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Value drift over time
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Cursitor Doom
May 17, 2019, 1:26:06 PM5/17/19
to
Before I junked that RF sig gen I snipped a selection of resistors out of
it just to see how far away from their nominal values they have strayed
over the past ~65 years. I shall report back in due course....
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it just to see how far away from their nominal values they have strayed
over the past ~65 years. I shall report back in due course....
--
This message may be freely reproduced without limit or charge only via
the Usenet protocol. Reproduction in whole or part through other
protocols, whether for profit or not, is conditional upon a charge of
GBP10.00 per reproduction. Publication in this manner via non-Usenet
protocols constitutes acceptance of this condition.
Mike Coon
May 17, 2019, 4:19:11 PM5/17/19
to
In article <qbmqra$mh3$3...@dont-email.me>, cu...@notformail.com says...
y.o too ;-)
Mike.
>
> Before I junked that RF sig gen I snipped a selection of resistors out of
> it just to see how far away from their nominal values they have strayed
> over the past ~65 years. I shall report back in due course....
I can hardly wait! I must have some dating back to before when I was 10
> Before I junked that RF sig gen I snipped a selection of resistors out of
> it just to see how far away from their nominal values they have strayed
> over the past ~65 years. I shall report back in due course....
y.o too ;-)
Mike.
tabb...@gmail.com
May 17, 2019, 6:18:22 PM5/17/19
to
NT
Cursitor Doom
May 18, 2019, 11:22:32 AM5/18/19
to
On Fri, 17 May 2019 21:19:07 +0100, Mike Coon wrote:
> I can hardly wait!
Then I shall keep you in suspense no longer.
Here's what I found from a random selection of old components I snipped
out. Firstly, pretty much *all* the capacitors were fine. The 350VDC
Hunts capacitors could easily have been new. An Erie plate ceramic of
0.01uF likewise. A Dubilier type SM22 50pf cap, however, had gone up to
62pF. That one was one of the ones used for tuning. The biggest changes
were as expected in the carbon resistors, all of which aged to higher
values like so:
27k became 38.6k
another 27k ----> 29k
100k ----> 107k
10 ----> 10.7
3.3k ----> 4.2k
4.1k ----> 5.2k
15k ----> 20.7k
220k ----> 246k
8.2k ----> 9.9k
400k ----> 509k
These were all marked with a silver tolerance band, so clearly Taylor
back then at least not *that* bothered about accuracy.
> I can hardly wait!
Then I shall keep you in suspense no longer.
Here's what I found from a random selection of old components I snipped
out. Firstly, pretty much *all* the capacitors were fine. The 350VDC
Hunts capacitors could easily have been new. An Erie plate ceramic of
0.01uF likewise. A Dubilier type SM22 50pf cap, however, had gone up to
62pF. That one was one of the ones used for tuning. The biggest changes
were as expected in the carbon resistors, all of which aged to higher
values like so:
27k became 38.6k
another 27k ----> 29k
100k ----> 107k
10 ----> 10.7
3.3k ----> 4.2k
4.1k ----> 5.2k
15k ----> 20.7k
220k ----> 246k
8.2k ----> 9.9k
400k ----> 509k
These were all marked with a silver tolerance band, so clearly Taylor
back then at least not *that* bothered about accuracy.
Cursitor Doom
May 18, 2019, 11:28:38 AM5/18/19
to
On Sat, 18 May 2019 15:22:29 +0000, Cursitor Doom wrote:
> The 350VDC Hunts capacitors could easily have been new.
Same type as this: https://tinyurl.com/y6a9ywtz
> The 350VDC Hunts capacitors could easily have been new.
tabb...@gmail.com
May 18, 2019, 12:25:38 PM5/18/19
to
On Saturday, 18 May 2019 16:22:32 UTC+1, Cursitor Doom wrote:
> On Fri, 17 May 2019 21:19:07 +0100, Mike Coon wrote:
>
> > I can hardly wait!
>
> Then I shall keep you in suspense no longer.
>
> Here's what I found from a random selection of old components I snipped
> out. Firstly, pretty much *all* the capacitors were fine. The 350VDC
> Hunts capacitors could easily have been new. An Erie plate ceramic of
> 0.01uF likewise. A Dubilier type SM22 50pf cap, however, had gone up to
> 62pF. That one was one of the ones used for tuning. The biggest changes
> were as expected in the carbon resistors, all of which aged to higher
> values like so:
>
> 27k became 38.6k
>
> another 27k ----> 29k
>
> 100k ----> 107k
>
> 10 ----> 10.7
>
> 3.3k ----> 4.2k
>
> 4.1k ----> 5.2k
>
> 15k ----> 20.7k
>
> 220k ----> 246k
>
> 8.2k ----> 9.9k
>
> 400k ----> 509k
>
>
> These were all marked with a silver tolerance band, so clearly Taylor
> back then at least not *that* bothered about accuracy.
Most Rs in valve kit are far from critical. 5% would have cost them more than 10%. 20% were more common.
> On Fri, 17 May 2019 21:19:07 +0100, Mike Coon wrote:
>
> > I can hardly wait!
>
> Then I shall keep you in suspense no longer.
>
> Here's what I found from a random selection of old components I snipped
> out. Firstly, pretty much *all* the capacitors were fine. The 350VDC
> Hunts capacitors could easily have been new. An Erie plate ceramic of
> 0.01uF likewise. A Dubilier type SM22 50pf cap, however, had gone up to
> 62pF. That one was one of the ones used for tuning. The biggest changes
> were as expected in the carbon resistors, all of which aged to higher
> values like so:
>
> 27k became 38.6k
>
> another 27k ----> 29k
>
> 100k ----> 107k
>
> 10 ----> 10.7
>
> 3.3k ----> 4.2k
>
> 4.1k ----> 5.2k
>
> 15k ----> 20.7k
>
> 220k ----> 246k
>
> 8.2k ----> 9.9k
>
> 400k ----> 509k
>
>
> These were all marked with a silver tolerance band, so clearly Taylor
> back then at least not *that* bothered about accuracy.
NT
Cursitor Doom
May 18, 2019, 2:13:50 PM5/18/19
to
On Sat, 18 May 2019 09:25:35 -0700, tabbypurr wrote:
> Most Rs in valve kit are far from critical. 5% would have cost them more
> than 10%. 20% were more common.
I just put it down to post-war lack of availability but your guess is as
> Most Rs in valve kit are far from critical. 5% would have cost them more
> than 10%. 20% were more common.
good as mine.
My experience with valves is not that great. I'm really more of the
germanium semiconductor era. ;-)
Mike Coon
May 18, 2019, 5:24:37 PM5/18/19
to
In article <qbpi0s$jmv$2...@dont-email.me>, cu...@notformail.com says...
I was an apprentice in the factory test bay) was made of those...
Mike.
>
> My experience with valves is not that great. I'm really more of the
> germanium semiconductor era. ;-)
I believe the first computer I got my hands on (just to play with while
> My experience with valves is not that great. I'm really more of the
> germanium semiconductor era. ;-)
I was an apprentice in the factory test bay) was made of those...
Mike.
MOP CAP
May 18, 2019, 9:20:44 PM5/18/19
to
I was in the elctronic surplus bisness from the 60's to the end of the
century. Most people thought that
Allen-Bradleys were the gold standard. One cusomer complained and we
started checking samples.
They were all out of tolerance. A-B's speck sheet specified how to
measure. For a given resistance
range you applied a specified voltage and measured the current.
As an aside: In the 50's I ran across some carbon comp. resistors that
had been modified.
Apparently the person was short of cash or in a hurry. The person took
a CC and a triangular file
and raised the CC to the value neede.
CP
century. Most people thought that
Allen-Bradleys were the gold standard. One cusomer complained and we
started checking samples.
They were all out of tolerance. A-B's speck sheet specified how to
measure. For a given resistance
range you applied a specified voltage and measured the current.
As an aside: In the 50's I ran across some carbon comp. resistors that
had been modified.
Apparently the person was short of cash or in a hurry. The person took
a CC and a triangular file
and raised the CC to the value neede.
CP
Cursitor Doom
May 19, 2019, 7:09:10 AM5/19/19
to
On Sat, 18 May 2019 18:20:37 -0700, MOP CAP wrote:
> Apparently the person was short of cash or in a hurry. The person took a
> CC and a triangular file and raised the CC to the value neede.
We used to do the same sort of thing with xtals in the days when they
> Apparently the person was short of cash or in a hurry. The person took a
> CC and a triangular file and raised the CC to the value neede.
were expensive and hard to come by.
tabb...@gmail.com
May 19, 2019, 11:01:26 AM5/19/19
to
On Sunday, 19 May 2019 12:09:10 UTC+1, Cursitor Doom wrote:
> On Sat, 18 May 2019 18:20:37 -0700, MOP CAP wrote:
>
> > Apparently the person was short of cash or in a hurry. The person took a
> > CC and a triangular file and raised the CC to the value neede.
>
> We used to do the same sort of thing with xtals in the days when they
> were expensive and hard to come by.
Couldn't do that with my oldest crystal, it's in a valve glass envelope. 5kHz IIRC.
> On Sat, 18 May 2019 18:20:37 -0700, MOP CAP wrote:
>
> > Apparently the person was short of cash or in a hurry. The person took a
> > CC and a triangular file and raised the CC to the value neede.
>
> We used to do the same sort of thing with xtals in the days when they
> were expensive and hard to come by.
NT
Fox's Mercantile
May 19, 2019, 11:19:26 AM5/19/19
to
On 5/19/19 10:01 AM, tabb...@gmail.com wrote:
> On Sunday, 19 May 2019 12:09:10 UTC+1, Cursitor Doom wrote:
>> On Sat, 18 May 2019 18:20:37 -0700, MOP CAP wrote:
>>
>>> Apparently the person was short of cash or in a hurry. The person took a
>>> CC and a triangular file and raised the CC to the value neede.
>>
>> We used to do the same sort of thing with xtals in the days when they
>> were expensive and hard to come by.
Except you didn't use a file. You used 600 grit silicon carbide paper
> On Sunday, 19 May 2019 12:09:10 UTC+1, Cursitor Doom wrote:
>> On Sat, 18 May 2019 18:20:37 -0700, MOP CAP wrote:
>>
>>> Apparently the person was short of cash or in a hurry. The person took a
>>> CC and a triangular file and raised the CC to the value neede.
>>
>> We used to do the same sort of thing with xtals in the days when they
>> were expensive and hard to come by.
and a piece of glass for a flat surface.
>
> Couldn't do that with my oldest crystal, it's in a valve glass envelope. 5kHz IIRC.
take apart to get to the crystal slab inside.
--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com
Cursitor Doom
May 19, 2019, 11:51:06 AM5/19/19
to
On Sun, 19 May 2019 10:19:17 -0500, Fox's Mercantile wrote:
> Except you didn't use a file. You used 600 grit silicon carbide paper
> and a piece of glass for a flat surface.
Yup, the principle is the same, though. For the final fine 'adjustment'
> Except you didn't use a file. You used 600 grit silicon carbide paper
> and a piece of glass for a flat surface.
we'd use Vim, which is a kitchen scouring powder in the UK and many times
less aggressive than 600 grit.
whit3rd
May 19, 2019, 4:12:54 PM5/19/19
to
On Saturday, May 18, 2019 at 8:22:32 AM UTC-7, Cursitor Doom wrote:
> Here's what I found from a random selection of old components I snipped
> out.
> Here's what I found from a random selection of old components I snipped
> out.
> 27k became 38.6k
>
> another 27k ----> 29k
>
> 100k ----> 107k
Good to know, but the aging of composition resistors doesn't tell us much
>
> another 27k ----> 29k
>
> 100k ----> 107k
about carbon film resistors (the common low-spec type nowadays) or
metal film (the common high-spec type) and manufacturer coatings
and such are likely to be changing from year to year as well.
Probably, because conductive (metallic or semimetallic) items are positive
valence, oxidation will raise resistance with time, for almost
anything. How much time, is still a mystery (for almost anything
we build today, at any rate).
There's too much chemistry involved to make a really good long-life
high accuracy projection for most real components. Humidity, ozone,
fungus, air pollution... so MANY variables.
tabb...@gmail.com
May 19, 2019, 4:24:21 PM5/19/19
to
NT
Cursitor Doom
May 19, 2019, 6:45:14 PM5/19/19
to
On Sun, 19 May 2019 13:24:18 -0700, tabbypurr wrote:
> You can eliminate all those with glass, vacuum & getter. Then you find
> one day that the getter is oxidised & the bulb contains hydrogen.
I was under the impression that glass was impermeable even to omnipresent
> You can eliminate all those with glass, vacuum & getter. Then you find
> one day that the getter is oxidised & the bulb contains hydrogen.
hydrogen. Or is there a path via where the base pins protrude?
Fox's Mercantile
May 19, 2019, 8:50:39 PM5/19/19
to
On 5/19/19 5:45 PM, Cursitor Doom wrote:
> I was under the impression that glass was impermeable even to omnipresent
> hydrogen. Or is there a path via where the base pins protrude?
Hydrogen atoms are really really small.
> I was under the impression that glass was impermeable even to omnipresent
> hydrogen. Or is there a path via where the base pins protrude?
Trying to keep hydrogen in or out is always problematic.
Clifford Heath
May 19, 2019, 9:14:56 PM5/19/19
to
On 20/5/19 10:50 am, Fox's Mercantile wrote:
> On 5/19/19 5:45 PM, Cursitor Doom wrote:
>> I was under the impression that glass was impermeable even to omnipresent
>> hydrogen. Or is there a path via where the base pins protrude?
>
> Hydrogen atoms are really really small.
> Trying to keep hydrogen in or out is always problematic.
Also, a kilogram of hydrogen at a given pressure takes more space than
> On 5/19/19 5:45 PM, Cursitor Doom wrote:
>> I was under the impression that glass was impermeable even to omnipresent
>> hydrogen. Or is there a path via where the base pins protrude?
>
> Hydrogen atoms are really really small.
> Trying to keep hydrogen in or out is always problematic.
any other gas.
tabb...@gmail.com
May 20, 2019, 12:48:02 AM5/20/19
to
On Sunday, 19 May 2019 23:45:14 UTC+1, Cursitor Doom wrote:
> On Sun, 19 May 2019 13:24:18 -0700, tabbypurr wrote:
>
> > You can eliminate all those with glass, vacuum & getter. Then you find
> > one day that the getter is oxidised & the bulb contains hydrogen.
>
> I was under the impression that glass was impermeable even to omnipresent
> hydrogen. Or is there a path via where the base pins protrude?
Glasslinger did a mass spec analysis to discover that gassy valves contain hydrogen. I don't know whether that permeates through the glass (unlikely since most valves stay hard), leaks in through pin sealing defects or is the result of remaining water vapour reacting with the getter. Either way a getter that could capture it would be a good thing probably.
> On Sun, 19 May 2019 13:24:18 -0700, tabbypurr wrote:
>
> > You can eliminate all those with glass, vacuum & getter. Then you find
> > one day that the getter is oxidised & the bulb contains hydrogen.
>
> I was under the impression that glass was impermeable even to omnipresent
> hydrogen. Or is there a path via where the base pins protrude?
https://www.youtube.com/watch?v=16vOoF_XUB8
NT
Mike Coon
May 20, 2019, 3:11:35 AM5/20/19
to
In article <rvOdnSbLyqpFZHzB...@giganews.com>,
jda...@att.net says...
bigger. Helium is bad too because then the atoms come at you singly...
Mike.
jda...@att.net says...
>
> Hydrogen atoms are really really small.
> Trying to keep hydrogen in or out is always problematic.
In practice you get molecules on the two-fer principle which are much
> Hydrogen atoms are really really small.
> Trying to keep hydrogen in or out is always problematic.
bigger. Helium is bad too because then the atoms come at you singly...
Mike.
John Robertson
May 20, 2019, 8:40:53 AM5/20/19
to
On 2019/05/18 11:22 a.m., Cursitor Doom wrote:
> On Fri, 17 May 2019 21:19:07 +0100, Mike Coon wrote:
>
>> I can hardly wait!
>
> Then I shall keep you in suspense no longer.
>
> Here's what I found from a random selection of old components I snipped
> out. Firstly, pretty much *all* the capacitors were fine. The 350VDC
> Hunts capacitors could easily have been new. An Erie plate ceramic of
> 0.01uF likewise. A Dubilier type SM22 50pf cap, however, had gone up to
> 62pF. That one was one of the ones used for tuning. The biggest changes
> were as expected in the carbon resistors, all of which aged to higher
> values like so:
>
> 27k became 38.6k (bad)
> On Fri, 17 May 2019 21:19:07 +0100, Mike Coon wrote:
>
>> I can hardly wait!
>
> Then I shall keep you in suspense no longer.
>
> Here's what I found from a random selection of old components I snipped
> out. Firstly, pretty much *all* the capacitors were fine. The 350VDC
> Hunts capacitors could easily have been new. An Erie plate ceramic of
> 0.01uF likewise. A Dubilier type SM22 50pf cap, however, had gone up to
> 62pF. That one was one of the ones used for tuning. The biggest changes
> were as expected in the carbon resistors, all of which aged to higher
> values like so:
>
>
> another 27k ----> 29k (within 10%)
>
> 100k ----> 107k (within 10%)
>
> 10 ----> 10.7 (ditto)
>
> 3.3k ----> 4.2k (bad)
>
> 4.1k ----> 5.2k (bad)
>
> 15k ----> 20.7k (bad)
>
> 220k ----> 246k (barely bad - just above 10%)
>
> 8.2k ----> 9.9k (bad)
>
> 400k ----> 509k (bad)
>
>
> These were all marked with a silver tolerance band, so clearly Taylor
> back then at least not *that* bothered about accuracy.
>
No, those resistors have drifted since their original construction.
>
> These were all marked with a silver tolerance band, so clearly Taylor
> back then at least not *that* bothered about accuracy.
>
People did have ohm-meters back then and would verify values on
resistors particularly if they were colour deficient or colour blind as
I did, testing Rs when building kits - red/green deficient vision. I
still check almost all resistors I come across with a meter as I don't
trust my green, dark red, and brown differentiation.
If they are in power circuits - plate or cathode or voltage dropping
then those do drift as they were only compressed carbon and heat/cooling
cycles would cause them to change value - usually upwards as you have
discovered. I consider your values typical of tube gear that is 40 or
more years old.
1920s resistors were a chunk of carbon rod with a wire wrapped around
each end then dipped in a sealant - how long do you think that value
would last within X%? Wire wound resistors external connections were
pressure bonded to the resistance wire, not uncommon for that joint to
fail over time...
Like I said earlier you HAVE to verify all the resistors as they wander
over time. Modern Rs are much more reliable when operated under their
rated wattage.
John :-#)#
--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."
tabb...@gmail.com
May 20, 2019, 1:19:31 PM5/20/19
to
On Monday, 20 May 2019 13:40:53 UTC+1, John Robertson wrote:
> 1920s resistors were a chunk of carbon rod with a wire wrapped around
> each end then dipped in a sealant - how long do you think that value
> would last within X%? Wire wound resistors external connections were
> pressure bonded to the resistance wire, not uncommon for that joint to
> fail over time...
I presume you mean carbon composition rod. Pure carbon would give too few ohms to have much use in a valve radio.
> 1920s resistors were a chunk of carbon rod with a wire wrapped around
> each end then dipped in a sealant - how long do you think that value
> would last within X%? Wire wound resistors external connections were
> pressure bonded to the resistance wire, not uncommon for that joint to
> fail over time...
Some Rs used metal caps instead of wires, and were mounted in a clip-in holder. I guess they needed to be replaced sometimes as different valves sometimes needed different grid leak values.
> Like I said earlier you HAVE to verify all the resistors as they wander
> over time. Modern Rs are much more reliable when operated under their
> rated wattage.
>
> John :-#)#
NT
Cursitor Doom
May 20, 2019, 6:46:16 PM5/20/19
to
atom. Heliums come singly alright, which is one of the reasons, along
with small size, they're used for this kind of leak testing.
Message has been deleted
whit3rd
May 21, 2019, 3:09:55 AM5/21/19
to
On Monday, May 20, 2019 at 3:46:16 PM UTC-7, Cursitor Doom wrote:
> On Mon, 20 May 2019 08:11:31 +0100, Mike Coon wrote:
>
> On Mon, 20 May 2019 08:11:31 +0100, Mike Coon wrote:
>
> May seem counter-intuitive, but hydrogen is not actually the smallest
> atom. Heliums come singly alright, which is one of the reasons, along
> with small size, they're used for this kind of leak testing.
Good point; also, the H2 molecule has two 1S-like electrons, which is
> atom. Heliums come singly alright, which is one of the reasons, along
> with small size, they're used for this kind of leak testing.
very similar to a Helium atom, and just about as slippery.
H2 molecules are lighter than He atoms, on average.
John Robertson
May 21, 2019, 8:04:46 AM5/21/19
to
On 2019/05/20 1:19 p.m., tabb...@gmail.com wrote:
> On Monday, 20 May 2019 13:40:53 UTC+1, John Robertson wrote:
>
>> 1920s resistors were a chunk of carbon rod with a wire wrapped around
>> each end then dipped in a sealant - how long do you think that value
>> would last within X%? Wire wound resistors external connections were
>> pressure bonded to the resistance wire, not uncommon for that joint to
>> fail over time...
>
> I presume you mean carbon composition rod. Pure carbon would give too few ohms to have much use in a valve radio.
Thanks, I did mean composite.
> On Monday, 20 May 2019 13:40:53 UTC+1, John Robertson wrote:
>
>> 1920s resistors were a chunk of carbon rod with a wire wrapped around
>> each end then dipped in a sealant - how long do you think that value
>> would last within X%? Wire wound resistors external connections were
>> pressure bonded to the resistance wire, not uncommon for that joint to
>> fail over time...
>
> I presume you mean carbon composition rod. Pure carbon would give too few ohms to have much use in a valve radio.
>
> Some Rs used metal caps instead of wires, and were mounted in a clip-in holder. I guess they needed to be replaced sometimes as different valves sometimes needed different grid leak values.
yes, you did keep a drawer of grid resistors handy if you wanted best
performance out of your rig.
>
>
>> Like I said earlier you HAVE to verify all the resistors as they wander
>> over time. Modern Rs are much more reliable when operated under their
>> rated wattage.
>>
>> John :-#)#
>
> as long as it's well under. Rated life for power Rs operated at specced power can be terrible.
>
>
> NT
>
Heck Molex pin connectors are rated at 25 insertions if I recall
correctly, and they are heavily used in arcade games...
Spec sheets do need to be read after all.
John :-#)#
Ralph Mowery
May 21, 2019, 10:20:11 AM5/21/19
to
In article <1c3fb9af-1eba-4642...@googlegroups.com>,
whi...@gmail.com says...
>
>
Hydrogen is also explosive or will burn. That is another reason not to
just spray it out for leak detection.
I think that hydrogen may be the smallest atom, but they often join in
pairs to make up a larger molicule. Some other atoms that are normally
gas do the same thing.
whi...@gmail.com says...
>
> > May seem counter-intuitive, but hydrogen is not actually the smallest
> > atom. Heliums come singly alright, which is one of the reasons, along
> > with small size, they're used for this kind of leak testing.
>
>
> > May seem counter-intuitive, but hydrogen is not actually the smallest
> > atom. Heliums come singly alright, which is one of the reasons, along
> > with small size, they're used for this kind of leak testing.
>
>
> Good point; also, the H2 molecule has two 1S-like electrons, which is
> very similar to a Helium atom, and just about as slippery.
> H2 atoms are lighter than He, on average.
> very similar to a Helium atom, and just about as slippery.
>
>
Hydrogen is also explosive or will burn. That is another reason not to
just spray it out for leak detection.
I think that hydrogen may be the smallest atom, but they often join in
pairs to make up a larger molicule. Some other atoms that are normally
gas do the same thing.
Cursitor Doom
May 21, 2019, 6:51:58 PM5/21/19
to
On Tue, 21 May 2019 10:20:02 -0400, Ralph Mowery wrote:
> Hydrogen is also explosive or will burn. That is another reason not to
> just spray it out for leak detection.
>
> I think that hydrogen may be the smallest atom, but they often join in
> pairs to make up a larger molicule. Some other atoms that are normally
> gas do the same thing.
Oh boy. Where do I start?
> Hydrogen is also explosive or will burn. That is another reason not to
> just spray it out for leak detection.
>
> I think that hydrogen may be the smallest atom, but they often join in
> pairs to make up a larger molicule. Some other atoms that are normally
> gas do the same thing.
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