Di box

[Pbassred]

Is a DI box mearly a transformer? If so what impeadence? Do active DI boxes have any advantage?

[Frank Berry]

A DI box is nothing but an isolation transformer.
Active isn't a good idea. You really need the isolation to avoid ground loops.

[Frank Berry]

They're usually 600:600 ohm transformers for line level sources.
Bridging transformers (10k:10k) will also work.

[Pbassred]

Stupid thing is: I have searched the maplins site and RS components for "matching", "1:1", "600", and "10k" . Nothing

[usekgb]

A DI box converts a high impedence unbalanced instrument signal to a low impedence balanced signal. DI's are normally used to send instrument such as keyboards or bass guitars down a snake or in to a mic pre-amp. A passive DI is basically just an impedence matching transformer with a pad and a ground lift switch. An active DI uses various electronics to match impedences. They both have their advantages. A passive DI can convert signals in both directions while an active DI can only go from Hi Z to Low Z. An active DI generally has more headroom in the low frequencies and is often used on bass guitar, keyboard, and for DJ's. When a passive DI is pushed very hard, the transformer can begin to saturate causing LF distortion.

Cheers,
Zach

[slor]

Frank, you posted that a bridging transformer (10K - 10K) would work for a DI.... Can you explain? I was under the impression that you wanted to end up with lo-Z in a DI box....

Thanks,
Seth

[theAnonymous1]

I was under the impression that you wanted to end up with lo-Z in a DI box

Wouldn't that require an isolation transformer + output buffer (hence active DI box)?