Alesis QUADRAVERB, Service Manual

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Alesis QuadraVerb Service Manual------ 8 08/13/04
7.8 DAC Adjustment Installation
It may also be necessary to install a DAC adjust trimpot to decrease DAC noise. The
components required are a 250K trimpot (R43), 2 200K resistors (R20 and R44), and a 1M resistor
(R45). See diagram 8 for locations.*
7.9 Increasing Output Gain
It may be necessary to change the gain of the output stage to accommodate the users of
some amplifier effects loops. To do this, change R11, and R12, to a value between 4.7K and 10K
(the larger the value, the higher the gain).*
* - The application of these items are left to the discretion of the technician.
7.10 QV I/P Filter Kit Installation
The following update enhances the input filter of the Quadraverb by increasing the number of
filter poles from 4 to 6. This gives a corresponding increase in the filter rolloff rate, and eliminates
problems encountered when using the QV with high bandwidth samplers such as the Ensoniq ESQ-
1, the Roland D-50, or the EMU Proteus.
Here is a list of components that will be changed or added:
Component New Value Added Diagram
* R16 9.1K ------- 7
R19 4.3K ------- 7
R23 680R ------- 7
R24 2.4K ------- 7
R25 27K ------- 7
* R26 33K ------- 7
* RA ------- 3.6K 7
* RB ------- 1.3K 7
R42a ------- 750R 8
C35 47pF ------- 7
C36 .033uF ------- 7
C42 1500pF ------- 7
C43 .033uF ------- 7
C44 100pF ------- 7
* CA ------- 3300pF 7
* CB ------- .01uF 7
**R20 ------- 200K 8
**R44 ------- 200K 8
**R45 ------- 1M 8
**R43 ------- 250Ktrm 8
* Requires special installation, see below.
** Recommended, but not necessary.