Mono from a stereo amplifier

[SimonTHK]

Hello electro tech online

I have been reading up on this subject, since I want my amplifier to play mono and not stereo. I never need stereo for my purpose.

But I have few problems to figure out how.

So I know that a stereo amplifier has 2 seperate amplifiers inside that play each channel (right and left). Somehow I want these to work together and give me a mono output.
I do know how to put two amplifiers in parallel and the power output can be increased, but in this case they still need to get a mono signal.

What about a bridge where I use both plus ports on both channels? How will this work if I have stereo on my two internally amplifiers? Should they not still be receiving a mono signal or would that work? (I myself doubt).

So my idea is to create a mono signal on my input signals (output from a cd player). I read something about phase reverse and y balanced cable. But I cannot figure out how to phase reverse and how should this y cable be connected?
Can anyone lead me in the direction for my next step? Im getting closer

thank you

Edit: Actually I guess the biggest problem are that everything is recorded in stereo and send out in stereo from any kind of player I might use (mp3, cd, computer). I cannot just build my own amplifier and use that, I still need to somehow make the 2 stereo channels into 1 mono. So how is that?

 

[SimonTHK]

So I found this:
you will need
to provide a mono signal to the amplifier. The common thought is to use
a Y-adapter to "combine" the left and right channels. However, by
using a Y-adapter, you are actually summing the line voltages and
directly shorting the left and right channels at the head unit, which
could cause problems.

The correct way to create a mono signal is to cut off the ends of the
RCA cables, combine the signal grounds (the outer shield), and then use
a 1 kOhm (1/4 watt, 5% tolerance) resistor to each of the center
conductors. Solder and insulate the resistors so that you don't short
them prematurely, and then connect the two resistors together. Connect
the summed signal ground to the shield of the new RCA plug, and the
summed center conductor to the center pin of the RCA plug.

Can anyone confirm this?

 

[Reloadron]

Give this a read as it runs with what you mention. However, 10 K Ohm would seem a better choice. The loss is explained in the link. Short of electronics and using mixer, it will work.

Ron

 

[SimonTHK]

That is just what I need, thank you very much.
I was about to buy a mixer, but this is so simple

 

[KJ6EAD]

If you're using a large connector such as a 1/4" phone plug (trs to some) or an XLR, you can build the summer into the connector.

 

[Diver300]

What about a bridge where I use both plus ports on both channels? How will this work if I have stereo on my two internally amplifiers? Should they not still be receiving a mono signal or would that work? (I myself doubt).

To run a stereo amplifier as a mono signal in bridge mode, you need run both channels from the same signal, but with one of those signals reversed. That is quite involved and needs an suitable signal inverter.

Many large stereo amplifiers have what is needed for bridge mode built in, which makes it easy to use.

 

[unclejed613]

if you're not afraid of making an internal modification to the amp (and know how to find the amp's internal feedback and input circuits), you can try this.... **broken link removed** it changes a stereo amp into a bridged mono amp with a very simple modification.