For the purposes of a common orientation, we will assume that you are looking at the
component side of the board, with the front panel facing you. Refer to Diagram 7 for individual
component orientation.
Solder one leg of R16 to the left feed through of the original R16 (let the other leg stand
straight up). Solder one leg of RB to the right feed through of the original R16. Scrape the solder
mask off of the ground plane under the original R16, then solder one leg of CB to the exposed
ground plane (again, leaving the other leg sticking up). Twist the three free-standing leads together
to form a "teepee", and solder them together. Repeat this procedure with R26, RA, and CA. (R26 on
the left, RA on the right. The ground plane between R26 and R27 is the easiest place to attach CA.)
Solder R42a in parallel with R42 (if this is forgotten, the "de-emphasis" will not be correct, and
the unit will sound "shrill").
It is recommended (but not absolutely necessary) to install R20 (200K), R44 (200K), R45
(1M), and the 250K trimpot (R43). (When it comes time to adjust the DAC, use a fast LEZLIE
program, and adjust the trimpot for minimum output noise with no input signal and maximum output
level.)
Replace the rest of the components per the above value change list.
To test, hook the unit up to a signal source, and amplifier. Adjust the DAC trimpot. Audibly,
the unit should not sound "shrill" (too much high end), or "muddy" (too little high end). Highs should
sound clean up to about 18KHz before rolling off. If a signal/sweep generator is available, the
frequency response can be specifically compared to the provided Bode plot (diagram 9). Use the
right input channel. Adjust the input level to the QV to about 1Vp-p, sweeping from 20Hz to 25KHz.
Observe the filters output at U3 pin 7. Any large deviations from the plot indicate a problem and
should be troubleshot.
Diagram 6
Alesis QuadraVerb Service Manual------
9
08/13/04
Содержание QUADRAVERB
Страница 1: ...Alesis QuadraVerb Service Manual i 08 13 04 Alesis QuadraVerb Service Manual Revision 1 00 6 28 94 ...
Страница 16: ...Diagram 7 Alesis QuadraVerb Service Manual 10 08 13 04 ...
Страница 17: ...Diagram 8 Diagram 9 Alesis QuadraVerb Service Manual 11 08 13 04 ...
Страница 20: ...9 0 Schematics Alesis QuadraVerb Service Manual 14 08 13 04 ...
Страница 21: ...Alesis QuadraVerb Service Manual 15 08 13 04 ...
Страница 45: ...Service Manual History 6 28 94 1 00 First release Alesis QuadraVerb Service Manual 39 08 13 04 ...
Страница 46: ...NOTES Alesis QuadraVerb Service Manual 40 08 13 04 ...