Drawmer 1962 Digital Vacuum Tube Pre-Amplifier - Manual (Page 23)

1962 OPERATORS’ MANUAL 19
STEREO LINK
Stereo Link:
Averages the left and right channel signals to provide the same degree of
gain reduction to both limiters and balance any low / high dynamic enhance.
This prevents any image shifting which could occur whenever the left and
right signal dynamics varied from each other by any significant degree.
Stereo link is enabled when the LED is lit.
If in stereo linked mode, then each processing module such as EQ, Tube
Drive, etc. should ideally be set to the same settings, and simultaneously
enabled, as the control-circuitry for both channels responds to the higher of
the two channel settings, which could cause an image shift.
CONFIGURATION
Configuration Jumpers:
A simple adjustment of two internal PCB jumpers (one for each channel)
enables the front panel Channel Output Level setting to be passed onto the
Channel Pan control in the Stereo Mix section and therefore onwards to the
Digital Section. The normal and recommended factory setting for both
jumpers is for Stereo Mix Channel Pan to be pre Channel Output Level
control.
It is less desirable option for the Mix section and the Digital Source Chs
(channels) feed to be made post-level control for several reasons:
1) Digital output noise will be increased by 4dB.
2) There is a greater chance of a digital overload, undoing the control and
safety feature of the limiter.
3) Any digital output level will be un-calibrated, unless the channel output
level control is set to the +20dB position.
To perform this change:
1: Disconnect the mains power cable from the unit.
2: With a number 1 pozidrive screwdriver, remove the 8 screws that retain the
top cover. (ie: two on each side; two at the rear and two counter-sunk screws
along the top at the front edge).
3: Locate the jumper blocks referenced as J12.
<
For channel 1 (or left) this is the upper PCB. The jumper is centrally
positioned along the rear edge of the PCB.
< For channel 2 (or right) this is the lower PCB. Its jumper is central to
the unit, near the small IDC connector for the digital unit.
4: Lift off the shorting jumper block and replace on the centre pin and previously
free pin. In most cases, the jumper has been replaced by soldering the
pins together.
5: Replace the top cover ensuring the correct screws are used for their intended
positions.