Hello all!
I run a vintage capacitor store through my website and EBay. In addition to a vintage components/hardware and audio how-to-focused website. The store is just a small part of the entire thing.
Note: Not attempting to sell anything with this thread, solely looking for information and catalog/data book shares. I mention this, because there will be many more times I ask this question, haha. I have searched the forums before bothering to post.
I occasionally come across capacitors that test through the roof for ESR, Q-Factor, Insulation Resistance, and Capacitance accuracy, but have no clear brand shown. Or whatever is shown, doesn't seem to be enough to find out anything about the capacitor. Just because they test well, doesn't mean they are appropriate for tone capacitors, I always research the materials inside.
Now this is obviously a film capacitor, from the label directly on the thing, to the way it's built/shaped. I checked on a few of the markings shown and I know "ACWKG" is just short for AC Working Voltage.
"Film Cap" could be Film Cap Inc. a vintage cap company, so that is one possibility. Finding almost anything on that company, aside from the one catalog I have on my site, is nearly impossible (due to the name itself).
URT, I found two possibilities. There is a company called United Resistive Technologies, but obviously they focus on fixed resistors, variables, etc. It's possible: CGW, Texas Instruments, Sprague, Mallory and more, all made capacitors, resistors and more. The other possibility is that I have seen capacitors that use URT as their model/name.
I can't find a single thing on "IOACB," Google will literally come back with nothing and ask you to change the order of the letters. I tried playing with I vs 1 and O vs 0, but no dice. It's likely the MPN, or date + factory identification of some kind.
For year of manufacturing, most people think they are 1960's to 1970's and a few thought the font looks a lot like Sprague's font. Has anyone ever seen green Sprague film capacitors? I sure haven't!
I would love to know what these guys are! I have asked many vintage/HiFi/Repair/etc groups on FB. So far, not a single person has been able to say what these are!!
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Current Catalog Brands: > 45
Total Catalogs/Data Books/etc.: > 300
Secondly, I have finally got my catalog database to a point where I want to share it with the public! Electronic Component Catalogs & Databooks – Hallman Labs
There are no ads on my website (in general). Catalogs database access requires no registration and of course, totally free. I am doing this to help others and also to prevent these from being lost to history.
If you have any catalogs, data sheets, data books, technical papers, technical manuals, white papers, patents or anything else you think would be of interest (which aren't already on the site). Please contact me, either through this site or through my site. (My email is on there, but I'm not listing it here)
Thanks in advance for any information or new catalog shares.
I run a vintage capacitor store through my website and EBay. In addition to a vintage components/hardware and audio how-to-focused website. The store is just a small part of the entire thing.
Note: Not attempting to sell anything with this thread, solely looking for information and catalog/data book shares. I mention this, because there will be many more times I ask this question, haha. I have searched the forums before bothering to post.
I occasionally come across capacitors that test through the roof for ESR, Q-Factor, Insulation Resistance, and Capacitance accuracy, but have no clear brand shown. Or whatever is shown, doesn't seem to be enough to find out anything about the capacitor. Just because they test well, doesn't mean they are appropriate for tone capacitors, I always research the materials inside.
Now this is obviously a film capacitor, from the label directly on the thing, to the way it's built/shaped. I checked on a few of the markings shown and I know "ACWKG" is just short for AC Working Voltage.
"Film Cap" could be Film Cap Inc. a vintage cap company, so that is one possibility. Finding almost anything on that company, aside from the one catalog I have on my site, is nearly impossible (due to the name itself).
URT, I found two possibilities. There is a company called United Resistive Technologies, but obviously they focus on fixed resistors, variables, etc. It's possible: CGW, Texas Instruments, Sprague, Mallory and more, all made capacitors, resistors and more. The other possibility is that I have seen capacitors that use URT as their model/name.
I can't find a single thing on "IOACB," Google will literally come back with nothing and ask you to change the order of the letters. I tried playing with I vs 1 and O vs 0, but no dice. It's likely the MPN, or date + factory identification of some kind.
For year of manufacturing, most people think they are 1960's to 1970's and a few thought the font looks a lot like Sprague's font. Has anyone ever seen green Sprague film capacitors? I sure haven't!
I would love to know what these guys are! I have asked many vintage/HiFi/Repair/etc groups on FB. So far, not a single person has been able to say what these are!!
-------------------------------------------------------------------------------------------------------
Current Catalog Brands: > 45
Total Catalogs/Data Books/etc.: > 300
Secondly, I have finally got my catalog database to a point where I want to share it with the public! Electronic Component Catalogs & Databooks – Hallman Labs
There are no ads on my website (in general). Catalogs database access requires no registration and of course, totally free. I am doing this to help others and also to prevent these from being lost to history.
If you have any catalogs, data sheets, data books, technical papers, technical manuals, white papers, patents or anything else you think would be of interest (which aren't already on the site). Please contact me, either through this site or through my site. (My email is on there, but I'm not listing it here)
Thanks in advance for any information or new catalog shares.
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There are various websites in the UK I know about personally with zero affiliation to any commercial enterprise where plenty of information on old school components is supplied freely .
Many years ago I bought my AVO VCM from a guy in the London area who was an ex radio engineer and the money went to a local cats charity .
While I don't doubt the good intentions this type of advertising created real anger on Electronics World among the professional engineers as a guy came on asking for every bit of original data on a certain electronics engineer of the 40,s now highly celebrated in film and lauded among his peers .
He was given personal papers from old professional engineers ,invited to their homes on the understanding he would --free of charge use the papers in a serial of articles to be published in EW .
What he really did was compile them into books and SELL ! them --at a high price , to say the Letters page of EW was set on fire was an understatement and articles appeared condemning his actions and it left a very sour taste in many people,s mouths.
No apology was given and he wouldn't answer any questions.
Many years ago I bought my AVO VCM from a guy in the London area who was an ex radio engineer and the money went to a local cats charity .
While I don't doubt the good intentions this type of advertising created real anger on Electronics World among the professional engineers as a guy came on asking for every bit of original data on a certain electronics engineer of the 40,s now highly celebrated in film and lauded among his peers .
He was given personal papers from old professional engineers ,invited to their homes on the understanding he would --free of charge use the papers in a serial of articles to be published in EW .
What he really did was compile them into books and SELL ! them --at a high price , to say the Letters page of EW was set on fire was an understatement and articles appeared condemning his actions and it left a very sour taste in many people,s mouths.
No apology was given and he wouldn't answer any questions.
That is TERRIBLE. I wish there was something I could do to make it so that was never possible, for anyone to do with the materials on my site. That is the exact opposite of what I am trying to do and that gives all of us, who put in the effort to do this, a bad name in the vintage community.
I continue to build on this database for many reasons, but the 2 primary ones are: To help those repairing vintage equipment or trying to locate information on a specific component. As well as for those who are component and/or vintage geeks.
The thing is, anyone could compile a book using my database (and others like it), it's not just the creator who has the ability (at least for my site). I am glad you brought this up, it gives me something to think about.
If anyone has any ideas of how to prevent that, I'd love to hear it.
I guess watermarking the PDFs helps to prevent this, since most people aren't going to bother editing every single page of a PDF. For my uploads though, I just included a header at the bottom, which is easily cropped out.
"Film cap" is a known (by me at least) manufacturer of..... film caps (surprise, surprise), and I have a number of examples in my drawers.
I do not know much more about it: I bought these caps decades ago, probably in surplus store, and they were regular mylar or polycarbonate type.
Your example seems to be a "X" type, perhaps X3, and IOACB might refer to a regulatory spec, or an OEM internal spec.
They look OK for across-the-mains applications, by their marking, but I would be cautious about that (no safety mark, etc)
I do not know much more about it: I bought these caps decades ago, probably in surplus store, and they were regular mylar or polycarbonate type.
Your example seems to be a "X" type, perhaps X3, and IOACB might refer to a regulatory spec, or an OEM internal spec.
They look OK for across-the-mains applications, by their marking, but I would be cautious about that (no safety mark, etc)
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Thank you SO much for your input! You have no idea how exciting it is to hear from someone who has not only seen them, but has some!
Did you mean to say it's an AC3 type? I don't see any X's!!
So, you think the brand is just "FilmCap"? Is this a different brand from Film Cap Inc?
Any idea on how old the caps were when you bought them a decade ago?
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I see, I never thought about that either. Very interesting!
Thanks for your input and I hope you can possibly help me in the future on these same sorts of questions.
I'll just have to sell it as "FilmCap" and explain what that means, let the performance speak for itself. Perhaps whoever said they recognized the font as Sprague was correct? I'd feel deceitful going off anything like that though, I need a catalog or legit reference. I'm not the sort of seller to just label a capacitor, something that it may not be.
I am currently working on building a Quadrature Bridge, as explained by Sam Groner and Scott Warner in Linear Audio Vol 12. This will allow me to measure THD down to about -160dB.
The only issue with this design is the fact you must "create" a reference capacitor for each and every capacitance value that you need to test. This reference capacitor is many lower valued caps wired together (such as C0G), for the lowest distortion possible. This isn't a big deal if testing a lot of the same value, but testing individual values for some might be a pain.
I am trying to decide if I want to build a board in Eagle and get it made. One that is essentially a super low THD capacitor array with slide switches. Probably 30 or 40 total positions, with the bridge nearby. First, I am going to definitely do it the old fashion way. If I did make one like that, I'd probably do the low end (based on my stock) 0.001uF to 1uF.
The only reason I might not do that, is because I want to build Cyril Bateman's insanely good design in Lin Audio Vol 9 and Electronics World (see here) It's harder to make, for sure, but it's much easier to use once you have it done. He made it so 7 segment display panels work just fine for showing THD directly.
Sorry for rant, haha.
Thanks for your input and I hope you can possibly help me in the future on these same sorts of questions.
I'll just have to sell it as "FilmCap" and explain what that means, let the performance speak for itself. Perhaps whoever said they recognized the font as Sprague was correct? I'd feel deceitful going off anything like that though, I need a catalog or legit reference. I'm not the sort of seller to just label a capacitor, something that it may not be.
I am currently working on building a Quadrature Bridge, as explained by Sam Groner and Scott Warner in Linear Audio Vol 12. This will allow me to measure THD down to about -160dB.
The only issue with this design is the fact you must "create" a reference capacitor for each and every capacitance value that you need to test. This reference capacitor is many lower valued caps wired together (such as C0G), for the lowest distortion possible. This isn't a big deal if testing a lot of the same value, but testing individual values for some might be a pain.
I am trying to decide if I want to build a board in Eagle and get it made. One that is essentially a super low THD capacitor array with slide switches. Probably 30 or 40 total positions, with the bridge nearby. First, I am going to definitely do it the old fashion way. If I did make one like that, I'd probably do the low end (based on my stock) 0.001uF to 1uF.
The only reason I might not do that, is because I want to build Cyril Bateman's insanely good design in Lin Audio Vol 9 and Electronics World (see here) It's harder to make, for sure, but it's much easier to use once you have it done. He made it so 7 segment display panels work just fine for showing THD directly.
Sorry for rant, haha.
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Cyril Bateman ? I practically worship the guy his articles in EW should be read by the whole world of audio .
After years of JLH being ridiculed for his early years "capacitor sounds " in which he listed a range of different types of capacitors and the "sound " they made ( or modified the music) Cyril produced his own designed equipment showing John had a point , funnily enough none of John,s detractors apologized.
He had one major detractor I wont name.
Remember John just used his ears which must have been more "golden " than the group of UK "golden ears " in Hi-Fi Choice and other UK hi-fi magazines.
After years of JLH being ridiculed for his early years "capacitor sounds " in which he listed a range of different types of capacitors and the "sound " they made ( or modified the music) Cyril produced his own designed equipment showing John had a point , funnily enough none of John,s detractors apologized.
He had one major detractor I wont name.
Remember John just used his ears which must have been more "golden " than the group of UK "golden ears " in Hi-Fi Choice and other UK hi-fi magazines.
Haha, that is hilarious. I had heard something along those lines, but not the total story.
On Bateman, I have been playing around with the idea of writing a tribute article on him. He passed away about 10-15 years ago, maybe 2008 (going off memory).
I just haven't come up with something I felt worthy of using his name. I'll probably wait until I make his capacitor tester. When I do that beast, I'll detail the entire process. From making the Geber files, to building and using it. Somewhere he has Gerber files already, but I can't seem to find them anymore. I saved it somewhere though!
I hope to do that before the end of my Senior Year (in the next 12 months). Stay tuned if interested!
Bateman is partly responsible for my vintage capacitor store
(soon to be more than that), when I read his articles, it really sparked something in me about capacitors in general. That helped me out a bunch in Semiconductors-I (finished last semester)! I am a Comp-E, but I wouldn't mind going back to get an audio engineering degree too. We'll see.If you think its "hilarious " it wasn't "hilarious " to JLH at the time and being the English gentleman he was he did not reply in kind.
Then lets speak engineering if Cyril Bateman some time later justified John,s articles on capacitors/resistors etc by purely scientific /technical tests using own his own cutting edge designs (at the time ) why then the sarcasm ?
You heard ? -- I replied in the same magazine Letters pages throughout the whole decade and more at that particular time it didn't go down well from a certain engineers point of view .
Abrasiveness in dealing with others (fellow engineers ) there also went badly .
Then lets speak engineering if Cyril Bateman some time later justified John,s articles on capacitors/resistors etc by purely scientific /technical tests using own his own cutting edge designs (at the time ) why then the sarcasm ?
You heard ? -- I replied in the same magazine Letters pages throughout the whole decade and more at that particular time it didn't go down well from a certain engineers point of view .
Abrasiveness in dealing with others (fellow engineers ) there also went badly .
I didn't want to mention his name Jan but now you have posted it ---yes your right .
If ever there was a Spiv-rip-of-merchant-fly-man-lowlife that guy who appealed to genuinely decent engineers for original documents unable to be replaced it was him and to use it for personal profit of a giant of a man in his field well words fail me .
Did you follow the outrage Jan --I did .
If ever there was a Spiv-rip-of-merchant-fly-man-lowlife that guy who appealed to genuinely decent engineers for original documents unable to be replaced it was him and to use it for personal profit of a giant of a man in his field well words fail me .
Did you follow the outrage Jan --I did .
I just meant it's very ironic that Bateman was treated like that, knowing what we know now about all of his work in capacitors and cap testing.
The part that was hilarious, was what you said about the other guy having "more golden" ears than the rest of the group, wasn't sure if that was meant to be a jab or serious.
Edit: I've not heard of this Blumlein thing, but I'm going to try and look it up! Was Blumlein the engineer that the person wanted all the information on?
I've seen his name mentioned in the past for stereo sound, so I am assuming that is who it was on.
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Well, I was (partly) wrong: Filmcap does also E-caps: I found a number of examples in my drawers.
These are 100µ/6V3, and probably date back from the late sixties or early seventies:
They are NOS, and still functional: their ESR @100Hz is 2.4Ω, to be compared with 0.94Ω for a modern, plain-vanilla Multicomp example.
Not bad when you think about it: such an ESR value was quite normal ~50 years ago when it was manufactured, and it didn't drift, leak or dry so it's still OK, though a bit weak by today's standards.
I think they are of British origin: I seem to remember that they were bought in the UK
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Well, I was (partly) wrong: Filmcap does also E-caps: I found a number of examples in my drawers.
These are 100µ/6V3, and probably date back from the late sixties or early seventies:
They are NOS, and still functional: their ESR @100Hz is 2.4Ω, to be compared with 0.94Ω for a modern, plain-vanilla Multicomp example.
Not bad when you think about it: such an ESR value was quite normal ~50 years ago when it was manufactured, and it didn't drift, leak or dry so it's still OK, though a bit weak by today's standards.
I think they are of British origin: I seem to remember that they were bought in the UK
VERY cool!
Thank you for sharing what you found out. They definitely look 1960's to 1970's (as you had said before).
I think I am going to sell them as FilmCap then, only wish I could find something out about this company. Do you think they are in the UK?
Apparently, it is/was indeed a British company:
FILMCAP LIMITED - Overview (free company information from Companies House)
FILMCAP LIMITED - Overview (free company information from Companies House)
Thank you sooooo much!! This is precisely the sort of hard info I was looking for!
Can't wait to see what we find out about my next mystery capacitor/s.
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