line level DI

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line level DI

Postby chrisp » Wed Sep 28, 2016 12:13 pm

As I understand it, a typical DI does three things -

(a) it converts impedance from high to low
(b) it isolates to remove hum issues
(c) it drops the guitar / pedal signal to make it suitable for a mic level input to handle

I'm looking for something to do (a) and (b) but not (c) - in fact I want the signal to be line level so it can straight to my AD converter. Is the answer here as simple as a 1:2 or 1:4 transformer, or will I need to load either side in series or parallel to get the impedance where it needs to be?
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Re: line level DI

Postby rob » Thu Sep 29, 2016 6:41 pm

you can't achieve a and b while maintaining ( or increasing ) level

there is no free lunch

( besides the one's Rick, Gareth and Chris have bought me )
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Re: line level DI

Postby Linear » Fri Sep 30, 2016 4:55 pm

ha!

some DI's (like the tech21 sansamp) has a switchable XLR output which will do either mic or line level.

so this does all 3 but it is active... handiest thing on bass i reckon!

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Re: line level DI

Postby Paul Maybury » Fri Sep 30, 2016 5:03 pm

Whatever you use, it will have to be active to achieve what you want.
I use GT Bricks. The Sansamps are great too. Any mic amp with a di will do it though.
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Re: line level DI

Postby chrisp » Sat Oct 01, 2016 9:30 am

Cheers guys - I was wondering whether it was possible to avoid the whole 'drop it to mic level and then amp it all the back', but as Rob says there ain't no free lunch. I might knock together a JLM DI and simple BA kit sort of thing then.
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Re: line level DI

Postby zenelectro » Sat Oct 01, 2016 2:08 pm

chrisp wrote:As I understand it, a typical DI does three things -

(a) it converts impedance from high to low
(b) it isolates to remove hum issues
(c) it drops the guitar / pedal signal to make it suitable for a mic level input to handle

I'm looking for something to do (a) and (b) but not (c) - in fact I want the signal to be line level so it can straight to my AD converter. Is the answer here as simple as a 1:2 or 1:4 transformer, or will I need to load either side in series or parallel to get the impedance where it needs to be?


What AD converter are you using?
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Re: line level DI

Postby chrisp » Sat Oct 01, 2016 4:19 pm

Apogee Ensemble FW - it has two hi-Z inputs but they parallel mic inputs that I was hoping to use, well, for mics! I was hoping to plug a sort-of DI into one the four line input channels (5-8).
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Re: line level DI

Postby zenelectro » Sat Oct 01, 2016 5:24 pm

chrisp wrote:Apogee Ensemble FW - it has two hi-Z inputs but they parallel mic inputs that I was hoping to use, well, for mics! I was hoping to plug a sort-of DI into one the four line input channels (5-8).


The Ensemble specs say 2 x 2M ohm Hi Z inputs for inst - this is where gita should go - obviously but the rest are
Mic/Line (usually chip amps) that can cater for anything that will drive the 3k input Z.

All you need is a battery powered buffer box, it should drive the 3k no probs. There are plenty available.
You shouldn't have earth loop probs if gtr effects are battery or isolated PS run.

cheers
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Re: line level DI

Postby zenelectro » Sat Oct 01, 2016 5:27 pm

chrisp wrote:Apogee Ensemble FW - it has two hi-Z inputs but they parallel mic inputs that I was hoping to use, well, for mics! I was hoping to plug a sort-of DI into one the four line input channels (5-8).


The Ensemble specs say 2 x 2M ohm Hi Z inputs for inst - this is where gita should go - obviously but the rest are
Mic/Line (usually chip amps) that can cater for anything that will drive the 3k input Z.

All you need is a battery powered buffer box, it should drive the 3k no probs. There are plenty available.
You shouldn't have earth loop probs if gtr effects are battery or isolated PS run.

cheers
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Re: line level DI

Postby chrisp » Sat Oct 01, 2016 11:24 pm

Simple solution Terry, thanks - might give that a go first
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