Page 1
ASHLY
ouuner's manual
' FD(-SERIES
CFT-SERIES
MO&FET POWER AMPLIFIERS
ASHLV
ASHLY AUDIO, INC.
FTX REV 01-0693
Page 2
lower than their maximum rating). The MOSFET will even withstand a dead
shorted output resulting in very high drain current without any protection circuitry
for a very short time.
MOSFETS also do not have a “storage time” associated with them (a
phenomenon found in bipolar transistors in which a certain amount of time is
required to turn the transi.stor off). Therefore the MOSFET is said to be a “fast”
device which can function very accurately with high amplitude/high frequency
signals and transient waveforms.
The unmatched reliability of the power MOSFET output devices and the
integrity of the rugged mechanical design of the FTX series amplifiers ensure years
of maintenance-free service.
UNPACKING
Ж
.....i
к
fíiMEMSTONS
17.0"
..□..
As a pari of our system of quality control, every Ashly product is carefully
inspected before leaving the factory to ensure flawless appearance. After unpack
ing, please inspect for any physical damage. Save the shipping carton and all
packing materials, as they were carefully designed to reduce to minimum the
possibility of transportation damage should the unit again require packing and
shipping, in the event that damage has occurred, immediately notify your dealer so
that a written claim to cover the damages can be initiated.
The right to any claim against a public carrier can be forfeited if the carrier is
not notified promptly and if the shipping carton and packing materials are not
available for inspection by the carrier. Save ail packing materials until the claim has
been settled.
POWER
Connect the FTX series amplifier to a standard 3-wire grounded electrical
outlet supplying 120 volts, 50-60 Hz (some export models are wired for 240 volts).
The power consumption is given in the specifications section.
STANDARD CONNECTIONS AND CONTROLS
The rear panel of a FTX-2000 amplifier with the standard input panel is shown
in figure I. For descriptions of other input options available, see the section on input
options.
1.5"
i ь
u
FTX/P70 Seríes Amplifiers
19.0"
FTX1000, FIX 1500, P70-400 Amplifiers
18.375"
FTX2000, P70-800 Amplifiers
и
'q;
_£ir:
3.0" 3.5"
.
1. I
2.25" 5.22"
Ashly FTX/CFT Owners Manual
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Ashly FTX/CFT Owners Manual
Page 11
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DESIGN THEORY
Ashly FIX series amplifier circuits are totally discrete using high-voltage,
wide bandwidth electronics. The input section is a complimentary Darlington
differential amplifier stage for high common-mode rejection, low noise and low
distortion. All voltage gain stages in the ampl ifier operate class A for low distortion.
The quasi-compHmentary MOSFET output stage has almost infinite current gain,
therefore the output driver stages are nearly lossless. Ail circuitry within the
feedback loop is discrete which allows the amplifier to recover instantly and cleanly
without any spikes or glitches from a dipped condition. This overall design
approach inherently assures low noise, low distortion, and excellent transient and
overload response.
Inputs are bridging and active balanced, and all input connections can operate
as balanced or unbalanced. Tum-on delay relays are not needed because of the
symmetry of the totally discrete complementary electronics.
Figure }: FTX-2000 Rear Panel With Standard input
The MOSFET output devices do not require short-circuit protection and V.L
limiting circuitry, thus enabling a simpler, more reliable electronic design. Rear
panel accessible speaker fuses are provided to protect the amplifier from prolonged
output shorts. These fuses are wired within the feedback loop of the amplifiers to
ensure that they do not alter the audio fidelity. All electronic components are
mounted to rugged glass-epoxy circuit boards. Large computer-grade electrolytic
capacitors assure tong service.
The FTX series amplifiers are packaged in a rugged 16-gauge .steel chasses.
The power transformer is located at the frontcenter of the chassis to minimize front
panel torsion. Each channel’s electronics and heat sink are identical yet completely
independent and modular, each with a single plug-in connector for ease of servicing.
Large custom black-anodized extruded aluminum heat sinks with fan cooling
provide plenty of thermal headroom.
The CFT-1800 utilizes quiet convection cooling for studio control rooms,
home hi-fi, and other applications where low ambient noise is essential. Like the
FTX series, theCFT-lSOOis a modular design for ease of servicing. Because of the
passive cooling in the CFT-1800, thermal headroom is somewhat reduced from that
of forced air cooling, thus making it inadvisable to drive 4 ohm loads at continuous
high power with this amplifier. It is also important to allow for free air circulation
above the amplifier to achieve optimum cooling action.
1. mpuTS
The standard input panel of the FTX series amps is equipped with balanced
1/4" tip-ring-sleeve (TRS) phone jacks, balanced XLR jacks, and balanced screwterminal inputs. The three types of connectors are internally wired in parallel and
may be used with balanced or unbalanced connections. The inputs are configured
for pin 2 hot, meaning that a positive voltage applied to pin 2 will result in a positive
output voltage across the speaker terminals. Pin 2 of the XLR jack is equivalent to
the tip of the 1/4" TRS jack as shown in figure I, An optional plug-in input
transformer is available on all FTX amplifiers.
cozzOIZlZ]
¡Figure 2: Input Connectors
5 " Rvu.t; I ......
It is recommended that balanced input connections be used when possible to
reduce ground-loop and environment-induced hum and noise. If an unbalanced
input connection is used, then the (-) connection (XLR pin 3) should be connected
to Input ground (XLR pin 1). if the 1/4" input jack is used unbalanced, the use of
a mono (tip-sleeve) plug will automatically tie the (~) connection to input ground.
Ashh FTX/CFT Owners Manual
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Ashlv FTX/CFT Owners Manual
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Pages
Page 4
The CHASSIS GROUND tenninal is internally connected to the chassis, the AC earth
ground, and the power iimplifter’s signal ground. The INPUT GROUND tenninal is tied
to the XLR pin 1 and the 1/4" jack sleeve. It is recommended that the input and chassis
ground terminals remain connected with the factory-supplied jumper strap.
in situations where the power amp and its signal source are separated by great
distances, a ground voltage diilerence may exist between the amp's chassis ground and the
inputcable'sground. Connectionofthesetw'ogroundsthroughihejumperstrapmaycause
large ground currents to flow (which is known as a ground loop), causing a hum noise in
the amp’s output. Unless you have such a situation with a hum problem that cannot be
solved by using balanced input connections, the ground jum^Kr strap should remain in
place.
2. NORMAUBRiOGING SWITCH
This switch selects between NORMAL mode in the “out” position where both
channels are in-phase, and BRIDGING mode In the “in” position where channel 2
is switched out-of-phase. In bridging mode, the channel 1 red binding post is the (+)
in- phase speaker output terminal and the channel 2 red binding post becomes the
(-) out~of~phase speaker terminal. To make the switch non-accessibie, its gray
button is removable by simply pulling it straight off.
3. STEREO/MONO SWITCH
This switch selects between STEREO mode in the “out” position and MONO
mode (where channel I input is routed to both channels of the amp) in the “in”
position, in mono mode, an input signal needs only to be connected to channel 1.
To make the switch non-accessibie, its gray button is removable by simply pulling
it straight off.
4. LEVEL CONTROLS
The level controls allow attenuation (calibrated in dB) of the input signal. In
MONO mode, the CHANNEL ONE level control affects both output levels and
CH ANNEL TWO level control is unused. It is recommended that the level controls
are operated at full level (0 dB attenuation) in most situations to maximize the
headroom in the signal source.
5. SPEAKER OUTPUTS
A pair of dual banana binding posts provide the stereo speaker outputs, in
BRIDGING mode, the channel 1 red binding post is the (+) in-phase speaker output
terminal and the channel 2 red binding post becomes the (-) out-of-phase speaker
terminal. CAUTION! NEVER CONNECT THE TWO RED BINDING
POSTS TOGETHER OR CONNECT EITHER RED BINDING POST TO A
BLACK BINDING POST!
Output
Low \
Level
10 o
/,N
5
dS
0
Modes
1 as
Ch.gjCh-l
I.Low High tFR)
a,Low I Low
3. Bridged Low
Ch.a is {+1
\ mSH ;
/■
High (FR|
__ Highpass
aMM. Fait Range
CAunOM: Never Send Fell Range
Signai To High Frequency Drivers.
t-l
-3-l\
/
-6 ^
input
Level
Balanced Input
{Pin 2 Hot)
_l
Figure 8: Crossover Input Option
-
---------
Microphone inputs [Mono] -
* „1. -2-
i i; i i ii ''kj'C'
\ / ji v\ X / //' tisvd
f)
( HSnd
\
' /
V {
V'
0 10
, Ch.1
/ \
f
V
....
f \
0 10 0 10
Ch.£
■ Line Level
/ a \\ \ ;■ Mic 1
(
HSnd
N i /
\
Î /
X/
...
/ \
/ \
0 10
Ch,4
Ch.3
L = Amfritfier Charitiei 1 Output
R = Amplifier Channei £ Output
Mono Mode Sums the Stsroo Signait
Line Inputs-
Figure 9: Mic/Line Mixer Input Option
Phase-
Level
*360
A A
5
Input
, , Ground
IN i S
X X XX
10 0
Mio 2
Level
/ i \
Cnaasis
Ground
-J—
\y
I
LowCut
(Mica Crilyî
0
----
fPre Level]
— Master
Leve!
4 f s
3^ '
£-
/
0
-L
^ ctrrTJ
- insert Points
(Post Master Level J
CD
Horn EQ
R3WERCARD input Option!
Crossover
Frequency:
XR-1
Two-Way i
Crossover
Installed
aadS/Oct.i
O
Aux
Low Oct
/
-s
0"
Send
I
RoUjrn
Alèx
Hign Out
¡Pré Lewjl]
Stereo M. Norm
Mono jm. Bridge
v,.y V....X
ASHL^
MM-6
POWERCABD
input Opdon
Mic/üne Mixer
Ashly FTX/CFT Owners Manual
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Ashly FTX/CFT Owners Manual
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Page 9
Page 5
CROSSOVER INPUT OPTION
The crossover input option provides fixed-froquency 24 dB/octave high-pass and
low pass filtei^ allowing the two amplifier channels to operate bi-amped, full range with low
out both channels low out, or bridged low out. Auxilliary low and high outputs are available
for connecting additional amplifiers, included widi the crossover input option are single in
line package (SIP) resistor networks which allow preselection between stimdard crossover
frequencies of 160Hz, 500Hz, and 1,2KHz. 360° of phase control is provided for proper
acoustical alignment of high and low frequency drivers. Constant Directivity Horn EQ is
provided for both small and large hom designs. A 3rd-order 20 Hz high-pass filter is
included on the low frequency crossover output to remove inaudible subsonic signals.
MIC/LJNE MIXER INPUT OPTION
The mixer input option provides four high-impedance line inputs and two
balanced low-impedance microphone inputs, each with its own level control. A
switchable 200 Hz high-pass filter is provided on the mic inputs to reduce unwanted
low frequency noise. An interna! jumper allows selection of 15 Volt phantom power
applied to the mic inputs for use with condenser mics. The option has a master level
control and selectable stereo, mono and bridging modes, insert Points are available
for patching external processing into the left and right channels.
METERS
The FTX amplifiers are equipped with front panel meter displays which
respond to peak output voltage. An eleven-segment, three-color LED display
covers a 27 dB range. The green LED’s at the left end of the meter arrays indicate
a normal thermal status. In the event that the amplifier overheats, these LED’s will
turn off but the power switch will remain illuminated, indicating the thermal
protection status. When the heat sinks return to safe operating temperatures, the amp
will turn itself back on and illuminate the left-most green LED’s. In the event of a
blown speaker fuse, the meter display of the affected channel turns fully on. THIS
DOES NOT MEAN THERE IS DC AT THE OUTPUT!
о
о
figure 3: FTX~2000 Front Panel
TYPICAL APPLICATIONS
Qî.S
Limiter
Thresbotd Umit
(dB) I
+18
-N
■15
+3'^ V
■6
1
4 f 6 //
Ч
...
./ О 10
Limiter Leve!
tn/Out
Stereo
Mono
Channei Э
) ( ; +13.
, , , , Ground
(+) И Î
Figure 7: Limiter Input Option
Ashly FTX/CFT Owners Manual
Norm
Bridge
Ch.1
Umteer , ,
ThresMiJ wfTiït
ieJB} f
.as '■
'■ N
+3Vj
C-®
■ Б
[-) [+Ì
X Xi X
X
Chassis
Ground
•••••••••••••
POWERCAPD input Option
CL-2
Stereo limiter
14 4^6
O ^ 10 \
(пДЭиЕ
' Channel 1 (Mono)
Page 8
Levd Limiter
STEREO OPERATION
lissitiâsg i t S
Figure 4: Operation in Normal Stereo Mode
••••••••••••••••••••
Ashly FTX/CFT Owners Manual
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MONO OPERATION
Moni; S^viíí.h tn
To operate in bridging mode, depress both the MONO switch and the
BRIDGING switch . The MONO switch depressed routes the channel 1 input to
both amplifier channels and the BRIDGING switch depressed inverts the phase of
the input signal before it is fed to the channel 2 power amp section. The two
amplifiers' outputs are therefore 180 degrees out-of~ phase. The channel 1 red
binding post is used as the positive speaker terminal and the channel 2 red binding
post becomes the negative speaker terminal. The black binding posts are not used.
CAUTION!
providing more power to a single speaker. However, each output channel “sees”just
one-half of the load impedance when in bridging mode. For example, connecting
an 8-ohm speaker in bridging mode presents a 4-ohm load to each channel of the
amplifier. Use caution when operating in bridging mode not to exceed the power
handling capability of the speaker and the minimum load impedance on the amp.
NEVER GROUND EITHER RED BINDING POST!
In bridging mode, the output voltage applied to the speaker is doubled, thus
Figure 5: Operation in Normal Mono Mode
With the MONO switch depressed, the channel I input is routed to both
amplifierchannels. Both channels are then controlled by the channel I level control.
Both outputs will be identical and can be connected to separate speakers. CAU
TION! NEVER CONNECT THE RED BiNDiNG POSTS TOGETHER!
BRIDGING OPERATION
Both Swh<:ht>s In
Figure 6: Operation in Bridging Mode
INPUT OPTIONS
Input option panels areavailable to provide built-in featuics such asasfôreocompressorlimiter, a mic and line mixer, acrossover for bi-amplified systems, and input transfcxmers for
signal isolation. Ashly FTX series amplifienj as well as ail other Ashly amps (excluding the
single rack spæe SR A-120) will accept Ashly input option panels.
A brief description of currently stocked input options follows. Consult your dealer
for detailed information on the input options, or call the factory.
TRANSFORMER INPUT OPTION
The input isolation transformer can be installed directly into the standard input
supplied with eveiy ASHLY amplifier (except for the single rack space SRA-120). No
soldering is necessary. The input transformer provides complete electrical isolation from
the amplifier and its signal source to eliminate any ground-induced hum noise. The
transformer input also further reduces any common-mode noise and radio frequency
interference. The transformer option must be instal led in the standard input panel and does
not change the operation of any switches or controls.
LIMITER INPUT OPTION
The limiter input option provides peak signal limiting from excessive input levels
for speaker protection and overall level control. Separate limiter threshold controls, limit
indicator LED’s and limit on/off switches are provided on each channel allowing fully
discrete stereo limiting operation.
ввфФбОФФОФООвОФФФО
Ashly FTX/CFT Owners Manual
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Ashly FTX/CFT Owners Manual
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Page 7
SPECIFICATIONS
CÜÊ I
5*31 Ssn sT
It
Output Power
EiA Spec.
(±1dB<1%THD20Hz-20KHz)
Stereo (Rated Per Channe!):
Mono Bridged:
FTC Spec.
{min power <,01 % SMPTE
IMD @ 8, <.02% IMO @ 4)
Stereo {Rated Per Channel):
Mono Bridged:
Total Harmonic Distortion
1
ÌM Distortion 80 (SMPTE)
Damping Factor
Bandwidth
Slew Rate
Frequency Response
Full Power input Sensitivity
Hum and Noise
{20Hz-20KHz unweighted)
Power Requirement 760 W Max. iOOW idle
li
Shipping Weight
FTX-1000
2 Ohms
4 Ohms
8 Ohms
4 Ohms
S Ohms 3S0 Watts RMS
4 Ohms
8 Ohms Ш0 Watts R.MS 175 Watts RMS
8 Ohms
(80)
(ÌHF) .01%
Size
190 Watts RMS
!20 Watts RMS
160 Waits RMS 275 Watts RMS 400 Watts RMS
320 Watts RMS
,007% iKHz
-0!%20Hz
.05% 20HZ-20K.HZ
.007%
>250 20Hz-lKHz
lOOKHz
40V/pS
±.2dB 20Hz-20KHz
I.IV
>!00d8 below lull output>100dB bdow fui! outpuí
120 VAC 50-60HZ 120VAC50-60HZ 120VAC 50-60HZ
(240V available)
irWx3.5"Hx17,rD
42 ibs. 4? Ibs. 65 Ibs,
FI'X-!50Q
CFT-iSOO
300 Watts RMS
200 Watts RMS
600 Watts RMS
550 Watts RMS
.007% IKBz
.0!%20Hz
.05% 20HZ-20KHZ
.007%
.01%
>250 20Hz-IKHz
lOOlCHz
40VyfiS
±.2dB 20Hz-20KHz
1.3 V
1200 W Max, 160W Idle1800 W Max, 220W Idle
(240V availabie)
í9"Wx3.5'’H.4l7.8’'D !9”Wx5.25”Hxi7.S’’D
FrX-2000
675 Watts RMS
500 Watts RMS
300 Watts RMS
¡350 Watts RMS
1000 Watts RMS
250 Watts RMS
800 Watts RMS
.007% IKHz
.01%20Hz
.05% 20HZ-20KFÍZ
.007%
.01%
>250 20Hz-lKHz
lOOKHz
50V/pS
±.2dB 20Hz-20KHz
1.7V
>!05tlB bciow fuíl outpuí
(240V availabie)
MOSFET POWER AMPLIFIERS
Models FTX‘1000, FTX-ÎS&O, FTX-2000, and CFTM800
TABLE OF CONTENTS
introduction
Standard Connections and Controls
Typical Applications..................................
Input Options............................................................................
Transformer Input Option........................................................ 8
Limiter Input Option..................................................................8
Crossover Input Option........
Mic/Line Mixer Input Option ....:
Design Theory..................................................................
Dimensional Diagrams .....
Specifications............................................................................
INTRODUCTION ... Wtiy MOSFETS?
The Ashly FTX series MOSFET amplifiers combine the sonic excellence of
a high-end stereo amp with the ruggednes.s and stamina necessary in pro audio. The
FTX series amps use power MOSFETs (metal-oxide-semi conductor, field-effect
transistors) for their superior audio fidelity and unmatched reliability as proven in
Ashly amps for over ten years. The CFT-1800 is a convection cooled hut electrical
equivalent of the FTX-1500,
MOSFET output devices are used in the FTX series amps because of their
superior performance characteristics over bipolar power transistors which are
normally used in conventional power amp designs. The power MOSFET is
inherently more self- regulating and does not exhibit the failure modes that bipolar
transistors are susceptible to. MOSFETS do not require any thermal runaway
compensation circuitry, thus making the design simpler and more reliable. MOS
FETS do not exhibit secondary breakdown (an instantaneous failure in bipolar
transistors when their collector current exceeds a .safe level, even at voltages much
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Ashh FTX/CFT Owners Manual Page 1
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