Tubular Blue "Molded" Capacitors - Who made them?

[mabinogeon]

Hi all,

This is another one of those questions that doesn't really matter, but I'm curious anyway.

I've heard the tubular blue molded caps in '60s Fender amps variously referred to as "Ajax", "Mallory", and "Sprague", but I just stumbled across a couple NOS .1µF 1000V caps that are labeled Packard-Bell.

Blue Caps

• mabinogeon
• Dec 6, 2020

The top two .047µF caps in that picture are the ground switch caps out of two '60s Fender amps I own.

Does anyone happen to have a definitive answer on this? Did Packard Bell manufacture their own components for use in their radios and TVs and computers back then? Or were these made by someone else and rebranded Packard Bell (that is my assumption)? Is there a datasheet for these floating around out there somewhere?

Thanks!

 

[King Fan]

Good question. I agree "Ajax" is the name you see almost everywhere, used by many people who seem smart enough to believe, but I've never even tried to look up 'Ajax' and see if it was even a brand or company or ??? When you do try to look up "Ajax capacitors" you certainly find a lot either for sale or argued about endlessly in threads.

To my eye those lower caps with the square ends don't look much like the round-end ones Fender used. Are they actually related? Did Packard Bell make caps or use caps someone else made?

I await enlightenment.

 

[Peegoo]

Ajax is the usual name assiciated with the blue "MOLDED Made in the USA" axial lead caps used in a whole lot of electronics from amps to radios to TVs and everything else. Some are labeled Packard Bell, but I'll bet they were made under contract for PB.

The lower caps with the corners on the end look like blue Micamold Tropicaps. These MTs are usually dark green in color; the shape is identical.

 

[mabinogeon]

To my eye those lower caps with the square ends don't look much like the round-end ones Fender used.

The lower caps with the corners on the end look like blue Micamold Tropicaps.

The plot thickens, as it were!

Here's another picture of the capacitors I have, this time of the ends:

Caps2

• mabinogeon
• Dec 7, 2020

They look pretty similar to me: same paper label, same color casing, same bump on the outer foil-side endcap.

Regarding the Tropicaps: I can't find where they ever made a 1000V cap, one in blue, and the construction appears different based on what I'm seeing on ebay.

Here's a pair, one with a "Molded" label and one with a Packard-Bell label: http://rover.ebay.com/rover/1/711-5...0001&campid=5338148343&icep_item=123182357161

 

[mabinogeon]

Something's up with TDPRI, it keeps chopping out chunks of my text at random.

 

[mabinogeon]

To my eye those lower caps with the square ends don't look much like the round-end ones Fender used.

The lower caps with the corners on the end look like blue Micamold Tropicaps.

It looks like some ""Molded" caps have square-ish ends and some have the more familiar rounded ends. Perhaps this is due to capacitance and voltage?

here's a "Molded" .022uF 200V with rounded ends: http://rover.ebay.com/rover/1/711-5...0001&campid=5338148343&icep_item=133536342757http://rover.ebay.com/rover/1/711-5...0001&campid=5338148343&icep_item=183750617568

And here's one with square ends: http://rover.ebay.com/rover/1/711-5...0001&campid=5338148343&icep_item=183750617568

Perhaps we've been dealing with two different types of capacitors all along and just didn't know it? Nah.

Perhaps we'll never know for sure?

 

[BobbyZ]

Like I said on the other forum, I've always heard Ajax, but have no idea if that's true or not.
Might just be one of life's mysteries we never solve.

 

[schmee]

The Fender blue style I always thought were Mallory. Ajax were the yellow caps in Tweed amps weren't they?

 

[BobbyZ]

Astron made the yellow caps used in the later tweeds and early brownface Fenders.

 

[schmee]

I came up with this, Ajax blue are similar but not the same as the Mallory. There was an Ajax Electronics in S. Calif starting in '53, so could have been the Leo connection. (I think more of a middle man, not a maker) :

 

[mabinogeon]

I came up with this, Ajax blue are similar but not the same as the Mallory. There was an Ajax Electronics in S. Calif starting in '53, so could have been the Leo connection. (I think more of a middle man, not a maker) :

Great info, thanks!

I think the blue caps with the paper labels are the same as the ones with the yellow text labels.

Some but not all blue Molded caps, whether they have the paper labels, the yellow text labels, square or rounded endcaps, or are branded Packard-Bell, are stamped "MC1" followed by a date code. So I think from that we can surmise they are all the same type of capacitor from the same manufacturer, but we're still no closer to confirming who that manufacturer was

MC1 Caps

• mabinogeon
• Dec 8, 2020

Perhaps the MC stands for Molded (or Mylar) Capacitor?

Fender started using them in 1961, as far as I can tell.

There was also an Ajax 705 series ceramic-shell mylar cap from the same time period: https://reverb.com/item/27981789-aj...ne-capacitor-for-1960s-les-paul-or-guitar-amp

 

[mabinogeon]

I emailed Fender and this was their reply:

"I ran your question by two of our senior amp techs and here was their response:

I can't say that I'm 100% certain, but I believe I'm very close to 100%. It has always been my understanding these were Mallory Capacitors. I have also heard that from some of the guys in R&D. That being said there were never any documents left laying around in old dusty file cabinets that specifically says what they are. I base my understanding from what I saw back in the day. My father was a member of MARS which was the Military Amateur Radio Society. As such he worked on a lot of old military communications equipment. The blue capacitors used in those products looked just like these and they Mallory stamped on them. GK is also correct in that MC designation would stand for Mallory Capacitor."

So there we have it! Mallory, probably most likely

 

[King Fan]

Good research. I think that makes the most sense. The fact that highly similar caps were rebranded for Packard Bell (and others? even Ajax?) suggests a big maker, and of the big makers Mallory makes the most sense.

Someone out there must have old Mallory catalogs and price lists. Hmm, wonder what the Mouser website looked like in the early '60s...

 

[theprofessor]

I just found this here at what I consider my "home" site -- TDPRI. I posted this yesterday over in the twin thread TGP, which I don't contribute to as frequently:

I often hear people refer to "Ajax" capacitors, too, but my understanding was that they were Mallory caps. Tom Wheeler mentions these in The Soul of Tone: "From the early 60's through the late 60's [Fender] used axial-lead, molded tubular caps made by Mallory; they were a dull blue, with white paper labels" (p. 309).

This jibes with what Fender told you, though it doesn't explain why others call them "Ajax" caps. Perhaps this is like a Coke/Pepsi thing, where they are both soft drinks of a similar ilk, but they are different brands of the "same" product? Or maybe Mallory re-branded them? Or vice-versa?

 

[mabinogeon]

I just found this here at what I consider my "home" site -- TDPRI. I posted this yesterday over in the twin thread TGP, which I don't contribute to as frequently:

I often hear people refer to "Ajax" capacitors, too, but my understanding was that they were Mallory caps. Tom Wheeler mentions these in The Soul of Tone: "From the early 60's through the late 60's [Fender] used axial-lead, molded tubular caps made by Mallory; they were a dull blue, with white paper labels" (p. 309).

This jibes with what Fender told you, though it doesn't explain why others call them "Ajax" caps. Perhaps this is like a Coke/Pepsi thing, where they are both soft drinks of a similar ilk, but they are different brands of the "same" product? Or maybe Mallory re-branded them? Or vice-versa?

And I spend more time on TGP than I do here on TDPRI

But there are a lot of folks who only frequent one or the other, which is why I posted this at both sites Thanks for your reply! I need to get a copy of that book.

There has to be a datasheet out there somewhere, so I will keep looking.

 

[mabinogeon]

Someone out there must have old Mallory catalogs and price lists.

I'm still looking (on and off) and haven't found one!

 

[Lowerleftcoast]

*Ajax* always makes me think of the Acme Company.

 

[24 track]

I have bags of the old caps I was thinking of getting a cap leakage monitor to test them , by leakage is how much DC current leaks out of these caps ,not the cap contents

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could be a usefull tool for the bench

 

[ETMusic777]

These are great caps for guitars. I put a .047 in my Tele with 500K pots, which are bright but the Cap gives it a tone of milky tone as I dial it down. Very nice.