Check the listing for details. API 512V 500 Series Discrete Microphone Preamp (5-pack) Bundle. Condition: New. Listed at 4975.00 USD. The API 512v 500 Series mic pre gives you all the features - and legendary sound - of the 512c, with a couple of valuable additions. First, API fitted the 512v with an output level control just below the input gain knob. This gives you more control over level-matching, which you'll especially appreciate if you work in a DAW-based studio. It also streamlines your setup, eliminating the need for 3rd-party attenuators. The second enhancement is the addition of a 3:1 output transformer tap switch, again, giving you more control over your gainstaging. Want more vintage iron in your sound? Tap the 3:1 button and you'll immediately lower your output level, so you can hit the transformer harder on the input side. The 512v also features a new combo input jack. In all other respects, the 512v is identical to the 512c - every inch a classic.