Can capacitors


ken chalfant
 

Greetings,

From time to time I see that someone is working to repair or restore an instrument with the old multi capacitor metal can components and that appears to be a never ending struggle.

The other night I reconnected with an old friend with whom I had not spoken in a couple of years.

He has always had an interest in restoring old audio equipment. As we visited he mentioned a company that still builds Mallory style metal can capacitors. My friend said they even use the old, original equipment.

I was very surprised and actually found that a little hard to believe, but it turns out to be true.

While I do not know about configurations, minimum quantities or pricing it appears this company makes those old style metal can multi-unit capacitors.

www.cemfg.com <http://www.cemfg.com/>

I have no financial interest - or really - any other interest in this - just hoping it helps some of our group.

Regards,

Ken


BobH
 

Another source is Tubes and More / Antique Electronic Supply https://www.tubesandmore.com/products/capacitors?filters=Type%3DMulti-Section%20/%20Can%20Type

I have no conection with this company, but have bought a few things from them through the years and it has been good.

BobH


Colin Herbert
 

Unless I'm reading it incorrectly, you will find that some of the can capacitors on this page were manufactured by CE, which was the company in Ken's post.
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of BobH
Sent: 05 December 2020 15:22
To: TekScopes@groups.io
Subject: Re: [TekScopes] Can capacitors

Another source is Tubes and More / Antique Electronic Supply https://www.tubesandmore.com/products/capacitors?filters=Type%3DMulti-Section%20/%20Can%20Type

I have no conection with this company, but have bought a few things from them through the years and it has been good.

BobH


Tom Phillips
 

CEDistribution & Tubes and More / Antique Electronic Supply are really the same company. The former is their wholesale outlet which sells only to registered distributors and the latter sells to the general public. In small quantities there is only a modest price difference for identical parts from each outlet.

There is a video series on the page at www.cemfg.com <http://www.cemfg.com/> which shows the can cap manufacturing process using the old Mallory equipment. It is interesting. The materials handling and process quality control are, of course, not up to modern standards and the resulting caps are not as reliable as the original Mallory parts. However, they have been successful with their niche market customers.


n4buq
 

Mallory Capacitor Company had a manufacturing facility here in Huntsville, Alabama. I don't know the exact dates of operation, but it was an active facility through the 1960s and probably well into or past the 1970s. The building was on the main drag and I must've passed it thousands of times. I always wondered what it looked like on the inside. The mother of one of my friends who lived across the street from me when I was very young worked there but I don't know what she did. They demolished the building a few years ago and there's a shopping/eating mall there now.

Good times...

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "ken chalfant" <kpchalfant@msn.com>
To: HP-Agilent-Keysight-equipment@groups.io, TekScopes@groups.io
Sent: Saturday, December 5, 2020 2:17:12 AM
Subject: [TekScopes] Can capacitors

Greetings,

From time to time I see that someone is working to repair or restore an
instrument with the old multi capacitor metal can components and that
appears to be a never ending struggle.

The other night I reconnected with an old friend with whom I had not spoken
in a couple of years.

He has always had an interest in restoring old audio equipment. As we
visited he mentioned a company that still builds Mallory style metal can
capacitors. My friend said they even use the old, original equipment.

I was very surprised and actually found that a little hard to believe, but it
turns out to be true.

While I do not know about configurations, minimum quantities or pricing it
appears this company makes those old style metal can multi-unit capacitors.

www.cemfg.com <http://www.cemfg.com/>

I have no financial interest - or really - any other interest in this - just
hoping it helps some of our group.

Regards,

Ken










Roy Thistle
 

On Sat, Dec 5, 2020 at 07:40 AM, Tom Phillips wrote:


There is a video series on the page at www.cemfg.com < http://www.cemfg.com/ >
which shows the can cap manufacturing process using the old Mallory equipment.
It is interesting. The materials handling and process quality control are, of
course, not up to modern standards and the resulting caps are not as reliable
as the original Mallory parts. However, they have been successful with their
niche market customers.
The OP cross posted this to the HP-x-x-equipment group.
If you watch the videos... it's all a lot dumber than it looks.
"However, they have been successful with their niche market customers." I agree with Tom's statement...it seems they have been... because there is obviously some money behind it. (Those videos aren't cheap to make... and actors cost money.)
But, I wonder how the people who buy this stuff find their way back home, at night... it must be on instinct... it sure isn't on clear thinking and good understanding.


greenboxmaven
 

I agree that, regrettably, these condensers do not measure up in reliability. I worked at a sound equipment boutique and had about a 10% failure rate of these condensers within three years. They are also quite expensive, which is justified by the small production volume and labor of making them. I have two old sound amplifiers of my own that had these condensers installed before I got them, and they have all failed less than ten years after they were made. I hope the manufacturers will take these statistics seriously and improve their quality. Meanwhile, I will continue opening old ones, removing the failed windings, and replacing them with modern individual condensers.

Bruce Gentry, KA2IVY

On 12/5/20 11:55, Roy Thistle wrote:
On Sat, Dec 5, 2020 at 07:40 AM, Tom Phillips wrote:

There is a video series on the page at www.cemfg.com < http://www.cemfg.com/ >
which shows the can cap manufacturing process using the old Mallory equipment.
It is interesting. The materials handling and process quality control are, of
course, not up to modern standards and the resulting caps are not as reliable
as the original Mallory parts. However, they have been successful with their
niche market customers.


Chuck Harris <cfharris@...>
 

Not to put you on the spot, but can you share with
us the types of failures you witnessed in these new
manufacture can capacitors?

It might allow us to determine what they are doing wrong.

For instance, can capacitors were originally made during
the era where the capacitor's aluminum wasn't pre anodized
before construction. They anodized it in place by
applying a current limited peak required voltage.

Capacitors built during that era have a much more reactive
(to aluminum) electrolyte, than do current manufacture
capacitors.

There have been many electrolyte failures since the
industrial espionage days when spies from China stole
bogus files detailing one highly regarded manufacturer's
recipe.. and hundreds of Chinese manufacturers, and a
few Japanese, made little time bombs using the purloined
recipe...

-Chuck Harris

greenboxmaven via groups.io wrote:

I agree that, regrettably, these condensers do not measure up in reliability. I
worked at a sound equipment boutique and  had about a 10% failure rate of these
condensers within three years.   They are also quite expensive, which is justified by
the small production volume and labor of making them.  I have two old sound
amplifiers of my own that had these condensers installed before I got them, and they
have all failed less than ten years after they were made. I hope the manufacturers
will take these statistics seriously and improve their quality. Meanwhile, I will
continue opening old ones, removing the failed windings, and replacing them with
modern individual condensers.

     Bruce Gentry, KA2IVY


On 12/5/20 11:55, Roy Thistle wrote:
On Sat, Dec  5, 2020 at 07:40 AM, Tom Phillips wrote:

There is a video series on the page at www.cemfg.com < http://www.cemfg.com/ >
which shows the can cap manufacturing process using the old Mallory equipment.
It is interesting. The materials handling and process quality control are, of
course, not up to modern standards and the resulting caps are not as reliable
as the original Mallory parts. However, they have been successful with their
niche market customers.








Ed Breya
 

Could a high failure rate be attributed to operating temperature? I'd think many of the replacements - at least the higher voltage ones - were used in tube audio and such, and maybe had pretty hot environments, or got cooked by being too close to power tubes.

Ed


greenboxmaven
 

The vast majority of failures were drastic reduction or total loss of capacitance in one or two sections. ESR would also go rather high. Overheating, shorting, and venting were rare. These problems tended to occur more often in higher voltage sections, 400 volts or more. Condensers that were all 350 volts or less did not fail very often, but still far more frequently than today's imported single section condensers.

Bruce Gentry, KA2IVY

On 12/5/20 13:14, Chuck Harris wrote:
Not to put you on the spot, but can you share with
us the types of failures you witnessed in these new
manufacture can capacitors?

It might allow us to determine what they are doing wrong.

For instance, can capacitors were originally made during
the era where the capacitor's aluminum wasn't pre anodized
before construction. They anodized it in place by
applying a current limited peak required voltage.

Capacitors built during that era have a much more reactive
(to aluminum) electrolyte, than do current manufacture
capacitors.

There have been many electrolyte failures since the
industrial espionage days when spies from China stole
bogus files detailing one highly regarded manufacturer's
recipe.. and hundreds of Chinese manufacturers, and a
few Japanese, made little time bombs using the purloined
recipe...

-Chuck Harris

greenboxmaven via groups.io wrote:
I agree that, regrettably, these condensers do not measure up in reliability. I
worked at a sound equipment boutique and had about a 10% failure rate of these
condensers within three years. They are also quite expensive, which is justified by
the small production volume and labor of making them. I have two old sound
amplifiers of my own that had these condensers installed before I got them, and they
have all failed less than ten years after they were made. I hope the manufacturers
will take these statistics seriously and improve their quality. Meanwhile, I will
continue opening old ones, removing the failed windings, and replacing them with
modern individual condensers.

Bruce Gentry, KA2IVY


On 12/5/20 11:55, Roy Thistle wrote:
On Sat, Dec 5, 2020 at 07:40 AM, Tom Phillips wrote:

There is a video series on the page at www.cemfg.com < http://www.cemfg.com/ >
which shows the can cap manufacturing process using the old Mallory equipment.
It is interesting. The materials handling and process quality control are, of
course, not up to modern standards and the resulting caps are not as reliable
as the original Mallory parts. However, they have been successful with their
niche market customers.








greenboxmaven
 

I think heat is a factor. Many classic sound amplifiers are rather compact, and the condensers do get hot. However, the originals withstood it well for decades before becoming unusable. The main failure of older ones was overheating, excess leakage that will not decrease with time, and often spectacular venting. Excessive hum or poor decoupling action were not that common in the equipment I restored. Some coupling condensers in tube sound gear were notorious for leakage, and were replaced pre-emptively. On the other hand, loss of capacitance was the number one failure of electrolytics in solid state gear, I can only recall one incedence of venting, and it was quite spectacular and loud. Repacing all of the electrolytics would transform a solid state amplifier or receiver from mediocre to excellent.

Bruce Gentry, KA2IVY

On 12/5/20 13:44, Ed Breya via groups.io wrote:
Could a high failure rate be attributed to operating temperature? I'd think many of the replacements - at least the higher voltage ones - were used in tube audio and such, and maybe had pretty hot environments, or got cooked by being too close to power tubes.

Ed





Chuck Harris <cfharris@...>
 

Ok, thanks for the info.

Here is what I think is happening:

When you have a current flowing across an electrolyte, with
a pair of aluminum electrodes, the electrolyte builds oxide
on one electrode, and the other stays relatively free of
oxide. This insulates the oxide coated electrode from the
electrolyte, and the current goes away... Not a problem,
that is what is supposed to happen.

But, if you have a current flowing across an electrolyte, with
a pair of dissimilar metal electrodes, such as aluminum and
steel or copper, one will sacrifice the other, depending on
which is the more reactive metal... usually the aluminum.

My guess is they used something like a steel, or copper, rivet
to connect the aluminum ribbon (that comes from the plates) to
the terminals. To protect the rivet, they applied a protective
coating to keep the electrolyte away.

The protective coating failed.

That failure allowed an electrolytic reaction, which caused the
ribbon to be etched through, which left the capacitor essentially
open circuit... low capacitance, and very high ESR.

-Chuck Harris

greenboxmaven via groups.io wrote:

The vast majority of failures were drastic reduction or total loss of capacitance in
one or two sections. ESR would also go rather high.  Overheating, shorting, and
venting were rare. These problems tended to occur more often in higher voltage
sections, 400 volts or more. Condensers that were all 350 volts or less did not fail
very often, but still far more frequently than today's imported single section
condensers.

      Bruce Gentry, KA2IVY


On 12/5/20 13:14, Chuck Harris wrote:
Not to put you on the spot, but can you share with
us the types of failures you witnessed in these new
manufacture can capacitors?

It might allow us to determine what they are doing wrong.

For instance, can capacitors were originally made during
the era where the capacitor's aluminum wasn't pre anodized
before construction.  They anodized it in place by
applying a current limited peak required voltage.

Capacitors built during that era have a much more reactive
(to aluminum) electrolyte, than do current manufacture
capacitors.

There have been many electrolyte failures since the
industrial espionage days when spies from China stole
bogus files detailing one highly regarded manufacturer's
recipe.. and hundreds of Chinese manufacturers, and a
few Japanese, made little time bombs using the purloined
recipe...

-Chuck Harris

greenboxmaven via groups.io wrote:
I agree that, regrettably, these condensers do not measure up in reliability. I
worked at a sound equipment boutique and  had about a 10% failure rate of these
condensers within three years.   They are also quite expensive, which is justified by
the small production volume and labor of making them.  I have two old sound
amplifiers of my own that had these condensers installed before I got them, and they
have all failed less than ten years after they were made. I hope the manufacturers
will take these statistics seriously and improve their quality. Meanwhile, I will
continue opening old ones, removing the failed windings, and replacing them with
modern individual condensers.

      Bruce Gentry, KA2IVY


On 12/5/20 11:55, Roy Thistle wrote:
On Sat, Dec  5, 2020 at 07:40 AM, Tom Phillips wrote:

There is a video series on the page at www.cemfg.com < http://www.cemfg.com/ >
which shows the can cap manufacturing process using the old Mallory equipment.
It is interesting. The materials handling and process quality control are, of
course, not up to modern standards and the resulting caps are not as reliable
as the original Mallory parts. However, they have been successful with their
niche market customers.














Roy Thistle
 

On Sat, Dec 5, 2020 at 10:02 AM, greenboxmaven wrote:


these condensers do not measure up in reliability
Let's agree (or agree to disagree, if you do) that we can only consider the "reliability" of these things subjectively.
Where is there any objective reliability data published on them?
There's plenty of reliability data for the Mallory FC type capacitors... which these things are being compared to.
Watch the videos: their whole premise, AFACT, is that because these "vintage" capacitors are manufactured on some... supposedly 1920's salvaged Mallory manufacturing machinery... that will make your "vintage" Fender (et. al.) amplifier sound better.
What's up with that?


Dave Voorhis
 

On 5 Dec 2020, at 20:13, Roy Thistle <roy.thistle@mail.utoronto.ca> wrote:

… Watch the videos: their whole premise, AFACT, is that because these “vintage" capacitors are manufactured on some... supposedly 1920's salvaged Mallory manufacturing machinery... that will make your "vintage" Fender (et. al.) amplifier sound better.
What's up with that?
Same as all the other audiophoolery around cryogenically treated tubes/valves and wires; capacitors of magic vintage or casing materials and/or colour; strategically room-placed sonically-enhancing crystals; transformers made of solid unobtanium and the like: it sells high-priced products for maximum profit.

The sad part is that some people actually fall for the sellers' ludicrously incredible pseudoscientific claims (and the sellers clearly know this.)


Roy Thistle
 

On Sat, Dec 5, 2020 at 11:22 AM, greenboxmaven wrote:


The vast majority of failures were drastic reduction or total loss of
capacitance in one or two sections. ESR would also go rather high.
Overheating, shorting, and venting were rare.
Yes... lots of time these Mallory FC type .et al. caps in a can... there was a "drastic reduction or total loss of capacitance in one or two sections" ... often heard in old radios as a loud hum in the speaker. I've heard tell of FCs shorting... (often told as fact on sites selling replacements... and in the lore too... claiming things like tubes and transformers destroyed)... but, I think FCs shorting was quite rare. Old timey service guys... I remember... used to have a good one(s) in their kits... fitted with leads and alligator clips... to bypass suspect FCs.
When we were kids... not so good kids... we used to connect old scavenged FC, in reverse polarity, across old car batteries. Now that was a short!
Similarly, and not much better behaved... we used to spook the lab tech by doing it with those, single value, single-ended radially leaded types (rubber plug, and scored Al top)... were all familiar with.


Mark Goldberg
 

I've rebuilt solid state amplifiers. New technology capacitors, well
chosen, are way better than the old ones. It is easier to choose for
power supply filter caps. In a similar size case you get several times
the capacitance, a fraction of the ESR and higher voltage ratings. You
just need to find a way to fit the new ones mechanically. The only
reason to use old caps is for looks or if the circuit relied on having
crappy caps with high ESR and low capacitance. You may have to limit
the power-up surge current. The result is a better power supply with
better performance at low frequencies.

For caps in the audio chain, you need to choose more judiciously. Some
of the new high capacitance formulations change capacitance with
voltage more, which can cause distortion. But, you can choose better
ones which are available. Being an EE, I've been able to understand
the circuit and choose correctly most of the time.

In general, capacitors are way better now in every way.

Transformers are another matter. Some of the knowledge of how to make
good ones seems to have been lost, but there are still good ones out
there. Again, choose carefully. It is harder to do that in a power
supply where you don't know the design well.

The huge increase in automotive electronics had resulted in better
parts that work over a wider temperature range. I generally design
with -40C to +85C or +125C parts even for commercial designs that may
have used 0 - 70C parts in the past. The high volume and low cost of
automotive rated components is a big plus these days. They are also
better with vibration.

All this applies equally to test equipment.

For discretes and specialized ICs, obsolescence is indeed a problem.
Some smart folks have designed good replacements though with modern
components using a different design.

Regards,

Mark

On Sat, Dec 5, 2020 at 1:22 PM Dave Voorhis <voorhis@gmail.com> wrote:

On 5 Dec 2020, at 20:13, Roy Thistle <roy.thistle@mail.utoronto.ca> wrote:

… Watch the videos: their whole premise, AFACT, is that because these “vintage" capacitors are manufactured on some... supposedly 1920's salvaged Mallory manufacturing machinery... that will make your "vintage" Fender (et. al.) amplifier sound better.
What's up with that?
Same as all the other audiophoolery around cryogenically treated tubes/valves and wires; capacitors of magic vintage or casing materials and/or colour; strategically room-placed sonically-enhancing crystals; transformers made of solid unobtanium and the like: it sells high-priced products for maximum profit.

The sad part is that some people actually fall for the sellers' ludicrously incredible pseudoscientific claims (and the sellers clearly know this.)





Roy Thistle
 

On Sat, Dec 5, 2020 at 12:22 PM, Dave Voorhis wrote:


Same as all the other audiophoolery
I'm glad you said it... because that's... AFAIC... that's just what it is all about.
Not to reflect on the OP, who is trying to help people... but, were now engaged in a discussion mostly about "audiophoolery" ... and not much more... at least so FAICT.
Worse IMO, the spammers have latched on.


greenboxmaven
 

Having had direct experience with audio enthusiests, some of the ideas they have are almost beyond belief. However, enjoyment of the equipment is subjective on many things, and if the listener or performer thinks it makes the sound better, then it does.

Bruce Gentry KA2IVY

On 12/5/20 15:13, Roy Thistle wrote:
On Sat, Dec 5, 2020 at 10:02 AM, greenboxmaven wrote:

these condensers do not measure up in reliability
Let's agree (or agree to disagree, if you do) that we can only consider the "reliability" of these things subjectively.
Where is there any objective reliability data published on them?
There's plenty of reliability data for the Mallory FC type capacitors... which these things are being compared to.
Watch the videos: their whole premise, AFACT, is that because these "vintage" capacitors are manufactured on some... supposedly 1920's salvaged Mallory manufacturing machinery... that will make your "vintage" Fender (et. al.) amplifier sound better.
What's up with that?





Tom Lee
 

Yes, but some people put more /psycho /in psychoacoustics than seems healthy. Google for the Tice Audio Clock, just as one example.

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 12/5/2020 16:39, greenboxmaven via groups.io wrote:
Having had direct experience with audio enthusiests, some of the ideas they have are almost beyond belief. However, enjoyment of the equipment is subjective on many things, and if the listener or performer thinks it makes the sound better, then it does.

      Bruce Gentry   KA2IVY


On 12/5/20 15:13, Roy Thistle wrote:
On Sat, Dec  5, 2020 at 10:02 AM, greenboxmaven wrote:

these condensers do not measure up in reliability
Let's agree (or agree to disagree, if you do) that we can only consider the "reliability" of these things subjectively.
Where is there any objective reliability data published on them?
There's plenty of reliability data for the Mallory FC type capacitors... which these things are being compared to.
Watch the videos: their whole premise, AFACT, is that because these "vintage" capacitors are manufactured on some... supposedly 1920's salvaged Mallory manufacturing machinery... that will make your "vintage" Fender (et. al.) amplifier sound better.
What's up with that?









greenboxmaven
 

I was trying to be polite to those deeply affected. I actually saw a guitar player and another technican try several rectifier tubes in a guitar amplifier, all new and identical from the same case, to find the one that sounded best. It was almost a seance!.

Bruce Gentry, KA2IVY

On 12/5/20 19:47, Tom Lee wrote:
Yes, but some people put more /psycho /in psychoacoustics than seems healthy. Google for the Tice Audio Clock, just as one example.