[Edward Morris]

I have a Fisher preamp that I purchased off of ebay. With the plug inserted
one way, the chassis leaks 80 VAC to ground. The plug inserted the opposite
way leaks 188 VAC to ground.

I took the transformer off of the chassis totally isolated from the chassis
and the voltages are exactly the same. There are no ceramic caps connected
to the AC line as I've seen in various other tube equipment.

After I replaced all the coupling caps, the bypass electrolytic caps, the
main electrolytic can and the bias supply caps, the AC leak is still the
same.

Is this voltage normal? If not, what would be the things you would look for
that could cause this voltage leak?

Thanks for any help,
Eddie

[Ryan DelGobbo]

On Jul 14, 12:41 pm, "Edward Morris" wrote:
I have a Fisher preamp that I purchased off of ebay. With the plug inserted
one way, the chassis leaks 80 VAC to ground. The plug inserted the opposite
way leaks 188 VAC to ground.




If your meter has 20 billions ohms per volt, the reading might be
normal.....

Seriously, are you sure your meter is OK?

[Patrick Turner]

Edward Morris wrote:

I have a Fisher preamp that I purchased off of ebay. With the plug inserted
one way, the chassis leaks 80 VAC to ground. The plug inserted the opposite
way leaks 188 VAC to ground.

I took the transformer off of the chassis totally isolated from the chassis
and the voltages are exactly the same. There are no ceramic caps connected
to the AC line as I've seen in various other tube equipment.

After I replaced all the coupling caps, the bypass electrolytic caps, the
main electrolytic can and the bias supply caps, the AC leak is still the
same.

Is this voltage normal? If not, what would be the things you would look for
that could cause this voltage leak?

Thanks for any help,
Eddie

I assume the PT is an isolation type.

The chassis should be directly connected to the green/yellow earth wire
from the wall socket.

The 0V rail of the amp should be a separate rail from the chassis and
only connected to the chassis at one point and via a 10 ohm high wattage
resistance.
When this is done, what is the voltage between 0V rail and chassis?

Patrick Turner.

[Phil Allison[_3_]]

"Edward Morris"

I have a Fisher preamp that I purchased off of ebay. With the plug
inserted one way, the chassis leaks 80 VAC to ground. The plug inserted
the opposite way leaks 188 VAC to ground.

(snip)
Is this voltage normal?

** Yes.

You are measuring with a DMM that has 10 megohms input resistance - right ?

So it converts TINY little leakage currents into large voltages.

Eg. 20 uA into 10 Mohms = 200 volts.

All it proves is there is about 250 pF of capacitance, primary to secondary,
in the AC tranny.

Ground the chassis for god's sake.



....... Phil

[Patrick Turner]

Phil Allison wrote:

"Edward Morris"

I have a Fisher preamp that I purchased off of ebay. With the plug
inserted one way, the chassis leaks 80 VAC to ground. The plug inserted
the opposite way leaks 188 VAC to ground.

(snip)
Is this voltage normal?

** Yes.

You are measuring with a DMM that has 10 megohms input resistance - right ?

So it converts TINY little leakage currents into large voltages.

Eg. 20 uA into 10 Mohms = 200 volts.

All it proves is there is about 250 pF of capacitance, primary to secondary,
in the AC tranny.

Ground the chassis for god's sake.

Correct Phil. But why not he ground the chassis for Edward's sake, since
God has no qualms about electrocuting Edward if he's a silly billy.

Patrick Turner.


...... Phil

[Edward Morris]

Thanks everybody for your comments. Patrick, I don't know what you mean by
0V rail but terminal strips all over the chassis are riveted to the chassis
with wire soldered to them.

I just wanted to check with all the knowledgeable people here to see if that
chassis voltage is normal. I'll definitely ground the chassis.

My meter is a True RMS radio shack type multimeter. Does that make a
difference?

Eddie

"Patrick Turner" wrote in message
...


Phil Allison wrote:

"Edward Morris"

I have a Fisher preamp that I purchased off of ebay. With the plug
inserted one way, the chassis leaks 80 VAC to ground. The plug inserted
the opposite way leaks 188 VAC to ground.

(snip)
Is this voltage normal?

** Yes.

You are measuring with a DMM that has 10 megohms input resistance -
right ?

So it converts TINY little leakage currents into large voltages.

Eg. 20 uA into 10 Mohms = 200 volts.

All it proves is there is about 250 pF of capacitance, primary to
secondary,
in the AC tranny.

Ground the chassis for god's sake.

Correct Phil. But why not he ground the chassis for Edward's sake, since
God has no qualms about electrocuting Edward if he's a silly billy.

Patrick Turner.


...... Phil

[Phil Allison[_3_]]

"Edward Morris"
Thanks everybody for your comments. Patrick, I don't know what you mean
by
0V rail but terminal strips all over the chassis are riveted to the
chassis
with wire soldered to them.

I just wanted to check with all the knowledgeable people here to see if
that
chassis voltage is normal. I'll definitely ground the chassis.

My meter is a True RMS radio shack type multimeter. Does that make a
difference?


** Nearly any "digital multimeter" will have 10 or 11 Megohms input
impedance on all the AC and DC voltage ranges.

Gotta be aware of that.

Just like back in the old VTVM days.

Anyone here still use one of them ???



..... Phil

[sortech]

Edward Morris wrote:
Thanks everybody for your comments. Patrick, I don't know what you mean by
0V rail but terminal strips all over the chassis are riveted to the chassis
with wire soldered to them.

I just wanted to check with all the knowledgeable people here to see if
that
chassis voltage is normal. I'll definitely ground the chassis.

My meter is a True RMS radio shack type multimeter. Does that make a
difference?

Eddie

"Patrick Turner" wrote in message
...


Phil Allison wrote:

"Edward Morris"

I have a Fisher preamp that I purchased off of ebay. With the plug
inserted one way, the chassis leaks 80 VAC to ground. The plug
inserted
the opposite way leaks 188 VAC to ground.

(snip)
Is this voltage normal?

** Yes.

You are measuring with a DMM that has 10 megohms input resistance -
right ?

So it converts TINY little leakage currents into large voltages.

Eg. 20 uA into 10 Mohms = 200 volts.

All it proves is there is about 250 pF of capacitance, primary to
secondary,
in the AC tranny.

Ground the chassis for god's sake.

Correct Phil. But why not he ground the chassis for Edward's sake, since
God has no qualms about electrocuting Edward if he's a silly billy.

Patrick Turner.


...... Phil

I use the same meter and have noticed the same thing on lots of amps. I
think it is due to capacitance between various things and is normal. If
some thing like an outdoor antenna or a satellite dish is connected to
the system somewhere you all ready have a ground and grounding the amp
may lead to ground loop problems that induce hum or oscillation. For
this reason make sure your system is only grounded at one point.
Eric

[[email protected]]

On Jul 15, 12:53*am, sortech wrote:

I use the same meter and have noticed the same thing on lots of amps. I
think it is due to capacitance between various things and is normal. If
some thing like an outdoor antenna or a satellite dish is connected to
the system somewhere you all ready have a ground and grounding the amp
may lead to ground loop problems that induce hum or oscillation. For
this reason make sure your system is only grounded at one point.

Yes to all of the above.

But, just on general principles, replace the line-bypass caps with the
correctly rated types. Over time and of that vintage they often begin
to leak.

http://www.justradios.com/X1Y2capacitors.html

And make sure that the chassis is grounded if you are still getting
measurable voltage after replacement. Electricity doesn't care where
it goes nor if you are in the way when it does.

Peter Wieck
Melrose Park, PA

[Patrick Turner]

Edward Morris wrote:

Thanks everybody for your comments. Patrick, I don't know what you mean by
0V rail but terminal strips all over the chassis are riveted to the chassis
with wire soldered to them.

In well made amps, the chassis is never used to convey currents flowing
in what is usually shown on the schematic as a 0V rail.

In poorly made amps, the chassis *is* the 0V rail, and this invites hum
problems.

So the 0V rail should be a thick copper wire running above the tube
sockets under the chassis and to which all grounded audio circuit parts
and OV dc rails are connected. At a point near the amp RCA input socket,
connection is made from the 0V buss rail to the 0V terminal of the RCA
socket. from the same point a 10 ohms x 5W R is connected to the
chassis, so there is 10r resistance between the audio circuit 0V and the
chassis.

But regardless of however good bad or ugly the circuit has been wired
up, it is essential that the any metal case work including metal covers
over transformers and chokes or capacitors all be firmly connected to
the gree/yellow wire from the wall socket.
If the power tranny has an earth shield, it to should be taken to the
chassis, rather than taken to the 0V audio circuit buss rail.


I just wanted to check with all the knowledgeable people here to see if that
chassis voltage is normal. I'll definitely ground the chassis.

Indeed ground the chassis.

My meter is a True RMS radio shack type multimeter. Does that make a
difference?

Any garden variety volt meter should read very low voltage between the
audio 0V rail and the chassis, which MUST me taken to MOTHER EARTH,
because that is a very basic safety regulation which may prevent you or
your relatives, friends and pets from being electrocuted if something
goes wrong with a power transformer, and believe me, things do go wrong
with tube amp PTs when they have been stressed during a time when an
output tube saturates for awhile.

It is usually extremely unlikely that the mains active line will short
circuit to the HT winding or heater windings which are indirectly
connected to the 0V audio rail. If that happens, usually the mains fuse
will blow immediately, and you can't use the amp. It is unlikely that
you might fuse open the 10 ohm between 0V rail and chassis.

But this 10R provides a higher Z signal path to the chassis than a
preamp you may be using which has its chassis damn well connected
directly to the 0V rail. When 2 pieces of gear which have power supplies
within, and both have the chassis directly connected to the audio 0V
rail or have the chassis acting as the 0V rail, then you will often get
annoying hum, because you have ehat is called a damn earth loop, and you
must reduce the current around the earth loop by inserting some small
value resistance which has many times greater resistance than the 0V
outer braid of an interconnect cable between power and pre-amp. Then
very little hum voltage will appear across the 0V braid of the cables,
and the hum is thus attenuated to negligible levels.

I cannot stress enough to all readers the importance of maintaining good
practice when building or modifying gear.

Never assume anything, unless it is to assume you are wrong until you
have proven you are right.

Patrick Turner.


Eddie

"Patrick Turner" wrote in message
...


Phil Allison wrote:

"Edward Morris"

I have a Fisher preamp that I purchased off of ebay. With the plug
inserted one way, the chassis leaks 80 VAC to ground. The plug inserted
the opposite way leaks 188 VAC to ground.

(snip)
Is this voltage normal?

** Yes.

You are measuring with a DMM that has 10 megohms input resistance -
right ?

So it converts TINY little leakage currents into large voltages.

Eg. 20 uA into 10 Mohms = 200 volts.

All it proves is there is about 250 pF of capacitance, primary to
secondary,
in the AC tranny.

Ground the chassis for god's sake.

Correct Phil. But why not he ground the chassis for Edward's sake, since
God has no qualms about electrocuting Edward if he's a silly billy.

Patrick Turner.


...... Phil

[Patrick Turner]

Phil Allison wrote:

"Edward Morris"
Thanks everybody for your comments. Patrick, I don't know what you mean
by
0V rail but terminal strips all over the chassis are riveted to the
chassis
with wire soldered to them.

I just wanted to check with all the knowledgeable people here to see if
that
chassis voltage is normal. I'll definitely ground the chassis.

My meter is a True RMS radio shack type multimeter. Does that make a
difference?

** Nearly any "digital multimeter" will have 10 or 11 Megohms input
impedance on all the AC and DC voltage ranges.

Gotta be aware of that.

Just like back in the old VTVM days.

Anyone here still use one of them ???

.... Phil

I have had several given to me. All have been utterly fuct by their
previous owners.
The worst was one left inside a boat cabin on salt water for months or
years perhaps.
Completely phuct. The guy donating thought he was being so fukkin
generous.

I have my auto ranging all solid state Fluke, and its good enough for
me, although I have managed to stuff the 0-300mVdc range.

Unfortunately, DMM are hopeless to measure ac voltage accurately at
above 2kHz, so I made my own 6 range volt meter, with input limiting and
all solid state, able to go from 10mV to 1,000V, 2Hz to 1MHz, with high
enough input resistance. Its been going 0ver 12 years now without me
zapping it with too much Vin.

Patrick Turner.

[Don Pearce[_3_]]

On Wed, 15 Jul 2009 14:29:26 GMT, Patrick Turner
wrote:

Unfortunately, DMM are hopeless to measure ac voltage accurately at
above 2kHz, so I made my own 6 range volt meter, with input limiting and
all solid state, able to go from 10mV to 1,000V, 2Hz to 1MHz, with high
enough input resistance. Its been going 0ver 12 years now without me
zapping it with too much Vin.

Patrick Turner.

Huh? My Fluke is good for about 60kHz, above which it starts dropping
off a bit.

d

[John Byrns]

In article ,
"Phil Allison" wrote:

"Edward Morris"
Thanks everybody for your comments. Patrick, I don't know what you mean
by
0V rail but terminal strips all over the chassis are riveted to the
chassis
with wire soldered to them.

I just wanted to check with all the knowledgeable people here to see if
that
chassis voltage is normal. I'll definitely ground the chassis.

My meter is a True RMS radio shack type multimeter. Does that make a
difference?


** Nearly any "digital multimeter" will have 10 or 11 Megohms input
impedance on all the AC and DC voltage ranges.

Gotta be aware of that.

Just like back in the old VTVM days.

Anyone here still use one of them ???

Yes, I love my old VTVM, can't beat it.

--
Regards,

John Byrns

Surf my web pages at, http://fmamradios.com/

[GregS[_3_]]

In article , John Byrns wrote:
In article ,
"Phil Allison" wrote:

"Edward Morris"
Thanks everybody for your comments. Patrick, I don't know what you mean
by
0V rail but terminal strips all over the chassis are riveted to the
chassis
with wire soldered to them.

I just wanted to check with all the knowledgeable people here to see if
that
chassis voltage is normal. I'll definitely ground the chassis.

My meter is a True RMS radio shack type multimeter. Does that make a
difference?


** Nearly any "digital multimeter" will have 10 or 11 Megohms input
impedance on all the AC and DC voltage ranges.

Gotta be aware of that.

Just like back in the old VTVM days.

Anyone here still use one of them ???

Yes, I love my old VTVM, can't beat it.


I can see slight movements of the meter when looking
for leakage resistance, that no regular meter
is going to show with the VTVM, happens to be a Senior Voltohmyst.

Most maintenaince manuals show near the front, the correct
procedure for measuring chassis leakage, which controls
both impedance and bandwidth.

greg

[:-:Ghost Chip:-:]

"John Byrns" wrote in message
...
In article ,
"Phil Allison" wrote:

"Edward Morris"
Thanks everybody for your comments. Patrick, I don't know what you
mean
by
0V rail but terminal strips all over the chassis are riveted to the
chassis
with wire soldered to them.

I just wanted to check with all the knowledgeable people here to see if
that
chassis voltage is normal. I'll definitely ground the chassis.

My meter is a True RMS radio shack type multimeter. Does that make a
difference?


** Nearly any "digital multimeter" will have 10 or 11 Megohms input
impedance on all the AC and DC voltage ranges.

Gotta be aware of that.

Just like back in the old VTVM days.

Anyone here still use one of them ???

Yes, I love my old VTVM, can't beat it.

--
Regards,

John Byrns

Surf my web pages at, http://fmamradios.com/

I have 2; a Heathkit and an Eico. Even replaced the 1.5v D cell with a wall
wart supply.

[fryzz]

A lot of these older designs have a .01uF ceramic cap connected from
both sides of the AC line to ground. It was considered "good
practice" back in the day. The thing about these caps, especially
after 50 years, is that "when they are good, they are very, very good,
and when they are bad, they are horrid". And who know, maybe there's
more HF crap floating around on the AC line these days. I usually
just disconnect them, seems they cause more problems than they solve.
Frank

I have a Fisher preamp that I purchased off of ebay. *With the plug inserted
one way, the chassis leaks 80 VAC to ground. *The plug inserted the opposite
way leaks 188 VAC to ground.

Is this voltage normal? *If not, what would be the things you would look for
that could cause this voltage leak?

[Edward Morris]

Thanks Frank and thanks to all for your intelligent advice.

Eddie

"fryzz" wrote in message
...
A lot of these older designs have a .01uF ceramic cap connected from
both sides of the AC line to ground. It was considered "good
practice" back in the day. The thing about these caps, especially
after 50 years, is that "when they are good, they are very, very good,
and when they are bad, they are horrid". And who know, maybe there's
more HF crap floating around on the AC line these days. I usually
just disconnect them, seems they cause more problems than they solve.
Frank

I have a Fisher preamp that I purchased off of ebay. With the plug
inserted
one way, the chassis leaks 80 VAC to ground. The plug inserted the
opposite
way leaks 188 VAC to ground.

Is this voltage normal? If not, what would be the things you would look
for
that could cause this voltage leak?

[[email protected]]

On Jul 16, 10:15*pm, "Edward Morris" wrote:

...
A lot of these older designs have a .01uF ceramic cap connected from
both sides of the AC line to ground. *

AKA Line-Bypass Caps. And still good-practice today.

Replace them - don't just cut them out. I gave a link to a good source
previously.

Peter Wieck
Melrose Park, PA

[Phil Allison[_3_]]

Peter Wieck
Criminal Psychpath
Melrose Park, PA

A lot of these older designs have a .01uF ceramic cap connected from
both sides of the AC line to ground.

AKA Line-Bypass Caps. And still good-practice today.


** Dangerous and very illegal in any civilised place.


Replace them - don't just cut them out.

** Criminal advice.

Particularly so in any 230 volt country.


YOU ****ING KNOW NOTHING ASSHOLE !!!!!!!!!!!




...... Phil

[[email protected]]

On Jul 17, 8:56*am, "Phil Allison" wrote:

Peter Wieck
Criminal Psychpath
Melrose Park, PA

A lot of these older designs have a .01uF ceramic cap connected from
both sides of the AC line to ground.

AKA Line-Bypass Caps. And still good-practice today.

Yo, Dude!

It's a 60s-vintage Fisher tube pre-amp. So, good practice. And last I
looked, not in a 230V country although I hardly see where that would
make any difference under similar conditions with equipment of similar
vintage.

So, your next round of medication is working enough that you have been
let out of the institution (at least temporarily)? Wecome back with
your usual half-truths, hip-shot (and typically bad) advice and so
forth! Yes, sometimes you come up with a gem but for the most part you
are viewing the world from the perspective of that most interesting of
species the 'vanishing bird' - loudly squawking and flying in ever
decreasing circles until finally it disappears up its own fundament
leaving nothing but a bad smell.

Good luck to you - your life must be pretty awful and I do feel sorry
for you. Pity that you cannot connect the dots very well any more.
There is a lot of latent knowledge there.

Peter Wieck
Melrose Park, PA

[Edward Morris]

Thank for the advice Peter but the preamp doesn't have any AC line bypass
caps.

Eddie

wrote in message
...
On Jul 17, 8:56 am, "Phil Allison" wrote:

Peter Wieck
Criminal Psychpath
Melrose Park, PA

A lot of these older designs have a .01uF ceramic cap connected from
both sides of the AC line to ground.

AKA Line-Bypass Caps. And still good-practice today.

Yo, Dude!

It's a 60s-vintage Fisher tube pre-amp. So, good practice. And last I
looked, not in a 230V country although I hardly see where that would
make any difference under similar conditions with equipment of similar
vintage.

So, your next round of medication is working enough that you have been
let out of the institution (at least temporarily)? Wecome back with
your usual half-truths, hip-shot (and typically bad) advice and so
forth! Yes, sometimes you come up with a gem but for the most part you
are viewing the world from the perspective of that most interesting of
species the 'vanishing bird' - loudly squawking and flying in ever
decreasing circles until finally it disappears up its own fundament
leaving nothing but a bad smell.

Good luck to you - your life must be pretty awful and I do feel sorry
for you. Pity that you cannot connect the dots very well any more.
There is a lot of latent knowledge there.

Peter Wieck
Melrose Park, PA

[Phil Allison[_3_]]

Peter Wieck
Criminal Psychpath
Melrose Park, PA

A lot of these older designs have a .01uF ceramic cap connected from
both sides of the AC line to ground.

AKA Line-Bypass Caps. And still good-practice today.


** Dangerous and very illegal in any civilised place.


Replace them - don't just cut them out.

** Criminal advice.

Particularly so in any 230 volt country.

WHICH THE OP IS IN !!!!!!!!!!!

YOU ****ING KNOW NOTHING ASSHOLE !!!!!!!!!!!




...... Phil

[Eeyore[_3_]]

Edward Morris wrote:

I have a Fisher preamp that I purchased off of ebay. With the plug inserted
one way, the chassis leaks 80 VAC to ground. The plug inserted the opposite
way leaks 188 VAC to ground.

The VOLTAGE is irrelevant. Measure the current.

Graham


--
due to the hugely increased level of spam please make the obvious adjustment to
my email address

[Eeyore[_3_]]

Phil Allison wrote:

"Edward Morris"

I have a Fisher preamp that I purchased off of ebay. With the plug
inserted one way, the chassis leaks 80 VAC to ground. The plug inserted
the opposite way leaks 188 VAC to ground.

(snip)
Is this voltage normal?

** Yes.

You are measuring with a DMM that has 10 megohms input resistance - right ?

So it converts TINY little leakage currents into large voltages.

Eg. 20 uA into 10 Mohms = 200 volts.

All it proves is there is about 250 pF of capacitance, primary to secondary,
in the AC tranny.

Ground the chassis for god's sake.

Phil is right.

Graham

--
due to the hugely increased level of spam please make the obvious adjustment to
my email address

[Eeyore[_3_]]

Edward Morris wrote:

Thanks everybody for your comments. Patrick, I don't know what you mean by
0V rail but terminal strips all over the chassis are riveted to the chassis
with wire soldered to them.

I just wanted to check with all the knowledgeable people here to see if that
chassis voltage is normal. I'll definitely ground the chassis.

My meter is a True RMS radio shack type multimeter. Does that make a
difference?

Not of any consequence in this application.

Graham

--
due to the hugely increased level of spam please make the obvious adjustment to
my email address

[Bret L]

My meter is a True RMS radio shack type multimeter. *Does that make a
difference?

** Nearly any "digital multimeter" will have 10 or 11 Megohms input
impedance on all the AC and DC voltage ranges.

Gotta be aware of that.

Just like back in the old VTVM days.

Anyone here still use one of them ???

Yes, I love my old VTVM, can't beat it.

--


I have three Flukes-an 87, a 45 and a 867B GMM-and I use them
constantly plus several el cheapos I keep around. Still, I use a
Simpson 260, a RCA Senior VoltOhmyst and a HP 410C from time to time.

Actually the RCA is the best amongst analogs for all around bench
work, but the HP is accurate into the low VHF range. They no longer
make accurate high impedance RF voltmeters because everyone uses fast
scopes, RF power meters and spectrum analyzers nowadays. Or, that's
what the test equipment companies

[Bret L]

Unfortunately, DMM are hopeless to measure ac voltage accurately at
above 2kHz, so I made my own 6 range volt meter, with input limiting and
all solid state, able to go from 10mV to 1,000V, 2Hz to 1MHz, with high
enough input resistance. Its been going 0ver 12 years now without me
zapping it with too much Vin.


Most current quality DMMs are good to 10 or 100 kHz. Besides that,
it's pretty dumb to build a voltmeter when perfectly good HPs can be
had for less than the price of a new quality meter movement.

[Phil Allison[_3_]]

"Bret Likes to Troll "

Unfortunately, DMM are hopeless to measure ac voltage accurately at
above 2kHz, so I made my own 6 range volt meter, with input limiting and
all solid state, able to go from 10mV to 1,000V, 2Hz to 1MHz, with high
enough input resistance. Its been going 0ver 12 years now without me
zapping it with too much Vin.


Most current quality DMMs are good to 10 or 100 kHz.


** Absolute BULL**** !!


Besides that,
it's pretty dumb to build a voltmeter when perfectly good HPs can be
had for less than the price of a new quality meter movement.


** ROTFL !!

What " meter movement " ???

Never heard of digital panel meters - fool.



...... Phil

[Bret L]

On Jul 16, 6:59*pm, fryzz wrote:
A lot of these older designs have a .01uF ceramic cap connected from
both sides of the AC line to ground. *It was considered "good
practice" back in the day. *The thing about these caps, especially
after 50 years, is that "when they are good, they are very, very good,
and when they are bad, they are horrid". *And who know, maybe there's
more HF crap floating around on the AC line these days. *I usually
just disconnect them, seems they cause more problems than they solve.


In those days the "correct" practice was to connect each of the two
input lines to some small value of AC rated cap and each to ground so
that if one plugged the set in and isolated it from everything else
the chassis would come up to half the line voltage BUT at a tiny
available current. That's the way the old Ampex tape machines were and
in audio Ampex set the standard, well, in the pro installs. You had
ONE ground line that went to each box and was grounded at ONE point.

That was true of HP test equipment as well as late as the 90s because
if you put on a cheater and plugged in any of their test sets, you'd
get half line voltage. at the outside of all the RF connectors-if you
used a very high impedance meter to measure. For certain measurements
we had to float all the grounds and use isoformers and run one ground
jumper in the screen room. This was technically verboten but it was
the only way to run the test. We had LF/VLF receivers operating at a
quarter microvolt for 10 dB quieting which is pushing the thermal
limit for systems without cryo amplifiers. There are still some
220/240 volt countries with two pin outlets AFAIK , so this standard
can't be dead yet.

We were better off when audio equipment was allowed to be two wire
because if you knew what you were doing you could be way quieter than
with the modern three wire plug except in the best conditions. It's
virtually impossible to really banish ground loops with three wire
power cords and unbalanced interconnects, unless you make up ringload
signal cables , and then if more than a couple boxes are involved
everything goes to hell because the ground in the power cord isn't
taht good.

[Bret L]

On Jul 19, 11:39*pm, "Phil Allison" wrote:
"Bret Likes to Troll "

Pot. Kettle. Black.


Unfortunately, DMM are hopeless to measure ac voltage accurately at
above 2kHz, so I made my own 6 range volt meter, with input limiting and
all solid state, able to go from 10mV to 1,000V, 2Hz to 1MHz, with high
enough input resistance. Its been going 0ver 12 years now without me
zapping it with too much Vin.

Most current quality DMMs are good to 10 or 100 kHz.

** Absolute BULL**** *!!

http://us.fluke.com/usen/Products/Fluke+289.htm

"True-rms AC bandwidth 100 kHz "


Besides that,
it's pretty dumb to build a voltmeter when perfectly good HPs can be
had for less than the price of a new quality meter movement.

** ROTFL *!!

*What " meter movement " ???

*Never heard of digital panel meters *- *fool.

Heard of 'em. Don't like 'em. Next question, cunnusface?

[Phil Allison[_3_]]

"Bret Likes to Tell LIES "

Unfortunately, DMM are hopeless to measure ac voltage accurately at
above 2kHz, so I made my own 6 range volt meter, with input limiting
and
all solid state, able to go from 10mV to 1,000V, 2Hz to 1MHz, with high
enough input resistance. Its been going 0ver 12 years now without me
zapping it with too much Vin.

Most current quality DMMs are good to 10 or 100 kHz.

** Absolute BULL**** !!

http://us.fluke.com/usen/Products/Fluke+289.htm

"True-rms AC bandwidth 100 kHz "


** One, isolated example proves what - exactly ???

Only that Bret is a ****ING LIAR

& a ****ING IMBECILE.




Besides that,
it's pretty dumb to build a voltmeter when perfectly good HPs can be
had for less than the price of a new quality meter movement.

** ROTFL !!

What " meter movement " ???

Never heard of digital panel meters - fool.


Heard of 'em. Don't like 'em.


** What this anencephanic **** says he

likes or does not like is of NO CONSEQUENCE

to ANY THING !!!!!!!!!!!!!!!!!


Next question,


** How is the giant brain tumor of yours going ??





...... Phil

[Patrick Turner]

Phil Allison wrote:

"Bret Likes to Tell LIES "

Unfortunately, DMM are hopeless to measure ac voltage accurately at
above 2kHz, so I made my own 6 range volt meter, with input limiting
and
all solid state, able to go from 10mV to 1,000V, 2Hz to 1MHz, with high
enough input resistance. Its been going 0ver 12 years now without me
zapping it with too much Vin.

Most current quality DMMs are good to 10 or 100 kHz.

** Absolute BULL**** !!

http://us.fluke.com/usen/Products/Fluke+289.htm

"True-rms AC bandwidth 100 kHz "

** One, isolated example proves what - exactly ???

Only that Bret is a ****ING LIAR


I re-checked my Fluke, and with a low Z signal source, and sure, it has
very little BW.

Maybe Bret was talking about some other model which I don't have.

But all the other DMM I have ever used are quite hopeless above 2kHz.



& a ****ING IMBECILE.

Besides that,
it's pretty dumb to build a voltmeter when perfectly good HPs can be
had for less than the price of a new quality meter movement.

** ROTFL !!

What " meter movement " ???

Never heard of digital panel meters - fool.

Heard of 'em. Don't like 'em.

My Fluke has a bar meter which roughly indicates voltage on the LED
display as well as the digit read out.


I made my own analog voltmeter with opamps and a wide band amp and
rectifiers to measure 1mV to 1,000V, 1Hz to 1mHz.

I could not buy one anywhere for a reasonable price in 1994.

Patrick Turner.

[Bret L]

I re-checked my Fluke, and with a low Z signal source, and sure, it has
very little BW.

Maybe Bret was talking about some other model which I don't have.

But all the other DMM I have ever used are quite hopeless above 2kHz.

The low end ones are made for the electrical trade and are low BW on
purpose. But you do not need the $400 model to get full audio
bandwidth.




& a ****ING IMBECILE.

Yes, Phil Allison very certainly is. Glad someone noticed after all
this time.

Besides that,
it's

My Fluke has a bar meter which roughly indicates voltage on the LED
display as well as the digit read out.

I made my own analog voltmeter with opamps and a wide band amp and
rectifiers to measure 1mV to 1,000V, 1Hz to 1mHz.

I could not buy one anywhere for a reasonable price in 1994.

Patrick Turner.

In 1994 I was getting both US and UK magazines that featured ads for
HP VTVMs-the ones with the little Eimac diode in the probe, originally
costing the price of a new Volkswagen-for either US $100 or UK £100,
i.e., then $160 or so AFAIK, and the shipping from either place to
Australia probably being less than half that, again. That was before I
was big on the Internet. There was no eBay and if you had net access
you either bought off a newsgroup like sci.electronics.equipment or
from a dealer like *ucker.

In 2000-2005 there were piles of them at all the hamfests I attended.
About 2006 they all vanished. The tube roller ****s would buy them up,
take the tubes out and throw them in the dumpster. Now a HP lunchbox
AC VTVM is worth a couple hundred bucks if it has the probe and a good
Eimac diode tube in it because the Collins collectors all have to have
one. The separate HP DC VTVM is worth a few bucks and is fascinating
because it is motor driven chopper stabilized.

I'm told that the European made instruments to seek out are the Bruel
& Kjaer and the Siemens. Philips are troublesome, according to
Europeans I know who have immigrated here. I don't know about Brit
instruments besides AVO (they made tube testers and passive VOMs but
VTVMs?) and the desirable but rare Radford box.

[Phil Allison[_3_]]

"Bret LIAR" posts to NOBODY !!


Patrick Turner

I re-checked my Fluke, and with a low Z signal source, and sure, it has
very little BW.

Maybe Bret was talking about some other model which I don't have.

But all the other DMM I have ever used are quite hopeless above 2kHz.


The low end ones are made for the electrical trade


** ABSOLUTE ****ING LIE !!!!


and are low BW on purpose.


** ABSOLUTE ****ING LIE




...... Phil