DecadentLinux...@decadence.org wrote:
================================
>
> > ** The AC supply has a fair amount of 3rd and 5th harmonics that
> > are often more audible that the fundamental.
> > But SFA 2nd.
> > Magnetic hum fields radiated from transformers is mostly 3rd
> > to.
> >
> But if it gets rectified, the ripple on a badly designed supply
> exhibits noise at f*2.

** Well yes,

the hum you hear from an amp with bad filter electros is 100 or 120Hz.

....... Phil

Ricky wrote:
============
>>
> > > > A narrow notch rings as badly as a narrow peak when fed with
> > > > a spiky signal.
> > >
> > > At what frequency does it ring?

> > ** Ringing (as seen on a scope) is at the same frequency as the notch minimum.
> > But you will not find it in a spectrum analysis.
>
> Let's construct a mind experiment to analyze that idea.
> If you stimulate a notch filter with an impulse,
> a signal containing all frequencies in equal amplitude,
> what will emerge from the notch filter is a ring at the frequency
> at which the filter is supposed to have a null?
>

** But will not show up on a spectrum analysis.
That will look as expected, ie missing a chunk.

> Is that logically consistent with the frequency response of the filter?

** The " ringing" seen on a scope is an *artefact* - created by missing
and phase shifted components of the input signal.
Same goes for square wave inputs.
All components must be there in the right amounts and phase relationships to get a square looking result.
Brilliant example for " cognitive dissonance" for most people.

....... Phil

On 8.4.22 5.18, Ricky wrote:
> On Thursday, April 7, 2022 at 9:31:47 PM UTC-4, Ricky wrote:
>> On Thursday, April 7, 2022 at 1:29:01 PM UTC-4, Tauno Voipio wrote:
>>> On 7.4.22 2.52, Phil Allison wrote:
>>>> Ricky wrote:
>>>> ==========
>>>>
>>>>> An adequately narrow band reject filter would have virtually no impact on the signal of interest.
>>>>
>>>> ** Shame you have never looked at the phase and amplitude curve of such a filter.
>>>>
>>>>
>>>>> It only need be wide enough to accommodate the normal variations in mains frequency.
>>>>
>>>> ** About 0.1Hz is all the AC supply varies by.
>>>>
>>>>
>>>> ...... Phil
>>> Right!
>>>
>>> A narrow notch rings as badly as a narrow peak when fed with
>>> a spiky signal.
>> At what frequency does it ring?
>
> The reason I ask, is because if the ringing is high enough frequency, it is out of band and can be filtered out. I'm willing to bet there is an inverse relationship between the half bandwidth of the notch and the ringing frequency. If it is narrow enough (which is what is desired) it will produce ringing that is far out of band and easily filtered. I believe I read the ECG bandwidth is 150 Hz. I expect it would not be too hard to push the ringing frequency up to a range that is easily filtered.
>
> On doing a bit of research on the matter, it seems to be a much discussed topic, but with no definitive solution. However, here is a paper that seems to say the solution is really in the way the electrodes are attached.
>
> https://www.aami.org/docs/default-source/bi-t/bit/2012-bit-nd-ecg.pdf
>

So, you're approaching the beef now.

The kilo-ohm impedances of electrodes are there *after* cleaning
the skin and removing the dear chest hair. There was also electrode
paste between the siver plate of the electorode and the skin.

You did not respond to my question about a reference electrode.

--

-TV

On 4/7/2022 4:19 AM, Phil Allison wrote:
> erichp...@hotmail.com wrote:
> =======================
>>>
>>>>> My guess is that the hum is coming from your patient / target.
>>>>>
>>>>> The capacitance of an average person is about ...
>
>> I think that when OP tried battery power he was still examining the
>> output on a mains connected scope? Interesting would be what is seen
>> with a battery powered scope and the whole system free of any connection
>> to mains ground.
>
> ** That is my contention too, posted 2 days ago.
>>
> The ECG amp will probably be heavily low pass filtered
>> somewhere along the chain so the HF interference won't be seen at the
>> output but it's 100Hz modulation rate will be?
>
> ** Huh ? 100Hz ?
>
> Think is is just simple capacitive coupled injection of the AC supply voltage wave.
> The bane of many poorly shielded electric guitars .
>
>
> ...... Phil
>

You can tell a guitarist it's a good idea to shield the cavity, 7/10
times he won't listen though and if you start talking about "capacitive
coupled injection" he's even less likely to.

On Fri, 8 Apr 2022 16:14:53 -0400, bitrex <user@example.net> wrote:

>On 4/7/2022 4:19 AM, Phil Allison wrote:
>> erichp...@hotmail.com wrote:
>> =======================
>>>>
>>>>>> My guess is that the hum is coming from your patient / target.
>>>>>>
>>>>>> The capacitance of an average person is about ...
>>
>>> I think that when OP tried battery power he was still examining the
>>> output on a mains connected scope? Interesting would be what is seen
>>> with a battery powered scope and the whole system free of any connection
>>> to mains ground.
>>
>> ** That is my contention too, posted 2 days ago.
>>>
>> The ECG amp will probably be heavily low pass filtered
>>> somewhere along the chain so the HF interference won't be seen at the
>>> output but it's 100Hz modulation rate will be?
>>
>> ** Huh ? 100Hz ?
>>
>> Think is is just simple capacitive coupled injection of the AC supply voltage wave.
>> The bane of many poorly shielded electric guitars .
>>
>>
>> ...... Phil
>>
>
>You can tell a guitarist it's a good idea to shield the cavity, 7/10
>times he won't listen though and if you start talking about "capacitive
>coupled injection" he's even less likely to.

Some years ago, I was the unofficial chief (and only) engineer of a
local guitar maker (the owner is a friend of mine).

You don't try to convince the guitarist (who just wants low noise),
you talk to the guitar maker (who just wants to know exactly how to do
that). And few guitar makers are electronic engineers.

The remedy for capacitive injection was to electro statically shield
the routed cavity, originally by carefully fitted brass foil shielding
tubs, then (after I arrived) by nickel-dust based shield paint sprayed
thickly on the walls of the cavity. The DC resistance between any two
points on the cavity wall was about 20 ohms. The underside of the
pick guard had an aluminum foil layer glued on. These shields were
all grounded to the shield of the coax wire from guitar to amp. The
strings were also grounded.

The remedy for magnetic interference, chiefly at power frequencies and
harmonics, is various kinds of humbucking construction.

Joe Gwinn

PS: What I also did was to invent various kinds of jigs and fixtures,
and introduce them to various kinds of tool not found in luthier tool
catalogs. This collectively had a large impact on their manufacturing
costs. JMG

On Friday, April 8, 2022 at 7:47:21 AM UTC-4, Tauno Voipio wrote:
> On 8.4.22 5.18, Ricky wrote:
> > On Thursday, April 7, 2022 at 9:31:47 PM UTC-4, Ricky wrote:
> >> On Thursday, April 7, 2022 at 1:29:01 PM UTC-4, Tauno Voipio wrote:
> >>> On 7.4.22 2.52, Phil Allison wrote:
> >>>> Ricky wrote:
> >>>> ==========
> >>>>
> >>>>> An adequately narrow band reject filter would have virtually no impact on the signal of interest.
> >>>>
> >>>> ** Shame you have never looked at the phase and amplitude curve of such a filter.
> >>>>
> >>>>
> >>>>> It only need be wide enough to accommodate the normal variations in mains frequency.
> >>>>
> >>>> ** About 0.1Hz is all the AC supply varies by.
> >>>>
> >>>>
> >>>> ...... Phil
> >>> Right!
> >>>
> >>> A narrow notch rings as badly as a narrow peak when fed with
> >>> a spiky signal.
> >> At what frequency does it ring?
> >
> > The reason I ask, is because if the ringing is high enough frequency, it is out of band and can be filtered out. I'm willing to bet there is an inverse relationship between the half bandwidth of the notch and the ringing frequency. If it is narrow enough (which is what is desired) it will produce ringing that is far out of band and easily filtered. I believe I read the ECG bandwidth is 150 Hz. I expect it would not be too hard to push the ringing frequency up to a range that is easily filtered.
> >
> > On doing a bit of research on the matter, it seems to be a much discussed topic, but with no definitive solution. However, here is a paper that seems to say the solution is really in the way the electrodes are attached.
> >
> > https://www.aami.org/docs/default-source/bi-t/bit/2012-bit-nd-ecg.pdf
> >
> So, you're approaching the beef now.
>
> The kilo-ohm impedances of electrodes are there *after* cleaning
> the skin and removing the dear chest hair. There was also electrode
> paste between the siver plate of the electorode and the skin.
>
> You did not respond to my question about a reference electrode.

That should be addressed to the OP. It's not my setup.

I've already mentioned that current practice either uses a single reference electrode, or combines the signals from all electrodes to use as a common reference for all electrodes. This gives N signals for N leads rather than N-1 signals.

What are you looking for with the question?

When you mention kilo-ohm impedances, that is low relative to the amplifier input. It's also low enough for stray coupling to only produce a relatively low voltage in the signal. That is what the OP is seeing, a low voltage "hum" on his signal. It actually would not take much filtering to make that noise virtually invisible.

You didn't answer my question about the frequency of the notch filter ringing.

I believe the required characteristics of the notch filter in this application would not produce noticeable ringing.

--

Rick C.

+-+ Get 1,000 miles of free Supercharging
+-+ Tesla referral code - https://ts.la/richard11209

Joe Gwinn wrote:
==============
>>
> >> Think is is just simple capacitive coupled injection of the AC supply voltage wave.
> >> The bane of many poorly shielded electric guitars .
>>
> >> ...... Phil
>>>
>
> The remedy for capacitive injection was to electro statically shield
> the routed cavity, originally by carefully fitted brass foil shielding
> tubs, then (after I arrived) by nickel-dust based shield paint sprayed
> thickly on the walls of the cavity. The DC resistance between any two
> points on the cavity wall was about 20 ohms. The underside of the
> pick guard had an aluminum foil layer glued on. These shields were
> all grounded to the shield of the coax wire from guitar to amp. The
> strings were also grounded.
>
> The remedy for magnetic interference, chiefly at power frequencies and
> harmonics, is various kinds of humbucking construction.
>

** All these things were well known and adopted by makers like Gibson in the 1950s.
But they were a luxury brand sold to professionals.
A radio repair man called Leo Fender began making similar things, very cheaply.
https://en.wikipedia.org/wiki/Leo_Fender#Early_life

Working at a time when triac dimmers were unknown and likewise safety earthing - he gave almost no attention to ES shielding.
His famous Stratocaster guitar has only a token effort at such and is a first class receiver of hum and buzzing from the AC supply.
Nearby fluoro lighting drives one crazy.
https://insounder.org/under-hood-9-evolution-stratocasters-electronics-wiring

Note the use of plastic covered pickups, unshielded wiring and no cavity shielding at all.
Fender relied on the player earthing themselves via the steel strings to proved any measure of shielding.
AFAIK even recent examples are little better.
The instrument is considered to be is '"sacred" by players and must not be changed.

........ Phil

On Thu, 7 Apr 2022 19:23:40 -0700 (PDT), Ricky
<gnuarm.deletethisbit@gmail.com> wrote:

>On Thursday, April 7, 2022 at 10:01:41 PM UTC-4, palli...@gmail.com wrote:
>> Ricky wrote:
>> ===============
>> >Tauno Voipio wrote:
>> > Phil Allison wrote:
>> >
>> > > >
>> > > >> An adequately narrow band reject filter would have virtually no impact on the signal of interest.
>> > > >
>> > > > ** Shame you have never looked at the phase and amplitude curve of such a filter.
>> > > >
>> > > Right!
>> > >
>> > > A narrow notch rings as badly as a narrow peak when fed with
>> > > a spiky signal.
>> >
>> > At what frequency does it ring?
>> ** Ringing (as seen on a scope) is at the same frequency as the notch minimum.
>> But you will not find it in a spectrum analysis.
>
>Let's construct a mind experiment to analyze that idea. If you stimulate a notch filter with an impulse, a signal containing all frequencies in equal amplitude, what will emerge from the notch filter is a ring at the frequency at which the filter is supposed to have a null?
>
>Is that logically consistent with the frequency response of the filter?

Might I suggest a variation of Jan's idea?

1. Digitize the waveform
2. Feed a 50Hz signal of equal amplitude into a mixer together with
the digitized waveform.
3. Adjust the phase of the 50Hz signal until the interference is
cancelled out.

I believe this method will have the least detrimental effect on the
desired trace.
In fact it might be possible to use an app like Audacity to do all the
above with just a few mouse clicks, as I'm pretty sure there's a spot
frequency filter somewhere in the software.

Cursitor Dope wrote:

====================
> >
>
> 1. Digitize the waveform
> 2. Feed a 50Hz signal of equal amplitude into a mixer together with
> the digitized waveform.
> 3. Adjust the phase of the 50Hz signal until the interference is
> cancelled out.

** Huh ???

Makes no sense at all.

> In fact it might be possible to use an app like Audacity to do all the
> above with just a few mouse clicks, as I'm pretty sure there's a spot
> frequency filter somewhere in the software.

** FYI Mr Dope

The AC mains wave drifts in frequency and phase and changes amplitude in the ECG trace with a host of external factors.

........ Phil

On Friday, April 8, 2022 at 7:56:53 PM UTC-4, Cursitor Doom wrote:
> On Thu, 7 Apr 2022 19:23:40 -0700 (PDT), Ricky
> <gnuarm.del...@gmail.com> wrote:
>
> >On Thursday, April 7, 2022 at 10:01:41 PM UTC-4, palli...@gmail.com wrote:
> >> Ricky wrote:
> >> ===============
> >> >Tauno Voipio wrote:
> >> > Phil Allison wrote:
> >> >
> >> > > >
> >> > > >> An adequately narrow band reject filter would have virtually no impact on the signal of interest.
> >> > > >
> >> > > > ** Shame you have never looked at the phase and amplitude curve of such a filter.
> >> > > >
> >> > > Right!
> >> > >
> >> > > A narrow notch rings as badly as a narrow peak when fed with
> >> > > a spiky signal.
> >> >
> >> > At what frequency does it ring?
> >> ** Ringing (as seen on a scope) is at the same frequency as the notch minimum.
> >> But you will not find it in a spectrum analysis.
> >
> >Let's construct a mind experiment to analyze that idea. If you stimulate a notch filter with an impulse, a signal containing all frequencies in equal amplitude, what will emerge from the notch filter is a ring at the frequency at which the filter is supposed to have a null?
> >
> >Is that logically consistent with the frequency response of the filter?
> Might I suggest a variation of Jan's idea?
>
> 1. Digitize the waveform
> 2. Feed a 50Hz signal of equal amplitude into a mixer together with
> the digitized waveform.
> 3. Adjust the phase of the 50Hz signal until the interference is
> cancelled out.
>
> I believe this method will have the least detrimental effect on the
> desired trace.
> In fact it might be possible to use an app like Audacity to do all the
> above with just a few mouse clicks, as I'm pretty sure there's a spot
> frequency filter somewhere in the software.

Sure, that will work for an amateur setup like what is discussed here... as long as nothing moves during the recording. That will only work for a stationary signal.

--

Rick C.

++- Get 1,000 miles of free Supercharging
++- Tesla referral code - https://ts.la/richard11209

On Fri, 8 Apr 2022 16:14:36 -0700 (PDT), Phil Allison
<pallison49@gmail.com> wrote:

>Joe Gwinn wrote:
>==============
>>>
>> >> Think is is just simple capacitive coupled injection of the AC supply voltage wave.
>> >> The bane of many poorly shielded electric guitars .
>>>
>> >> ...... Phil
>>>>
>>
>> The remedy for capacitive injection was to electro statically shield
>> the routed cavity, originally by carefully fitted brass foil shielding
>> tubs, then (after I arrived) by nickel-dust based shield paint sprayed
>> thickly on the walls of the cavity. The DC resistance between any two
>> points on the cavity wall was about 20 ohms. The underside of the
>> pick guard had an aluminum foil layer glued on. These shields were
>> all grounded to the shield of the coax wire from guitar to amp. The
>> strings were also grounded.
>>
>> The remedy for magnetic interference, chiefly at power frequencies and
>> harmonics, is various kinds of humbucking construction.
>>
>
>** All these things were well known and adopted by makers like Gibson in the 1950s.
>But they were a luxury brand sold to professionals.
>A radio repair man called Leo Fender began making similar things, very cheaply.
>https://en.wikipedia.org/wiki/Leo_Fender#Early_life

That's my understanding too.

>Working at a time when triac dimmers were unknown and likewise safety earthing - he gave almost no attention to ES shielding.
>His famous Stratocaster guitar has only a token effort at such and is a first class receiver of hum and buzzing from the AC supply.
>Nearby fluoro lighting drives one crazy.
>
><https://insounder.org/under-hood-9-evolution-stratocasters-electronics-wiring>
>
>Note the use of plastic covered pickups, unshielded wiring and no cavity shielding at all.
>Fender relied on the player earthing themselves via the steel strings to proved any measure of shielding.
>AFAIK even recent examples are little better.

All true.

>The instrument is considered to be is '"sacred" by players and must not be changed.

Also true.

One thing that people do is to put a larger coil in the bottom of the
routed-out tub, and use that to humbuck the old-school singlecoil.
With good ES shielding and grounding of everything, this can help a
lot. There is a patent on this, but I don't recall the number
offhand.

Joe Gwinn

Joe Gwinn wrote:
===============
>>
> >> >> Think is is just simple capacitive coupled injection of the AC supply voltage wave.
> >> >> The bane of many poorly shielded electric guitars .
> >>>
>> >>>>
> >>
> >> The remedy for capacitive injection was to electro statically shield
> >> the routed cavity, originally by carefully fitted brass foil shielding
> >> tubs, then (after I arrived) by nickel-dust based shield paint sprayed
> >> thickly on the walls of the cavity. The DC resistance between any two
> >> points on the cavity wall was about 20 ohms. The underside of the
> >> pick guard had an aluminum foil layer glued on. These shields were
> >> all grounded to the shield of the coax wire from guitar to amp. The
> >> strings were also grounded.
> >>
> >> The remedy for magnetic interference, chiefly at power frequencies and
> >> harmonics, is various kinds of humbucking construction.
> >>
> >
> >** All these things were well known and adopted by makers like Gibson in the 1950s.
> >But they were a luxury brand sold to professionals.
> >A radio repair man called Leo Fender began making similar things, very cheaply.
> >https://en.wikipedia.org/wiki/Leo_Fender#Early_life
> That's my understanding too.
> >Working at a time when triac dimmers were unknown and likewise safety earthing - he gave almost no attention to ES shielding.
> >His famous Stratocaster guitar has only a token effort at such and is a first class receiver of hum and buzzing from the AC supply.
> >Nearby fluoro lighting drives one crazy.
> >
> ><https://insounder.org/under-hood-9-evolution-stratocasters-electronics-wiring>
> >
> >Note the use of plastic covered pickups, unshielded wiring and no cavity shielding at all.
> >Fender relied on the player earthing themselves via the steel strings to proved any measure of shielding.
> >AFAIK even recent examples are little better.
> All true.
> >The instrument is considered to be is '"sacred" by players and must not be changed.
> Also true.
>
> One thing that people do is to put a larger coil in the bottom of the
> routed-out tub, and use that to humbuck the old-school singlecoil.
> With good ES shielding and grounding of everything, this can help a
> lot. There is a patent on this, but I don't recall the number
> offhand.
>

** There is no huge problem with players standing a few metres away from any AC transformers in the vicinity.
The mag field from an AC transformer is purely short range.
The need for humbucking PUs arose from those who sit next to or even on top of their amps.

As it happens, nearly all humbucking PUs have full ES shielding too, so are dead quiet.

........ Phil

Foulmouthed Australian troll...

--
Phil Allison <pallison49@gmail.com> wrote:

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> Newsgroups: sci.electronics.design
> Date: Tue, 5 Apr 2022 14:48:34 -0700 (PDT)
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> Injection-Info: google-groups.googlegroups.com; posting-host=27.33.69.193; posting-account=B_tJMAoAAAAmar-1r2H3x4CMhbFEou3n
> NNTP-Posting-Host: 27.33.69.193
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> User-Agent: G2/1.0
> MIME-Version: 1.0
> Message-ID: <cbab2f4d-9771-481b-8577-a2badf6dfa02n@googlegroups.com>
> Subject: Re: Mains hum
> From: Phil Allison <pallison49@gmail.com>
> Injection-Date: Tue, 05 Apr 2022 21:48:35 +0000
> Content-Type: text/plain; charset="UTF-8"
> Lines: 12
> Xref: reader02.eternal-september.org sci.electronics.design:665184
>
> Ricky the IDIOT puked:
>
> =====================
>
>> I see the signal, it is clearly not sinusoidal.
>
> ** That is the fucking heart beat you moron !!!
> The 50/60 Hz hum is the superimposed fine wiggling.
>
> Rest of this retarded wanker's absurd drivel snipped.
>
>
> .... Phil
>
>

The John Doe troll stated the following in message-id
<sdhn7c$pkp$4@dont-email.me>:

> The troll doesn't even know how to format a USENET post...

And the John Doe troll stated the following in message-id
<sg3kr7$qt5$1@dont-email.me>:

> The reason Bozo cannot figure out how to get Google to keep from
> breaking its lines in inappropriate places is because Bozo is
> CLUELESS...

And yet, the clueless John Doe troll has continued to post incorrectly
formatted USENET articles that are devoid of content (latest example on
Sun, 10 Apr 2022 05:28:39 -0000 (UTC) in message-id
<t2tpu6$d1p$1@dont-email.me>).

NOBODY likes the John Doe troll's contentless spam.

Further, John Doe stated the following in message-id
<svsh05$lbh$5@dont-email.me> posted Fri, 4 Mar 2022 08:01:09 -0000
(UTC):

> Compared to other regulars, Bozo contributes practically nothing
> except insults to this group.

Yet, since Wed, 5 Jan 2022 04:10:38 -0000 (UTC) John Doe's post ratio to
USENET has been 56.7% of its posts contributing "nothing except insults"
to USENET.

This posting is a public service announcement for any google groups
readers who happen by to point out that the John Doe troll does not even
follow the rules it uses to troll other posters.

rUSc9rxOsuD0

On Sun, 10 Apr 2022 06:15:37 GMT, Edward Hernandez
<dtgamer99@gmail.com> wrote:

>The John Doe troll stated the following in message-id
><sdhn7c$pkp$4@dont-email.me>:
>
>> The troll doesn't even know how to format a USENET post...
>
>And the John Doe troll stated the following in message-id
><sg3kr7$qt5$1@dont-email.me>:
>
>> The reason Bozo cannot figure out how to get Google to keep from
>> breaking its lines in inappropriate places is because Bozo is
>> CLUELESS...
>
>And yet, the clueless John Doe troll has continued to post incorrectly
>formatted USENET articles that are devoid of content (latest example on
>Sun, 10 Apr 2022 05:28:39 -0000 (UTC) in message-id
><t2tpu6$d1p$1@dont-email.me>).
>
>NOBODY likes the John Doe troll's contentless spam.

You don't speak for everyone here. I personally find JD's posts very
relevant, thought-provoking and entertaining. Keep it up, JD!

On Sunday, April 10, 2022 at 12:50:21 PM UTC-4, Cursitor Doom wrote:
> On Sun, 10 Apr 2022 06:15:37 GMT, Edward Hernandez
> <dtga...@gmail.com> wrote:
>
> >The John Doe troll stated the following in message-id
> ><sdhn7c$pkp$4...@dont-email.me>:
> >
> >> The troll doesn't even know how to format a USENET post...
> >
> >And the John Doe troll stated the following in message-id
> ><sg3kr7$qt5$1...@dont-email.me>:
> >
> >> The reason Bozo cannot figure out how to get Google to keep from
> >> breaking its lines in inappropriate places is because Bozo is
> >> CLUELESS...
> >
> >And yet, the clueless John Doe troll has continued to post incorrectly
> >formatted USENET articles that are devoid of content (latest example on
> >Sun, 10 Apr 2022 05:28:39 -0000 (UTC) in message-id
> ><t2tpu6$d1p$1...@dont-email.me>).
> >
> >NOBODY likes the John Doe troll's contentless spam.
> You don't speak for everyone here. I personally find JD's posts very
> relevant, thought-provoking and entertaining. Keep it up, JD!

You are confused. JD seems to have a predilection for posting metric tonnes of BS between the very few relevant posts. Edward is talking about the spam posts. That's why he wrote "contentless spam" in place of "thought-provoking".

--

Rick C.

+++ Get 1,000 miles of free Supercharging
+++ Tesla referral code - https://ts.la/richard11209

Ricksy is confused.

Eddie's "contentless spam" came from one of my posts.

Eddie has never contributed anything to USENET, except when he got spanked
in the electronics repair group.

https://groups.google.com/g/sci.electronics.repair/c/MesPLcGU4BE

Hurt Eddie is taking that out on USENET.

Ricksy loves a troublemaker...

--
Ricky <gnuarm.deletethisbit@gmail.com> wrote:

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> Newsgroups: sci.electronics.design
> Date: Sun, 10 Apr 2022 10:08:14 -0700 (PDT)
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> References: <o70p4h94qqbdftsoe1el8suv1gmklc9np2@4ax.com> <11aa16e2-b06b-4256-abe5-da0de50e9c5bn@googlegroups.com> <cbab2f4d-9771-481b-8577-a2badf6dfa02n@googlegroups.com> <t2tpu6$d1p$1@dont-email.me> <dCu4K.172050$I_K3.30356@usenetxs.com> <uj265hlj286n11b727tdell3tm25loipm3@4ax.com>
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> Message-ID: <fec8505d-b73b-4d5c-8b6f-7e9efc50148cn@googlegroups.com>
> Subject: Re: Mains hum
> From: Ricky <gnuarm.deletethisbit@gmail.com>
> Injection-Date: Sun, 10 Apr 2022 17:08:15 +0000
> Content-Type: text/plain; charset="UTF-8"
> Lines: 32
> Xref: reader02.eternal-september.org sci.electronics.design:665733
>
> On Sunday, April 10, 2022 at 12:50:21 PM UTC-4, Cursitor Doom wrote:
>> On Sun, 10 Apr 2022 06:15:37 GMT, Edward Hernandez
>> <dtga...@gmail.com> wrote:
>>
>> >The John Doe troll stated the following in message-id
>> ><sdhn7c$pkp$4...@dont-email.me>:
>> >
>> >> The troll doesn't even know how to format a USENET post...
>> >
>> >And the John Doe troll stated the following in message-id
>> ><sg3kr7$qt5$1...@dont-email.me>:
>> >
>> >> The reason Bozo cannot figure out how to get Google to keep from
>> >> breaking its lines in inappropriate places is because Bozo is
>> >> CLUELESS...
>> >
>> >And yet, the clueless John Doe troll has continued to post incorrectly
>> >formatted USENET articles that are devoid of content (latest example on
>> >Sun, 10 Apr 2022 05:28:39 -0000 (UTC) in message-id
>> ><t2tpu6$d1p$1...@dont-email.me>).
>> >
>> >NOBODY likes the John Doe troll's contentless spam.
>> You don't speak for everyone here. I personally find JD's posts very
>> relevant, thought-provoking and entertaining. Keep it up, JD!
>
> You are confused. JD seems to have a predilection for posting metric tonnes of BS between the very few relevant posts. Edward is talking about the spam posts. That's why he wrote "contentless spam" in place of "thought-provoking".
>
> --
>
> Rick C.
>
> +++ Get 1,000 miles of free Supercharging
> +++ Tesla referral code - https://ts.la/richard11209
>
>

The John Doe troll stated the following in message-id
<sdhn7c$pkp$4@dont-email.me>:

> The troll doesn't even know how to format a USENET post...

And the John Doe troll stated the following in message-id
<sg3kr7$qt5$1@dont-email.me>:

> The reason Bozo cannot figure out how to get Google to keep from
> breaking its lines in inappropriate places is because Bozo is
> CLUELESS...

And yet, the clueless John Doe troll has continued to post incorrectly
formatted USENET articles that are devoid of content (latest example on
Sun, 10 Apr 2022 17:21:07 -0000 (UTC) in message-id
<t2v3m3$b45$5@dont-email.me>).

NOBODY likes the John Doe troll's contentless spam.

Further, Troll Doe stated the following in message-id
<svsh05$lbh$5@dont-email.me> posted Fri, 4 Mar 2022 08:01:09 -0000
(UTC):

> Compared to other regulars, Bozo contributes practically nothing
> except insults to this group.

Yet, since Wed, 5 Jan 2022 04:10:38 -0000 (UTC) Troll Doe's post ratio
to USENET has been 56.7% of its posts contributing "nothing except
insults" to USENET.

This posting is a public service announcement for any google groups
readers who happen by to point out that the John Doe troll does not even
follow the rules it uses to troll other posters.

4n1YqFVLKYL6

On 2022-04-10 19:08, Ricky wrote:
> On Sunday, April 10, 2022 at 12:50:21 PM UTC-4, Cursitor Doom wrote:
>> On Sun, 10 Apr 2022 06:15:37 GMT, Edward Hernandez
>> <dtga...@gmail.com> wrote:
>>
>>> The John Doe troll stated the following in message-id
>>> <sdhn7c$pkp$4...@dont-email.me>:
>>>
>>>> The troll doesn't even know how to format a USENET post...
>>>
>>> And the John Doe troll stated the following in message-id
>>> <sg3kr7$qt5$1...@dont-email.me>:
>>>
>>>> The reason Bozo cannot figure out how to get Google to keep from
>>>> breaking its lines in inappropriate places is because Bozo is
>>>> CLUELESS...
>>>
>>> And yet, the clueless John Doe troll has continued to post incorrectly
>>> formatted USENET articles that are devoid of content (latest example on
>>> Sun, 10 Apr 2022 05:28:39 -0000 (UTC) in message-id
>>> <t2tpu6$d1p$1...@dont-email.me>).
>>>
>>> NOBODY likes the John Doe troll's contentless spam.
>> You don't speak for everyone here. I personally find JD's posts very
>> relevant, thought-provoking and entertaining. Keep it up, JD!
>
> You are confused. JD seems to have a predilection for posting metric tonnes of BS between the very few relevant posts. Edward is talking about the spam posts. That's why he wrote "contentless spam" in place of "thought-provoking".
>

Do me, and everyone else, a pleasure and killfile him.

Jeroen Belleman

Here we go again...

Someone who loves to talk about their imaginary kill file friend.
It is not technically capable enough to ignore a THREAD BRANCH, so it whines
when others reply to an (allegedly) kill-filed poster.

Stop whining, nobody is responsible for you...

Jeroen Belleman <jeroen@nospam.please> wrote:

> On 2022-04-10 19:08, Ricky wrote:
>> On Sunday, April 10, 2022 at 12:50:21 PM UTC-4, Cursitor Doom wrote:
>>> On Sun, 10 Apr 2022 06:15:37 GMT, Edward Hernandez
>>> <dtga...@gmail.com> wrote:
>>>
>>>> The John Doe troll stated the following in message-id
>>>> <sdhn7c$pkp$4...@dont-email.me>:
>>>>
>>>>> The troll doesn't even know how to format a USENET post...
>>>>
>>>> And the John Doe troll stated the following in message-id
>>>> <sg3kr7$qt5$1...@dont-email.me>:
>>>>
>>>>> The reason Bozo cannot figure out how to get Google to keep from
>>>>> breaking its lines in inappropriate places is because Bozo is
>>>>> CLUELESS...
>>>>
>>>> And yet, the clueless John Doe troll has continued to post incorrectly
>>>> formatted USENET articles that are devoid of content (latest example on
>>>> Sun, 10 Apr 2022 05:28:39 -0000 (UTC) in message-id
>>>> <t2tpu6$d1p$1...@dont-email.me>).
>>>>
>>>> NOBODY likes the John Doe troll's contentless spam.
>>> You don't speak for everyone here. I personally find JD's posts very
>>> relevant, thought-provoking and entertaining. Keep it up, JD!
>>
>> You are confused. JD seems to have a predilection for posting metric
tonnes of BS between the very few relevant posts. Edward is talking about
the spam posts. That's why he wrote "contentless spam" in place of "thought-
provoking".
>>
>
> Do me, and everyone else, a pleasure and killfile him.
>
> Jeroen Belleman
>

Poor liddle Eddie got spanked and just can't get over it.

Unless Eddie is nym-shifting, it has never posted anything NORMAL
except when it got a severe spanking...

https://groups.google.com/g/sci.electronics.repair/c/MesPLcGU4BE

Is the stalker a nym-shifting troll, or a newbie netcop wannabe?

See also...
Peter Weiner <dtgamer99@gmail.com>
Edward H. <dtgamer99@gmail.com>
Edward Hernandez <dtgamer99@gmail.com>

Eddie is an example for all newbies. Don't get spanked!

Spanked Eddie...

--
Edward Hernandez <dtgamer99@gmail.com> wrote:

> Path: eternal-september.org!reader02.eternal-september.org!2.eu.feeder.erje.net!feeder.erje.net!feeder1.feed.usenet.farm!feed.usenet.farm!news-out.netnews.com!news.alt.net!fdc2.netnews.com!peer02.ams1!peer.ams1.xlned.com!news.xlned.com!peer01.ams4!peer.am4.highwinds-media.com!news.highwinds-media.com!fx01.ams4.POSTED!not-for-mail
> From: Edward Hernandez <dtgamer99@gmail.com>
> Subject: Re: Mains hum
> Newsgroups: sci.electronics.design,free.spam
> References: <o70p4h94qqbdftsoe1el8suv1gmklc9np2@4ax.com> <11aa16e2-b06b-4256-abe5-da0de50e9c5bn@googlegroups.com> <cbab2f4d-9771-481b-8577-a2badf6dfa02n@googlegroups.com> <t2tpu6$d1p$1@dont-email.me> <dCu4K.172050$I_K3.30356@usenetxs.com> <uj265hlj286n11b727tdell3tm25loipm3@4ax.com> <fec8505d-b73b-4d5c-8b6f-7e9efc50148cn@googlegroups.com> <t2v3m3$b45$5@dont-email.me>
> Lines: 36
> Message-ID: <qsE4K.1472441$8b1.1220420@usenetxs.com>
> X-Complaints-To: https://www.astraweb.com/aup
> NNTP-Posting-Date: Sun, 10 Apr 2022 17:27:50 UTC
> Date: Sun, 10 Apr 2022 17:27:50 GMT
> X-Received-Bytes: 2122
> Xref: reader02.eternal-september.org sci.electronics.design:665738 free.spam:17909
>
> The John Doe troll stated the following in message-id
> <sdhn7c$pkp$4@dont-email.me>:
>
>> The troll doesn't even know how to format a USENET post...
>
> And the John Doe troll stated the following in message-id
> <sg3kr7$qt5$1@dont-email.me>:
>
>> The reason Bozo cannot figure out how to get Google to keep from
>> breaking its lines in inappropriate places is because Bozo is
>> CLUELESS...
>
> And yet, the clueless John Doe troll has continued to post incorrectly
> formatted USENET articles that are devoid of content (latest example on
> Sun, 10 Apr 2022 17:21:07 -0000 (UTC) in message-id
> <t2v3m3$b45$5@dont-email.me>).
>
> NOBODY likes the John Doe troll's contentless spam.
>
> Further, Troll Doe stated the following in message-id
> <svsh05$lbh$5@dont-email.me> posted Fri, 4 Mar 2022 08:01:09 -0000
> (UTC):
>
>> Compared to other regulars, Bozo contributes practically nothing
>> except insults to this group.
>
> Yet, since Wed, 5 Jan 2022 04:10:38 -0000 (UTC) Troll Doe's post ratio
> to USENET has been 56.7% of its posts contributing "nothing except
> insults" to USENET.
>
> This posting is a public service announcement for any google groups
> readers who happen by to point out that the John Doe troll does not even
> follow the rules it uses to troll other posters.
>
> 4n1YqFVLKYL6
>
>

The John Doe troll stated the following in message-id
<sdhn7c$pkp$4@dont-email.me>:

> The troll doesn't even know how to format a USENET post...

And the John Doe troll stated the following in message-id
<sg3kr7$qt5$1@dont-email.me>:

> The reason Bozo cannot figure out how to get Google to keep from
> breaking its lines in inappropriate places is because Bozo is
> CLUELESS...

And yet, the clueless John Doe troll has continued to post incorrectly
formatted USENET articles that are devoid of content (latest example on
Sun, 10 Apr 2022 17:54:27 -0000 (UTC) in message-id
<t2v5kj$3av$2@dont-email.me>).

NOBODY likes the John Doe troll's contentless spam.

Further, John Doe stated the following in message-id
<svsh05$lbh$5@dont-email.me> posted Fri, 4 Mar 2022 08:01:09 -0000
(UTC):

> Compared to other regulars, Bozo contributes practically nothing
> except insults to this group.

Yet, since Wed, 5 Jan 2022 04:10:38 -0000 (UTC) John Doe's post ratio to
USENET has been 56.8% of its posts contributing "nothing except insults"
to USENET.

This posting is a public service announcement for any google groups
readers who happen by to point out that the John Doe troll does not even
follow the rules it uses to troll other posters.

jGjlGZ4zmCCO

Single key ignore sub-thread is the most valuable USENET filter, by far.

On Sat, 9 Apr 2022 17:46:30 -0700 (PDT), Phil Allison
<pallison49@gmail.com> wrote:

>Joe Gwinn wrote:
>===============
>>>
>> >> >> Think is is just simple capacitive coupled injection of the AC supply voltage wave.
>> >> >> The bane of many poorly shielded electric guitars .
>> >>>
>>> >>>>
>> >>
>> >> The remedy for capacitive injection was to electro statically shield
>> >> the routed cavity, originally by carefully fitted brass foil shielding
>> >> tubs, then (after I arrived) by nickel-dust based shield paint sprayed
>> >> thickly on the walls of the cavity. The DC resistance between any two
>> >> points on the cavity wall was about 20 ohms. The underside of the
>> >> pick guard had an aluminum foil layer glued on. These shields were
>> >> all grounded to the shield of the coax wire from guitar to amp. The
>> >> strings were also grounded.
>> >>
>> >> The remedy for magnetic interference, chiefly at power frequencies and
>> >> harmonics, is various kinds of humbucking construction.
>> >>
>> >
>> >** All these things were well known and adopted by makers like Gibson in the 1950s.
>> >But they were a luxury brand sold to professionals.
>> >A radio repair man called Leo Fender began making similar things, very cheaply.
>> >https://en.wikipedia.org/wiki/Leo_Fender#Early_life
>> That's my understanding too.
>> >Working at a time when triac dimmers were unknown and likewise safety earthing - he gave almost no attention to ES shielding.
>> >His famous Stratocaster guitar has only a token effort at such and is a first class receiver of hum and buzzing from the AC supply.
>> >Nearby fluoro lighting drives one crazy.
>> >
>> ><https://insounder.org/under-hood-9-evolution-stratocasters-electronics-wiring>
>> >
>> >Note the use of plastic covered pickups, unshielded wiring and no cavity shielding at all.
>> >Fender relied on the player earthing themselves via the steel strings to proved any measure of shielding.
>> >AFAIK even recent examples are little better.
>> All true.
>> >The instrument is considered to be is '"sacred" by players and must not be changed.
>> Also true.
>>
>> One thing that people do is to put a larger coil in the bottom of the
>> routed-out tub, and use that to humbuck the old-school singlecoil.
>> With good ES shielding and grounding of everything, this can help a
>> lot. There is a patent on this, but I don't recall the number
>> offhand.
>>
>
>** There is no huge problem with players standing a few metres away from any AC transformers in the vicinity.
> The mag field from an AC transformer is purely short range.
> The need for humbucking PUs arose from those who sit next to or even on top of their amps.

Not so fast. A classic source of widespread hum fields is wiring
errors or failures in the power wiring of the venue.

In the US, ring busses are not allowed, so out and back currents are
close to one another, and their magnetic fields largely cancel. Unless
someone reversed power neutral (white wire in the US) and safety
ground (green wire). Which I have personally encountered.

War story: I've also encountered broken neutrals in 240 Vac
split-phase (+120 - 0 - +120) power cables. I was attending a summer
stock play (where my kid sister was acting) held outside on the
grounds of a local school, as the light of day faded, I was looking
idly at the stage lighting, and noticed that some lights wee too blue
and other were too yellow. These lights are incandescent. Hmm. After
the play, I approached the Director and asked him if he was having
problems with things blowing out. Stunned look ... how did you
know??? Told him of the too blue and too yellow lights, and that this
implied a broken neutral. He was very interested. So we went along
the main feed cable, opening Edison connectors. We quickly found one
with the neutral completely un-connected. Director was *very* happy -
he would have had to pay for all those brand dearly-departed new
electronic dimmers. But it was the rental company's fault.

As for ring busses, which are allowed in Europe and I assume
Australia, while if both rings are intact, magnetic fields will
generally cancel, all it takes is a single ring break to force
significant currents to take the long way around.

> As it happens, nearly all humbucking PUs have full ES shielding too, so are dead quiet.

Yes, that's true these days.

I did find the patent I mentioned above. It's US 7,259,318 to Illich
Chiliachki of California. The patent is now expired because later
maintenance fees were not paid.

Joe Gwinn

Joe Gwinn wrote:
================
>
> >** There is no huge problem with players standing a few metres away from any AC transformers in the vicinity.
> > The mag field from an AC transformer is purely short range.
> > The need for humbucking PUs arose from those who sit next to or even on top of their amps.
>
> Not so fast. A classic source of widespread hum fields is wiring
> errors or failures in the power wiring of the venue.

** So you say.

> In the US, ring busses are not allowed,

** Nor here - only in the UK AFAIK.

Such a buss feed a loop of AC outlets ( active and neutral) from both ends.

> > As it happens, nearly all humbucking PUs have full ES shielding too, so are dead quiet.

> Yes, that's true these days.

** Been true since the 1950s.

All the popular humbuckers ( Gibson, Fender and Asian clones) are metal cased.

....... Phil