Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: whoops on December 25, 2016, 09:54:19 pm
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Hi,
can you help me identify which type of capacitor in terms of "Dielectric Material" is the own shown in the attached picture?
I'm unsure if it is a Paper type or Polyester.
It's fitted in a mid 60's Gretsch reverb unit. The same type capacitor was used by Valco in Gretsch and Supro amplifiers.
The capacitor has "Standard" written. I dont know if "Standard" refered to the brand or to capacitor type.
Thanks
(http://i1124.photobucket.com/albums/l579/ilcaccillo/1uf%20cap%20-%20logo.png)
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I had the same ones in a 1950s Masco.. the wax type and the one you have in the photo. Sorry I can't help with the dialectric.
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This one I'm not sure if it's surrounded by a hard wax, or if it's a polyester type.
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Why do you want to know?
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A lot different reasons.
Learning, curiosity and because I'm doing a service in a Gretsch unit I have and it's good to identify the caps that have an higher failure rate compared to others.
Are you familiar with these "Standard" capacitors? Any info to share?
Thank you
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Never heard of "Standard Capacitor" but it sounds like a typical gimmicky name for the 40's & 50's.
Do you suspect the 1µF cap to be bad? If so, you could always pull it out & cut it open (use rubber gloves in case any goo inside is hazardous).
For its size you know it's not electrolytic. Could be metallized paper, could be a plastic film.
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Here's the perfect replacement for that cap...
https://www.tubesandmore.com/products/capacitor-musicap-400v-polypropylene-coupling (https://www.tubesandmore.com/products/capacitor-musicap-400v-polypropylene-coupling)
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Never heard of "Standard Capacitor" but it sounds like a typical gimmicky name for the 40's & 50's.
Do you suspect the 1µF cap to be bad? If so, you could always pull it out & cut it open (use rubber gloves in case any goo inside is hazardous).
For its size you know it's not electrolytic. Could be metallized paper, could be a plastic film.
Well the unit is from 63, so I suspect from components drifting the values like resistors, and caps drying out, leaking, etc.
For the Resistors I'm just tracing the circuit with the schematic and measuring their value. I found some differences between the circuit and the schematic, could be due to later revisions in the schematic or in my unit, could also be production mistakes .
As for the Caps, I replaced all the Electrolytic caps already, the Filtering caps were long gone.
I left the Ceramic caps and two 1uf 400v "Standard" red colour caps (the one in the picture).
So to answer you question I don't have a particular reason at the moment to suspect this cap besides being and older unit so it's nice to be suspicious and measure everything while restoring in order to minimize future problems.
I dont have my ESR meter at the moment, but I can measure them for ESR, Capacitance and Leakage in the next days.
If this cap is Wax in Paper I would replace it in a pinch.
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Here's the perfect replacement for that cap...
https://www.tubesandmore.com/products/capacitor-musicap-400v-polypropylene-coupling (https://www.tubesandmore.com/products/capacitor-musicap-400v-polypropylene-coupling)
LOLOLOLOLOLOLOL
it's 13 dollars, but it's a MUSICAP!!!!!
Well, I have locally an old distributor of Philips electronic Components, they have a big stock from 30 years ago NOS parts, they never updated the prices in the last 20 years. So I can get Philips MKT Film capacitors for 13 cents, much better than 13 dollars. LOL
Although being high quality the Philips MKT are not Musicaps, but at least they are Orange, and it seems that people say that Orange coloured capacitors sound amazing!
Sluckey let me know if you need some Philips MKT capacitors, Polysterene or Polycarbonate.
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it's 13 dollars, but it's a MUSICAP!!!!!
Oh no. The price starts at $13. The one you need is $21.95.
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it's 13 dollars, but it's a MUSICAP!!!!!
Oh no. The price starts at $13. The one you need is $21.95.
Well I took the $21.95 went out and bought all of these:
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Sluckey do you have any idea if the red 1uf "Standard" cap is a waxed type or plastic type?
Thanks(http://i1124.photobucket.com/albums/l579/ilcaccillo/1uf%20cap%20-%20logo.png)
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I think those are Mylar what ever that is there super hard, I have some but there white with black ring.
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I think those are Mylar what ever that is there super hard, I have some but there white with black ring.
Thank you so much Scsoul
Do your caps also have "Standard" written on them?
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Yes
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I took some other capacitors from the unit out,
all have "Standard" written on them.
One of them says Mylar the others don't
I got suspicious that these might be Paper in Wax capacitors because of the paper/card that surrounds them.
(http://i1124.photobucket.com/albums/l579/ilcaccillo/IMG_0619.jpg)