Hello all.

I'm not a sound wizard by any means although I've been into this for a while, but I guess I never cared much for the theory.

Since I recently got a mixer (ZED10FX) to connect my mics and guitar, and now I;m thinking of connecting (just for kicks) the iPod/iPad, I started getting lost in the terminology and have spent countless hours trying to figure out things...

Well, now I understand that TSR = Stereo and TS = Mono (well not in the meaning of the acronym but put in practical words), so for instance a guitar cable is always TS (but I guess one could use TSR for impractical reasons).

Also I understand that Stereo from a 3.5mm jack is unbalanced vs Stereo from some other source that can be balanced.
So TSR and TS have nothing to do with being balanced or not.

I get that if I have an unbalanced signal and need to connect to a balanced input, I would require a DI box in the middle, or something like that in order to balance the unbalanced.

I don't get if the level of the signal (low as in mic, line as in iPod, high as in guitar) has anything to do with the balance.

So as you can see so far I think I might be mixing some terminology.

But mostly, it baffles me that my mixer says it has 4 mono channels (3,4 have Hi-Z input), but then in the manual it states those mono channels (each has a 1/4" input and XLR input, you take one over the other) have a TSR wiring? So it is weird, if they are mono how come they have TSR? Aren't they supposed to be TS? (The mixer also has a couple stereo channels but they have the usual RCA dual input and a 1/4 TSR).

Thanks for your time
Last edited by kpsychedelic on Tue May 08, 2012 9:09 am; edited 1 time in total

I would suggest reading this:

http://en.wikipedia.org/wiki/TRS_connector


(Note the table under 'Tip-ring-sleeve terminology' which demonstrates that the same TSR cable could be used as a send/return cable, a stereo cable, or a balanced mono cable. Thats because its not about the cable, its about the circuitry the cables connect.)

and this
http://en.wikipedia.org/wiki/Balanced_audio

and for Hi-Z, maybe this:

http://www.recordingreview.com/articles/blogs/86/The-Differe nce-Between-Line-Level-and-Hi-Z.html

(Hi-Z basically means high impedance. if your source has a high impedance you want a high-Z input or you lose part of bandwidth of the source)

balanced vs. unbalanced is a method of noise rejection.

basically you have two lines with copies of the signal on each, only the copies are inverted.

if you subtract these from each other and divide by two, you get the original signal. ( 1 - (-1) = 2 )

only the line probably has some noise added to it, which you've just subtracted from itself giving zero, meaning you have the signal and no noise. (ideally.)

low "Z" which means impedance or resistance vs. high "Z" means just that you're either using a lot of power (current, or "I") or barely any.

if you have a lot of current flowing it means you're less likely to pick up induced current from stuff like radio waves or other sources of noise from EMI types of sources. "electro-magnetically induced". (or from strings vibrating in front of magnets.)

if you have barely any it means you're less likely to be draining away all the power supplied from your guitar pickups for example.

that's about it. everything else is just an issue of how we connect A to B.

There's a couple of things you need to seperate in order to understand it all.

1) The physical plug. There are many types around, there are some conventions but there's no real correlation between the plug type and the signal type travelling through it. For instance, a 1/4" TRS plug (not TSR, it's the acronym for Tip-Ring-Sleeve) could be used for a stereo headphone but also for eg. guitars. These are at the extremes of impedance. Another example: XLR plugs can be used for both line level signals and microphones. Bottom line: a plug is just a connector; it needs to make contact in a convenient way. Chances are the TRS and XLR inputs on your mixer are hard-wired together.

2) The signal level and impedance. These two metrics together define the strength and the type of amplification needed to convert it to "standard" line level. Some examples:
* Line level signals have medium level and medium impedance.
* Headphones have a medium level and low impedance. The voltage is comparable with that of regular "line level" but the lower impedance gives it more power. It's usually alright to connect a headphone output of an MP3 player, iPa/od etc to a regular line input on a mixer or amp.
* Speakers have a high level and even lower impedance than headphones, producing far more power.
* Microphones have a low level and medium impedance. They need lots of gain.
* Guitars have a medium level but very high impedance. Not much gain needed, but the power is quite low, requiring a special treatment.

3) Balanced vs Unbalanced. The standard is unbalanced. It's usually fine. Unless circumstances require it to be balanced: using microphones and having extremely long cable runs. Balanced cables have two conductors in the center with a shielded ground around. Interference will be picked up equally by both, and thus cancels itself out.
Since interference is at a very low level, it gets very noticable with microphones. But guitars output a higher voltage, so the signal is less prone to interference, so a balanced connection is not needed.
Most mixers will have no problems when connecting something unbalanced to its balanced input. It's like a backwards compatible protocol.
Since a balanced connection requires a total of 3 conductors (positive, negative and ground) only TRS and XLR plugs are used for it. Never RCA, that's always unbalanced.

To answer some of your concrete questions:
Just use the "line" inputs of your mixer. It's fine and safe...
Not quite. TS has only two conductors, so only one (mono) signal can go through. TRS has three, and it can be used as unbalanced stereo or balanced mono.
Ideally yes. But in practice you can do without since most balanced inputs do also accept unbalanced gear.
That is for balanced connections.

Thanks so much guys, I think for some reason now I see the light!


You're right that the XLR and TRS on each channel are "hard-wired".
But so, it would be the same to use XLS ot TRS? Or am I better off just using the TRS?


The stereo channels on the mixer have RCA ins, so that means they are unbalanced right?


Ok but so in the end, I think it goes like this:
I have an unbalanced out from the iPad, which would, via a 3.5mm to TRS 1/4" adapter, get into the mixer and become balanced "inside".
But then, I don't know if using the mono channel of the mixer (in which case I guess I'd get a straight or single 3.5mm to 1/4" cable that would go into the mono line-in) and if the signal would get mixed up? (Like stereo to mono???) or better using a 3.55m to a split TRS dual L-R 1/4" cable that I could connect to the line-ins of one of the stereo channels?

It would be best to use a stereo cable to connect the iPad to a stereo channel.

So you mean something like this?

But what if I was to connect it to a mono channel (I only have one stereo so..., and I'd like to connect an iPod as well at the same time).

And now that I remember I think monoprice helped confuse me more as they always state TRS cable (Stereo) or TS Cable (Mono), which according to this thread is invalid.

But another question pops out.
Guitar cables are always TS (or usually) and they go into a Hi-Z balanced input, what happens if I were to use a TRS?
Moreover, if the mixer has a balanced line-in, which is, nicely asking for a TRS jack, what If I used a cable like in the picture above to connect the iPad (I know the stereo out of the iPad is unbalanced so it would "match" just like the guitar does with the common 1/4" TS cable), would that be ok?

Oh I think i got lost again

Edit:

I think I kinda have the answer for the guitar part, probably from this:



Which would mean the best way to connect the guitar to the Hi-Z line-in (mono) would be using TRS NOT TS, right?

Yes ... that's exactly what I mean.
Wrong.

Why? Because it's unbalanced signal so it's better of traveling on a TS?

What if we're talking about the line out of the iPad to the Mono of the Mixer, would it better receive TS as well?

I get confussed because all line inputs on the mixer are TRS...

you need to ground one side of the balanced input or you'll get half level or worse, if you try to pass a stereo signal in there you'll get (left - right) / 2.

therefore, use a normal phone jack.

The iPad has a stereo output ... it should be connected to a stereo input on the mixer. The ZED 10 has a stereo input on phono connections (ST-1b). I'd use that to connect the iPad.

Are you replying to my question on connecting stereo to mono?
If so what is a normal phone jack, you mean 3.4mm to 1/4" TRS?


But then should I use 3.5mm to 1/4" TRS or TS (the manual says the channel is TRS).

Sorry for being such a n00b, but all of this keeps getting more and more confusing (specially the part where ALL inputs on the mixer are labeled TRS but then for instance apparently I should NOT use TRS cable but TS for Hi-Z from the guitar).

You need a 3.5mm TRS mini-jack to stereo RCA. Like this ...
http://www.thomann.de/gb/the_sssnake_yrk2030.htm

If they are hard-wired indeed, then the only fair argument to chose one over the other is which one fits to what you throw at it with the least use of adapters.

Having read the owner's guide of your A&H ZED-10 (have you??), the XLR and TRS jacks on mono inputs are not directly hard-wired. They have a cirquit inbetween with different gains: XLR is for mics and TRS for line level. The mono channel line input jack sockets take balanced or unbalanced, as expected. All the stereo inputs are unbalanced.
Yes, RCA is unbalanced by definition. I already wrote that, didn't I?
No, not really. If you connect the 3.5mm to a 1/4" TRS adapter, then on the TRS plug you have the left channel on the tip and right channel on the ring, with the sleeve being common ground. That's stereo on a single plug, same wiring as headphones use. That is a different wiring than balanced (mono) on TRS, which has tip being positive, ring is negative and sleeve for ground.

The simplest solution in this case is to use a bog-standard 3.5mm --> RCA cable, plug that into a stereo channel of the mixer, which by chance also has RCA inputs. You could also fit 1/4" TS adapters on the RCA plugs and plug those on a pair of TRS inputs. The signal is then still unbalanced, but the mixer is so kind to forgive you that. The buffering opamp inside will take care of that. You might need an extra bit of gain, but if it works then who cares.
Downside of using two mono channels instead of a single stereo channel, is that you have to remember setting each of their pannings to extreme left & right, and you need to move two faders. It can be done, but the stereo channel is made for this and much more convenient.
Then you get only the left or right channel. You can hear it, but in mono only.
No, the A&H ZED-10 has two stereo channels called "ST1" and "ST2", and also an extra "Playback" stereo input. But it's only the ST1 that features RCA connectors. You could use the 1/4" inputs by fitting some simple RCA-TS adapters.
Not quite... TRS has three conductors and can be used for unbalanced stereo or balanced mono. TS has just two conductors, suitable for unbalanced mono only.
That depends on how you wire it If the ring is wired to the sleeve, it's exactly the same as a TS plug. If the ring is wired to the tip or left unconnected, it probably depends on the mixer what happens.
Read page 15 & 18 of your owner's manual again:

kpsychedelic - you have to stop thinking that TS/TRS has anything to do with the signal. All it is, is how many wires there are in the cable (if fully wired).

TS = 2 wires (1 to tip and 1 to sleeve)
TRS = 3 wires (1 to tip, 1 to Ring and 1 to sleeve)
XLR = 3 wires
RCA (also known as Phono) has 2 wires.

The signal then requires a certain number of wires:

Unbalanced Mono needs 2 wires (signal and ground) so can use either RCA,TS, TRS or XLR (just because it has 3 wires in the cable, it deosn't have to use them all, TRS wires work fine even in just TS sockets - it wll just see the Ring and Sleeve as one wire)

Balanced Mono needs 3 wires (signal, inverted signal and ground) so can use TRS or XLR

Stereo needs 3 wires (left signal, right signal and ground) so can use TRS or XLR (or of course you can use 2 TS/RCA cables)


What this wire does is take the left audio signal and send it to the white RCA audio signal connector, the right audio signal to the red audio signal connector and then splits the ground wire in 2 and sends it to the both the ground wire on the red and white RCA connectors.