question about DI

[FALKEN]

I have three different levels I am thinking of and trying to figure out how they interact with the DI. I know this is elementary but I gotta ask. You have mic level, line level, and instrument level. I thought that a DI coverts instrument level to line level and vice-versa. but DI's have XLR out. and they can be passive. so I am thinking they actually covert instrument level to mic level? is this correct? then the signal must be boosted by a mic pre? I have a SansAmp DI and this puts out what I thought was line level. but that has a battery. can somebody please clear this up?? maybe a link to a primer or something would be appropriate...

 

[Kryptik]

Pasive DI's change to mic level I believe. Actives might change to line, but I'm not sure.

 

[guttadaj]

There's no real difference between what active and passive DI's do. The difference is in how they do it - more of an internal, under-the-hood kinda thing. Basically the passives don't need any power because they use transformers to convert the signals, and the actives use active electronics to do it (hence they need power).

Check this out.

HTH
-Jeff

 

[FALKEN]

ok kewl. so a DI changes a high impedance instrument signal into a low impedance mic signal. great. I guess they are not to take a line signal from a mixer aux into an instrument amp...what do you need for that?

 

[DonF]

I guess they are not to take a line signal from a mixer aux into an instrument amp...what do you need for that?

Reamp: http://www.reamp.com/

Never used one, but that's what it's designed for.

Don

 

[fazil]

I guess they are not to take a line signal from a mixer aux into an instrument amp...what do you need for that?

If I'm not mistaking, you can reverse passive DI's. Plug your aux out in your DI's "output" and feed the "input" to the amps input.

I'm not sure this will work, never tried (don't even own a passive DI) but it'd be cool if it works.
Correct me if it's wrong!

I guess you're going to reamp ?


greets, Arno

 

[treymonfauntre]

i'm also under the assumption that a passive di works both ways, as fazil just said.

 

[DonF]

Yes, a passive DI will work in both directions.

 

[FALKEN]

yes, all of the above are correct. except is a line level the same as a mic level?

 

[Kryptik]

No. A line level is generaly hotter than a mic level, I think. Usually it's the preamp that boosts the mic level to a line level.

 

[FALKEN]

No. A line level is generaly hotter than a mic level, I think. Usually it's the preamp that boosts the mic level to a line level.

exactly right. so, how can you send a line out to a box that is made to accept a mic signal (or instrument). ?

then what really gets me is that most mixers accept a mic or line on the same channel....wha???

 

[Kryptik]

For reamping I take it? Radial makes the X-Amp box for about $180. Alot of people just use a passive DI in reverse though.

Mixers have line in because line mixing is part of mixing.
Basically you can put the ouput of an effects unit, harmonizer, etc. into the line in. Stuff like that is actually pretty common. My mixer has no returns so in order to use effects, they need to go into a channel.

 

[FALKEN]

true, i'll just try it then I guess. even though i still feel like i will be overloading the amps input. I guess that depends on the output volume from the aux...yes that must be it.

 

[DonF]

A passive DI drops the signal level regardless of which way the signal is flowing through it. So it may get a line-level signal fairly close to what the instrument amp expects. It's worth a try, anyway.

 

[guttadaj]

then what really gets me is that most mixers accept a mic or line on the same channel....wha???

That's what the Gain is for on those mic/line channels that some mixers have, which use a mixer's onboard preamps. You generally need to crank up the gain some on a mic input plugged into one of those channels whereas you don't so much for a line input.

 

[guttadaj]

Also, check out this thread for some more discussion on re-amping and the use of DI boxes.

 

[FALKEN]

so THAT'S what the pad is for!! WORD.

 

[nkjanssen]

A basic DI changes impedence, not signal level.

 

[DonF]

Sorry, wrong. In a passive DI some insertion loss is inevitable.

 

[nkjanssen]

Sorry, wrong. In a passive DI some insertion loss is inevitable.

The original poster thought that the purpose of a DI was to convert instrument level to line level, and vice versa. It is not. It is to match impedence. If you think some small signal loss, as an artifact of going through the transformer in a passive DI, means that DI's are for converting signal levels, you've got your head up your ass. Sorry.