207d
instruction Manual
Aphex Systems Ltd. Model 207D
Page 26
207d
2-ch tube mic preamp with adc
Page 27
Aphex Systems Ltd. Model 207D
transformerless balanced, usually called “active bal-
anced”. Transformer balanced outputs are becoming
outdated because of their high cost and their sonic
limitations. However, they can still be found on a lot
of older equipment.
Within the transformerless class, there are several
types of circuits that are used by different manufac-
turers. These different types of output circuits all look
just about alike to any balanced line, but they act dif-
ferently when driving an unbalanced line. You need
to observe the proper cable wiring for each type of
output circuit. We strongly recommend that you refer
to your various equipment manuals to find out what
is used in each case before hooking up to unbalanced
lines.
When connecting a balanced output to a balanced
input, however, you don’t need to know what kind
of balanced output you are dealing with. Simply
treat it generically.
Appendices
PART 1: BALANCED OUT to BALANCED IN
OK for Microphones
Standard store-bought cable. Shield grounded at both ends.
Positives: Good for microphones.
Negatives: May cause ground loops through the shield grounds if used
to connect equipment together.
Preferred for Line Levels
Shield grounded at receiving end only.
Positives: Stops ground loops and reduces noise.
Negatives: None
OK
Standard store-bought cable. Shield is grounded at both ends.
Positives: Both ends are interchangeable.
Negatives: May cause ground loops through shield contacts.
BETTER
Custom cable. Shield is grounded at receiving end only.
Positives: Stops ground loops and reduces noise.
Negatives: Should be oriented so lifted shield is at sending end.
1/4” TRS Phone to 1/4” TRS Phone Balanced Cables
XLR to XLR
XLR to 1/4” TRS Phone Balanced Cables
Stereo Phone Plug
Female XLR
Male XLR
From an Output
No Connect
Stops Ground Loops
Stereo Phone Plug
To an Input
To an Input
From an Output
No Connect
No Connect
Stops Ground Loops
R