Low noise resistors

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TonyP wrote:
> "Arny Krueger" <arnyk@hotpop.com> wrote in message
> news:IP6dnSdQi_yD2C7d4p2dnA@comcast.com...
>>> But how are they audible, only when doing a direct comparison with
>>> something else?
>> It's often apparent without comparison.
>
> Not sure how you would know whether it's the equipment or the record?

Keep the equipment properly tuned up.

> If they put test tones on every record you may have a shot.

I do have a number of test records, spanning decades.

>>> Which then is the more accurate?

>> The one you get when you get the FR of the playback equipment right.

> Not necessarily. If the record has say 3dB droop at HF compared to the
> master tape,

That would be an artistic choice made by the mastering engineer.

>then the cartridge/pre-amp with a 3dB rise will be more
> accurate for that record.

That would be a FR error I seek to eliminate.

>>> How do you know? Does it matter if it sounds good to you?
>
>> I find that if you get the FR of the playback equipment right, more
>> different recordings sound good to me.

> I already stated that you should set the response flat using a good
> test record. Then you can ignore the 1-2 dB variations from RIAA that
> your cartridge/pre-amp might have, safe in the knowledge that the
> records you play will be far more than that anyway. Compensate with
> EQ as necessary.

Works for me, but I want to minimize the need for added eq.

>>> Not at all, since the records frequency variation will be all over the
>> place.

>> Right, but I find that there is a natural centerline out there
>> someplace.

> I don't, but getting as flat as possible with a test record, is a
> good place to start anyway.

We kinda-sorta agree.

>>> Simply adjust tone controls to taste. That's what the mastering
>>> engineer does anyway!

>> It's nice to be able to play a stack of recordings without constantly
>> fiddling with the gear.

> Of course you can, but that doesn't mean they will all sound similar
> in tone, or similar to what the mixing or mastering engineers heard.

I can if I presume he set up his playback system competently, and I do the
same.

> You can't even expect that from CD's.

I surely expect that from CDs.

>>> I don't usually ABX them to the master
>>> tapes. So I have no idea which pressings are more accurate. Only
>>> which sound better to me at the time.

>> Yes, but if you can tune the playback system so that it is closer to
>> the median without adjustments, it takes less individual adjustment
>> to sound right with a variety of recordings.

> Of course, but that was never the argument.

I'm happy to be in agreement. ;-)

>>> IME the mixing/mastering, total EQ will be *MUCH* greater overall.

>> Not necessarily. While I'm not shy about applying eq, I often make
>> recordings where many tracks if not the whole mixdown has minimal or
>> zero eq.

> Sure, but that would be the exception, not the rule.

As I tune up my recording setup, its getting to be more of the rule.

>>> And not flat to any reference whatsoever.
>> We all carry a reference around in our heads - it's the composite of
>> everything we've ever heard.

> Yep, and everybody's is different. To be a reference, you need a
> common standard.

Well yes, but common experiences can be the basis for an approximate ad-hoc
standard.
 
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Detector195@yahoo.com (Detector195) writes:
> [...]
> Where I have seen it make a difference is in something like a
> transimpedance front end for optical detection, where the resistor is
> often the dominant noise source.

What about a differential receiver or instrumentation amplifier where
you're trying to establish a given input impedance?
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"Arny Krueger" <arnyk@hotpop.com> wrote in message
news:IP6dnSdQi_yD2C7d4p2dnA@comcast.com...
> > But how are they audible, only when doing a direct comparison with
> > something else?
> It's often apparent without comparison.

Not sure how you would know whether it's the equipment or the record?
If they put test tones on every record you may have a shot.

> > Which then is the more accurate?
> The one you get when you get the FR of the playback equipment right.

Not necessarily. If the record has say 3dB droop at HF compared to the
master tape, then the cartridge/pre-amp with a 3dB rise will be more
accurate for that record.

> > How do you know? Does it matter if it sounds good to you?

> I find that if you get the FR of the playback equipment right, more
> different recordings sound good to me.

I already stated that you should set the response flat using a good test
record. Then you can ignore the 1-2 dB variations from RIAA that your
cartridge/pre-amp might have, safe in the knowledge that the records you
play will be far more than that anyway. Compensate with EQ as necessary.

> > Not at all, since the records frequency variation will be all over the
> place.
> Right, but I find that there is a natural centerline out there someplace.

I don't, but getting as flat as possible with a test record, is a good place
to start anyway.

> > Simply adjust tone controls to taste. That's what the mastering
> > engineer does anyway!
> It's nice to be able to play a stack of recordings without constantly
> fiddling with the gear.

Of course you can, but that doesn't mean they will all sound similar in
tone, or similar to what the mixing or mastering engineers heard. You can't
even expect that from CD's.

> > When listening to records I don't usually ABX them to the master
> > tapes. So I have no idea which pressings are more accurate. Only
> > which sound better to me at the time.

> Yes, but if you can tune the playback system so that it is closer to the
> median without adjustments, it takes less individual adjustment to sound
> right with a variety of recordings.

Of course, but that was never the argument.

> > IME the mixing/mastering, total EQ will be *MUCH* greater overall.
>
> Not necessarily. While I'm not shy about applying eq, I often make
> recordings where many tracks if not the whole mixdown has minimal or zero
> eq.

Sure, but that would be the exception, not the rule.

> > And not flat to any reference whatsoever.
> We all carry a reference around in our heads - it's the composite of
> everything we've ever heard.

Yep, and everybody's is different. To be a reference, you need a common
standard.

TonyP.
 
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"Arny Krueger" <arnyk@hotpop.com> wrote in message
news:euudnQSQo5FZ5y7dRVn-sA@comcast.com...
> > Not sure how you would know whether it's the equipment or the record?
> Keep the equipment properly tuned up.

Sure, but proves nothing by itself, without a reference for each recording.
How do you know if it's supposed to sound like that, or the cutter or
stamper is worn out?

> > If they put test tones on every record you may have a shot.
> I do have a number of test records, spanning decades.

So do I, but I prefer to listen to music myself.

> > Not necessarily. If the record has say 3dB droop at HF compared to the
> > master tape,
> That would be an artistic choice made by the mastering engineer.

Or a worn cutter, stamper, stylus. Lot's of possibilities.

> >then the cartridge/pre-amp with a 3dB rise will be more
> > accurate for that record.
> That would be a FR error I seek to eliminate.

Fair enough, I seek maximum listening enjoyment. Each to his own.

> > I already stated that you should set the response flat using a good
> > test record. Then you can ignore the 1-2 dB variations from RIAA that
> > your cartridge/pre-amp might have, safe in the knowledge that the
> > records you play will be far more than that anyway. Compensate with
> > EQ as necessary.
> Works for me, but I want to minimize the need for added eq.

No argument there, but I just smile at the people who play vinyl with all
controls flat, and think they have a sound the same as the original :)

> > Of course you can, but that doesn't mean they will all sound similar
> > in tone, or similar to what the mixing or mastering engineers heard.
> I can if I presume he set up his playback system competently, and I do the
> same.

Were talking about vinyl here right?
(I'll ignore speakers for the sake of argument)

> > You can't even expect that from CD's.
> I surely expect that from CDs.

I won't ignore speakers and listening rooms here though. CD just eliminates
part of the corruption chain.

> > Yep, and everybody's is different. To be a reference, you need a
> > common standard.
> Well yes, but common experiences can be the basis for an approximate
ad-hoc
> standard.

Yes, well, sorta, maybe :)

TonyP.
 
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"Arny Krueger" <arnyk@hotpop.com> wrote in message
news:euudnQSQo5FZ5y7dRVn-sA@comcast.com...
> > Not sure how you would know whether it's the equipment or the record?
> Keep the equipment properly tuned up.

Sure, but proves nothing by itself, without a reference for each recording.
How do you know if it's supposed to sound like that, or the cutter or
stamper is worn out?

> > If they put test tones on every record you may have a shot.
> I do have a number of test records, spanning decades.

So do I, but I prefer to listen to music myself.

> > Not necessarily. If the record has say 3dB droop at HF compared to the
> > master tape,
> That would be an artistic choice made by the mastering engineer.

Or a worn cutter, stamper, stylus. Lot's of possibilities.

> >then the cartridge/pre-amp with a 3dB rise will be more
> > accurate for that record.
> That would be a FR error I seek to eliminate.

Fair enough, I seek maximum listening enjoyment. Each to his own.

> > I already stated that you should set the response flat using a good
> > test record. Then you can ignore the 1-2 dB variations from RIAA that
> > your cartridge/pre-amp might have, safe in the knowledge that the
> > records you play will be far more than that anyway. Compensate with
> > EQ as necessary.
> Works for me, but I want to minimize the need for added eq.

No argument there, but I just smile at the people who play vinyl with all
controls flat, and think they have a sound the same as the original :)

> > Of course you can, but that doesn't mean they will all sound similar
> > in tone, or similar to what the mixing or mastering engineers heard.
> I can if I presume he set up his playback system competently, and I do the
> same.

Were talking about vinyl here right?
(I'll ignore speakers for the sake of argument)

> > You can't even expect that from CD's.
> I surely expect that from CDs.

I won't ignore speakers and listening rooms here though. CD just eliminates
part of the corruption chain.

> > Yep, and everybody's is different. To be a reference, you need a
> > common standard.
> Well yes, but common experiences can be the basis for an approximate
ad-hoc
> standard.

Yes, well, sorta, maybe :)

TonyP.
 
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Randy Yates <yates@ieee.org> wrote in message news:<brkceybs.fsf@ieee.org>...
> Detector195@yahoo.com (Detector195) writes:
> > [...]
> > Where I have seen it make a difference is in something like a
> > transimpedance front end for optical detection, where the resistor is
> > often the dominant noise source.
>
> What about a differential receiver or instrumentation amplifier where
> you're trying to establish a given input impedance?

Ah, I had not thought of that application. And I think there are
actually low inductance wirewound resistors on the market, where they
run half of the turns backwards on the coil form.
 
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I just saw this thread and noted, by the way, prompt accurate information
from IsaacWingfield responding to the original question.

"Detector195" in news:6213f73a.0405251734.5d5d23e0@posting.google.com...
>
> . . . I took two resistors as
> "signal sources" to compare their noise spectra.
> One was a 100k 1/4 W metal film, the other was
> a 100k 1/8 W carbon film.

(Careful -- two variables changed at once. An issue of possible distraction
to some readers, more really than of misleading conclusions.)

>
> The carbon film had 6 percent more voltage noise from essentially
> zero up to 20 kHz, give or take 1 percent. This is about 0.5 dB.
> Does anybody out there have a real "professional" spectrum
> analyzer or digital scope? This should be an easy measurement
> if you have the right equipment.

Those data sound reasonable to me. Without going into details, I have done
many measurements as queried above. I use some very exquisite equipment for
low-noise measurements, some of the best available in the last few decades;
we have a lab full of it for such purposes. (By the way, you generally want
analog, or at least good-analog-front-end, instruments to measure low-freq.
noise spectra with low floors. And/or, build outboard low-noise preamps for
the purpose and keep them in the same lab.) My end applications were not
specifically audio, but I measured in the same frequency range. (I was
concerned with "making" resistors in monolithic form, and possible sources
of "excess" noise).

The whole issue here is the "excess" noise that Isaac Wingfield already
concisely explained. Typically it arises not in uniform resistive materials
but in interfaces between different materials, or between different crystals
or clusters of material. Commercial component resistors of metal or metal
film, common and fairly cheap anyway, have the general reputation of the
lowest excess noise, followed by carbon film. Carbon composition resistors
(polycrystalline I think, and very common construction for wired reasistors
when I was younger) have the worst reputation.

Issues of the power rating of a resistor are only peripherally related to
its noise sources. Self-heating capable of significantly raising a
resistor's Kelvin temperature (which is what counts) from the usual 300-350
found in operating electronic equipment would mean that the resistor is run
at a high power level, which argues independently for a higher power-capable
resistor, regardless of noise considerations. (Resistors, like people, are
most reliable when not overheated.)

I still think Isaac Wingfield said it more concisely. -- Max Hauser