Jas-Audio GREEN POWER 120 - Manual (Page 3)

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LED INDICATORS
When the Green Power GP-120 amplifier is first switched on, the pilot lamp above the button
will glow green.
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LED on the right displays input source number (1 to 4) and volume level in dB numeric notations. At power on, GP-120 is by
default to show input source from 2; volume level is then set at minimum and is shown as -80dB. Pressing corresponding buttons
on the faceplate to change volume level and select input source as desired. Alternatively, adjustment and changes can be effected
by using the remote control.
PROTECTION MODE
The Green Power GP-120 amplifier features a protection mechanism against shorting the s peak er cabl es. The amp will then
become muted so as to avoid damage to the voice coil of the loudspeakers. When this occurs, switch the amplifier off at once. Check
speaker cable connections to make sure that plugs are not in contact with each other or shorting occurs. Never attempt to short plugs of
speaker cables when the other ends of the cables are connected to terminals when the amplifier is in operation or being switched on.
In the event of a failure of the amplifier, the output and/ or the mains supply should be disconnected. User may require to return the amp
to the dealer for servicing.
LED Display
Please check with the dealer first for advice.
REMOTE CONTROL
The remote control RC-1 handset as shown on the left is designed to operate the JAS Green Power
GP-120 Integrated amplifier. It allows the user to operate the volume control, input mute and selection of
source input.
OP AMP REPLACEMENT
GP-120 features interchangeability of Op amp in its power amp circuitry. Installed with a piece of Philips NE5532 is of JFET in its internal
circuitry. GP-120 amplifier performs with adequate power to deliver dynamic sound, warm and details with a taste of “tube” amplification.
RC-1
Below is the procedure for changing Dual Op Amp:
1.
unscrew to open the cover of the amplifier;
2. locate the socket on the PCB as shown in the picture;
3. remove OP Amp by wiggling it so as to lift up from the IC socket;
4. alight latch of OP Amp with that appears on the IC socket;
5. press the entire OP Amp with all pins straight down into the IC socket.
Below is the procedure for changing Single Op Amp:
1.
unscrew to open the cover of the amplifier;
2. locate the sockets on the PCB as shown in the picture;
3. remove OP Amp by wiggling it so as to lift up from the IC socket;
4. alight latch of OP Amp with that appears on the IC socket;
5. press the entire single OP Amp with all pins straight down into the IC socket on one side;
6. do the same with another piece of single OP Amp into the other IC socket on the other side;
7. make sure that of pins of OP Amps are in contact with the sockets.
OP AMP REPLACEMENT
Suggested list of replacement Dual OP Amps:
1.
AD827 --- characterized by crystal clear high frequency and bouncing bass, peak gain at 50MHz;
SR at 300V/
s;
2. EI2244 --- timbre tends to be neutral, energy inclined to the high frequency side;
3. OP249 --- a product of PMI, US; characterized by neutral and balanced sound, accurate in
sound reproduction;
4. OPA2604; --- a product of Burr Brown; renowned as one of the best in delivering warm and
smooth sound that would expect from tubes, exquisite and smooth timbre.
Suggested list of replacement Single OP Amps:
1.
NE5534 --- a twin of NE5532; as there is less interference as what would occur in using the dual
OP Amp, sound is soft, warm with details, and it is musical;
2. OPA604 --- a product of Burr Brown, the single version of OPA2604, characterized by warm and
smooth sound; more richness in the mid-range.
SPECIFICATION
Measured at 230V or 115V
Power Output into 4
Ω
(both channels driven) at rated mains voltage > 120 Watts
Total Harmonic distortion (20 Hz to 20 kHz) < 0.1%
Input Impedance 47K
Ω