The MBM capacitors are a type of metallized paper-in-oil capacitors that were commonly used in electronic and audio equipment, particularly in the mid-20th century. These capacitors were primarily manufactured in the former Soviet Union (USSR).
Here are some key features and characteristics of the MBM paper-in-oil capacitors:
Construction: MBM capacitors are constructed using a metallized paper impregnated with mineral oil. The metallized paper dielectric is wound into a cylindrical shape, and the whole assembly is enclosed in a aluminium housing to protect it from environmental factors.
Value and Tolerance: They come in various capacitance values, often ranging from 0.005uF to 1uF, with relatively high tolerances, typically around 10%.
Voltage Rating: The voltage rating of these capacitors varies, but they are usually rated for relatively low to medium voltage applications, often between 160V and 1500V.
Sound Quality: MBM capacitors gained popularity in the audio community because they were believed to have certain sonic qualities. Some audiophiles considered them to contribute to warm and rich sound characteristics in audio equipment. However, these opinions are subjective and may not be universally agreed upon.
Vintage Components: MBM capacitors are considered vintage components, and they are no longer in mass production. They were commonly found in old tube amplifiers, radios, and other vintage electronics.
Durability: The use of oil impregnation in these capacitors was intended to improve their long-term stability and prevent the drying out and aging that can affect capacitors over time. This feature contributed to their reputation for durability.
Obsolete and Hard to Find: Since they are no longer produced and have been largely replaced by modern capacitor technologies, finding authentic MBM capacitors in good condition can be a challenge. Some audiophiles and vintage audio equipment enthusiasts seek them out for restoration projects.
It's worth noting that while MBM capacitors have their own unique character and aesthetic appeal, they may not always meet the exacting technical specifications required for modern electronic applications. As with any vintage electronic components, if you're using or replacing them in vintage equipment, it's important to be cautious about their condition and consider the potential impact on the device's performance.
