Just some questions (1 Viewer)

[Will Pomeroy]

I just have a few questions that I’d like to ask:

1) What would happen if I were to put an already high power signal (from a receiver into another amp? would it just destroy everything?

2) What’s the difference between a passive x-over and an active one?

3) What’s does discrete mean, when used in the context of "Discrete signals" or "Discrete amp"

Thanks very much, any answer would be greatly appreciated

 

[Jim Mc]

Do not feed the output of one amp into the input of another.

Discrete means "seperate or individual".

 

[Bill Catherall]

I'll answer #1. I don't know #2. Jim got #3 correct.

What would happen if I were to put an already high power signal (from a receiver into another amp? would it just destroy everything?

It depends what you're doing. There are some amps in powered subwoofers that do infact have what are called "speaker level" inputs. Usually these are used when you want to use the subwoofer's internal crossover. Instead of using the subwoofer pre-amp output in the receiver (or if your receiver doesn't have one) then you take the right and left speaker outputs from the receiver and plug them into the right and left speaker level inputs on the sub. Then you run speaker wire from the left and right speaker outputs to the left and right speakers. If an amp has speaker level inputs then you can run a high power signal to them and no harm will come of it. If however you run a high power signal to "line level" inputs (or pre-amp inputs) then yes you will kill the amp.

 

[Bill Catherall]

Ok...I found the answer to #2

• Active crossovers:
• Active crossovers are placed before the power amplifier in any system (including stereos.)
• Active crossovers have an active element in them (usually an op-amp.) This is to provide buffering. In effect buffering keeps one stage of a system from interacting with the one before it. Imagine if changing speakers made your CD player perform differently. That would be a nightmare. Buffering eliminates this. Active crossovers are buffered.
• Active crossovers need a power supply for the op-amps (or their replacement.)
• Active crossovers deal with much lower power circuits than passive ones. This is because the signal has not been amplified to the speakers level yet.
• This is a biggie. Active crossovers need a separate power amp for every output from the crossover. If you have a two way crossover, you need two amplifier channels per speaker.
• Active crossovers are more efficient with amplifier power than passive because they can not dissipate amplifier power.
• Active crossovers can use many amplifiers of lower power to form the equivalent of a single, more powerful amplifier.
  Passive crossovers:
• A passive crossover is placed between the power amplifier and the speaker.
• The passive crossover interacts with the impedance of the speaker.
• A typical passive crossover will have less parts because it has no power supplies or buffer stages.
• Passive crossovers deal with much higher voltage and current signals than active crossovers.
• Parts cost more for passive crossovers because they must deal with more power (but there are less parts.)
• Passive crossovers conveniently can be hidden inside speaker boxes because they come after the amplifier stages.
• Passive crossovers usually contain at least one resistor, which consumes power that will not find its way to the speaker, making the speaker / crossover less efficient.
• The whole speaker can run off of one amplifier channel, no matter how many ways the crossover splits up. This may result in a very significant cost savings.