Shure M367 Changing Limiter Release Time to ONE Second, Changing Limiter Threshold Presets

CHANGING LIMITER RELEASE TIME TO ONE SECOND

6. Calculate resistor R6 value as follows:

Remove resistor R741 (about 15 mm behind ribbon cable assembly W813).

R6 =

1

CHANGING LIMITER THRESHOLD PRESETS

1.Select the equivalent resistor values for the desired limiter thresholds from the following table. Then fill in the following work sheet with the resistor selections.

Limiter Threshold		Requiv		Limiter Threshold (				Requiv
(dBm into 600 Ω)		(kΩ)		dBm into 600 Ω)				(kΩ)
0		18			10			81
1		21			11			93
2		25			12			105
3		30			13			122
4		35			14			139
5		41			15			156
6		47			16			175
7		54			17			194
8		62			18			215
9		71
DIP Switch S701			Limiter Threshold			Requiv (above)
Position 2	Position 3		–		dBm			–
up	up		high		_____		kΩ = R1
down	up		med. high		_____		kΩ = R2
up	down		med. low		_____		kΩ = R3
down	down		low		_____		kΩ = R4

2.Remove resistors R721, R731, R732, R733, R734 and R735 (surrounding IC U704).

3.Locate empty pads X732, X733, X734 and X735 (surrounding IC U704).

4.Select a 1/4 W, 1% resistor closest in value to R1 (from the work sheet), and solder it to the holes of X732.

Note: Use parallel or series combinations of resistors to match the chosen values as closely as possible if 1% resistors are not available.

5. Calculate resistor R5 value as follows:

1 – 1

R3 R1

Select a 1/4 W, 1% resistor closest in value to R6 and solder it to the holes of X734.

7. Calculate resistor R7 value as follows:

R7 =						1
		1	–		1	–		1	–		1
	R4			R1			R5			R6

Select a 1/4 W, 1% resistor closest in value to R7 and solder it to the holes of X735. (See Changing Limiter Threshold Presets: Samples Calculations later in the Appendix for an example of limiter threshold preset component calculations.)

CHANGING LIMITER THRESHOLD PRESETS: SAMPLES CALCULATIONS

For the following limiter thresholds:

DIP Switch S701		Limiter Threshold		Requiv
Position	Position	–	dBm	–
2	3
up	up	high	12	105
				kΩ=R1
down	up	med. high	8	62 kΩ=R2
up	down	med. low	4	35 kΩ=R3
down	down	low	0	18 kΩ=R4

1.Obtain a 105 kΩ, 1/4 W, 1% resistor and solder it to the holes of X732.

2.Obtain a 150 kΩ, 1/4 W, 1% resistor and solder it to the holes of X733.

		1
R5 =	1	1	= 151.4 k:
	62,000	105,000

3.Obtain a 52.3 kΩ, 1/4 W, 1% resistor and solder it to the holes of X734.

R5 =

1

		1
R6 =	1	1	= 52.5 k:
	35,000	105,000

1 – 1

R2 R1

Select a 1/4 W, 1% resistor closest in value to R5 and solder it to the holes of X733.

4.Obtain a 49.9 kΩ, 1/4 W, 1% resistor and solder it to the holes of X735.

			1
R7 =	1	1		1	1
	18,000	105,000	150,000		52,300

= 49.4 k:

10