Many anolog outputs, into one input on a AMP - without switching sources

[whitebaity]

Hi all.

Love the forum, thanks for time to look here.
I've sold Audio for 10 years in NZ, started in car audio and ended home audio. Im am a massive audiophile, i cant do cheap audio, it makes me want to hurt myself. ;-)

But Ive just built a new house and I want to cheat a little... the best way I can, knowing a few will roll eyes here... But please, this is why im here, sorting the best way to do this!

_I dont want to change source of my audio gear - and nor do my family, as im complex!
So wither im using Optical, USB DAC, Chrome Cast Audio, 3.5mm Audio out from differant gaming/media computers - I want all these feeds going into one input of my amps.

Crazy I know. Ive used RCA 2 into 1 plugs, Aliexpress non active mixer that is working...
Cross talk heaven etc etc i know! ...TBH, it doesnt sound as bad as I expected. Volume is lower. I only have one source playing at one time.

May I ask my question - What is the best way to achieve many anolog outputs - to go into one input of the amps?

I currently use this, but it kills me knowing its not the best so here I am asking the question! x

https://www.aliexpress.com/item/1005001966534915.html?spm=a2g0s.9042311.0.0.b4e84c4dIVZ2I1
"AIYIMA Stereo Audio Mixer Distributor Multi-Channel Source Reverberator Free Switch for Headphones 3.5mm+RCA (5 Input 1 Output)"

Thank you, lay it on me!

 

[DonH56]

Optical is digital so it would have to go into some sort of DAC device first to produce an analog output.

Not only are you mixing all the outputs together, you are shorting the outputs of different sources, which may damage some of the components over time. Even if a component is off, its output state is probably undefined, so may load the other sources and/or be damaged by them.

You should just get a RCA switch and use it. Some inexpensive passive ones: https://www.amazon.com/s?k=rca+switch&ref=nb_sb_noss_1 You can also buy remote-controlled versions. Put labels on the switches for the different sources and teach everyone how to turn a switch or push a button. I have faith they will handle it.

 

[DVDdoug]

Crazy I know. Ive used RCA 2 into 1 plugs, Aliexpress non active mixer that is working...

Bad idea... It's OK to connect two (or more) inputs together, such as driving two amplifiers from one source, but you should NEVER short outputs together!

A line output is designed to drive a 10K-100K line-input. (A headphone output is also "compatible" and it's capable of driving much-lower impedance loads. The headphone output on a computer doubles as a line-output.)

But it has a much lower source impedance. Usually less than 1K and possibly less than 100 Ohms. i.e. You do NOT want "impedance matching". We want a low impedance driving a higher impedance. With power amplifiers the ratio between speaker impedance and output impedance is called "damping factor" and it's often around 100. (And I'm sure you'd never connect the outputs from two power amps together...)

When you connect outputs together you are "loading" the circuit and various bad things can happen. And the more things you connect, the worse it gets... You probably know that connecting two 8-Ohm speakers gives you 4-Ohms and if you connect too many speakers you can fry the amp.

What you need is a mixer even if there is only signal-input at at time. But most mixers only have analog inputs.

You can build a 2-input fixed-passive mixer with a pair of resistors (4 resistors for stereo) but you get a 6dB loss and the loss gets worse as you add more inputs. (If you use all of the inputs, the mixed signal gets-back most of that loss. (The AliExpress mixer is passive... No power supply and no "chips".)

Note that most "pro" mixers have "mono" inputs that can be panned left or right. That means with 8 sources you'd need a 16-channel mixer. Some have one or two stereo inputs and "DJ mixers" usually have stereo inputs plus a mono mic input. Most DJ mixers won't have enough inputs for you. You'll also have to make sure it has line inputs. (Switchable mic/line inputs are common.) Most also have XLR or TRS inputs so you'll need adapter cables.

 

[JSmith]

What is the best way to achieve many analogue outputs - to go into one input of the amps?

Some of the NAD integrated amps have an autosense feature from standby and input signal... might be worth a look at this or a higher powered model;


https://www.listeningpost.co.nz/pro...grated-amplifier-__I.352962__C.27254__N.27756

Otherwise maybe look around and see if there is a pre-amp with a similar function.



JSmith