Line Preamplifier
After nearly 10 years of existence, the modern classic Heider® FD312 has gotten a rework! We are pleased to present the Heider® FD312 H2.
Besides the immediately apparent monochrome front panel and controls, here are the main differences:
A custom exclusive CAPI version of the RE-0887 input transformer
A pair of exclusive Litz wire 2503 output transformers
A pair of our potted CA-0252 discrete opamps
The impedance load switch was moved to the PCB and its front panel position replaced with a crowd favorite 80Hz High Pass Filter
The impedance load switch is default set to 450 ohms and does not affect level in Line mode
Phantom power is defeated when Line mode is selected
Sonically all of the changes add up to capturing a more 3D space surrounding the microphone. It appears more clear than the OG version while also sounding more analog. Bigger, deeper, sweeter.
The Heider® FD312 H2 is a special and unique preamp module that stands out in today's crowded 500 series market. The preamp stage has been carefully modeled after the preamps in the famous Wally Heider Recording Studio 4 console custom built by Frank DeMedio circa 1972. The original pre's were stock 312 cards modified by DeMedio. Frank removed the AP2622 input transformer and replaced it with a custom wound Ed Reichenbach RE-0887. The RE-0887 has a very special tonal quality with some of the most buttery smooth mids you will ever encounter! This tone has been retained with our CA-0887.
To enhance this special preamp circuit even further, we chose to employ a stepped 'fader' and active booster stage, very reminiscent of our popular 2-stage VP28 preamp. This is essentially the same booster circuit that was used in the early to mid '70's vintage API consoles. In remaining true to the Heider® circuit, all AC coupling capacitors have been removed from the audio path. We don't think coupling caps are evil, they are just not needed in this particular circuit. This fader booster stage has 12dB of gain 'in hand', exactly like a real console. This allows for many different gain combinations. You can crank the fader and reduce the preamp gain or in contrast, attenuate the 2nd stage and crank the preamp gain for some sweet, additional harmonic content.
The original Heider/DeMedio preamp cards used stock AP2503 output transformers. With the desire to have something unique, we are using our 2503-Litz wire outputs. The very same that we use in our Platinum line of preamps.
In trying to be loyal to the console signal path, both gain stages have a 2503-Litz output transformer. The first or preamp stage output transformer provides +6dB of gain, blocks DC from the stepped fader and imparts a little more character into the overall circuit, as compared to a 'direct' output.
The operational amplifiers are the pure heart of any preamp like the Heider® H2. We naturally wanted to stay as close as possible to the discrete Studio Systems opamps from the early '70's. In a current commercially available product, we strongly believe that our potted CA-0252 opamps are the closest thing alive. Each Heider® H2 contains two of these glorious discrete blocks of love.
Each and every Heider® FD312 H2 is hand assembled, burned in and tested at CAPI headquarters in Nashville Tennessee.
The H2 Pink is identical to the stock FD312 H2 with the exception of a beautiful pink faceplate. These units are a Special Edition and will only be made occasionally in limited quantities.
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