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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets.

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Old 12th Apr 2018, 10:45 pm   #1
Stylo N M
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Default Change Philips black pitch capacitors to Mullard mustards?

Hi, I just wondered what others thought? In some of my restorations like my Philips Disc Jockey Major record players, I've replaced the original Philips black pitch capacitors where possible with C296 Mullard mustard types.

I say where possible, because I've struggled to find a Mullard mustard of a voltage any higher than 1,000 volts. So where it is possible, is the Mullard mustard a reasonable choice for replacing the original black pitch types?

Thanks, Paul.
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Old 13th Apr 2018, 9:24 am   #2
Station X
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Default Re: Change Philips black pitch capacitors to Mullard mustards?

Mullard mustard capacitors have a good reputation and are priced accordingly. I doubt they're electrically any better than modern polypropylene and similar types of cap though.
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Old 13th Apr 2018, 9:35 am   #3
dazzlevision
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Default Re: Change Philips black pitch capacitors to Mullard mustards?

Philips/Mullard C296 series Polyester dielectric capacitors are a very reliable component and they look more "period" than the usual bright yellow modern types, when fitted as replacement parts in vintage equipment. However, to buy them now is an expensive business, as sellers have latched on to their popularity for use in vintage equipment restorations!

As fas as I know, the C296 series was only available with a maximum voltage rating of 400Vdc.

I'm fortunate in having salvaged many C296 capacitors from equipment that I've scrapped over several decades. Philips/Mullard ceased production of these components in the early-mid 1980s.
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Old 13th Apr 2018, 10:11 am   #4
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Default Re: Change Philips black pitch capacitors to Mullard mustards?

If only I had known when back in the day we scrapped loads of Philips sets 9170 springs to mind .Mick.
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Old 13th Apr 2018, 9:20 pm   #5
Stylo N M
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Default Re: Change Philips black pitch capacitors to Mullard mustards?

Thanks graham, thanks dazzlevision, yes that's right i've only ever seen them in 160 volts and 400 volts, so it's a bit of an impossible task to try and do a blanket replacement if required.

I was trying to keep the period apearence, and i knew the philips mullard mustards very rarely faild, or driftered even after a good baking from valves close by.

Paul.
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Old 14th Apr 2018, 8:07 pm   #6
Maarten
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Default Re: Change Philips black pitch capacitors to Mullard mustards?

Quote:
Originally Posted by Stylo N M View Post
Hi, I just wondered what others thought? In some of my restorations like my Philips Disc Jockey Major record players, I've replaced the original Philips black pitch capacitors where possible with C296 Mullard mustard types.

I say where possible, because I've struggled to find a Mullard mustard of a voltage any higher than 1,000 volts. So where it is possible, is the Mullard mustard a reasonable choice for replacing the original black pitch types?
Since paper capacitors (such as the black pitch ones) have a higher allowed dV/dt, lower dissipation factor, higher practical max. WV than polyester ones (such as mustard ones), not all types can be replaced by polyester. Paper capacitors with 800, 1000, 1300 volts WV are usually used where a higher dV/dt or lower loss are important. Also in places where the higher WV means some extra safety such as in mains filtering or mains isolation. Those should be replaced with polypropylene (MK, MK/MKP or MKP) capacitors of the same or higher WV. For mains isolation (between mains and chassis for example) a class Y2 capacitor with >275VAC WV is recommended.
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Old 14th Apr 2018, 8:33 pm   #7
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Default Re: Change Philips black pitch capacitors to Mullard mustards?

Maarten mentions a few places where the high voltage or dV/dt rating of the paper caps may have been required, such as isolation caps. However, in something like a record player or other low power domestic audio equipment, such circuit positions are few and far between; a 400V Mustard will do pretty much everything else regardless of the voltage rating of the original paper cap. One more exception I can think of would include across output and bias oscillator transformers.
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Old 15th Apr 2018, 8:16 pm   #8
Stylo N M
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Default Re: Change Philips black pitch capacitors to Mullard mustards?

Thank you maarten for your input, thanks lucien, yes the tone correction capacitor rated at 4.7nF 4,700pF accross the sound output transformer, must be rated at 1,000 volts, so i use a more modern type for this like the yellow film capacitors.

Paul.
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