View Full Version : Line levels.. can someone explain this..
Not quite a production thing, but i've noticed this for a while, and cant readily explain it.
Lets say i'm going to record from my Amps 2nd tape loop (normal hifi amp, marantz), into my PC. See if this makes sense..
Now i only have one PC -> RCA cable, so at the moment it is plugged from the PC line out, into an AUX in on my amp.
Now lets say i'm playing from my minidisc on the amp, which is on the tape loop. When i unplug the PC->RCA cable from the AUX sockets and plug it into the second tape loop's OUT on the amp (with the other end still in the line-out on the pc, i'll move that next!), the music that is coming through the speakers goes really quiet, until i unplug the end from the back of the PC, at which point it goes back to normal volume. And it stays there when i put it in the Line OUT on my PC.
I'm just wondering why, when you have basically a line-out on your pc connected to a line-out on your amp (or mine at least), the leves that you hear through the speakers drop right down, even when you're using a totally different channel on the amp to play music with? like another tape loop or the cd deck or something. (altho only tested on tape loop).
Is this bad for your amp? Is it the same across a lot of amps? I'm sure my old one used to do it too.
This seems a bit hard to follow.. I dont have problems with the levels as such when everythign is wired up fine, just when i'm half way through moving the wires around, and using the amp at the same time, this happens.
supressor
30-01-2003, 05:29 PM
sounds like some kind of grounding type problem..not that that helps..sorry! erm...yeah..next! :confused:
Bumfat
30-01-2003, 07:19 PM
poi..i'm normally good with stuff like this but you have succeeded in confusing me! but......
you cant "have line out on PC connected to line out of the amp"
is this deliberate obfuscation?
Yes, its like when i'm halfway through moving the cables (ie i've moved the amp end, but not the pc) - its connected lineout-lineout.. But at that moment, the sound levels that are coming through my speakers (if for example i'm playing a CD or MD at the time) drop right down!
And then once i move the PC end of the wire.. all is fine!
woody
30-01-2003, 08:29 PM
you lost me about halfway through mate sorry :confused:
Bumfat
30-01-2003, 09:14 PM
poi..well dont!
get another cable!
ad_rewind
30-01-2003, 09:33 PM
I've got a headache after readin that Poi! :spaced:
Connecting 2 line outs (even temporarily) is obviously gonna mess with the sound init? Wouldn't have thought it would be too good for your amp / pc to be connected like that either ...
When messing about with leads in n outa my amp -- I always turn the amp off ... just incase ...
Like bumfat says -- just buy another/more cables; they're not expensive! (ya cheapskate!) :p
I've bought the extra cables today, but there's still problems with me having to swap things over (damn TV tuner card)..
I just wanted to know the logical reasoning behind it.. :p
In a pinch: Why does connecting line-out(amp) to line-out(pc), cause the sound levels on the amp to drop right down?
Bumfat
30-01-2003, 10:12 PM
answer..we dont know but you shouldnt be doing it anyway!
why dont you plug 'line in to line in' then wonder why you dont get any sound?
:agree:
supressor
31-01-2003, 09:38 AM
cos it should be line in to line out..any other way would cause....trouble.... :conf:
surpressor; yes i know that!
Never mind eh.. I'm just a geek at nature and want to explain the phenomenon that i see before me. I have heard about "balanced" outputs (or something like that), and my guess is its something to do with some kind of protection circuit to stop you blowing things up. Either that or its just a battle of power between amp and soundcard. Any road, i'll leave it all alone now.
supressor
31-01-2003, 12:30 PM
sorry mate..wasnt being patronising! butr ive had similar things happen with various amps and its usually from outputs fighting each other in some weird way that nobody can explain :holmes:
woody
31-01-2003, 01:20 PM
you say the sound levels on your amp drops right down?
where are your speakers connected to?
what is your amp switched to? aux yeah?
well if you are trying to listen to the aux channel (pc line out)through your amp line in then that wont work, if you are running the line out of your pc into the line out of your amp then you are not really running any input into your amp are ya?
the amp's line out will probably work as a very shit line in aswell purely because it will be A connection, not the right one but it is still a connection so it will still work...yeah?
im even more confused now
nope you've not understood me at all here woody, i've given up trying to explain now tho!
woody
31-01-2003, 01:32 PM
right, ive just re-read that first post:
you have your minidisc into your amps tape loop right?
the "music" is coming out of the minidisc, into the tape loops IN and out of the amp to the speakers
a tape loop is exactly that, a loop.
that means you can run something into it and something out of it at the same time.
so you can have music coming into the tape loop's IN and out through the speakers, and ALSO out via the tape loop's OUT to another destination like a PC where you can record it.
you with me so far peeps?
so while you are listening to the music connected to the tape loop's IN, there is a free output (the tape loop OUT) which you could be using to send the same data somewhere else...
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basically, it is going into the PC and then back out of the same connection it is going to and back into the tape loop and out through the speakers, so you are sharing the connection, which means you get less volume (and probably shit quality aswell yeah?).
does tha make any sense? i'm going mad here :D
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