I have some idea, but I can't prove it to you. I could give you a reference, but I doubt that you would follow up on it.
john curl said:
But then, some have and deem other things to be more important. And they understand the subtlties and that yes, there is a an effect, but ... I'll leave it at that.
It was just a comment on Vishay taking the obvious next step because they perceive a marketing oppotunity at what no doubt is a price that will be worth their while. If you want to pay $20. a resistor and you have people that want this attention to detail have at it.
It didn't warrant an insult.
I would like to give a short history of resistor selection over the decades.
First, there were carbon resistors. These were the essence of almost all TV's, radios, even hi fi's from the '30's through the 60's. There were different grades, but the range was 20%, 10% and even 5%. It was not just poor selection that created these tolerances, BUT TEMPCO, because the resistor could easily drift out of range as it heated up. Also there was an added noise called EXCESS NOISE that was dependent on the voltage across the resistor. For special applications, such as precision attenuators, there were 1% metal film resistors that cost about 20 times more, each. As I recall, Ampex paid about $1.00 each ($5 in today's money). We only used them sparingly.
The first person who I found to use 1% metal film resistors exclusively was Mark Levinson, in the early '70's. Later, it became very easy to get 1% film resistors, and 'everybody' in hi end audio tends to use them exclusively. I can buy the highest quality (subjectively) for 5-10 cents in quantities of 100 or so. However, most mid fi designers use resistors that cost 5-10 times less than I pay. I can't predict the subjective result.
Of course, there are many beautifully made resistors that are used in aerospace. These can have glass cases, .01% precision, YET actually appear to sound lousy for audio circuits. SY, if you want to try a few, be my guest. In 1980 I made a preamp using these quality resistors. It now resides in my closet. Resistors? I'm pretty sure, since I was using Levinson modules of my own design for the active electronics and a P&G studio fader for the volume control. I used these other components in other designs with great success.
Now WHY? Well the super quality resistors have heavy gold plated Kevlar leads, and are magnetic. Maybe this is why. Sometimes you just have to try and see. If it doesn't work for you, then OK, don't use it.
First, there were carbon resistors. These were the essence of almost all TV's, radios, even hi fi's from the '30's through the 60's. There were different grades, but the range was 20%, 10% and even 5%. It was not just poor selection that created these tolerances, BUT TEMPCO, because the resistor could easily drift out of range as it heated up. Also there was an added noise called EXCESS NOISE that was dependent on the voltage across the resistor. For special applications, such as precision attenuators, there were 1% metal film resistors that cost about 20 times more, each. As I recall, Ampex paid about $1.00 each ($5 in today's money). We only used them sparingly.
The first person who I found to use 1% metal film resistors exclusively was Mark Levinson, in the early '70's. Later, it became very easy to get 1% film resistors, and 'everybody' in hi end audio tends to use them exclusively. I can buy the highest quality (subjectively) for 5-10 cents in quantities of 100 or so. However, most mid fi designers use resistors that cost 5-10 times less than I pay. I can't predict the subjective result.
Of course, there are many beautifully made resistors that are used in aerospace. These can have glass cases, .01% precision, YET actually appear to sound lousy for audio circuits. SY, if you want to try a few, be my guest. In 1980 I made a preamp using these quality resistors. It now resides in my closet. Resistors? I'm pretty sure, since I was using Levinson modules of my own design for the active electronics and a P&G studio fader for the volume control. I used these other components in other designs with great success.
Now WHY? Well the super quality resistors have heavy gold plated Kevlar leads, and are magnetic. Maybe this is why. Sometimes you just have to try and see. If it doesn't work for you, then OK, don't use it.
What's the spec for voltage coefficient of resistance? That's where a lot of the fancy stuff falls down.
>A parting thought experiment,
>why does burn in ALWAYS improve things?
Because your ears are what gets 'burned in'
and your expectations are positive .....
>why does burn in ALWAYS improve things?
Because your ears are what gets 'burned in'
and your expectations are positive .....
MikeBettinger said:
Nothing against the JC-2, but Valin is *not* a tough critic to impress. He is actually probably the most crooked reviewer in the business (at least in this country). Last year he was caught selling $20,000 worth of loaner cables on Audiogon. He made up some story that he loaned them to a neighbor and it was the neighbor who sold them. The problem with the story was that when the cable company asked for the other $30,000 of loaner cables back, that Valin couldn't produce them either. Presumably he had already sold them on Audiogon.
The funny part is that when the TAS management found out about his thievery they didn't fire him -- they loaned him the money to pay the manufacturer back.
As far as being "hard to impress", have you looked at his speaker reviews over the last few years? About 3 times a year he found some "incredible" new speaker that made all of his old references obsolete. The only interruption in this regular succession of new "breakthrough" speakers was the Magico Mini, which lasted about a year. (Although that actually should count as three speakers -- the original version, the revised version, and then with the Wilson-Benesch subwoofers as companions).
But in the latest issue he has dropped the Magicos like a hot potato (probably because their big brother got a good review in Stereophile). This was their "Golden Ear" awards issue. And get this -- Valin awarded a "Golden Ear" award to a *prototype*! I guess he wanted to be sure that he was truly on the cutting edge this time!
john curl said:
"Best" is a word that requires a context. Many of the "best" circuits
offered up at DIYAudio are good because people will actually try
to build them.
Scott mentioned the Son of Zen, not what I would think of as a
candidate for "best", but haas been popular because a lot of guys
are not afraid of assembling some big hardware - they're intimidated
by all the little parts. SOZ with only two power transistors in nice big
packages offers a lower barrier to entry.
These same people then often progress to more sophisticated
projects.
Scott's phono stage is particularly attractive in this context - and
it's topical: Minimalist, no feedback, and a balanced phono input.
What's not to like?
😎
Charles, please don't debunk my review. It is fair, not underly critical, and I do make good bang for the buck. Jonathan Valin did screw up with the cable, but he made his amends, and you just won't leave him alone. This is not the first time that you have attacked him in print. Talk about a vendetta.
Now if you want to talk about HP, that is a pretty good story!
Now if you want to talk about HP, that is a pretty good story!
Nelson, you have your place on this website. You can talk about anything that you want, there. Scott can start his own thread with these simple circuits, that, incidentally, can't be made anymore, because nobody can afford the parts.
I am not here to criticize another's circuit, but if I got out my 'red pencil', Scott would then be legitimately mad at me. I don't want to do that, any more than I want to correct circuits in 'Audio Xpress'. Still, it seems to be that it is best to have the highest standards represented on this thread.
I am not here to criticize another's circuit, but if I got out my 'red pencil', Scott would then be legitimately mad at me. I don't want to do that, any more than I want to correct circuits in 'Audio Xpress'. Still, it seems to be that it is best to have the highest standards represented on this thread.
I was driving a lotus 7 daily when i was designing for Spectral years ago. It was great but incredibly challenging to use as a family car. However there was a probation officer in the local Lotus club who drove his for work. They were cheap to run if you fixed them yourself.
The Naked Vishay has been available from Texas components for a few years. I have used them and they are very good. But resistors can be an order of magnitude better still for some applications. The bulk metal resistors are the closest to wirewound resistors in basic performance. The alloy is matched to the ceramic substrate to keep the tempco very close to zero. The pattern on the surface is to compensate the L against the C and allow triming.
The special alloy used for the next step up in resistors (Evenohm) apparently has become a very rare commodity. the remaining manufacturer of lab standard resistors in the US told me that the metallurgists who created it have all retired or died and the vendor lost the recipe. The latest equivalent technology is something that Fluke makes using something similar to the Vishay bulk metal process. The current reference standard for resistance at DC is a collection of Josephson Junctions.
Out of curiosity I have acquired two instruments for looking at resistors is extreme ways. One is a Quan-Tech resistor analyzer that I can use to check the "excess noise" generation of a resistor. Carbon is by far the worst and its very probable that audible modulation of the noise could be heard as a function of the audio signal. Wirewound resistors with very good terminations are the best, and by as much as 20-30 dB improvement.
The other is a RE CLT-1 that really does measure the distortion of a resistor. And this is usually, again, termination related.
The other parameters, voltage coefficient, tempco, stability, and frequency response can all play into the sound in ways we can't easily test for. I just try to use the best I can find, and use the equipment to weed out the parts that won't be good.
The Naked Vishay has been available from Texas components for a few years. I have used them and they are very good. But resistors can be an order of magnitude better still for some applications. The bulk metal resistors are the closest to wirewound resistors in basic performance. The alloy is matched to the ceramic substrate to keep the tempco very close to zero. The pattern on the surface is to compensate the L against the C and allow triming.
The special alloy used for the next step up in resistors (Evenohm) apparently has become a very rare commodity. the remaining manufacturer of lab standard resistors in the US told me that the metallurgists who created it have all retired or died and the vendor lost the recipe. The latest equivalent technology is something that Fluke makes using something similar to the Vishay bulk metal process. The current reference standard for resistance at DC is a collection of Josephson Junctions.
Out of curiosity I have acquired two instruments for looking at resistors is extreme ways. One is a Quan-Tech resistor analyzer that I can use to check the "excess noise" generation of a resistor. Carbon is by far the worst and its very probable that audible modulation of the noise could be heard as a function of the audio signal. Wirewound resistors with very good terminations are the best, and by as much as 20-30 dB improvement.
The other is a RE CLT-1 that really does measure the distortion of a resistor. And this is usually, again, termination related.
The other parameters, voltage coefficient, tempco, stability, and frequency response can all play into the sound in ways we can't easily test for. I just try to use the best I can find, and use the equipment to weed out the parts that won't be good.
On those Vishay naked resistors, are these really 'naked'? I mean, is there no encapsulation over the resistive element? To protect them from air-borne oxidants and other agressive pollutants?
Jan Didden
Jan Didden
scott wurcer said:
Scott,
I wish we had know/realised that at the time. I remember I had strong discussions with Walt because I didn't want to list the 797 as a candidate for the regs because of the difficulty to stabilize it in this application (especially for a diy'er without test equipment to verify things). Especially for diy'ers that are used to hang the best low-esr foil caps they can afford off a regulator, thereby virtually guaranteeing instability.
In a sense, that 797 is too smart for its own good. How many application designers realise/understand that capacitive error correction?
Jan Didden
I wonder which opamps today would be good candidates. Personally AD825 has caused no problems but AD797 has always been a bit more sensitive against oscillations. Of fast opamps I have only tested AD817, AD825 and AD797 but OPA134 has worked good according to others.
Later on I will test LME49710.
Later on I will test LME49710.
If I say: Use regular caps, they will use low-esr. Why? Low-esr is "better"! Why? They have read it somewhere.janneman said:
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