Information

RECOMMENDED BIAS SETTINGS

If You Are Using	Then Consider	Here Is Why It Is The Right Choice
3M 226	3M 966	966 is the perfect choice with lots of benefits is Bias Compatible with 226 has same Signal-to-Noise Ratio as 226 has 6 dB less Print Through than 226
	OR
	3M 996	996 is a step up to a +9dB mastering tape has 3 dB more Headroom than 226 has 3 dB greater Signal-to-Noise than 226 has 3 dB less Print Through than 226
3M 806	3M 908	908 is the perfect choice with lots of benefits is Bias Compatible with 806 has same +3 dB Max. Oper. Level as 806 has same Signal-to-Noise Ratio as 806 has 5 dB less Print Through than 806
	OR
	3M 966	966 is a step up to a +6 dB mastering tape has 3 dB more Headroom than 806 has 3 dB greater Signal-to-Noise than 806 has 3 dB less Print Through than 806
3M 808 (For Nagra)	3M 908	908 is the best Nagra tape ever manufactured performs great without rebiasing has 4 dB less Print Through than 808 BUT with "rebiasing" has 3 dB more Headroom than 808 has 3 dB greater Signal-to Noise than 808
	OR
	3M 966	966 is the best tape for Stereo Nagra performs great without rebiasing has 1 dB less Print Through than 808 BUT with "rebiasing" has 6 dB more Headroom than 808 has 6 dB greater Signal-to Noise than 808

RECOMMENDED BIAS SETTINGS

MUSIC MASTERING TAPE (Highest Signal-to-Noise)

Tape#	Speed	Record Head Gap	10 kHz Over Bias
	lps	mils	dB
3m996	75	0.125	9
		0.25	6.5
		0.5	4
	15	0.125	6.5
		0.25	4
		0.5	3
	30	0.125	3
		0.25	2
		0.5	1.5

3M 966 3M 967 3M 250 3M 226 3M 227	75	0.125	7.5
		0.25	5
		0.5	3.5
	15	0.125	5.5
		0.25	3
		0.5	2.5
	30	0.125	2.5
		0.25	1.5
		0.5	1

GENERAL MASTERING TAPE

Tape#	Speed	Record Head Gap	10 kHz Over Bias
	lps	mils	dB
3M 806 3M 807 3M 908	75	0.125	6
		0.25	4
		0.5	3
	15	0.125	3
		0.25	1.5
		0.5	1
	30	0.125	1.5
		0.25	1
		0.5	0.5

BIAS SETTINGS Proper bias setting depends on the tape speed and the record head gap length. Smaller or narrower gaps require more over bias as shown in the table.

Record Head Gap Length	Recorder Model Numbers
0.25 mil (6.4 µm)	All models except those listed in the 0.50 mil chart below
0.50 mil (12.7 µm)	Ampex AG440, 1000 (newer models), ATR 100 series, Otari 7800, 5050B(F), MKII-1

OPERATING LEVEL CROSS REFERENCE CHARTS

Maximum Recommended Operating Level	ANSI Level	DIN Level
3M 966	520 nWb/m (+9 dB)	570 nWb/m (+5 dB)
3M 966/226/250	370 nWb/m (+6 dB)	410 nWb/m (+2 dB)
3M 806/908	250 nWb/m (+3 dB)	280 nWb/m (-1 dB)
3M 808	185 nWb/m ( 0 dB)	200 nWb/m (-4 dB)

Your desired operating level may be different from the reference fluxivity level on your reproduce alignment tape. If this is the case, use the chart above to normalize the operating level to the reference level found on typical reproduce equalization for optimum frequency response using the reproduce alignment tape.

Any combination of signal-to-noise and headroom can be achieved. Using less than the full signal-to-noise capability of the tape (by reducing the operating level) will result in lower distortion, less audible print-through and more headroom.

The reference (fluxivity) level of 320 nWb/m is commonly used in Europe. Due to difference in flux measurement techniques, this is equivalent to approximately 290 nWb/m when measured by American Standard Flux measurement technique as in this chart.

Desired Operating Level		Reference Fluxivity Level on Reproduce Alignment Tape
		ANSI				290nWb/m
ANSI	DIN	DIN				320nWb/m
520 nWb/m (+9 dB)	570 nWb/m (+5 dB)	-9 VU	-8 VU	-6 VU	-5 VU	-3VU
370 nWb/m (+6 dB)	410 nWb/m (+2 dB)	-6 VU	-5 VU	-3 VU	-2 VU	0VU
290 nWb/m (+4 dB)	320 nWb/m (0 dB)	-4 VU	-3 VU	-1 VU	0 VU	+2 VU
250 nWb/m (+3 dB)	280 nWb/m (-1 dB)	-3 VU	-2 VU	0 VU	+1 VU	+3 VU
200 nWb/m (+1 dB)	220 nWb/m (+3 dB)	-1 VU	0 VU	+2 VU	+3 VU	+5 VU
185 nWb/m (0 dB)	200 nWb/m (-4 dB)	0 VU	+1 VU	+3 VU	+4 VU	+6 VU

PROCEDURE:

Determine the desired operating level.

Determine the reference (fluxivity) level of the reproduce alignment tape you are using.

In the chart, find the VU reading at the point where the values from steps 1 and 2 intersect.

When reproducing the reference level tone from the calibration tape, set reproduce gain so the VU meter reading found in step 3 is achieved.

EXAMPLE:

Desired operating level for 3M 806 is 250 nWb/m.

Reference level on alignment tape is 185 nWb/m.

The VU reading is -3 VU at the intersection of the column and row from steps 1 and 2.

Set reproduce gain so VU meter reads -3 VU when reproducing the reference level tone from the calibration tape.