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InnerTUBE Audio Tube 87 Retro-Fit Kit – No Longer Available

Turn your U-87 from standard solid state into a true tube microphone

Product Description

Turn your U-87 from standard solid state, into a true tube microphone.  The changeover is accomplished quickly and easily by the user in one minute or less. 

This retrofit is non-destructive, and can be reverted back easily if one should ever want to use the retrofit at another studio.  There are identical retrofits for both the older standard type as well as the newer a-i, with equally impressive results. 

As one U-87 owner who utilizes the retrofit in a variety of applications said, "I used to like how my solid state 87 sounded until I heard it tubed.  Now because of the added sonic dimension and clarity, I won't use it unless it is tubed". 

The retrofit has been a consistent winner time and again, in critical blind listening tests between itself and top world class solid state and tube microphones.  Those who have conducted these microphone "shootouts" are like yourself, professionals in the audio field.  They have been surprised and are greatly impressed when they learn the microphone they chose as best sounding overall is the retrofit. 

The Retrofit Kit Includes:

  • The internal Tube Retrofit pre-amp assembly
  • Power Supply with continuously variable pattern pot
  • Cables for the mic (7-pin), and power supply (Grounded AC)
  • Instructions for change over (click for instructions)
  • All components are pre-assembled and ready for installation.

Product Specifications

Condition New
Tube or Solid State Tube

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I would like to thank VK for the wonderful sales assistance, service and prices. This was my first purchase with you and it won't be my last. I only wish I'd discovered you years ago!
Matthew R.
I had two Grammy wins this year - Ray LaMontagne & Carolina Chocolate Drops. Both made with help from Vintage King!
Ryan F.
In almost 20 years in Pro audio buying, never did I receive a unit so well packed and exactly as described. Works flawlessly. The whole process has been so smooth. I will never hesitate to do business with you guys in the future and will recommend you to everyone I know.
Martin C.
This was my first experience buying something from Vintage King (although I surf the "used" categories on the website frequently!), and, despite being on the other side of the world, I had absolutely no trouble and everything went very smoothly.
Phil T.