How to correctly utilise a 4 channel amp for non standard set up.

[Trdat]

I have a 4 channel cheap Chinese power amp which I have talked about in a previous post regarding the fan noise. Now, I am aware that it is essentially a stereo amp with 2 channels each side but I am confused then why I have 4 inputs? Wouldn't 2 inputs suffice ..?

What I would like to know, is if I can have 2 different sources into the inputs(say two different DAC's) with two different sets of speakers. One set to the one source. Of course I will have the one source turned off with the speaker cable pulled out of the speaker I am not listening to. And even more carefull that the right speaker is connected to the correct input/source. Would that work?

Or better still do I need a seperate source for the second pair of speakers? This is connected to my first question because if I use one source and have two pairs of speakers connected to the amp meaning that I have a xlr cable into input 1 and input 3 and use the speaker set for output 2 and output 4 what happens then? Essentially input 1 and 3 would be empty. I would like to use it like for ease but I am presuming that this is not right. Even a si mple explanation would help me uderstand why this would not be correct.

I am sure its simple enough but there is no way to know this unless told.

 

[somebodyelse]

It's more like having 2 stereo amps in one box, with a shared power switch. Much like a stereo amp is like 2 mono amps in one box with a shared power switch. Input 1 drives output 1, input 2 drives output 2 and so on - they're all separate. For ease of use you probably need an appropriate preamp or switch box to sit between your source(s) and the amp inputs. What exactly are you trying to achieve? It may be something you can do with an off the shelf box or two, or you might need to make something.

 

[Trdat]

It's more like having 2 stereo amps in one box, with a shared power switch. Much like a stereo amp is like 2 mono amps in one box with a shared power switch. Input 1 drives output 1, input 2 drives output 2 and so on - they're all separate. For ease of use you probably need an appropriate preamp or switch box to sit between your source(s) and the amp inputs. What exactly are you trying to achieve? It may be something you can do with an off the shelf box or two, or you might need to make something.

TO be honest I do have a switch box which will allow me to switch between two preamps. The one source will still play through the 4 channels. I have tried this and it does, connecting to input 1 and input 4 will still play out of output 2 and 3. I am happy to disconnect. This is something I will try right now, but that means I will need two preamps, which defeats the purpose.

What I am trying to achieve is using one preamp connected to one set of speakers which is for my home theatre use and another set of speakers for music listening. This way I dont need two preamps. I am happy to disconnect the speakers that I am not listening to. But that would leave one set of speakers on the output of 2 and 4 when the input might(when I physically disconnect the speaker connection) be in input 1 and 3. Would that work then?

 

[Trdat]

Actually even if I used a switcher I would still have the same problem as once switched to the second pre amp the input would not match the output number of the speakers.(Input 1 and 3 would be the preamp in while the output will be output 2 and 4) Hence why I toggled with the option of actually having two different prea amps into the inputs and just switching between two pre amps. But that leaves me with the problem that all 4 speakers will play. I can disconnect the speakers I am not listening to. I just would like to know if this can cause any problems doing it this way?

 

[somebodyelse]

TO be honest I do have a switch box which will allow me to switch between two preamps. The one source will still play through the 4 channels. I have tried this and it does, connecting to input 1 and input 4 will still play out of output 2 and 3. I am happy to disconnect. This is something I will try right now, but that means I will need two preamps, which defeats the purpose.

I'm confused - are you saying that the amp channels aren't independent, or does that only happen when you use the switch box? Do you have any documentation for the amp? Until we know how the amp inputs actually work all bets are off!

 

[Trdat]

I'm confused - are you saying that the amp channels aren't independent, or does that only happen when you use the switch box? Do you have any documentation for the amp? Until we know how the amp inputs actually work all bets are off!

I think we are both understanding each other differently in regards to the switch box. Lets keep it simple and forget about the switch box.

4 inputs 4 outputs on a 4 channel power amp, they are meant to be independant from each other but when I connect to the one side of the stereo amp so for instance use input 1 and have a speaker connected to output 1 and 2 on that same stereo side both will play.

Now, if using one input uses 2 channels on the one stereo side why would I need to use both inputs? That is the million dollar question?

No documentation, other than a small leaflet ill check it out and see if it says anything but I doubt it.

 

[somebodyelse]

Some testing required then - it's not behaving as a conventional 4 channel amp would. Including whether it's doing things on the basis of signal, or just there being a connector plugged in.

 

[RayDunzl]

Looking at the pictures:

https://www.sinbosen.com/pid1828921...small-1U-stereo-digital-karaoke-amplifier.htm

It is a 4 channel amplifier.

Or:

It can be bridged and used as a more powerful 2 channel amplifier.

What I would like to know, is if I can have 2 different sources into the inputs(say two different DAC's) with two different sets of speakers.

I'd say "yes".

 

[somebodyelse]

Need to check the state of the 'link' buttons by the inputs.

 

[Trdat]

It can be bridged and used as a more powerful 2 channel amplifier.

Ive been advised not to bridge this model, I do not know why.

I'd say "yes".

The saleperson just got back to me and this was her answer.

"one channel 1/2 speaker is ok , but can not 3 speaker"

So I am guessing that yes it is okay to have only two inputs and 4 speakers or even like how i mentioned having input 1 and 3 used and speakers on output 2 and 4. If I have understood correctly.

 

[Trdat]

Need to check the state of the 'link' buttons by the inputs.

Need to check the state of the 'link' buttons by the inputs.

Can you please tell me what the link button does? I absolutely have no idea.

 

[Trdat]

Some testing required then - it's not behaving as a conventional 4 channel amp would. Including whether it's doing things on the basis of signal, or just there being a connector plugged in.

So your saying a conventional 4 channel amp works with the input in with the matching output speaker?

 

[somebodyelse]

Can you please tell me what the link button does? I absolutely have no idea.

It's not clear. The PDF documentation on that page appears to be for a different amp model which has a mono/stereo switch instead. Whether they messed up the link, or just don't have a manual for this model, I don't know. My guess is that when 'off' the input feeds the respective output separately, and when 'on' one input will feed both of those channels. My guesses haven't been very good so far though, so you'll have to test it.

So your saying a conventional 4 channel amp works with the input in with the matching output speaker?

Yes - all channels separate is normal. There may be other modes of operation too, but you'd have some documentation to say how it worked.

 

[Trdat]

It's not clear. The PDF documentation on that page appears to be for a different amp model which has a mono/stereo switch instead. Whether they messed up the link, or just don't have a manual for this model, I don't know. My guess is that when 'off' the input feeds the respective output separately, and when 'on' one input will feed both of those channels. My guesses haven't been very good so far though, so you'll have to test it.

Yes - all channels separate is normal. There may be other modes of operation too, but you'd have some documentation to say how it worked.

Thanks for this. I just tried the link button and it does separate the amps. So I am curious now ifcan I play different source into each input? At least say input 1 and 3 same source and input 2 and 4 a totally different source playing different music? Is this possible...?

Also you mentioned it is essentially 2 stereo amps I'm one box. So if I have link off which input is stereo? Is it still stereo? From left to right? I want to understand if it still plays in stereo mode and which inputs will be stereo say odd number or even? Thanks, even if you give me an idea of what it should be traditionally I'll experiment.

I think the answer to my original question is yes. The amp is working like a traditional amp and with what the sales person said it seems with the link on it allows me to use 2 inputs with 4 speakers or non matching inputs with 2 speakers. Appreciate the help.

 

[Trdat]

Anyone got any input on my last question? Should be standard with 4 channels amps.

 

[somebodyelse]

The amp doesn't know or care what you use the channel for - left, right, front, back etc. are just labels like 1, 2, 3, 4. If I remember correctly you have 2 pairs of speakers, and want to use one pair or the other - something like this

 

[Trdat]

The amp doesn't know or care what you use the channel for - left, right, front, back etc. are just labels like 1, 2, 3, 4. If I remember correctly you have 2 pairs of speakers, and want to use one pair or the other - something like this

Okay so when the link button is off it doesn't play stereo? It must still play stereo right? Because technicall its still 2 stereo amps in one box...

Thanks for diagram.

 

[somebodyelse]

Okay so when the link button is off it doesn't play stereo? It must still play stereo right? Because technicall its still 2 stereo amps in one box...

I don't understand the question. Stereo is two independent channels that we use for left and right. I understood from what you said before that you had tested it and found that with the link button off it had 4 independent channels, so it's up to you how you use those channels. As an example you could play stereo from 2 separate sources to speakers in 2 rooms.

 

[Trdat]

I don't understand the question. Stereo is two independent channels that we use for left and right. I understood from what you said before that you had tested it and found that with the link button off it had 4 independent channels, so it's up to you how you use those channels. As an example you could play stereo from 2 separate sources to speakers in 2 rooms.

I think I was misunderstanding a concept that should have been known to me. The stereo information comes from the preamp. So, yes its up to me how I want to play them. And the other thing I wanted to know is if I could play from 2 different sources and you reckon its possible, which is also great to know. My confusion was based on the sales rep saying that its just a 4 channel amp that plays from one source and can't be played independantly. I will keep experimenting but I think I got it down pat now.