FRONT PANEL
1. MOUNTING
Sturdy one piece aluminum handles make for easy transporting along
with facilitating rack installation. The rack mounting holes are designed
on ISO standard spacing. Four 10-32 x .5” phillip machine screws are
normally used to secure the amp. Rear support brackets are not required.
2. POWER SWITCH
Check the power amp connections and verify the AC line power source
before engaging the POWER switch. The yellow LED unmistakably indi-
cates that all circuits are properly powered up. This color was chosen so
the operator could see other red indicators from a distance.
3. CHANNEL LEVEL CONTROL
A precision 41 step input LEVEL attenuate is used to adjust the volume
levels. To deliver the amps full power without reducing headroom of the
signal source, the level controls should be turned up approximately 1/3
(15 on the dial).
4. CHANNEL SIGNAL INDICATOR
The green SIGNAL LED indicators will start to flash when there is a signal
passing to your speakers (-30dBM). This lets you know when the amp is
passing a signal to your speakers.
5. CHANNEL CLIP INDICATOR
The red CLIP LED indicators will start to flash when each channel has reached
its maximum output. Occasional flashing caused by lower bass frequencies
is OK. However, consistent flashing caused from higher frequencies may
damage high frequency drivers (excessive distortion). This does not cause
damage to the amp.
6. EQ EXPAND SWITCH
This switch, when set to its ‘in’ position will boost the highs and lows
by +4dB at 80Hz and 12kHz. This works well as a loudness contour when
operating at low volume levels or adds flavor when using it in a bass or
guitar rack. When set to the ‘out’ position it provides a flat output response.
Try it both ways and set as desired.
REAR PANEL
7. XLR CHANNEL INPUTS
For most professional applications, use the XLR balanced input. This
will help to reduce hum and allow of longer cable runs from your signal
source (mixer, etc). Because this is a balanced input, the gain will be 6
dB higher than using the 1/4” input jack with a non balanced line. XLR
pin configuration: Pin 1: Grounded through the GROUND LIFT switch, Pin
2: positive Bal. signal and Pin 3: negative Bal. signal.
8. CHANNEL 1/4” PHONE JACK INPUT
This stereo phone jack is designed to receive either balanced or unbalanced
input signals. Balanced signals coming into this jack should be wired with
the connector’s tip going to and the connector’s ring to signal -.
9. SPEAKER OUTPUTS
The standard 1/4” SPEAKER jacks are used for most applications. Turn
the amp off before connecting your speakers.
10. SPEAKER BINDING POSTS
For heavy-duty speaker connections, use the rear BINDING POSTS to con-
nect your speakers. Wire sizes up to 7 gauge (50 amps) can be inserted
into the binding posts “side holes”. Larger cable can be used with “banana”
plugs which plug into the ends of the binding post (remove colored caps).
Binding posts are spaced on ISO standards. Use the two center RED bind-
ing posts for BRIDGE speaker connections (see 11 BRIDGE MODE).
11. BRIDGE MODE—
25V/70V DISTRIBUTION SYSTEMS
The HT150 can be operated in bridge mode if you require a 25V / 70V
distribution speaker system or a high powered mono (single channel) amp.
With your amp off, push in the rear BRIDGE switch after you have made
your speaker connections to the rear center RED binding posts (ch 1 is
+ and ch 2 is -). No other speaker jack or binding post can to be used at
the same time!”. The INPUT and LEVEL is handled by channel 1. Channel
2 is non-operational. The minimum speaker impedance is 4 ohms or a
25V distribution line. CAUTION: The power developed by bridging your
amp can destroy most speaker systems!
12. AC POWER
Your amp is designed to run on either 120V 60 Hz or 230V 50V depend-
ing on the model purchased. The voltage range for 120V is 95V to 132V
and for 230V it is 190V to 253V. The rear heavy-duty AC cord is designed
for your country. Be sure to check your power source before plugging
into a grounded (3 prong) outlet. Never defeat the grounded connection
or electrocution may result!
13. AC FUSE VALUES
(Slow Blow Type)
120V MODELS: 2.5AGC
230V MODELS: 1.25AGC
2
6
1
3
4
5
FRONT & REAR PANEL CONTROLS
8
7
11
12
13
9
10
11