Rane MS1S MS1S Mic Stage Manual - Page 19

Ground Lifts, systems never earth ground anything except cable TV, often a ground loop

Get Rane MS1S PDF manuals and user guides View all Rane MS1S manuals
Add to My Manuals
Save this manual to your list of manuals

Page 19 highlights

See Figure 4 for suggested cable assemblies for your particular interconnection needs. Find the appropriate output configuration (down the left side) and then match this with the correct input configuration (across the top of the page.) Then refer to the following pages for a recommended wiring diagram. Ground Lifts Many units come equipped with ground lift switches. In only a few cases can it be shown that a ground lift switch improves ground related noise. (Has a ground lift switch ever really worked for you?) In reality, the presence of a ground lift switch greatly reduces a unit's ability to be "properly" grounded and therefore immune to ground loop hums and buzzes. Ground lifts are simply another Band-Aid® to try in case of grounding problems. It is true that an entire system of properly grounded equipment, without ground lift switches, is guaranteed (yes guaranteed) to be hum free. The problem is most equipment is not (both internally and externally, AC system wise) grounded properly. Most units with ground lifts are shipped so the unit is "grounded" - meaning the chassis is connected to audio signal ground. (This should be the best and is the "safest" position for a ground lift switch.) If after hooking up your system it exhibits excessive hum or buzzing, there is an incompatibility somewhere in the system's grounding configuration. In addition to these special cable assemblies that may help, here are some more things to try: 1. Try combinations of lifting grounds on units supplied with lift switches (or links). It is wise to do this with the power off! 2. If you have an entirely balanced system, verify all chassis are tied to a good earth ground, for safety's sake and hum protection. Completely unbalanced systems never earth ground anything (except cable TV, often a ground loop source). If you have a mixed balanced and unbalanced system, do yourself a favor and use isolation transformers or, if you can't do that, try the special cable assemblies described here and expect it to take many hours to get things quiet. May the Force be with you. 3. Balanced units with outboard power supplies (wall warts or "bumps" in the line cord) do not ground the chassis through the line cord. Make sure such units are solidly grounded by tying the chassis to an earth ground using a star washer for a reliable contact. (Rane always provides this chassis point as an external screw with a toothed washer.) Any device with a 3-prong AC plug, such as an amplifier, may serve as an earth ground point. Rack rails may or may not serve this purpose depending on screw locations and paint jobs. 19

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
19
See Figure 4 for suggested cable assemblies for your particular intercon-
nection needs. Find the appropriate output configuration (down the left side)
and then match this with the correct input configuration (across the top of the
page.) °en refer to the following pages for a recommended wiring diagram.
Ground Lifts
Many units come equipped with ground lift switches. In only a few cases can
it be shown that a ground lift switch improves ground related noise. (Has a
ground lift switch ever
really
worked for you?) In reality, the presence of a
ground lift switch greatly reduces a unit’s ability to be “properly” grounded
and therefore immune to ground loop hums and buzzes. Ground lifts are sim-
ply another Band-Aid
®
to try in case of grounding problems. It is true that an
entire system of properly grounded equipment, without ground lift switches,
is guaranteed (yes
guaranteed
) to be hum free. °e problem is most equipment
is
not
(both internally and externally, AC system wise) grounded properly.
Most units with ground lifts are shipped so the unit is “grounded” —
meaning the chassis is connected to audio signal ground. (°is should be the
best and is the “safest” position for a ground lift switch.) If after hooking up
your system it exhibits excessive hum or buzzing, there is an incompatibility
somewhere in the system’s grounding configuration. In addition to these spe-
cial cable assemblies that may help, here are some more things to try:
1. Try combinations of lifting grounds on units supplied with lift switches (or
links). It is wise to do this with the power off!
2. If you have an entirely balanced system, verify all chassis are tied to a good
earth ground, for safety’s sake and hum protection. Completely unbalanced
systems never earth ground anything (except cable TV, often a ground loop
source). If you have a mixed balanced and unbalanced system, do yourself
a favor and use isolation transformers or, if you can’t do that, try the special
cable assemblies described here and expect it to take many hours to get
things quiet. May the Force be with you.
3. Balanced units with outboard power supplies (wall warts or “bumps” in the
line cord) do
not
ground the chassis through the line cord. Make sure such
units are solidly grounded by tying the chassis to an earth ground using a
star washer for a reliable contact. (Rane always provides this chassis point
as an external screw with a toothed washer.) Any device with a 3-prong AC
plug, such as an amplifier, may serve as an earth ground point. Rack rails
may or may not serve this purpose depending on screw locations and paint
jobs.