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InnerTUBE Audio Tube 87 Retro-Fit Kit (Demo Deal) – 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 change over is accomplished quickly and easily by the user in one (1) 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.
At innerTUBE Audio, our development team have been designing analogue and tube circuits for over 25 years.

Our engineers have been responsible for high quality maintenance and repair in state of the art studios throughout Southern California. They have had much experience in re-design and tweaking of existing well known circuits.We have worked closely with accomplished and well known recording and mixing engineers, with many great sounding albums to their credit.

It is with this background that we have designed the U-87 tube retrofit. The retrofit is a superior cost affective choice compared to new, re-issues or original tube microphones. The retrofitted U-87 is equal or better. Yes this is a strong statement, and, we would like an opportunity to prove it to you. All the components used in manufacture are new stock, tested and matched to exacting tolerances. The circuit is elegantly designed and bulletproof. We manufacture tube driven products only, no solid state ... ever!

Product Specifications

Condition Demo / B-Stock
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.