PT. Gambas_Natabo

The capsule:

Yes, the capsule is the heart of any mic. We offer both classic u47 capsules: The very early m7 or the later k47. We started making complete capsules years ago to service old u47. Many old neumann u47 meanwhile have one of our capsules inside. Our m7 is unique and absolutely identical to the old original m7. We use the same procedures and even the same brass materials to make the backplate as they used when these capsules were made originally in the 50s).

The transformer:

The bv8 transformer in the u47 is a special cross-wound type. Apart from the old mics, this method was commonly used in the old german tube equipment like telefunken/tab/siemens v72 and v76. The winding method has a certain influence on its sonic specs and any other transformer would inevitably make the mic sound different. Our bv8 has been made to original specifications for several years now, using the old techniques and materials.

We have used our replacement for many years as a 100% compatible spare part to replace broken bv8 transformers and it has repeatedly proven to be sonically equal to the old bv8.

The tube:

Most people have heard about the old vf14 in the u47 and a lot of speculation and hokus pokus continues to surround this tube and its possible replacements.

The main reason why it is difficult to replace a broken vf14 in an old u47 is the fact that there is only one single supply voltage (105v) coming from the power supply. Neumann came up years ago with a 'quick-and-easy' solution using a nuvistor as a replacement to the vf14. This tiny tube also works with the high voltage to heat it up, so it could be used with very little change in the old u47 design. Unfortunately this never worked out very well.

But there are some tubes in the telefunken "steeltube" family which are perfectly suitable to replace the old vf14 if they get an independent filament supply.

We use a telefunken steeltube in the new u47 which works excellently in the circuit and provides the same sonic quality as the vf14. Each tube is selected individual and the selection parameters are the same or even better as neumann used for the vf14..

Technically the only difference to the old u47 is that our u47w has a separate filament supply coming from the power supply.