CHD 7-702 User Manual Download Page 5

Page: 5 / 8

Stereo Bucket Brigade FX Unit

Module 7-702 v. 1.0

No part of this publication may be reproduced in any form without the written permission of CHD Elektroservis.

3. CONNECTION THE MODULE TO THE SYSTEM

Fig. 3 – Bus board connection

To connect the module, plug carefully the supplied

ribbon cable into the bus socket of your modular
case.

The colored marking of the ribbon cable

must be at the bottom of the bus connector!

Failure to check this may result in the module or

case PSU damage! (module is not protected against

permanent incorrect polarity).
The module uses

12V of the system only (pins Nr.

1 to 10), GATE, CV and +5V signals are not used
(see Fig. 3).

4. OPERATION

The controls and inputs/outputs are divided in three function blocks: “AUDIO”, “DELAY” and
“MODULATION”.

4.1. “AUDIO” BLOCK

The Audio block processes analog audio signals. Input signal is connected to AUDIO-IN [10] input, the
minimal input signal level for full gain is

2,5 V

. Optimal input gain level is adjustable by GAIN [9]

potentiometer so input voltage amplitude can be higher than

2,5 V

. The indication LED OVERLOAD

[8] should shortly blinked at maximum input signal level. If the LED lights permanently, the input

levels of BBD lines are overloaded and the audio signal is distorted thus.
The module outputs stereophonic signal – there are two audio outputs available OUTPUT-LEFT [14] a
OUTPUT-RIGHT [13]. Both outputs provide a signal of max

2,5 V

amplitude (accordingly to the

input signal levels and panel controls settings). This signal level conforms to standard input level +4
dB of professional amplifiers, mixers etc.

Both outputs have a mixed Dry (input) and Wet (BBD liens) signals. The required ratio of these

signals can be adjusted by MIX [12] potentiometer. In the left (DRY) position the input signal remains

unaffected, hence in the right (WET) position, the output signal comes solely from the analogue
delay lines.

It is possible to input the delayed signal from the BBD lines back at their inputs with the FEEDBACK
[11] potentiometer. The left position (MIN) eliminates the feedback completely, while the right

position (MAX) comes up to self-oscillation.

4.2. “DELAY” BLOCK

Basic time of the analogue delay lines is manually controllable by MANUAL [1] knob from approx. 4
ms (SHORT) to 25 ms (LONG). If the patch lead is connected in EXT-CV [2] input, the potentiometer

of the manual control is automatically disconnected and the delay length is controlled by external
control voltage. For full parameter range control, the external control voltage should be in the

range of 0 to +8 V. The lower control voltage enables longer delay time (0 V for LONG, +8 V for

SHORT).