. In preamplifiers we can use a heavily biased class A stage, even single-ended.
It is amusing just how much better many a so-called "Audio" Op-Amp does (measured and subjective) if we add a pulldown (or pullup - depends on the IC) CCS to the output and then a simple Mosfet (IRF710 is okay for preamps) and a LM317 current sink.
With a 5534 we can use a pullup CCS on pin5 and use that pin to drive our mosfet, with 20V and 50mA Bias we have a very good drive stage for anything that is not a headphone (say +20dBU into 600 Ohm) and get away with small heatsinks, so our BOM costs do not up in a ridiculous fashion.
Will such an external output stage make things better? Subjectively, quite a lot... But objectively, as we are always told the NE5543 is already perfect...
Samuel Groner, if you are reading, here is an opportunity to add a few more pages to your tome... Also try this on the OPA604 BTW...
Ciao T
Sure, but you possibly missed all those posts here that said that whatever you do to get wide ol bw, INCLUDING resistive loading of the Vas, is the best thing since sliced bread. Marcel's letter was triggered by that. We know YOU know better
I seem to have missed most of the posts that explicitly advocate VAS loading as methode of broadbanding. It seems a little counter intuitive to do so in a feedback amplifier.
It is of course absolutely necessary to load the amplification stages resistively in zero feedback circuits (Charles Hansen's designs are good examples).
The biggest issue in our amplifiers remains the output stage. In preamplifiers we can use a heavily biased class A stage, even single-ended.
It is amusing just how much better many a so-called "Audio" Op-Amp does (measured and subjective) if we add a pulldown (or pullup - depends on the IC) CCS to the output and then a simple Mosfet (IRF710 is okay for preamps) and a LM317 current sink.
With a 5534 we can use a pullup CCS on pin5 and use that pin to drive our mosfet, with 20V and 50mA Bias we have a very good drive stage for anything that is not a headphone (say +20dBU into 600 Ohm) and get away with small heatsinks, so our BOM costs do not up in a ridiculous fashion.
Will such an external output stage make things better? Subjectively, quite a lot... But objectively, as we are always told the NE5543 is already perfect...
Samuel Groner, if you are reading, here is an opportunity to add a few more pages to your tome...
Also try this on the OPA604 BTW...Ciao T
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