Hi,
I've read about active crossovers and their advantages compared to passive speaker-level filters. I already designed such a passive filter, now I'd like to try an active one. I got the following (probably simple) questions:
1) Do I need a preamplifier if I want to use active x-overs?
2) In speaker-line passive circuits, the positive (+) lead is the one from the amplifier's positive (+) output to the loudspeaker's positive (+) input. What the are positive (+) and negative (-) leads in line-level circuits?
In other words, I don't know to what the positive and negative leads in line-level circuits should be connected.
The x-over's output should be connected to the amplifier's input, right? I guess these inputs are RCA connections, just like the x-over's input connections... Where are the positive and negative 'connections'?
Thanks in advance
regards
Erwin
I've read about active crossovers and their advantages compared to passive speaker-level filters. I already designed such a passive filter, now I'd like to try an active one. I got the following (probably simple) questions:
1) Do I need a preamplifier if I want to use active x-overs?
2) In speaker-line passive circuits, the positive (+) lead is the one from the amplifier's positive (+) output to the loudspeaker's positive (+) input. What the are positive (+) and negative (-) leads in line-level circuits?
In other words, I don't know to what the positive and negative leads in line-level circuits should be connected.
The x-over's output should be connected to the amplifier's input, right? I guess these inputs are RCA connections, just like the x-over's input connections... Where are the positive and negative 'connections'?
Thanks in advance
regards
Erwin
I just designed an active crossover that also functions as a pre-amp (I added a volume control to the circuit). I just put a pot between the input stage and the low/high pass stages.
An RCA includes both the + and - wires. The center connector is the signal and the shield that surrounds it is ground.
Good info on active crossovers can be found here:
http://sound.westhost.com/index2.html
An RCA includes both the + and - wires. The center connector is the signal and the shield that surrounds it is ground.
Good info on active crossovers can be found here:
http://sound.westhost.com/index2.html
I think I can help with this one.
1. You will need a way to insert the crossover between the pre-amp circuit and the amp circuit. If you have an integrated amp or receiver it may be possible to use a tape loop to accomplish this. But, yes, the output of the preamp is the input to the crossover and the output of the crossover is routed to the input of the amp.
2. Typically, the negative is attached to the ground on the crossover. The positive is attached to the output of the opamp (or whatever). Doing the opposite reverses the phase. Same on the input of the crossover - positive to the opamp input (or whatever comes before the opamp input) and negative to ground.
You can certainly use RCA plugs. That's what is typically done, unless the design is balanced in which case XLR plugs are used.
Did I answer your questions?
1. You will need a way to insert the crossover between the pre-amp circuit and the amp circuit. If you have an integrated amp or receiver it may be possible to use a tape loop to accomplish this. But, yes, the output of the preamp is the input to the crossover and the output of the crossover is routed to the input of the amp.
2. Typically, the negative is attached to the ground on the crossover. The positive is attached to the output of the opamp (or whatever). Doing the opposite reverses the phase. Same on the input of the crossover - positive to the opamp input (or whatever comes before the opamp input) and negative to ground.
You can certainly use RCA plugs. That's what is typically done, unless the design is balanced in which case XLR plugs are used.
Did I answer your questions?
Hi,
rather than thinking of + & - how does talking about output and return sound?. Does that seem any clearer to you?
rather than thinking of + & - how does talking about output and return sound?. Does that seem any clearer to you?
preiter said:
That's interesting. When I saw the ground-symbol in an active crossover scheme I didn't know to what it should be connected, but it appears to be the negative wire from the RCA, right?
Paul Ebert said:
1. So I have to use a preamp if I want to use active x-overs? Can't it be connected between the output from a cd-player and the input from the amplifier?
2. As I mentioned above, I just didn't know how to connect the 'negative' wires in the circuit.
AndrewT said:
I do understand that, but I didn't know that RCA has 'positive' as well as 'negative' wire to which the circuit elements can be connected.
Hope I understand everything correctly 🙂
thank you for your answers!
Erwin
Hi,
You do not necessarily need a pre amp for crossover.Preamps are used to amplify source signal .For example , if your CD player puts 0,5V maximum at its output , and amplifier needs 1V at input to play at full volume , you need a preamp.
But if your amp plays at full volume now with the CD player , you don't need a preamp.
The negative plug in RCA is usually connected to ground.
regards,
Lukas.
You do not necessarily need a pre amp for crossover.Preamps are used to amplify source signal .For example , if your CD player puts 0,5V maximum at its output , and amplifier needs 1V at input to play at full volume , you need a preamp.
But if your amp plays at full volume now with the CD player , you don't need a preamp.
The negative plug in RCA is usually connected to ground.
regards,
Lukas.
Hi,
because we are dealing with AC signals then to be technically accurate there is never exclusively a positive connection and a negative connection.
An AC signal with a DC bias superimposed on it would have a +ve and complementary -ve, but this should only happen "inside" the equipment, not at the interface.
Some, talk of hot and cold indicating flow and return respectively, but this may be more confusing for a beginner struggling to understand the topic, since H & C are often reserved for a balanced connection with a separate ground (TRS and XLR).
Output and return are probably the most descriptive that also avoid confusion.
Any other descriptions?
because we are dealing with AC signals then to be technically accurate there is never exclusively a positive connection and a negative connection.
An AC signal with a DC bias superimposed on it would have a +ve and complementary -ve, but this should only happen "inside" the equipment, not at the interface.
Some, talk of hot and cold indicating flow and return respectively, but this may be more confusing for a beginner struggling to understand the topic, since H & C are often reserved for a balanced connection with a separate ground (TRS and XLR).
Output and return are probably the most descriptive that also avoid confusion.
Any other descriptions?
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