Looking for sensitive audio RMS meter


 

Hi all, looking for a true RMS meter that can do roughly ~DC to ~100
kHz measurement down to 1 uV and up to say tens of volts. Hoping to
find something inexpensive and can be calibrated. Can someone suggest
anything? Either Tek or HP/A/K or something else. Bench or portable is
fine. Battery operation a big plus either way. I'd like 5 digits or
more, but fewer is fine around 1 uV. My budget is a few hundred $.

Thanks


Bob Albert
 

HP 3456A

On Monday, May 10, 2021, 02:18:40 PM PDT, cheater cheater <cheater00social@gmail.com> wrote:

Hi all, looking for a true RMS meter that can do roughly ~DC to ~100
kHz measurement down to 1 uV and up to say tens of volts. Hoping to
find something inexpensive and can be calibrated. Can someone suggest
anything? Either Tek or HP/A/K or something else. Bench or portable is
fine. Battery operation a big plus either way. I'd like 5 digits or
more, but fewer is fine around 1 uV. My budget is a few hundred $.

Thanks


 

Thanks. The specs are impressive. However, I am also hoping to find
something much more compact than that if that's possible - any
suggestions?

On Mon, May 10, 2021 at 11:20 PM Bob Albert via groups.io
<bob91343=yahoo.com@groups.io> wrote:

HP 3456A
On Monday, May 10, 2021, 02:18:40 PM PDT, cheater cheater <cheater00social@gmail.com> wrote:

Hi all, looking for a true RMS meter that can do roughly ~DC to ~100
kHz measurement down to 1 uV and up to say tens of volts. Hoping to
find something inexpensive and can be calibrated. Can someone suggest
anything? Either Tek or HP/A/K or something else. Bench or portable is
fine. Battery operation a big plus either way. I'd like 5 digits or
more, but fewer is fine around 1 uV. My budget is a few hundred $.

Thanks











Liam Perkins
 

I have a couple of HP 3457s in good nick and looking for a home.

We just parted out a pair of 3456As for gold scrap (broke my heart) and
I can tell you the '57s are smaller and much lighter, same width give or
take but about 4" shallower front to back.

Liam

On Mon, May 10, 2021 at 3:18 PM cheater cheater <cheater00social@gmail.com>
wrote:

Hi all, looking for a true RMS meter that can do roughly ~DC to ~100
kHz measurement down to 1 uV and up to say tens of volts. Hoping to
find something inexpensive and can be calibrated. Can someone suggest
anything? Either Tek or HP/A/K or something else. Bench or portable is
fine. Battery operation a big plus either way. I'd like 5 digits or
more, but fewer is fine around 1 uV. My budget is a few hundred $.

Thanks






Bob Albert
 

I would be interested in one or both of those 3457s.
Bob K6DDX

On Monday, May 10, 2021, 04:13:47 PM PDT, Liam Perkins <hifi@telus.net> wrote:

    I have a couple of HP 3457s in good nick and looking for a home.

    We just parted out a pair of 3456As for gold scrap (broke my heart) and
I can tell you the '57s are smaller and much lighter, same width give or
take but about 4" shallower front to back.

    Liam

On Mon, May 10, 2021 at 3:18 PM cheater cheater <cheater00social@gmail.com>
wrote:

Hi all, looking for a true RMS meter that can do roughly ~DC to ~100
kHz measurement down to 1 uV and up to say tens of volts. Hoping to
find something inexpensive and can be calibrated. Can someone suggest
anything? Either Tek or HP/A/K or something else. Bench or portable is
fine. Battery operation a big plus either way. I'd like 5 digits or
more, but fewer is fine around 1 uV. My budget is a few hundred $.

Thanks






Liam Perkins
 

Also, have a look at the erstwhile Geller Labs site on the WayBack here:
https://web.archive.org/web/20131018055721/http://www.gellerlabs.com/index.html
and dig for the J-Can article, you'll find it highly informative. The
ultra-low noise SMD JFET he specs is history but I have a bunch and they're
also available on eBay although it's anyone's guess what they might
actually be. Rather than looking for a uV capable meter you're probably
farther ahead to build a little +40dB gain box, battery power it and put
panel mount BNCs on it for in-s and out-s.
A Google for J-Can will pull his PDF on the J-Can, a worthwhile read in any
case.
Liam

On Mon, May 10, 2021 at 5:13 PM Liam Perkins via groups.io <hifi=
telus.net@groups.io> wrote:

I have a couple of HP 3457s in good nick and looking for a home.

We just parted out a pair of 3456As for gold scrap (broke my heart) and
I can tell you the '57s are smaller and much lighter, same width give or
take but about 4" shallower front to back.

Liam

On Mon, May 10, 2021 at 3:18 PM cheater cheater <cheater00social@gmail.com
wrote:

Hi all, looking for a true RMS meter that can do roughly ~DC to ~100
kHz measurement down to 1 uV and up to say tens of volts. Hoping to
find something inexpensive and can be calibrated. Can someone suggest
anything? Either Tek or HP/A/K or something else. Bench or portable is
fine. Battery operation a big plus either way. I'd like 5 digits or
more, but fewer is fine around 1 uV. My budget is a few hundred $.

Thanks










George Kerber
 

Bob,
You might consider a HP distortion analyzer such as this one:
http://www.barrytech.com/hewlett-packard/analyzers/hp339a.html
https://www.ebay.com/itm/233587661597?hash=item3662e8db1d:g:KrMAAOSwiGBevSVB

Also, a Ballantine 323 True RMS analog AC voltmeter. Only measure to 300 uV.
https://www.ballantinelabs.com/323/
https://www.ebay.com/itm/384146432011?hash=item5970e9600b:g:j8MAAOSwcXBgk0HN

Both are somewhat portable.

An HP 3561A 100kHz FFT spectrum analyzer would probably meet your spec,
it's portable, but really hard to lug around.

George

On Mon, May 10, 2021 at 4:21 PM Bob Albert via groups.io <bob91343=
yahoo.com@groups.io> wrote:

I would be interested in one or both of those 3457s.
Bob K6DDX
On Monday, May 10, 2021, 04:13:47 PM PDT, Liam Perkins <hifi@telus.net>
wrote:

I have a couple of HP 3457s in good nick and looking for a home.

We just parted out a pair of 3456As for gold scrap (broke my heart) and
I can tell you the '57s are smaller and much lighter, same width give or
take but about 4" shallower front to back.

Liam

On Mon, May 10, 2021 at 3:18 PM cheater cheater <cheater00social@gmail.com
wrote:

Hi all, looking for a true RMS meter that can do roughly ~DC to ~100
kHz measurement down to 1 uV and up to say tens of volts. Hoping to
find something inexpensive and can be calibrated. Can someone suggest
anything? Either Tek or HP/A/K or something else. Bench or portable is
fine. Battery operation a big plus either way. I'd like 5 digits or
more, but fewer is fine around 1 uV. My budget is a few hundred $.

Thanks















 

On Tue, May 11, 2021 at 1:11 AM Liam Perkins <hifi@telus.net> wrote:

I have a couple of HP 3457s in good nick and looking for a home.
Thanks Liam. It seems like the 3457's lowest range for AC voltage is
30 mV, and I need to be able to measure tenths of a microvolt. Correct
me if I'm wrong please. The specs I've found weren't very conclusive.

On Tue, May 11, 2021 at 1:35 AM Liam Perkins <hifi@telus.net> wrote:

Also, have a look at the erstwhile Geller Labs site on the WayBack here:
https://web.archive.org/web/20131018055721/http://www.gellerlabs.com/index.html
and dig for the J-Can article, you'll find it highly informative. The
ultra-low noise SMD JFET he specs is history but I have a bunch and they're
also available on eBay although it's anyone's guess what they might
actually be. Rather than looking for a uV capable meter you're probably
farther ahead to build a little +40dB gain box, battery power it and put
panel mount BNCs on it for in-s and out-s.
A Google for J-Can will pull his PDF on the J-Can, a worthwhile read in any
case.
Liam
Thanks, that's a super useful pointer. I've found an article that goes
deep into the theory and build, but doesn't actually tell me much
about what the thing does. So it's a +40 dB amplifier? What is its
self-noise?

Would you be willing to sell me a few of those jfets? I would probably
like to set up a balanced measurement.

Best regards


George Kerber
 

You might also consider soundcard-based FFT for rms and spectrum
measurements to 100kHz and a laptop. There are a lot of choices and price
ranges. One professional package is by Pioneer Hill Software:
https://www.spectraplus.com/ Very nice, but $$$.

Another is Spectrum Lab, by DL4YHF Spectrum Lab (Audio Signal Analyser). I
have played with it a little, but it has a very steep learning curve.

George

On Mon, May 10, 2021 at 4:58 PM George Kerber via groups.io <gk5220=
gmail.com@groups.io> wrote:

Bob,
You might consider a HP distortion analyzer such as this one:
http://www.barrytech.com/hewlett-packard/analyzers/hp339a.html

https://www.ebay.com/itm/233587661597?hash=item3662e8db1d:g:KrMAAOSwiGBevSVB

Also, a Ballantine 323 True RMS analog AC voltmeter. Only measure to 300
uV.
https://www.ballantinelabs.com/323/

https://www.ebay.com/itm/384146432011?hash=item5970e9600b:g:j8MAAOSwcXBgk0HN

Both are somewhat portable.

An HP 3561A 100kHz FFT spectrum analyzer would probably meet your spec,
it's portable, but really hard to lug around.

George

On Mon, May 10, 2021 at 4:21 PM Bob Albert via groups.io <bob91343=
yahoo.com@groups.io> wrote:

I would be interested in one or both of those 3457s.
Bob K6DDX
On Monday, May 10, 2021, 04:13:47 PM PDT, Liam Perkins <
hifi@telus.net>
wrote:

I have a couple of HP 3457s in good nick and looking for a home.

We just parted out a pair of 3456As for gold scrap (broke my heart)
and
I can tell you the '57s are smaller and much lighter, same width give or
take but about 4" shallower front to back.

Liam

On Mon, May 10, 2021 at 3:18 PM cheater cheater <
cheater00social@gmail.com
wrote:

Hi all, looking for a true RMS meter that can do roughly ~DC to ~100
kHz measurement down to 1 uV and up to say tens of volts. Hoping to
find something inexpensive and can be calibrated. Can someone suggest
anything? Either Tek or HP/A/K or something else. Bench or portable is
fine. Battery operation a big plus either way. I'd like 5 digits or
more, but fewer is fine around 1 uV. My budget is a few hundred $.

Thanks



















 

Hi George,

On Tue, May 11, 2021 at 1:58 AM George Kerber <gk5220@gmail.com> wrote:

Bob,
Actually I'm the one looking for the volt meter :-)

You might consider a HP distortion analyzer such as this one:
http://www.barrytech.com/hewlett-packard/analyzers/hp339a.html
https://www.ebay.com/itm/233587661597?hash=item3662e8db1d:g:KrMAAOSwiGBevSVB
I love the fact that it's got a dBV display which is what I'd like to
be doing my measurements in anyways (it's for audio equipment).

Also, a Ballantine 323 True RMS analog AC voltmeter. Only measure to 300 uV.
https://www.ballantinelabs.com/323/
https://www.ebay.com/itm/384146432011?hash=item5970e9600b:g:j8MAAOSwcXBgk0HN
Thanks, any clue how much the Ballantine 323 costs? They don't have
any prices on their website. However, ebay shows units going for sub
$100 which is pretty great.

Any chance of being able to convert its scale to dBV? I would love to
not have to pull out a calculator every time I measure something.

Both are somewhat portable.

An HP 3561A 100kHz FFT spectrum analyzer would probably meet your spec,
it's portable, but really hard to lug around.
I'm afraid it might be way too large for me. Always liked how it
looks, but it's just not practical in my circumstances, and also I'm
not looking for a spectrum analyzer.

On Tue, May 11, 2021 at 2:35 AM George Kerber <gk5220@gmail.com> wrote:

You might also consider soundcard-based FFT for rms and spectrum
measurements to 100kHz and a laptop. There are a lot of choices and price
ranges. One professional package is by Pioneer Hill Software:
https://www.spectraplus.com/ Very nice, but $$$.

Another is Spectrum Lab, by DL4YHF Spectrum Lab (Audio Signal Analyser). I
have played with it a little, but it has a very steep learning curve.

George
I'm looking for a meter to measure total noise level, rather than its
spectrum. I agree that FFT measurements are useful in their own right.

I'm on a short budget. If I had the money I'd just buy Audio Precision.


Göran Krusell
 

hp 465 A amplifier!


George Kerber
 

Sorry about that. Best bet is to check out eBay listings for 323. It's
probably really pricey when purchased directly from Ballantine (I was about
$700 new in the 1970's). I was surprised to see it on their website.

FFT spectrum analyzer is perfect for noise measurements. You get the
spectrum and total noise level number if needed. I use a, not so portable,
HP 35665A. A good low noise preamp such as PAR 113 is a good complement to
any RMS meter or FFT analyzer.

George

On Mon, May 10, 2021 at 5:41 PM cheater cheater <cheater00social@gmail.com>
wrote:

Hi George,

On Tue, May 11, 2021 at 1:58 AM George Kerber <gk5220@gmail.com> wrote:

Bob,
Actually I'm the one looking for the volt meter :-)

You might consider a HP distortion analyzer such as this one:
http://www.barrytech.com/hewlett-packard/analyzers/hp339a.html
https://www.ebay.com/itm/233587661597?hash=item3662e8db1d:g:KrMAAOSwiGBevSVB

I love the fact that it's got a dBV display which is what I'd like to
be doing my measurements in anyways (it's for audio equipment).

Also, a Ballantine 323 True RMS analog AC voltmeter. Only measure to 300
uV.
https://www.ballantinelabs.com/323/
https://www.ebay.com/itm/384146432011?hash=item5970e9600b:g:j8MAAOSwcXBgk0HN

Thanks, any clue how much the Ballantine 323 costs? They don't have
any prices on their website. However, ebay shows units going for sub
$100 which is pretty great.

Any chance of being able to convert its scale to dBV? I would love to
not have to pull out a calculator every time I measure something.

Both are somewhat portable.

An HP 3561A 100kHz FFT spectrum analyzer would probably meet your spec,
it's portable, but really hard to lug around.
I'm afraid it might be way too large for me. Always liked how it
looks, but it's just not practical in my circumstances, and also I'm
not looking for a spectrum analyzer.

On Tue, May 11, 2021 at 2:35 AM George Kerber <gk5220@gmail.com> wrote:

You might also consider soundcard-based FFT for rms and spectrum
measurements to 100kHz and a laptop. There are a lot of choices and price
ranges. One professional package is by Pioneer Hill Software:
https://www.spectraplus.com/ Very nice, but $$$.

Another is Spectrum Lab, by DL4YHF Spectrum Lab (Audio Signal Analyser).
I
have played with it a little, but it has a very steep learning curve.

George
I'm looking for a meter to measure total noise level, rather than its
spectrum. I agree that FFT measurements are useful in their own right.

I'm on a short budget. If I had the money I'd just buy Audio Precision.






Liam Perkins
 

The 465A is an about 1960 design and isn't even in the ballpark

On Mon, May 10, 2021 at 6:46 PM Göran Krusell <mc1648pp@gmail.com> wrote:

hp 465 A amplifier!






Liam Perkins
 

I just lit up the 3457s with inputs shorted and they pass self-test. One of
them has Opt 007 which I -think- might be the 7th digit option but it's a
slog thru about 5lbs of manual to sort that for certain.
You started here saying tens of uV now you're into nVs which is a place
that ought to have a gate saying, "Abandon Hope All Ye Who Enter". Read a
slew of Jim Williams app notes from, I think, Analog Devices and start
buying coffee in 2 and 5lb tins because you're gonna need 'em nested like
Russian dolls.
What -are- you wanting to do ?

On Mon, May 10, 2021 at 7:05 PM Bill Perkins <hifi@telus.net> wrote:

The 465A is an about 1960 design and isn't even in the ballpark

On Mon, May 10, 2021 at 6:46 PM Göran Krusell <mc1648pp@gmail.com> wrote:

hp 465 A amplifier!






Liam Perkins
 

I'm going thru a PAR CR-4A LNA for a guy in Germany who wants to use it as
an effects box with his synth'. There are a couple of YTs by another guy
over there who loves his and has it make the God Awfullest noises you ever
heard, and he loves it. I think those guy get a kick out torturing
germanium . . .

On Mon, May 10, 2021 at 7:05 PM George Kerber <gk5220@gmail.com> wrote:

Sorry about that. Best bet is to check out eBay listings for 323. It's
probably really pricey when purchased directly from Ballantine (I was about
$700 new in the 1970's). I was surprised to see it on their website.

FFT spectrum analyzer is perfect for noise measurements. You get the
spectrum and total noise level number if needed. I use a, not so portable,
HP 35665A. A good low noise preamp such as PAR 113 is a good complement to
any RMS meter or FFT analyzer.

George

On Mon, May 10, 2021 at 5:41 PM cheater cheater <cheater00social@gmail.com
wrote:

Hi George,

On Tue, May 11, 2021 at 1:58 AM George Kerber <gk5220@gmail.com> wrote:

Bob,
Actually I'm the one looking for the volt meter :-)

You might consider a HP distortion analyzer such as this one:
http://www.barrytech.com/hewlett-packard/analyzers/hp339a.html
https://www.ebay.com/itm/233587661597?hash=item3662e8db1d:g:KrMAAOSwiGBevSVB

I love the fact that it's got a dBV display which is what I'd like to
be doing my measurements in anyways (it's for audio equipment).

Also, a Ballantine 323 True RMS analog AC voltmeter. Only measure to
300
uV.
https://www.ballantinelabs.com/323/
https://www.ebay.com/itm/384146432011?hash=item5970e9600b:g:j8MAAOSwcXBgk0HN

Thanks, any clue how much the Ballantine 323 costs? They don't have
any prices on their website. However, ebay shows units going for sub
$100 which is pretty great.

Any chance of being able to convert its scale to dBV? I would love to
not have to pull out a calculator every time I measure something.

Both are somewhat portable.

An HP 3561A 100kHz FFT spectrum analyzer would probably meet your spec,
it's portable, but really hard to lug around.
I'm afraid it might be way too large for me. Always liked how it
looks, but it's just not practical in my circumstances, and also I'm
not looking for a spectrum analyzer.

On Tue, May 11, 2021 at 2:35 AM George Kerber <gk5220@gmail.com> wrote:

You might also consider soundcard-based FFT for rms and spectrum
measurements to 100kHz and a laptop. There are a lot of choices and
price
ranges. One professional package is by Pioneer Hill Software:
https://www.spectraplus.com/ Very nice, but $$$.

Another is Spectrum Lab, by DL4YHF Spectrum Lab (Audio Signal
Analyser).
I
have played with it a little, but it has a very steep learning curve.

George
I'm looking for a meter to measure total noise level, rather than its
spectrum. I agree that FFT measurements are useful in their own right.

I'm on a short budget. If I had the money I'd just buy Audio Precision.










 

On Tue, May 11, 2021 at 2:46 AM Göran Krusell <mc1648pp@gmail.com> wrote:

hp 465 A amplifier!
Unfortunately, at 25 uV self-noise, the HP 465 A won't be helpful in
measuring noise on the order of 1uV.


 

On Tue, May 11, 2021 at 3:21 AM Liam Perkins <hifi@telus.net> wrote:

I'm going thru a PAR CR-4A LNA for a guy in Germany who wants to use it as
an effects box with his synth'. There are a couple of YTs by another guy
over there who loves his and has it make the God Awfullest noises you ever
heard, and he loves it. I think those guy get a kick out torturing
germanium . . .
You've got to be kidding me...

Anyways, this preamp looks like it wouldn't be too bad for my use.

On Mon, May 10, 2021 at 7:05 PM George Kerber <gk5220@gmail.com> wrote:

Sorry about that. Best bet is to check out eBay listings for 323. It's
probably really pricey when purchased directly from Ballantine (I was about
$700 new in the 1970's). I was surprised to see it on their website.

FFT spectrum analyzer is perfect for noise measurements. You get the
spectrum and total noise level number if needed. I use a, not so portable,
HP 35665A. A good low noise preamp such as PAR 113 is a good complement to
any RMS meter or FFT analyzer.

George

On Mon, May 10, 2021 at 5:41 PM cheater cheater <cheater00social@gmail.com
wrote:

Hi George,

On Tue, May 11, 2021 at 1:58 AM George Kerber <gk5220@gmail.com> wrote:

Bob,
Actually I'm the one looking for the volt meter :-)

You might consider a HP distortion analyzer such as this one:
http://www.barrytech.com/hewlett-packard/analyzers/hp339a.html
https://www.ebay.com/itm/233587661597?hash=item3662e8db1d:g:KrMAAOSwiGBevSVB

I love the fact that it's got a dBV display which is what I'd like to
be doing my measurements in anyways (it's for audio equipment).

Also, a Ballantine 323 True RMS analog AC voltmeter. Only measure to
300
uV.
https://www.ballantinelabs.com/323/
https://www.ebay.com/itm/384146432011?hash=item5970e9600b:g:j8MAAOSwcXBgk0HN

Thanks, any clue how much the Ballantine 323 costs? They don't have
any prices on their website. However, ebay shows units going for sub
$100 which is pretty great.

Any chance of being able to convert its scale to dBV? I would love to
not have to pull out a calculator every time I measure something.

Both are somewhat portable.

An HP 3561A 100kHz FFT spectrum analyzer would probably meet your spec,
it's portable, but really hard to lug around.
I'm afraid it might be way too large for me. Always liked how it
looks, but it's just not practical in my circumstances, and also I'm
not looking for a spectrum analyzer.

On Tue, May 11, 2021 at 2:35 AM George Kerber <gk5220@gmail.com> wrote:

You might also consider soundcard-based FFT for rms and spectrum
measurements to 100kHz and a laptop. There are a lot of choices and
price
ranges. One professional package is by Pioneer Hill Software:
https://www.spectraplus.com/ Very nice, but $$$.

Another is Spectrum Lab, by DL4YHF Spectrum Lab (Audio Signal
Analyser).
I
have played with it a little, but it has a very steep learning curve.

George
I'm looking for a meter to measure total noise level, rather than its
spectrum. I agree that FFT measurements are useful in their own right.

I'm on a short budget. If I had the money I'd just buy Audio Precision.













 

Hi Liam,
I would love a 3457A!

Anyone have a HP 3400A? That would completely suit Bob's requirements. BTW, I am also looking for one of those that works. I bought one on fleabay and it has serious problems.

-Chris


 

On Tue, May 11, 2021 at 3:20 AM Liam Perkins <hifi@telus.net> wrote:

I just lit up the 3457s with inputs shorted and they pass self-test. One of
them has Opt 007 which I -think- might be the 7th digit option but it's a
slog thru about 5lbs of manual to sort that for certain.
You started here saying tens of uV now you're into nVs which is a place
that ought to have a gate saying, "Abandon Hope All Ye Who Enter". Read a
slew of Jim Williams app notes from, I think, Analog Devices and start
buying coffee in 2 and 5lb tins because you're gonna need 'em nested like
Russian dolls.
What -are- you wanting to do ?
I want to be able to measure total noise down to -110 dBV, or possibly
-130 dBV if possible. This means resolving single microvolts and
tenths of microvolts.

On Mon, May 10, 2021 at 7:05 PM Bill Perkins <hifi@telus.net> wrote:

The 465A is an about 1960 design and isn't even in the ballpark

On Mon, May 10, 2021 at 6:46 PM Göran Krusell <mc1648pp@gmail.com> wrote:

hp 465 A amplifier!









 

On Tue, May 11, 2021 at 4:41 AM bhome1959 <bhome@sympatico.ca> wrote:

Hi Liam,
I would love a 3457A!

Anyone have a HP 3400A? That would completely suit Bob's requirements. BTW, I am also looking for one of those that works. I bought one on fleabay and it has serious problems.
Why does everyone keep on calling me Bob? What the heck...