[Andre Jute]

Iain Churches wrote:
"Peter Wieck" wrote in message
ups.com...
On Jun 6, 2:45 pm, "Iain Churches" wrote:
"Eeyore" wrote in message

...







Andre Jute wrote:

"The solution is not fancy
resistors (you usually can't get them in the right ratings) but to use
standard oversized metal films in smaller values in series, say 6x10K
rather than one 62K." Thus you get both the silence of the smaller
ohmic value of each resistor (6x10k makes less noise than one by 62K)
and the silence of the oversized resistors running cooler.

Can you elaborate on your point... "6x10k makes less noise than one by
62K" ?

Running a resistor cooler by using a larger bodied part will indeed
reduce
the
thermal noise contribution from it.

Perhaps for this very reason I have seen resistors replaced by several
parallel values to give the equivalent of the single value?

Iain- Hide quoted text -

- Show quoted text -

There are other reasons that do not bear repetition here, but
certainly spreading the load (and the associated heat build-up) is an
ancillary benefit. And if one does not have the correct heavier values
at hand, this is a valid expedient. Of course, unless each resistor is
(almost exactly) the same value, heat (load) will be distributed
across them by specific resistance.

Yes of course. I have seen several schematics with such parallel
networks, and a pal of mine in the UK made me a very useful
Excel spreadsheet in which one can enter the required value and
ascertain the resistors required for a two or three component
parallel equivalent. I find this very useful.

Regards to all
Iain

I see the posts of Worthless and suchlike only when other people quote
them. In this instance he seems to be waffling along, pompously
building some irrelevances into the appearance of knowing something.
He doesn't but I can't be bothered to trace and correct his ignorance;
even if I had the time to spare, I would find it more amusing to let
the wretched little man stew in his own stupidities.

For your own information I offer these corrections and expansions to
your exchanges with Wieckless:

1. Higher power resistors than required by the intended maximum
current in a circuit can lower thermal noise because they don't heat
up.

2. Parallel resistors contribute to the total thermal agitation noise
only to the extent of the resultant resistance, that is, always less
than any one resistor.

3. What I was talking about earlier, before the deliberate obfuscators
and the ignoramus gang got going, was current noise in plate
resistors. There is small noise across some resistors that is normally
ignored but with higher plate voltages (300V on octal preamp tubes is
*high* -- in vintage days, they ran those tubes at 90V or so) can be
measured. It can be reduced by using smaller-value resistors in
*series* to make up the correct value.

4. An example of where I used several of the "resistor" noise
reduction methods (including all the above, and together with other
noise cancellation tricks) because there it would matter is a diff amp
used to drive very refined headphones with extremely clean bass and a
wide band response. As I wrote to West, I can't see too many places
where one would worry about "excess noise" (same as "current noise",
despite what you can hear on RAT right now), except maybe a preamp and
a direct driver for electrostats, and perhaps some places in the
recording chain that would be of more interest to you than to me; in
general I am skeptical about noise cancellation methods because so
many of them are so hugely frequency-dependent and therefore uneven,
creating more problems than they solve, but the "resistor" methods and
a very few others (controlling the point on dual rail power supply
where the noise "sits" so as to cancel it more precisely, for
instance) do work, as I have just seen in my earphone amp protos.

HTH.

Andre Jute
Creator of Worthless Wieckless TM. All Rights Reserved by McCoy-Jute
Exploitation. Patent Pending. Licences still available for North Korea
and Lesotho. Our Attorneys are Bigger than Your Shysters.

[Peter Wieck]

On Jun 6, 7:24 pm, Andre Jute wrote:
Iain Churches wrote:
"Peter Wieck" wrote in message
oups.com...
On Jun 6, 2:45 pm, "Iain Churches" wrote:
"Eeyore" wrote in message

...

Andre Jute wrote:

"The solution is not fancy
resistors (you usually can't get them in the right ratings) but to use
standard oversized metal films in smaller values in series, say 6x10K
rather than one 62K." Thus you get both the silence of the smaller
ohmic value of each resistor (6x10k makes less noise than one by 62K)
and the silence of the oversized resistors running cooler.

Can you elaborate on your point... "6x10k makes less noise than one by
62K" ?

Running a resistor cooler by using a larger bodied part will indeed
reduce
the
thermal noise contribution from it.

Perhaps for this very reason I have seen resistors replaced by several
parallel values to give the equivalent of the single value?

Iain- Hide quoted text -

- Show quoted text -

There are other reasons that do not bear repetition here, but
certainly spreading the load (and the associated heat build-up) is an
ancillary benefit. And if one does not have the correct heavier values
at hand, this is a valid expedient. Of course, unless each resistor is
(almost exactly) the same value, heat (load) will be distributed
across them by specific resistance.

Yes of course. I have seen several schematics with such parallel
networks, and a pal of mine in the UK made me a very useful
Excel spreadsheet in which one can enter the required value and
ascertain the resistors required for a two or three component
parallel equivalent. I find this very useful.

Regards to all
Iain

I see the posts of Worthless and suchlike only when other people quote
them. In this instance he seems to be waffling along, pompously
building some irrelevances into the appearance of knowing something.
He doesn't but I can't be bothered to trace and correct his ignorance;
even if I had the time to spare, I would find it more amusing to let
the wretched little man stew in his own stupidities.

For your own information I offer these corrections and expansions to
your exchanges with Wieckless:

1. Higher power resistors than required by the intended maximum
current in a circuit can lower thermal noise because they don't heat
up.

2. Parallel resistors contribute to the total thermal agitation noise
only to the extent of the resultant resistance, that is, always less
than any one resistor.

3. What I was talking about earlier, before the deliberate obfuscators
and the ignoramus gang got going, was current noise in plate
resistors. There is small noise across some resistors that is normally
ignored but with higher plate voltages (300V on octal preamp tubes is
*high* -- in vintage days, they ran those tubes at 90V or so) can be
measured. It can be reduced by using smaller-value resistors in
*series* to make up the correct value.

4. An example of where I used several of the "resistor" noise
reduction methods (including all the above, and together with other
noise cancellation tricks) because there it would matter is a diff amp
used to drive very refined headphones with extremely clean bass and a
wide band response. As I wrote to West, I can't see too many places
where one would worry about "excess noise" (same as "current noise",
despite what you can hear on RAT right now), except maybe a preamp and
a direct driver for electrostats, and perhaps some places in the
recording chain that would be of more interest to you than to me; in
general I am skeptical about noise cancellation methods because so
many of them are so hugely frequency-dependent and therefore uneven,
creating more problems than they solve, but the "resistor" methods and
a very few others (controlling the point on dual rail power supply
where the noise "sits" so as to cancel it more precisely, for
instance) do work, as I have just seen in my earphone amp protos.

HTH.

Andre Jute
Creator of Worthless Wieckless TM. All Rights Reserved by McCoy-Jute
Exploitation. Patent Pending. Licences still available for North Korea
and Lesotho. Our Attorneys are Bigger than Your Shysters.- Hide quoted text -

- Show quoted text -

Good Christ....

The amount of tripe contained in the above is exactly why many new
viewers run directly for the hills... do not pass go, do not collect
$200.

Mr. Jute, when you actually post something not already stated, and in
fewer and better words, please come back. Otherwise, read your own
post on "getting back to roots".

I know that your brain damage and medications have this effect and
cause you to issue such fantasies, but as I noted before, they are
silly at best and dangerous at worst. Thank you for such a clear
example of both.

Peter Wieck
Wyncote, PA

[west[_4_]]

"west" wrote in message news:3gk9i.25$ng.18@trnddc05...
There are several different types of noise to avoid and reduce, if we can,
in designing tube circuits, from what I been studying. We can discuss
these
different types of noises in general but for now I would like to
concentrate
on 1 type of noise, current noise, the kind that is generated in a plate
load resistor. I believe that this is especially important in preamp
circuits.
Some tubies advocate that boutique components are all fluff and a waste of
money and I think they have a point, to a degree. However, will a low
noise
resistor make a difference in reducing plate current noise? If yes, then
they can make a difference.
The question is ...can we quantify this difference and how? I think it
would
be cool to measure this noise and simultaneously hear what difference a
low
noise boutique resistor can make. I may be off base with this idea, if so
chalk it up to an inexperienced but eager to learn Rodent. Thoughts?
Thanks.

Cordially,
west

Hold up gents. If you look at my OP, please notice that I said Plate Load
Current Noise. This is NOT Thermal or Johnson Noise. I think it can also be
referred to Triode Noise. Isn't this like Shot-Effect Noise, the noise
component of the plate current? I also think there is a mathematical
expression for it, perhaps Req (Requiv.). It is a voltage and I was
wondering if anyone actually measured it. If yes, then I believe that trying
different types of "boutique." plate load resistors while plotting the
voltage and comparing it to what you actually hear, should be very
informative and lots of fun.

west

[Peter Wieck]

On Jun 6, 9:35 pm, "west" wrote:

Hold up gents. If you look at my OP, please notice that I said Plate Load
Current Noise. This is NOT Thermal or Johnson Noise. I think it can also be
referred to Triode Noise. Isn't this like Shot-Effect Noise, the noise
component of the plate current?

"Triode noise"?

Only triodes are subject to this sort of noise?
Or plate currents on other sorts of tubes do not generate noise?

Even so, if this is noise generated by random effects of plate current
(shot-effect noise), how would a resistor (assuming good basic
quality, stability and appropriate current rating) affect shot-effect
noise... were this to actually exist in a measurable amount. Are you
sure that "shot-effect" is really what you mean? Triode noise is a
well understood phenomenon, but it isn't properly "shot noise".
Patrick Turner will set you straight on that.

Now, last I looked, normal tubes have almost no shot-effect noise in
the plate current. If only because the space-charge controls the
electron-flow to control it. So, if the noise source is as you
describe, it may not be measurable (above the normal noise-floor) in
typical tube circuits.

Copied from text (NOT MY WORDS):

Shot effect noise is fluctuations in the anode current due to the
random collection of electrons. We have already mentioned that the
anode current is controlled by the space charge around the filament.
It was discovered, to some surprise, that this correlated successive
electrons so that they were emitted regularly to maintain a constant
current, and therefore the shot effect was nearly completely
eliminated.

Perhaps Flicker Noise?

Some good information on tube noise (basic) may be found at:

http://www.john-a-harper.com/tubes201/

There is much else good and basic at this source.

And so forth.

Tubes is noisy beasts... resistors is not typically noisy beasts.
Resistors cannot have shot-effect noise.

And so forth.

Peter Wieck
Wyncote, PA

[Eeyore]

Iain Churches wrote:

a pal of mine in the UK made me a very useful
Excel spreadsheet in which one can enter the required value and
ascertain the resistors required for a two or three component
parallel equivalent. I find this very useful.

This is handy to make up unusual specific values, but I normally use resistors
in series to do this since it's so mech easier just to add the values together.
On a single sided pcb it can also assist track routeing.

Graham

[Eeyore]

Chris Hornbeck wrote:

Eeyore wrote:

Current noise is unrelated to any DC or AC current flow. It
might seem that more than just the OP are unaware of this.

You must be thinking of currant noise.

Just read through the whole current (currant?) thread.
It seems like only you and Patrick know the meaning of
excess noise or current noise. Or that they're unrelated.
Or that one applies to resistors and one doesn't,
ferzample.

Noise is a topic that folks here might appreciate a
short post about. Wanna take a swing?

Much thanks, as always,

Current noise and excess noise in resistors are the same thing IME.

Many names have been given to noise sources in circuitry other than the
inevitable 'white' thermal noise but many turn out on inspection to be a
different name for one of the others. Here's a few of them....

1/f noise, shot noise, excess noise, popcorn noise, red noise, current noise,
flicker noise, burst noise, recombination noise, partition noise....

Graham

[Eeyore]

west wrote:

Hold up gents. If you look at my OP, please notice that I said Plate Load
Current Noise. This is NOT Thermal or Johnson Noise.

Agreed.


I think it can also be referred to Triode Noise.

A new one on me.


Isn't this like Shot-Effect Noise, the noise component of the plate current?

No.


I also think there is a mathematical
expression for it,

Clearly there can't be since it's related to material purity and processing
which varies by manufacturer and resistor type.


perhaps Req (Requiv.). It is a voltage and I was
wondering if anyone actually measured it.

Yes. It used to be found on most resistor data sheets but it seems less common
now actually, possibly because few ppl are designing analogue circuitry any more
?


If yes, then I believe that trying
different types of "boutique." plate load resistors while plotting the
voltage and comparing it to what you actually hear, should be very
informative and lots of fun.

Youy really don't need to go any more 'boutique' than a good quality standard
metal film part from a normal commercial supplier for lowest noise.

Graham

[Chris Hornbeck]

On Thu, 07 Jun 2007 03:33:08 GMT, Eeyore
wrote:

Noise is a topic that folks here might appreciate a
short post about. Wanna take a swing?

Current noise and excess noise in resistors are the same thing IME.

In America "current noise" is a specific name for I-sub-n
and has a fixed meaning, completely unrelated to excess noise,
at least among engineering folks. What do *you* call I-sub-n?


Many names have been given to noise sources in circuitry other than the
inevitable 'white' thermal noise but many turn out on inspection to be a
different name for one of the others. Here's a few of them....

1/f noise, shot noise, excess noise, popcorn noise, red noise, current noise,
flicker noise, burst noise, recombination noise, partition noise....

I obviously asked the wrong person to help clear this matter up.

Since you don't come from a vacuum valve background, the confusions
about shot noise and partition noise are understandable. Several
others above are true examples of excess noise, and I'd hoped you
might have shed some light.


Thanks anyway,

Chris Hornbeck

[Eeyore]

Chris Hornbeck wrote:

Eeyore wrote:

Noise is a topic that folks here might appreciate a
short post about. Wanna take a swing?

Current noise and excess noise in resistors are the same thing IME.

In America "current noise" is a specific name for I-sub-n
and has a fixed meaning, completely unrelated to excess noise,

This is news to me. However it is the case that the terminology of noise has been
fairly lax in the past.


at least among engineering folks. What do *you* call I-sub-n?

That's what I call "input noise current". It's not the same as "current noise".
It's a specific device specification and is the noise component of an input
current to an op-amp typically.


Many names have been given to noise sources in circuitry other than the
inevitable 'white' thermal noise but many turn out on inspection to be a
different name for one of the others. Here's a few of them....

1/f noise, shot noise, excess noise, popcorn noise, red noise, current noise,
flicker noise, burst noise, recombination noise, partition noise....

I obviously asked the wrong person to help clear this matter up.

LOL !


Since you don't come from a vacuum valve background, the confusions
about shot noise and partition noise are understandable. Several
others above are true examples of excess noise, and I'd hoped you
might have shed some light.

I'd expect partition noise to be a quantum effect, in which case it will be
similar to shot noise.

It might be useful to separate those noise sources that are indeed quantum effect
types.

This would include recombination noise, and in turn shot noise. Not sure about 1/f
and flicker noise.

Graham

[Chris Hornbeck]

On Thu, 07 Jun 2007 04:13:35 GMT, Eeyore
wrote:

I'd expect partition noise to be a quantum effect, in which case it will be
similar to shot noise.

It might be useful to separate those noise sources that are indeed quantum effect
types.

This would include recombination noise, and in turn shot noise.

I've never heard "thermal" noises referred to as quantum effects,
and, at first blush, find it hard to accept, but I'm very keen
to learn. Is this a common usage in the civilized parts of the
globe?

Not sure about 1/f and flicker noise.

The cool thing about 1/f is that *nobody* is sure about it.
Twenty years ago it was still a mystery, so any more recent
thought is automagically suspect. Arf.

Thanks for any thoughts,

Chris Hornbeck

[Eeyore]

Chris Hornbeck wrote:

Eeyore wrote:

I'd expect partition noise to be a quantum effect, in which case it will be
similar to shot noise.

It might be useful to separate those noise sources that are indeed quantum effect
types.

This would include recombination noise, and in turn shot noise.

I've never heard "thermal" noises referred to as quantum effects,
and, at first blush, find it hard to accept, but I'm very keen
to learn. Is this a common usage in the civilized parts of the
globe?

I never said thermal noise was a quantum effect. Where did you get that idea ?


Not sure about 1/f and flicker noise.

The cool thing about 1/f is that *nobody* is sure about it.
Twenty years ago it was still a mystery, so any more recent
thought is automagically suspect. Arf.

There you go ! An intruiging mystery.

Graham

[Iain Churches]

"Eeyore" wrote in message
...


Iain Churches wrote:

a pal of mine in the UK made me a very useful
Excel spreadsheet in which one can enter the required value and
ascertain the resistors required for a two or three component
parallel equivalent. I find this very useful.

This is handy to make up unusual specific values, but I normally use
resistors
in series to do this since it's so mech easier just to add the values
together.
On a single sided pcb it can also assist track routeing.

Yes. I realise that in you SS designs things are done differently.
In tube circuitry, many people stick to 2W metal film resistors
and so some required values are missing from the range. Most
tube amps are either p to p or built on handwired boards, and so
the allocation of space for a side by side parallel pair is easy.

Regards
Iain

[Peter Wieck]

On Jun 6, 11:16 pm, Eeyore
wrote:
Iain Churches wrote:
a pal of mine in the UK made me a very useful
Excel spreadsheet in which one can enter the required value and
ascertain the resistors required for a two or three component
parallel equivalent. I find this very useful.

This is handy to make up unusual specific values, but I normally use resistors
in series to do this since it's so mech easier just to add the values together.
On a single sided pcb it can also assist track routeing.

Graham

I will repeat myself: The problem with series resistors is that every
resistor sees the same current load and therefore needs to be robust
enough to carry it. While with small-current circuits that is no
problem, with larger-current circuits, multiple additional failure
points are introduced. Given the availability of resistor values these
days, even precision-cut resistors (with a little time) at very
reasonable prices, it would seem that after a final value is
determined, a single correct resistor be introduced both for real-
estate purposes and for simplicity... always a virtue in circuit
design. And if one is looking for convenient "track route
manangement", jumpers are equally convenient.

Some of these problems also apply to parallel resistors but in these
cases the failure mode is primarily mechanical (in my experience).
Additionally, if clearances are tight, parallel resistors are a
convenient way to eliminate the need for a single honking resistor...
whereas with series-resistors all must be equally honking if needed.

Once again, as *most* of us are not constrained by the need for
production engineering on a commercial scale, whether a resistor costs
$0.04 or $7.95 (typical cost of a 3W precision-cut 0.5% resistor in
onesies - twosies) is typically simply not relevant if the design
requires it. Although many of us will hold our noses while writing the
check and look fondly on 1% resistors at a 10th of the cost.

Peter Wieck
Wyncote, PA

[Andre Jute]

Chris Hornbeck wrote:
On Wed, 06 Jun 2007 16:39:19 -0700, Andre Jute
wrote:

Pray explain the difference between current noise, excess noise. 1/f
noise, and flicker noise. lt's a trick question, of course.

These four types of noise are unrelated and come from four
different causes. Confusion among them is common, but
mistaken, although one term is generic enough to cover
the others.

Thanks, Chris. That won me 210 bucks in bets that you don't know that
current noise and excess noise (which you named earlier) are the same
thing.

All four you've listed can readily be described, but one of the
four has mysterious origins. It's a trick question, of course.

Yeah. Right. All four that I name (current noise, excess noise. 1/f
noise, and flicker noise) answer to the same formula.

Batter up!

Pulling hamburger patty through batter doesn't reconstitute steak. It
does add cholesterol.

Much thanks, as always,

Chris Hornbeck

Cheer up, old chap. This is the first time Poopie has proved more
knowledgeable than you on some subject. Only 99 more examples that he
is actually useful and you will be be able to pretend that you are
justified in having invited him here.

Andre Jute
The trouble with most people is not what they don't know, but what
they know for certain that isn't true. ---Mark Twain

[Eeyore]

Peter Wieck wrote:

Given the availability of resistor values these
days, even precision-cut resistors (with a little time) at very
reasonable prices, it would seem that after a final value is
determined, a single correct resistor be introduced both for real-
estate purposes and for simplicity...

You have to be joking. So-called precision resistors even in standard values are ~ £1
each !

Suppose your circuit needs 689 ohms - do you choose 681R or 698R (the usual E96
values) with a 1% error or do you use 680 ohms and 9.1 ohms in series and get it
'bang on' ?

Graham

[Peter Wieck]

On Jun 7, 9:00 am, Eeyore
wrote:
Peter Wieck wrote:
Given the availability of resistor values these
days, even precision-cut resistors (with a little time) at very
reasonable prices, it would seem that after a final value is
determined, a single correct resistor be introduced both for real-
estate purposes and for simplicity...

You have to be joking. So-called precision resistors even in standard values are ~ £1
each !

Suppose your circuit needs 689 ohms - do you choose 681R or 698R (the usual E96
values) with a 1% error or do you use 680 ohms and 9.1 ohms in series and get it
'bang on' ?

Graham

Graham, with respect, custom 1% resistors on this side of the pond run
about $1 - $1.25 onesies/twosies. They take a bit of time to acquire.
Non-custom 1% resistors at 3W run about $0.45 - $0.75. Mouser, Newark,
and several others are good sources.

Where things get esoteric is when one wants 1% margin-of-error (0.5%),
those units run $7-9, or £3-5.

It is still my contention and writing entirely for myself that what I
choose to build really has no costs constraints when it comes to items
of this nature... *when required*... as in not just for yiches. If I
put many hours into a design or a restoration or a repair to get it
just right, the incremental cost of even $50 for a few specialized
items over cheaper less satisfactory expedients is negligible. I need
to repeat, we as hobbyists are *not* constrained by mass-production
requirements, profit requirements or (presumably) time requirements.
Those that are will look at this entirely differently and I both
recognize and appreciate that.

Peter Wieck
Wyncote, PA

[Chris Hornbeck]

On Thu, 07 Jun 2007 06:14:25 GMT, Eeyore
wrote:

I've never heard "thermal" noises referred to as quantum effects,
and, at first blush, find it hard to accept, but I'm very keen
to learn. Is this a common usage in the civilized parts of the
globe?

I never said thermal noise was a quantum effect. Where did you get that idea ?

Shot noise is the thermal noise of a vacuum valve's transconductance
engine. It's even calculated as an equivalent resistance (the
reciprocal of transconductance) at some factor of room temperature,
usually about 2.5 .

Much thanks, as always,

Chris Hornbeck

[Chris Hornbeck]

On Thu, 07 Jun 2007 05:03:56 -0700, Andre Jute
wrote:

Yeah. Right. All four that I name (current noise, excess noise. 1/f
noise, and flicker noise) answer to the same formula.

You may and will believe as you wish, but in this case, you
will be incorrect.

Thanks, as always,

Chris Hornbeck

[Ian Iveson]

Chris wrote:

You may and will believe as you wish, but in this case, you
will be incorrect.

So we have a noise called "current noise" that is intirely unrelated
to current flow. Isn't that a trifle perverse?

I would have thought from its name that it would appear as some
frequency distribution of current, although perhaps regardless of
resistance and consequent voltage, and perhaps regardless of any other
current flow. Your cryptic statements so far suggest this is not true.

Why not just explain what you believe it to be? Or at least suggest
how we might find out.

cheers, Ian

[Eeyore]

Chris Hornbeck wrote:

Eeyore wrote:

I've never heard "thermal" noises referred to as quantum effects,
and, at first blush, find it hard to accept, but I'm very keen
to learn. Is this a common usage in the civilized parts of the
globe?

I never said thermal noise was a quantum effect. Where did you get that idea ?

Shot noise is the thermal noise of a vacuum valve's transconductance
engine. It's even calculated as an equivalent resistance (the
reciprocal of transconductance) at some factor of room temperature,
usually about 2.5 .

I can't relate what you say to my comment above. Shot noise is a quantum effect.

" Shot noise is a type of electronic noise that occurs when the finite number of
particles that carry energy, such as electrons in an electronic circuit or photons
in an optical device, is small enough to give rise to detectable statistical
fluctuations in a measurement. "
http://en.wikipedia.org/wiki/Shot_noise

Graham

[Eeyore]

Ian Iveson wrote:

Chris wrote:

You may and will believe as you wish, but in this case, you
will be incorrect.

So we have a noise called "current noise" that is intirely unrelated
to current flow. Isn't that a trifle perverse?

I would have thought from its name that it would appear as some
frequency distribution of current, although perhaps regardless of
resistance and consequent voltage, and perhaps regardless of any other
current flow. Your cryptic statements so far suggest this is not true.

Why not just explain what you believe it to be? Or at least suggest
how we might find out.

My understanding of what I prefer to call excess noise in resistors is that it
only occurs when there is indeed current flowing. As specified in terms of uV of
noise per Volt of applied DC, that applied DC V is what causes the current. Call
it 'current caused' noise if you like.

Graham

[Chris Hornbeck]

On Fri, 08 Jun 2007 03:00:52 GMT, "Ian Iveson"
wrote:

Why not just explain what you believe it to be? Or at least suggest
how we might find out.

You're right, of course. Lately I'm becoming the kind of asshole
I dislike the most, and I need to do a lot better.

So, OK. There are classically two broad categories of noise,
thermal and everything else. The "everything else" is called
excess noise, because .... well, because it's in excess of
predicted, right and true, and entirely proper, thermal noise.

But what is thermal noise? It's an expression of the randomness
(noise) of electrons living their happy little lives, hopping
from bed to bed, impregnating no one. The higher the temperature
of their world, the more they hop, and the larger the resistance
within which they're moving, the larger the voltage that their
movement generates. Maybe it's political; I dunno.

Thermal noise is predictable, expected, and absolutely unavoidable.
A resistor at such-n-such temperature *will*, without appelate court
recourse, generate (and I use the word very specifically) a known
voltage and spectrum of noise.

All other audio noises are lumped together under the blanket term
"excess noise". They're caused by all kinds of different mechanisms
and have all kinds of different sounds and characteristics.

So we have a noise called "current noise" that is intirely unrelated
to current flow. Isn't that a trifle perverse?

I would have thought from its name that it would appear as some
frequency distribution of current, although perhaps regardless of
resistance and consequent voltage, and perhaps regardless of any other
current flow. Your cryptic statements so far suggest this is not true.

I've rearranged the flow of your discussion to suit my own purposes.
Hoping you'll understand and forgive, let me close with this
truly trivial matter.

Active devices are often characterized with a pair of noise numbers,
equivalent input noise voltage (per root Hertz) and equivalent
input noise current (per root Hertz). These are an amazingly
useful way to describe real world performance because all we
need to know is source resistance and we can quickly know
room temperature (always close enough! in our world) equivalent
(meaning: referred to the input of the device) input noise.

The second number above, I-sub-n, or equivalent input noise
current, is simply multiplied by source resistance to generate
a number (called, in my circles "current noise") that's square
root of the sum of the squares "added" to the equivalent input
noise voltage over expected bandwidths (commonly rounded to 10
kiloHertz (for perhaps surprisingly good reasons).

There are many "excess" noises. I feel strongly that a builder
needs to distinguish among them. Not an excuse for being an
asshole, of course, and I'm sorry.


To answer your question "why not?" : because it takes an oversized
post like this to just touch on the topic. I already feel like
a fool for trying to post a Cliff Notes version of feedback issues,
and *nobody* has pitched in to help with that elephant, or seems
to care one way or another. Ce la vie.

Much thanks, as always,

Chris Hornbeck

[Chris Hornbeck]

On Fri, 08 Jun 2007 03:29:27 GMT, Eeyore
wrote:

Shot noise is the thermal noise of a vacuum valve's transconductance
engine. It's even calculated as an equivalent resistance (the
reciprocal of transconductance) at some factor of room temperature,
usually about 2.5 .

I can't relate what you say to my comment above. Shot noise is a quantum effect.

" Shot noise is a type of electronic noise that occurs when the finite number of
particles that carry energy, such as electrons in an electronic circuit or photons
in an optical device, is small enough to give rise to detectable statistical
fluctuations in a measurement. "
http://en.wikipedia.org/wiki/Shot_noise

Not to knock Wikipedia (but I can't help myself sometimes)...

Anyway, "shot noise" is classically (meaning in vacuum
valve circles, and historically) considered to be "classical"
physics, rather than a quantum effect. Gosh, I'm a whiz at
overstating the obvious, ain't I?

The article also claims that Johnson (thermal, in modern
terms) noise is a quantum effect.

I ain't buying either, and doubt that you do completely
either. Reads like a grad student's summation, frankly.
There I go getting bitchy again. I'm sorry.

Much thanks, as always,

Chris Hornbeck

[Andre Jute]

Thanks, Ian. The long finger filing cabinet is a marvellous place. it
is amazing how many mickey mouse "problems" go away when you simply
put them at the bottom of your in-tray and deny all knowledge of their
existence, together with a transparently insincere promise to attend
to them as soon as you return from lunch, then the sauna, then the
opera, then your midnight snack, after which you are of course firmly
ensconced in your bedroom, reading your Bible, totally beyond
interruption for merely temporal tantrums (1). This from Chris was
altogether too shrewish for a technical conference:

Ian Iveson wrote:
Chris wrote:

You may and will believe as you wish, but in this case, you
will be incorrect.

[snip, full version below]

Why not just explain what you believe it to be? Or at least suggest
how we might find out.

cheers, Ian

--so, instead of snapping something sharp, and taking into
consideration that Chris doesn't normally sound like the queers
waspish with unfullfilled aspiration familiar to me from my time in
the theatre, I slept on it, to awake, yo! hallelujah!, to discover you
handled the problem and a solution has appeared in print to everyone's
satisfaction.

Please believe me, my light tone is not to send you up but from vast
relief at finding another troubleshooter at work.

All hail to the long finger (2).

Andre Jute
Oh captain, my adjudant, convene the firing squad, if you please (1)

(1) Do you know the origin of the word tantrum? I have a letter here
from a lady whose surname is Tantrum inviting me to drink champagne at
the launch of a piano festival. Makes one wonder if it wouldn't be
politic to put aside my aversion to time-wasting cocktail party
chatter just this once and put in an appearance.

(2) "Long" is a very useful word where I live. Ladies of a certain
class here go about with a little saw in the car. If they see
something in another lady's garden that they like, they dash in and
take a cutting. It is not done to go so far up the drive that you can
actually see the house, of course. That is called "cropping the long
acre", and it probably has a longer-established, more pernicious
meaning of theft of the common (which I add merely to relate it back
to our earlier discussion of that wretchedly tendentious piece of
demagoguery, The Tragedy of the Commons).

(3) Just because this is a technical conference it does not follow
that we should be dull. This post is an onomatopoeic rendition of
current noise, with shot noise off for comparison and contrast.

Here is your entire original post:

Ian Iveson wrote:
Chris wrote:

You may and will believe as you wish, but in this case, you
will be incorrect.

So we have a noise called "current noise" that is intirely unrelated
to current flow. Isn't that a trifle perverse?

I would have thought from its name that it would appear as some
frequency distribution of current, although perhaps regardless of
resistance and consequent voltage, and perhaps regardless of any other
current flow. Your cryptic statements so far suggest this is not true.

Why not just explain what you believe it to be? Or at least suggest
how we might find out.

cheers, Ian

[Ian Iveson]

Chris Hornbeck wrote

So, OK. There are classically two broad categories of noise,
thermal and everything else. The "everything else" is called
excess noise, because .... well, because it's in excess of
predicted, right and true, and entirely proper, thermal noise.

But what is thermal noise? It's an expression of the randomness
(noise) of electrons living their happy little lives, hopping
from bed to bed, impregnating no one. The higher the temperature
of their world, the more they hop, and the larger the resistance
within which they're moving, the larger the voltage that their
movement generates. Maybe it's political; I dunno.

Thermal noise is predictable, expected, and absolutely unavoidable.
A resistor at such-n-such temperature *will*, without appelate court
recourse, generate (and I use the word very specifically) a known
voltage and spectrum of noise.

All other audio noises are lumped together under the blanket term
"excess noise". They're caused by all kinds of different mechanisms
and have all kinds of different sounds and characteristics.

So we have a noise called "current noise" that is intirely unrelated
to current flow. Isn't that a trifle perverse?

I would have thought from its name that it would appear as some
frequency distribution of current, although perhaps regardless of
resistance and consequent voltage, and perhaps regardless of any
other
current flow. Your cryptic statements so far suggest this is not
true.

I've rearranged the flow of your discussion to suit my own purposes.
Hoping you'll understand and forgive, let me close with this
truly trivial matter.

Active devices are often characterized with a pair of noise numbers,
equivalent input noise voltage (per root Hertz) and equivalent
input noise current (per root Hertz). These are an amazingly
useful way to describe real world performance because all we
need to know is source resistance and we can quickly know
room temperature (always close enough! in our world) equivalent
(meaning: referred to the input of the device) input noise.

The second number above, I-sub-n, or equivalent input noise
current, is simply multiplied by source resistance to generate
a number (called, in my circles "current noise") that's square
root of the sum of the squares "added" to the equivalent input
noise voltage over expected bandwidths (commonly rounded to 10
kiloHertz (for perhaps surprisingly good reasons).

There are many "excess" noises. I feel strongly that a builder
needs to distinguish among them. Not an excuse for being an
asshole, of course, and I'm sorry.


To answer your question "why not?" : because it takes an oversized
post like this to just touch on the topic. I already feel like
a fool for trying to post a Cliff Notes version of feedback issues,
and *nobody* has pitched in to help with that elephant, or seems
to care one way or another. Ce la vie.

Thanks :-)

Ian

[Patrick Turner]

west wrote:

"Patrick Turner" wrote in message
...


west wrote:

There are several different types of noise to avoid and reduce, if we
can,
in designing tube circuits, from what I been studying. We can discuss
these
different types of noises in general but for now I would like to
concentrate
on 1 type of noise, current noise, the kind that is generated in a plate
load resistor. I believe that this is especially important in preamp
circuits.
Some tubies advocate that boutique components are all fluff and a waste
of
money and I think they have a point, to a degree. However, will a low
noise
resistor make a difference in reducing plate current noise? If yes, then
they can make a difference.
The question is ...can we quantify this difference and how? I think it
would
be cool to measure this noise and simultaneously hear what difference a
low
noise boutique resistor can make. I may be off base with this idea, if
so
chalk it up to an inexperienced but eager to learn Rodent. Thoughts?
Thanks.

Cordially,
west

If you study RDH4 about noise and resistance, you won't need to ask your
question here
because the book has the answers.

Or, the question you might ask if you had studied RDH4 might be one
unanswered by RDH4,
and then its worth asking here, eh.

Are you asking what is the EXTRA noise a resistor generates when a DC or
AC flow exists?

Do you undertsand your own question?


Patrick Turner.

I think Phil A. answered your question already.

west

Neither you or Phil A have been informative on this subject.



Patrick Turner.

[Patrick Turner]

Andre Jute wrote:

west wrote:
There are several different types of noise to avoid and reduce, if we can,
in designing tube circuits, from what I been studying. We can discuss these
different types of noises in general but for now I would like to concentrate
on 1 type of noise, current noise, the kind that is generated in a plate
load resistor. I believe that this is especially important in preamp
circuits.
Some tubies advocate that boutique components are all fluff and a waste of
money and I think they have a point, to a degree. However, will a low noise
resistor make a difference in reducing plate current noise? If yes, then
they can make a difference.
The question is ...can we quantify this difference and how? I think it would
be cool to measure this noise and simultaneously hear what difference a low
noise boutique resistor can make. I may be off base with this idea, if so
chalk it up to an inexperienced but eager to learn Rodent. Thoughts? Thanks.

Cordially,
west

West:

This thread has already spiralled off into contending experts ego-
tripping. The two items of useful information in it is where Patrick
states the practical problem and where I tell you how to solve it.

Here Patrick states the problem: "the number of ohms was what
determined noise, and it mattered not one bit what kind of resistor it
was as long as the contacts to each end were mechanically tight"

Allow me to add to this.

Say you have a 60 kohm R plate load R feeding a 1/2 6SN7, Ia 5A,
bypassed
Rk, then noise in the 60k is shunted by the 10k Ra of the triode, so the
resistor noise
is very much reduced, but then the triode noise will be greater.
So the 60k load does little to increase noise.
If the very well chosen 6SN7 has 3uV of noise at its input even with
grid grounded,
and gain = 15, then there is 45uV of noise at the anode, and I leave you
to work
or how much noise would be in 60k at say 30C, and how much would add to
the 45uV.

If such a gain stage has a following coupling to a gain pot, or bias R,
the noise output
needs more calculation.

But ppl say a choke is the quietest element to use.

But I find an actice device such a san MJE50 as a CCS is NOT noisier
than the R,
and probably because it is shunted the triode noise which has Rout = Ra
= 10k.



And here I show how to solve the problem: "The solution is not fancy
resistors (you usually can't get them in the right ratings) but to use
standard oversized metal films in smaller values in series, say 6x10K
rather than one 62K." Thus you get both the silence of the smaller
ohmic value of each resistor (6x10k makes less noise than one by 62K)
and the silence of the oversized resistors running cooler. *That* is
why on all my amps the power resistors are, in strictly cost-
accounting engineering terms, overspecified; ditto for all the best
audiophile-designed tube amps. (The idiot Worthless Wieckless made an
offensive song and dance about overspecced resistors in my T39 Ultra-
Fi once because he is bog-ignorant -- I very carefully didn't explain
the real reason to him; he's such a wretched little man that nobody
else helped him out either. But those big ballast resistors account
for a good part of the silence of the amp.)

Perhaps you may have to think this through again.

OK, say you have 6 x 10k in series.

Each one makes a noise = noise of 60k x sq.rt of ( 60/10 ).
10k obviuously has less noise than 60k.

In fact the noise with 6 resistors in series = sq.rt ( sum of the
squares of each amount of noise )

And you should find that 0ne 60k resistor of 6 watts rating has exactly
the same noise at 6 x 10k x 1 watt in series.

If the 10k were all paralleled, noise would indeed be lower, but the R
wouldn't be right
for the anode load.
There are no free lunches on resistor noise to be had by series
connection
of well rated quality resistors, unless the connection leads to the R
operating
without any T rise. T rise makes noise worse; hot is noisier than
cooler.

A 60k anode load for a 6SN7 which comprises of say 10 x 600k x 1 watt
all paralleled to get
60k won't have any noise difference to ONE 6 watt 60k, or 10 x 6k x 1
watt in series,
providing the temp is the same, which is should be if the total 60k
wattage is the same,
or whatever is used to makes sure T remains the same.


All the rest is, as I say, audiophoolery or "experts" tripping over
each other in their eagerness to show off.

Nobody stops you experimenting for yourself though; discovering
whether you like one sort of component better than another is half the
fun of building your own tube amps. There was a time when I swore by
Dale "non-inductive" cathode resistors on 300B and 845; today I just
use the 50W ali-cased jobs out of the RS catalogue. And I still like
Solen polyprops better than any other kind; you can get Solens in the
widest possible range of values in high voltage ratings and they sound
right in my amps and don't take up as much space as the (more
expensive) motor run polys I can buy locally.

I like whatever nice metal film 1% R I can find; I use Welwyn from RS
Components mostly
ever since the Reistor Mafia, Vishay, took over Beyschlag, and the local
distributor was bought
by a darn american company.
The result of these changes meant Beyshlag price of 10c per R for a
genuine 1 watt went to 45c,
and you were compelled to buy 1,000 as the minimum number.

When you want to buy say 50 pcs of all standard values between 1ohm and
4.7M, its very expensive.

Just watch out with voltage ratings on resistors; even high value like
470k and 1M don't
like more than 250V sometimes across them. Welwyn sure don't, and I had
3 x 470k in parallel for a
tail between commoned cathodes in an LTP to -400V, and in both monoblocs
( Quad-II, very revised )
one of the 3 went to a short!

I like Wima polyprops; I cannot find anyone who can tell me better than
chance will predict,
ie, 50 - 50, which channel has all Wimas and which has all polesters, or
other types/brands of polyprops.

Patrick Turner.




Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

[Patrick Turner]

"François Yves Le Gal" wrote:

On Wed, 06 Jun 2007 04:04:40 -0700, Andre Jute wrote:

And here I show how to solve the problem: "The solution is not fancy
resistors (you usually can't get them in the right ratings) but to use
standard oversized metal films in smaller values in series, say 6x10K
rather than one 62K." Thus you get both the silence of the smaller
ohmic value of each resistor (6x10k makes less noise than one by 62K)
and the silence of the oversized resistors running cooler.

Noise voltage: E = SQR (4 * k * T * R * Df )
Noise power: P = E^2 = 4 * k * T * R * Df

With:
E = RMS voltage in V
k = 1.38·10-23 (Boltzmans constant)
T = temperature in Kelvin
R = resistance in Ohm
Df = Circuit bandwidth in Hz

Voltage spectral density: N = SQR (4 * k * T * R)
Power spectral density: S = 4 * k * T * R

Ntot = N1 + N2 + N3 ... + Nn
Stot = S1 + S2 + S3 ... + Sn

Now plug in the values....

Where R are in series, noise of each is squared, then summed to a total,
then the total noise id the sq.rt of the total of the summed squares.

So say you have 2uV, 4uV, 10uV of noise in 3 series R, and not shunted
by anything else,
total noise = sq.rt ( 4 + 16 + 100 )
= sq.rt 120 = approx 11uV.

The contribution of the 2uV and 4uV is negligible once the 3rd R has R
2.5 times 4uV.

So if the tube noise say 3.2 x R noise, R noise makes almost no
difference to total noise.

In a phono application, if input tube = 12AX7, and load = 100k,
the 100k makes little contribution.
If the vinyl noise is say 3 times the amp noise, then the amp
noise won't be noticed.

Having low noise in phono stages does place vinyl at its best though.
I like a fet driving into the cathode a gain triode with a 22k dc RL.

Patrick Turner.

[RdM]

Andre Jute in
rec.audio.tubes1181297050.598664.69190@e65g2000hs c.googlegroups.com:

(1) Do you know the origin of the word tantrum? I have a letter here
from a lady whose surname is Tantrum inviting me to drink champagne at
the launch of a piano festival. Makes one wonder if it wouldn't be
politic to put aside my aversion to time-wasting cocktail party
chatter just this once and put in an appearance.

Ah, Connie Tantrum. The New Ross Piano Festival. Perhaps you should go?
The various accommodations linked look OK. I'll celebrate my 55th, the 30th.

Most sources assert "origin unknown", one or two "uncertain", as you know...

The Kernerman English Multilingual Dictionary shows interesting similiarities
among Scandinavian and even Estonian equivalents, though - looks like rage?

Ross Matheson
--
Auckland, New Zealand.

"Perhaps I, too, will be renewed..."

[Andre Jute]

Patrick Turner wrote:
Andre Jute wrote:

west wrote:
There are several different types of noise to avoid and reduce, if we can,
in designing tube circuits, from what I been studying. We can discuss these
different types of noises in general but for now I would like to concentrate
on 1 type of noise, current noise, the kind that is generated in a plate
load resistor. I believe that this is especially important in preamp
circuits.
Some tubies advocate that boutique components are all fluff and a waste of
money and I think they have a point, to a degree. However, will a low noise
resistor make a difference in reducing plate current noise? If yes, then
they can make a difference.
The question is ...can we quantify this difference and how? I think it would
be cool to measure this noise and simultaneously hear what difference a low
noise boutique resistor can make. I may be off base with this idea, if so
chalk it up to an inexperienced but eager to learn Rodent. Thoughts? Thanks.

Cordially,
west

West:

This thread has already spiralled off into contending experts ego-
tripping. The two items of useful information in it is where Patrick
states the practical problem and where I tell you how to solve it.

Here Patrick states the problem: "the number of ohms was what
determined noise, and it mattered not one bit what kind of resistor it
was as long as the contacts to each end were mechanically tight"

Allow me to add to this.

Say you have a 60 kohm R plate load R feeding a 1/2 6SN7, Ia 5A,
bypassed
Rk, then noise in the 60k is shunted by the 10k Ra of the triode, so the
resistor noise
is very much reduced,

Yes, that is what I said, probably several days ago.

but then the triode noise will be greater.
So the 60k load does little to increase noise.
If the very well chosen 6SN7 has 3uV of noise at its input even with
grid grounded,
and gain = 15, then there is 45uV of noise at the anode, and I leave you
to work
or how much noise would be in 60k at say 30C, and how much would add to
the 45uV.

If such a gain stage has a following coupling to a gain pot, or bias R,
the noise output
needs more calculation.

But ppl say a choke is the quietest element to use.

Expensive. One of the most appealingly silent amps I ever built had a
choke as grid leak. Unfortunately I didn't save one of those vintage
chokes for reverse engineering. But an SS constant current load is
also has a pretty good noise performance.

But I find an actice device such a san MJE50 as a CCS is NOT noisier
than the R,
and probably because it is shunted the triode noise which has Rout = Ra
= 10k.

Rueful grin. I should read the whole post before I waste my breath
replying!

And here I show how to solve the problem: "The solution is not fancy
resistors (you usually can't get them in the right ratings) but to use
standard oversized metal films in smaller values in series, say 6x10K
rather than one 62K." Thus you get both the silence of the smaller
ohmic value of each resistor (6x10k makes less noise than one by 62K)

Considering how much consternation this statement caused among the
unwashed and the illiterate, I should perhaps have put the next phrase
in capitals to shout it from the rooftops:

and the silence of the oversized resistors running cooler.

Yes, that's right, punters, this works by NOT reducing the rating of
the resistors when you reduce the values and series them to make up
the total.

*That* is
why on all my amps the power resistors are, in strictly cost-
accounting engineering terms, overspecified; ditto for all the best
audiophile-designed tube amps. (The idiot Worthless Wieckless made an
offensive song and dance about overspecced resistors in my T39 Ultra-
Fi once because he is bog-ignorant -- I very carefully didn't explain
the real reason to him; he's such a wretched little man that nobody
else helped him out either. But those big ballast resistors account
for a good part of the silence of the amp.)

Perhaps you may have to think this through again.

Nah, I got it right first time. And I had Bill measure and calculate
the total noise when I first did this, a decade or more ago. It works.

OK, say you have 6 x 10k in series.

Each one makes a noise = noise of 60k x sq.rt of ( 60/10 ).
10k obviuously has less noise than 60k.

In fact the noise with 6 resistors in series = sq.rt ( sum of the
squares of each amount of noise )

And you should find that 0ne 60k resistor of 6 watts rating has exactly
the same noise at 6 x 10k x 1 watt in series.

If the 10k were all paralleled, noise would indeed be lower, but the R
wouldn't be right
for the anode load.
There are no free lunches on resistor noise to be had by series
connection
of well rated quality resistors, unless the connection leads to the R
operating
without any T rise. T rise makes noise worse; hot is noisier than
cooler.

Tres exactement. That is why I treated the attempt by the usual
hairsplitters to separate excess noise from thermal noise in a
practical application with derision. I understand why West wants to
separate them: the texts he's been reading do. But experienced DIYers
know that in practice they are interrelated for the reason Iain
Churches pointed out so bluntly: that we work with 2W resistors by
choice even when the cost-engineering answer would be an 0.6W
resistor.

A 60k anode load for a 6SN7 which comprises of say 10 x 600k x 1 watt
all paralleled to get
60k won't have any noise difference to ONE 6 watt 60k, or 10 x 6k x 1
watt in series,
providing the temp is the same, which is should be if the total 60k
wattage is the same,
or whatever is used to makes sure T remains the same.

But in practice bigger resistors are used when you split the value and
build it up again by series addition of resistance.

All the rest is, as I say, audiophoolery or "experts" tripping over
each other in their eagerness to show off.

Nobody stops you experimenting for yourself though; discovering
whether you like one sort of component better than another is half the
fun of building your own tube amps. There was a time when I swore by
Dale "non-inductive" cathode resistors on 300B and 845; today I just
use the 50W ali-cased jobs out of the RS catalogue. And I still like
Solen polyprops better than any other kind; you can get Solens in the
widest possible range of values in high voltage ratings and they sound
right in my amps and don't take up as much space as the (more
expensive) motor run polys I can buy locally.

I like whatever nice metal film 1% R I can find; I use Welwyn from RS
Components mostly
ever since the Reistor Mafia, Vishay, took over Beyschlag, and the local
distributor was bought
by a darn american company.
The result of these changes meant Beyshlag price of 10c per R for a
genuine 1 watt went to 45c,
and you were compelled to buy 1,000 as the minimum number.

When you want to buy say 50 pcs of all standard values between 1ohm and
4.7M, its very expensive.

Just watch out with voltage ratings on resistors; even high value like
470k and 1M don't
like more than 250V sometimes across them. Welwyn sure don't, and I had
3 x 470k in parallel for a
tail between commoned cathodes in an LTP to -400V, and in both monoblocs
( Quad-II, very revised )
one of the 3 went to a short!

I've gone right off kilovolt amps, among other reasons because it is
so difficult to get components of the right ratings. (It is years
since I published a kilovolt amp; I stopped doing that when I
discovered people were rushing out to buy their first soldering iron
and their first DMM -- with the intention of building one of my
kilovolt amps!)

I like Wima polyprops; I cannot find anyone who can tell me better than
chance will predict,
ie, 50 - 50, which channel has all Wimas and which has all polesters, or
other types/brands of polyprops.

I don't think it matters which polyprops you use, as long as you use
polys (and other films where suitable). I like the Solens because I
have a big stock and because they are small. I have custom-made 50uF
1200V which are (without finding them and measuring one) about an inch
diameter by about four inches high, very modest when you consider that
a standard good quality Italian Comal 47uF 450V motor run electro that
I can buy locally in bulk (for about the same price as a rare and
wonderful Solen!) is two inches diameter by about eight inches high,
and requires many caps and much real estate to make the value/rating
required. Even the standard motor run polys out of RS would require at
least four caps, much more real estate, and many more spondulicks than
the Solen. That's why Solen rules.

Sometimes i find the size of tube-capable components so overbearing
that I consider going over permanently to the Dark Side (where there
is only SS).

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

[Eeyore]

Andre Jute wrote:

Patrick Turner wrote:

But ppl say a choke is the quietest element to use.

Expensive. One of the most appealingly silent amps I ever built had a
choke as grid leak.

A classic deficiency of tube electronics that it needs such expensive molly-coddling.

Graham

[Andre Jute]

RdM wrote:
Andre Jute in
rec.audio.tubes1181297050.598664.69190@e65g2000hs c.googlegroups.com:

(1) Do you know the origin of the word tantrum? I have a letter here
from a lady whose surname is Tantrum inviting me to drink champagne at
the launch of a piano festival. Makes one wonder if it wouldn't be
politic to put aside my aversion to time-wasting cocktail party
chatter just this once and put in an appearance.

Ah, Connie Tantrum. The New Ross Piano Festival. Perhaps you should go?
The various accommodations linked look OK.

I'm just final throes of packaging up for market a major literary
project from a young protege. After that I'll have to catch up on
other responsibilities. Doubt whether I can make it.

I'll celebrate my 55th, the 30th.

Congratulations. Thanks for looking this up:

Most sources assert "origin unknown", one or two "uncertain", as you know...

No, I didn't, actually. I very rarely have to look up the words I
know, and I'm making a conscious effort not to learn any new ones.

The Kernerman English Multilingual Dictionary shows interesting similiarities
among Scandinavian and even Estonian equivalents, though - looks like rage?

A great-uncle of mine, a historian, worked at a desk both at home and
at college surrounded by a halfmoon of lecterns on which rested big
library-type dictionaries. I went to visit him with my painting
teacher and my favourite English teacher, and he said to me, "History
is about the meaning of the words we use to describe it." This was
before Noah Chomsky and others of that stripe were famous. As we drove
away, I said to my two teachers, "That's crap. History is what people
did, not the words they twisted afterwards to justify themselves." (My
actual history teacher was an ignorant clown; as soon as I could I
persuaded the headmaster to let me drop the formal study of history
because I would learn nothing from this fool.) The two teachers with
me said variants on, "That's an artist's viewpoint. Your uncle is
great historian; he has to know something." I'm sorry now I didn't
listen to him more carefully, not about the methodology but about my
own family's history.

- looks like rage?

A couple of days ago I was at an abbey that my ancestors sacked three
times in four centuries a millennium ago. I really wished I'd paid
more attention so that I knew more to pass on to the next generation.
My son was at a college where his great-grandmother's diaries are in
one of the collections; he never bothered to read them. Some people
have too much history. Yet the wives of American Senators and
Songressmen (they're both actually congressmen but you know what I
mean) come here and don't want to be taken to the ballet or the
National Gallery, they want to go to cemetries because Americans don't
have any.

Ross Matheson
--
Auckland, New Zealand.

"Perhaps I, too, will be renewed..."

Andre Jute
Habit is the nursery of errors. -- Victor Hugo

[Andre Jute]

Eeyore wrote:
Andre Jute wrote:

Patrick Turner wrote:

But ppl say a choke is the quietest element to use.

Expensive. One of the most appealingly silent amps I ever built had a
choke as grid leak.

A classic deficiency of tube electronics that it needs such expensive molly-coddling.

Graham

Poopie! So nice to hear from you. But, as usual, you are confused.
This time your confusion is between the necessary expense of building
the best equipment and the mollycoddling required to keep poorly
designed equipment running even inadequately. A tube amp with a choke
grid leak or a choke plateload you just build and play and forget
about; it lasts forever without attention. Zero mollycoddling, zero
negative feedback, maximum pleasure. Who cares about the expense
except those who can't afford the pleasure?

It is of course always worth saying that those challenged by their
taste or finances needn't choose tubes: there is always solid state
and I am told many unfortunates find SS perfectly adequate. I suspect
you will too.

Hope this unconfuses you at least until tomorrow.

Andre Jute
"You don't need global feedback to build a good-sounding amplifier."
-- Henry Pasternack

[west[_4_]]

"Andre Jute" wrote in message
oups.com...

Jon Yaeger wrote:
semen
Oops! That should be "seamen." What was I thinking???

Would you mind not telling us about your work. We're trying to clean
up RAT. Thanks for your understanding. -- Andre Jute

I'm sure you must realize that you make the shifty peddler's day when you
condescend to answer him.

west

[west[_4_]]

"Patrick Turner" wrote in message
...


west wrote:

"Patrick Turner" wrote in message
...


west wrote:

There are several different types of noise to avoid and reduce, if
we
can,
in designing tube circuits, from what I been studying. We can
discuss
these
different types of noises in general but for now I would like to
concentrate
on 1 type of noise, current noise, the kind that is generated in a
plate
load resistor. I believe that this is especially important in preamp
circuits.
Some tubies advocate that boutique components are all fluff and a
waste
of
money and I think they have a point, to a degree. However, will a
low
noise
resistor make a difference in reducing plate current noise? If yes,
then
they can make a difference.
The question is ...can we quantify this difference and how? I think
it
would
be cool to measure this noise and simultaneously hear what
difference a
low
noise boutique resistor can make. I may be off base with this idea,
if
so
chalk it up to an inexperienced but eager to learn Rodent. Thoughts?
Thanks.

Cordially,
west

If you study RDH4 about noise and resistance, you won't need to ask
your
question here
because the book has the answers.

Or, the question you might ask if you had studied RDH4 might be one
unanswered by RDH4,
and then its worth asking here, eh.

Are you asking what is the EXTRA noise a resistor generates when a DC
or
AC flow exists?

Do you undertsand your own question?


Patrick Turner.

I think Phil A. answered your question already.

west

Neither you or Phil A have been informative on this subject.



Patrick Turner.

I can't speak for Phil, but you're correct about me. Isn't that why I ask
the question? ... So, what's your point, Professor?

west

[Patrick Turner]

west wrote:

"Andre Jute" wrote in message
oups.com...

Jon Yaeger wrote:
semen
Oops! That should be "seamen." What was I thinking???

Would you mind not telling us about your work. We're trying to clean
up RAT. Thanks for your understanding. -- Andre Jute

I'm sure you must realize that you make the shifty peddler's day when you
condescend to answer him.

west

The award for the greatest shifty peddler who ever has been seen in a
long while
must go to a lady called Mary I saw last year in a local concert
which was broadcast on the national FM station Classic FM.

This lady played a concert harp, and used both hands and both feet to
peddle
everything pedle-able flat out in a hurry.
She made Jimmy Hendrix sound like a hopeless amateur
when she engaged with some electronic equipment and with her electrified
concert harp,
one of 3 harps on stage.

Bravo indeed!

Boy could she shift!

Lance Armstrong also peddles a bit, but makes no music while we all
wince
when we see him ride up mountains; poetry in motion? perhaps.
Boy does that man shift!

Let's here a cheer for the shifty peddlers.

Patrick Turner.

[Patrick Turner]

west wrote:

"Patrick Turner" wrote in message
...


west wrote:

"Patrick Turner" wrote in message
...


west wrote:

There are several different types of noise to avoid and reduce, if
we
can,
in designing tube circuits, from what I been studying. We can
discuss
these
different types of noises in general but for now I would like to
concentrate
on 1 type of noise, current noise, the kind that is generated in a
plate
load resistor. I believe that this is especially important in preamp
circuits.
Some tubies advocate that boutique components are all fluff and a
waste
of
money and I think they have a point, to a degree. However, will a
low
noise
resistor make a difference in reducing plate current noise? If yes,
then
they can make a difference.
The question is ...can we quantify this difference and how? I think
it
would
be cool to measure this noise and simultaneously hear what
difference a
low
noise boutique resistor can make. I may be off base with this idea,
if
so
chalk it up to an inexperienced but eager to learn Rodent. Thoughts?
Thanks.

Cordially,
west

If you study RDH4 about noise and resistance, you won't need to ask
your
question here
because the book has the answers.

Or, the question you might ask if you had studied RDH4 might be one
unanswered by RDH4,
and then its worth asking here, eh.

Are you asking what is the EXTRA noise a resistor generates when a DC
or
AC flow exists?

Do you undertsand your own question?


Patrick Turner.

I think Phil A. answered your question already.

west

Neither you or Phil A have been informative on this subject.



Patrick Turner.

I can't speak for Phil, but you're correct about me. Isn't that why I ask
the question? ... So, what's your point, Professor?

My dear learned friend, I humbly asked if *you* understood the question
you asked.

Its possible for someone perplexed mightily about some aspect of
electronic behaviours
to deposit a question to the supposed professors in this group, but not
quite know exactly
what they ask, or sufficiently define the matters troubling them, thus
rendering answers given about noise
be useless, including directions to Google, and or to books such as
RDH4.

Well trained experts can fall to this conundrum as can any newbie,
oldie,
or whatever.

As someone who has a medium understanding of noise in conductors, and in
vacuuum tube circuits,
is the the question you ask "apart from Johnson noise in resistors, what
is the noise caused by signal and dc
current flow in resistors?"

Allison swore at me over the issue, indicating that I didn't understand
your question,
and indicating I damn well should have, but of course as usual didn't
say what I should have understood.


Now just what was it that you asked?

Patrick Turner.



west

[Jon Yaeger]

in article xhUai.3065$pd5.1325@trnddc02, west at wrote on
6/10/07 10:55 AM:


"Andre Jute" wrote in message
oups.com...

Jon Yaeger wrote:
semen
Oops! That should be "seamen." What was I thinking???

Would you mind not telling us about your work. We're trying to clean
up RAT. Thanks for your understanding. -- Andre Jute

I'm sure you must realize that you make the shifty peddler's day when you
condescend to answer him.

west



Pest,

My delight in receiving attention from Andre is only exceeded by the thrill
of seeing what stupid and lazy drivel you've posted on any given day . . . .

[Iain Churches]

"Chris Hornbeck" wrote in message
...
On Fri, 08 Jun 2007 03:00:52 GMT, "Ian Iveson"
wrote:

Why not just explain what you believe it to be? Or at least suggest
how we might find out.

You're right, of course. Lately I'm becoming the kind of asshole
I dislike the most, and I need to do a lot better.

So, OK. There are classically two broad categories of noise,
thermal and everything else. The "everything else" is called
excess noise, because .... well, because it's in excess of
predicted, right and true, and entirely proper, thermal noise.

But what is thermal noise? It's an expression of the randomness
(noise) of electrons living their happy little lives, hopping
from bed to bed, impregnating no one. The higher the temperature
of their world, the more they hop, and the larger the resistance
within which they're moving, the larger the voltage that their
movement generates. Maybe it's political; I dunno.

Thermal noise is predictable, expected, and absolutely unavoidable.
A resistor at such-n-such temperature *will*, without appelate court
recourse, generate (and I use the word very specifically) a known
voltage and spectrum of noise.

All other audio noises are lumped together under the blanket term
"excess noise". They're caused by all kinds of different mechanisms
and have all kinds of different sounds and characteristics.

So we have a noise called "current noise" that is intirely unrelated
to current flow. Isn't that a trifle perverse?

I would have thought from its name that it would appear as some
frequency distribution of current, although perhaps regardless of
resistance and consequent voltage, and perhaps regardless of any other
current flow. Your cryptic statements so far suggest this is not true.

I've rearranged the flow of your discussion to suit my own purposes.
Hoping you'll understand and forgive, let me close with this
truly trivial matter.

Active devices are often characterized with a pair of noise numbers,
equivalent input noise voltage (per root Hertz) and equivalent
input noise current (per root Hertz). These are an amazingly
useful way to describe real world performance because all we
need to know is source resistance and we can quickly know
room temperature (always close enough! in our world) equivalent
(meaning: referred to the input of the device) input noise.

The second number above, I-sub-n, or equivalent input noise
current, is simply multiplied by source resistance to generate
a number (called, in my circles "current noise") that's square
root of the sum of the squares "added" to the equivalent input
noise voltage over expected bandwidths (commonly rounded to 10
kiloHertz (for perhaps surprisingly good reasons).

There are many "excess" noises. I feel strongly that a builder
needs to distinguish among them. Not an excuse for being an
asshole, of course, and I'm sorry.


To answer your question "why not?" : because it takes an oversized
post like this to just touch on the topic. I already feel like
a fool for trying to post a Cliff Notes version of feedback issues,
and *nobody* has pitched in to help with that elephant, or seems
to care one way or another. Ce la vie.

Chris. Excellent and enlightening post. Thanks for taking the time to
put it all into black and white.

Iain

[Iain Churches]

"Peter Wieck" wrote in message
ups.com...
On Jun 6, 9:35 pm, "west" wrote:

Some good information on tube noise (basic) may be found at:

http://www.john-a-harper.com/tubes201/

There is much else good and basic at this source.

Thanks Peter. Very good link.
Iain