MP caps for your mics...info from Siemens...
Feb 19, 2015 10:06:28 GMT -6
jsteiger and svart like this
Post by Deleted on Feb 19, 2015 10:06:28 GMT -6
Hi guys,
from time to time i read about you trying out all kind of caps for tube mic output. Somehow there seems to be some mystery about what to use in the place of the huge output cap.
Obviously, we try to use what was used originally, i.e. the MP caps.
MP stands for Metallpapier (metal paper). These caps are metal film caps that have paper as a dielectric instead of plastic. In the english speaking world they are also known as PIO caps (paper-in-oil).
MP caps have been widely used for audio in the first decades of the 20th century, they are ideal for duties in tube gear.
In times of short supply of quality capacitors, people even diyed even their own capacitors - MP capacitors - because of the very good availability of the materials.
The ingredients of an MP cap are metallized paper and the oil or wax product it is soaked in. That's it. No magic.
I read a mail reply from Siemens, the manufacturer of the MP caps, that were used AFAIK exclusively in the famous tube mics of Telefunken, Neumann etc... , to an inquiry about the differences in their MP caps in different decades, which states very clearly, that the only product they used in their MP caps ever is a very common purified mineral oil product: Vaseline.
This has been available in very constant pharmaceutical quality, it is cost efficient and therefore is ideal for the job.
Just wanted to let you know, to de-mystify this topic a bit. If you were in doubt, there is no need to buy any over-expensive NOS caps from a certain decade to get the "real thing"...
Best regards,
Martin
Source of information was www.jogis-roehrenbude.de , a nice german language website for geeks with alot of in detail german tube topics.
Unfortunately i can't find the link to the scanned Siemens mail anymore...
from time to time i read about you trying out all kind of caps for tube mic output. Somehow there seems to be some mystery about what to use in the place of the huge output cap.
Obviously, we try to use what was used originally, i.e. the MP caps.
MP stands for Metallpapier (metal paper). These caps are metal film caps that have paper as a dielectric instead of plastic. In the english speaking world they are also known as PIO caps (paper-in-oil).
MP caps have been widely used for audio in the first decades of the 20th century, they are ideal for duties in tube gear.
In times of short supply of quality capacitors, people even diyed even their own capacitors - MP capacitors - because of the very good availability of the materials.
The ingredients of an MP cap are metallized paper and the oil or wax product it is soaked in. That's it. No magic.
I read a mail reply from Siemens, the manufacturer of the MP caps, that were used AFAIK exclusively in the famous tube mics of Telefunken, Neumann etc... , to an inquiry about the differences in their MP caps in different decades, which states very clearly, that the only product they used in their MP caps ever is a very common purified mineral oil product: Vaseline.
This has been available in very constant pharmaceutical quality, it is cost efficient and therefore is ideal for the job.
Just wanted to let you know, to de-mystify this topic a bit. If you were in doubt, there is no need to buy any over-expensive NOS caps from a certain decade to get the "real thing"...
Best regards,
Martin
Source of information was www.jogis-roehrenbude.de , a nice german language website for geeks with alot of in detail german tube topics.
Unfortunately i can't find the link to the scanned Siemens mail anymore...
