ADDAC System ADDAC712 Addac712 Vintage Preamp User Guide
- June 9, 2024
- ADDAC System
Table of Contents
ADDAC System ADDAC712 Addac712 Vintage Preamp
DESCRIPTION
ADDAC712 is a dual channel discrete gain staging amplifier,based on a famous
discrete preamp board from the 70’s used in some legendary equipment.
What caught our attention was the character of it’s clipping and resulting
saturation/distortion.
The module can be used with modular signals to add a distortion/fuzz character
or as a preamp for an external source such as a line source, keyboard, guitar…
It’s also a great side companion for our ADDAC711 Balanced Inputs.
- At the top an On/Off [BYPASS] switch routes the signal into the Effect (Up: Active) or to the bottom output gain stage (Down: Bypassed).
- The ammount of amplification is set by the [GAIN] control, the maximum ammount of amplification can be set by the user using the [MAX GAIN] trimmer. Up to ±5.5v the incoming signal will keep it’s integrity, beyond this point saturation will start to increase.
- At aprox. ±6v a hard clipping will start to occur, this clipping also has a particular quality that at extreme levels it drifts the audio 0v bias reference, moving it upwards which results are similar to a Gate effect.
- In the middle, an x2 opamp based output gain stage with a clipping led, which monitors the clipping at the output, and an [OUTPUT] control to set the output volume.
- Having the top and middle gain stages provides flexibility allowing the user to completelly distort the signal on the top stage and tame it’s output level with the second stage.
- At the bottom, Input and Output for both channels (Left input is normalled into Right input).
Tech Specs:
- 6HP
- 4 cm deep
- 40mA +12V
- 40mA -12V
This module will also be available as a full DIY kit.
SIGNAL FLOW DIAGRAM
For feedback, comments or problems please contact us at: [email protected]
CONTROLS DESCRIPTION
Read User Manual Online (PDF format)
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