W W W . G O L D E N A G E P R E M I E R . C O M
II
CIRCUIT DESCRIPTION
The signal first enters an input transformer.
The primary of the input transformer has
two windings that are either connected in
series or in parallell which results in an
input impedance of either 1200 Ohm or 300
Ohm (in MIC mode).
The transformer are followed by two input
gain stages. For gains up to 40 dB, only one
of them is being used. For gains from 45
dB and up, the second gain stage is inserted in the signal path. Both gain
stages uses only three transistors each.
The signal then goes to the Insert connector with its bypass jumper, to the
output level potentiometer and from there on to the output stage. This stage
again only uses three transistors, the last one in the chain is a hefty 2N3055
power transistor run in class-A mode, driving the output transformer.
So, all in all, the complete signal chain only contains a maximum of nine
active elements. Compare that to the big number of transistors that are usu-
ally used in one single integrated circuit!
USING THE PRE-573 PREMIER
Using a preamplifier is not rocket science. Here are some points though to
help you getting the maximum out of the PRE-573 PREMIER:
As a start, mount the module in a 500 series rack unit. There are several
alternatives available from different manufacturers, the PRE-573 PREMIER
should work fine in most of them. Make sure that the rack unit power supply
is turned off when you mount or remove the PRE-573 PREMIER.
MIC / LINE INPUT
Connect your Mic or Line source to the input connector on the 500 rack unit
corresponding to the slot where the PRE-573 PREMIER is placed.
For Microphone sources:
1. Set the MIC - LINE switch in the MIC position.
2. Set the MIC/LINE - ACTIVE DI switch in the MIC/LINE position.
3. Set the PASSIVE DI switch in the downward off position.
4. 48 V if the connected mic needs phantom power. It is good
procedure to always disengage the phantom power and wait for about 10
seconds before unplugging a mic.
The 300 - 1200 switch will select the input impedance. 1200 ohm is the
normal position for most mics. Lowering the mic input impedance to 300
ohm will change the tone of many microphones and will give you one more
soundshaping option.
For Line level sources:
1. Set the MIC - LINE switch in the LINE position.
2. Set the MIC/LINE - ACTIVE DI switch in the MIC/LINE position.
3. Set the PASSIVE DI switch in the downward off position.
The LINE input mode will attenuate the input signal with about 30 dB and
also increase the input impedance to about 10 kohm.
If you want the smallest amount of coloration, always set the OUTPUT LEVEL
potentiometer at or close to maximum, and adjust the output level with the
stepped GAIN switch.
The +10 - 0 - +5 dB switch should normally be in the 0 position but you can
set it to +5 or +10 dB anytime you want to add gain.
The +5 and +10 dB positions of this switch corresponds to the -75 and -80
dB positions (with the PRE-573 PREMIER GAIN switch set to 70 dB) and the
-45 and -50 dB positions (with the PRE-573 PREMIER GAIN switch set to 40
dB ) in the classical 1073 unit.
This setup makes it possible to use both gain stages also for gains of 45 and
50 dB (with the +10 - 0 - +5 switch set to 0) for some added character.
If you want more character, turn the OUTPUT LEVEL potentiometer counter-
clockwise and increase the gain with the GAIN switch. This will drive the
input gain stage(s) harder and provoke more character from them.
DI INSTRUMENT INPUT
Instruments that are not connected to the mains AC power line can be con-
nected to the DI instrument TRS input on the front panel.
The DI input has two selectable modes, Passive and Active. The Active mode
uses a FET-buffer and has an input impedance of about 1,5 Mohm. The
signal is fed through the input transformer and then onwards to the gain
stage(s).
The Passive mode feeds the signal from the TRS jack directly to the gain
stage(s). It has an input impedance of about 100 kohm.
To use Active mode:
1. Set the MIC/LINE - ACTIVE DI switch to the ACTIVE DI position.
2. Set the PASSIVE DI switch in the off position, ie, the downward one.
To use Passive mode:
Set the PASSIVE DI switch in the On position, ie, the upward one.
PLEASE NOTE:
- DO NOT use a higher GAIN than about 70 dB in Passive mode and 50 dB in
Active mode (you can try it if needed but self oscillation might occur).
GAIN might have to be decreased a bit further when Air EQ is engaged to
avoid self oscillation.
- The DI input in Active mode has a much higher sensitivity than in Passive
mode so GAIN must be set lower than in Passive mode for the same output
level. The input impedance is also much higher so the DI input will load the
connected instrument less compared to the DI in Passive mode.
- The tone of most instrument will differ in the two modes giving you several
sound options.
- Some instruments will sound and work better in one of these modes, the
best way of finding out is to experiment.
- Signal sources connected to the 500 rack input can remain connected
when you use the DI input.
- DO NOT connect equipment to the DI input (unless they have a fully float-
ing, transformer balanced output). It is only intended for instruments like
guitars and basses. For all other signal sources, do use the MIC/LINE input
on the 500-rack. The reason is that the internal ground of the module and
hence the DI-input jack IS NOT the same as the 500 rack ground.
OTHER FUNCTIONS
The three position HP1 - OFF - HP2 highpass filter switch is located close to
the OUTPUT LEVEL control. The HP1 position has a -3dB frequency of about
45 Hz. The HP2 position has a -3dB frequency of about 180 Hz,
The three position AIR - OFF - PHASE switch works like this:
1. The Phase position simply reverses the phase by reversing the wires from
the secondary winding of the output transformer. Reversing the phase of the
signal is useful on a number of occasions, one is phase reversing the the
lower mic on a snare drum to make it sum in phase with the upper mic.
2. In the middle position of the switch, phase is not reversed.
3. Putting the switch in the upper AIR position
adds a boost of about 6 dB
centered at about 30 Khz. It will affect the range from about 5 kHz and up.
There is an unbalanced insert connector located at the back of the unit
where you can insert Golden Age Project/Premier 500 Series effect mod-
ules. The operating level is about -18 dBu. To activate the insert, the jumper
located close to the connector must be removed.
The output transformer used in the PRE-573 PREMIER is designed for
having an ideal load of about 600 ohm. The input impedance of most modern
units is 10 kohm or more. The PRE-573 PREMIER has a jumper selectable
600 ohm output termination resistor. The jumper, which is located at the
back of the unit, is connected from factory to set the load to the ideal 600
ohm when modern units are connected after the PRE-573 PREMIER.
Disengaging the termination resistor by removing the TERM jumper will
result in a slightly higher output level. The jumper should always be discon-
nected if an old-style unit with a low input impenace like 600 ohms is con-
nected after the PRE-573 PREMIER.
WARRANTY
The PRE-573 PREMIER is built to last. But as in any electronic device, com-
ponents can break down. If the unit has a problem and will need repair, you
should contact the reseller where you bought the unit.
The warranty period is decided by the Distributor for your country. The
Distributor will support Golden Age Premier resellers and end users with
repairs and spare parts.
REGISTRATION
You are welcome to register your unit at: www.goldenagepremier.com
---------------------------
I would like to thank you for chosing the PRE-573 PREMIER!
I hope it will serve you well and that it will help you in making
many great sounding recordings.
Bo Medin
Handmade high end pro audio for
a lot less than you would expect!
