Ashly Operating Manual for Power Amplifiers: FTX 1501 and FTX 2001 Models

Operating Manual - FTX-1001, FTX-1501, FTX-2001, CFT-1800 Power Amplifier

	FTX-1001	FTX-1501	FTX-2001
Idle	.5A	.6A	1.5A
8Ω loads	2 Amps	2.5 Amps	3.5 Amps
4Ω loads	3 Amps	4 Amps	6 Amps
2Ω loads	---	7 Amps	10 Amps

Table 3.1: Recommended AC line current capacity

All FTX Series III amplifiers consume less than 12 amps when operating at 1/8 power into 2Ω loads. This condition satisfies the UL, CSA and building electrical code requirements for a piece of audio equipment not to consume more than 80% of the current available when plugged into a grounded 15 amp outlet and operated at 1/8 of maximum power.

3.3AC Grounding Requirements

To reduce the risk of ground loop hum, all sys- tem ground references should originate at the same point in your AC power distribution . Never remove the amplifier’s ground pin as it is both unlawful and danger- ous, creating a potential shock hazard.

4.CABLE REQUIREMENTS

4.1Input Cables

Be sure to use shielded cable whether balanced or unbalanced. Shielding which is properly grounded will protect the signal from outside electrical interference such as RF, fluorescent lighting, even computer noise. As a general rule, unbalanced or single-ended (tip-sleeve) lines of less than 10 feet are satisfactory, but greater distances may require a balanced signal. Avoid running input lines in close proximity or parallel to long speaker lines, AC power cables, or power transformers, as this may gener- ate hum or oscillation.

4.2Output Cables

The FTX Series III amplifiers are capable of de- livering high levels of output current, therefore the wire gauge used for speaker cables is particularly important. Inadequate wire gauge adds significant resistance to the speaker’s own impedance, reducing the power which is actually delivered to the speaker. It will also result in a decrease in the damping factor and possible fire hazard.

Since power at the speaker load is a primary con- cern in system design, we have included a table to best determine appropriate wire gauge for your application. Table 4.1 lists the percentage of the speaker load power which would be lost in an arbitrary 100 ft run of 2-con- ductor cable. This table expresses the power loss as a percentage of the load’s power rather than the total am- plifier output power, so that you can use this table to ac- curately determine power loss to the load at other cable lengths. For example, if you plan to deliver 100 watts to an 8Ω load through 50 ft of 14 ga. cable, the power loss in the cable would be 3.2% ÷ 2 = 1.6% of 100 watts or

1.6watts lost in the cable. Table 4.1 also gives the resis- tance per 100 feet of common copper wire gauges.

Wire Gauge	Ω/100ft	8Ω load 4Ω load 2Ω load
#8	.0605Ω	0.8%	1.5%	3.0%
#10	.1018Ω	1.3%	2.5%	5.1%
#12	.1619Ω	2.0%	4.0%	8.1%
#14	.2575Ω	3.2%	6.4%	12.9%
#16	.4094Ω	5.1%	10.2%	20.5%
#18	.6510Ω	8.1%	16.3%	32.6%

Table 4.1: Percentage of speaker load power lost in 100 foot run of 2-conductor cable.

5.RACK-MOUNTING REQUIREMENTS

5.1Mechanical

All Ashly amps are designed to fit in standard 19-inch racks. The front panel rack-mount ears are suffi- ciently strong for most applications. If you desire further integrity for mobile racks, we recommend using the four additional holes in the back of the chassis for supplemen- tal rear-mounting (see dimensional drawings).

5.2Cooling

If using an FTX amplifier, be certain that both the front and back of the rack have unhindered access to free air flow. Fan direction is from front to back. It is not necessary to leave empty space above or below the FTX amplifiers, however the CFT-1800 will cool more efficiently with space above and below the chassis.

The following chart indicates max BTU per hour for each amp under varying load conditions, so that ac- curate assessment of room ventilation needs can be made. Thermal output is approximated by subtracting audio output power from the total power consumption of the amplifier. All values assume the amplifier is driving both channels and just peaking at the clipping level.

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