Manual-11
Time Delay Transplant Modification
We have added modification jumpers to the AC 22B.
These jumpers permit the transplanting of the Delay circuits
from one Output to another. As the units are shipped, the
Delay circuit is not installed on the High Frequency Outputs.
When the AC 22 was first designed, long throw horns were
more common than constant directivity horns (CD horns).
The long throw horn's diaphragm was the farthest sound
emitter from the front of the speaker enclosure, (see Fig. 1) so
no Delay was needed. The mid frequency and low frequency
drivers were always in front of the high frequency drivers,
therefore, the mid and low frequency drivers needed the
Delay circuits for proper time alignment.
Now, with the use of CD horns becoming more common,
occasionally there is a need to Delay the CD horn as its
diaphragm is usually in front of the other drivers in the
enclosure (see Fig. 2). If you are using CD horns, you should
also read the Constant Directivity Horn Equalization
Modification section on page Manual-14.
AC 22B Delay Transplant
Procedure
CHANNEL ONE:
1. Refer to the board layout diagram on page S1.
2. On the board layout locate W30 next to the Mono Sub
switch, and W11 behind the CH 1 Delay pot.
3. To remove the Delay 1 circuit from the Low Frequency
output, remove the W30 and W11 jumpers.
4. To get the Low Frequency output to work again, place a
long jumper from W30, Pin 1 to W11, Pin 2.
5. The Delay 1 circuit is now removed from all circuits.
6. To install the Delay 1 circuit into Channel 1’s High
Frequency output, find jumper W28 near Z102 and remove
it.
7. Install a long jumper from W30, Pin 2 to W28, Pin 1.
8. Install a long jumper from W11, Pin 1 to W28, Pin 2.
The Delay 1 circuit is now installed into Channel 1’s High
Frequency Output.
CHANNEL TWO:
1. Refer to the board layout diagram.
2. On the board layout locate W43 near Z203 and W45
behind the CH 2 Delay pot.
3. To remove the Delay 2 circuit from the Low Frequency
output, remove both the W43 and W45 jumpers.
4. To get the Low Frequency output to work again, place a
long jumper from W43, Pin 1 to W45 Pin 2.
5. The Delay 2 circuit is now removed from all circuits.
6. To install the Delay 2 circuit into Channel 2’s High
Frequency output, find jumper W56 and remove it.
7. Install a long jumper from W43, Pin 2 to W56, Pin 1.
8. Install a long jumper from W45, Pin 1 to W56, Pin 2.
The Delay 2 circuit is now installed into Channel 2 High
Frequency Output.
Fig. 4. Displacement with Long Throw Horn
Fig. 5. Displacement with Constant Directivity Horn
