N
Neil Bernard
- Jan 1, 1970
- 0
Hi I want a balanced output using two opamps (for audio) using a single rail
power supply +9v any ideas?
power supply +9v any ideas?
Neil said:Hi I want a balanced output using two opamps (for audio) using a single rail
power supply +9v any ideas?
Hi I want a balanced output using two opamps (for audio) using a single rail
power supply +9v any ideas?
Hi I want a balanced output using two opamps (for audio) using a single rail
power supply +9v any ideas?
John said:Use two resistors (or a pair of 5.1 volt zeners) in series across the
9 volts with a pair of .1 uf caps paralleling each of those parts to
produce an elevated zero signal reference.
Luhan said:John,
That pair of zeners in series is a "no-no" (at least with out some
resistor in there somewhere).
John said:A pair of 5.1 volt zeners across a 9 volt battery conducts almost no
current, while limiting the reference voltage to within a volt of the
center of the battery rails. 4.7 volt zeners would hold the reference
even closer to the center but would leak a bit more, especially if
they were both at the low voltage side of their tolerance.
Luhan said:Yo,
'limiting the reference voltage' is insufficient. All of the stages
using this for center line voltage would have an extra 'signal' injected
into them. It would be better to use just one zener with an appropriate
resistor on the other leg.
John Popelish said:Not better from a battery life viewpoint. The capacitors connected
across the zeners keep the voltage swing at the reference from
happening fast enough to effect the amplified signals much.
I suggest you try it... both ways. The two zener approach also makes
lots less high frequency noise, which does get through the opamps.
Costas said:But what if the supply rises to 10+ Volts? Often people use cheap
unregulated wall supplies as battery substitutes, and these can supply a few
volts above the rated voltage. The Zeners will then conduct hard and the
result won't be pretty...