Building in a DI

[Pbassred]

In my youth I built a passive DI out of a transformer, an XLR and 35mm film canister. I remember it worked too. Recently I bought a Line6 multi effects box which claims to have a DI out. Guess what? It ain't. Its an unbalanced 1/4in jack.

So I got to thinking that, rather than carry another box, I could revist my past and fit an XLR and a transformer. Anyone have any recomendations?


PS, info only :- Line6 Bass PodXT live

 

[beatpoet]

The manual says balanced and they don't have an XLR or 1/4" TRS jack on the thing?

 

[Pbassred]

Not on this model. Oddly the guitar version IS balanced ( I am told). The guts are the same (I am told), and the plug IS a TRS. However there is definatly no signal on the track to the ring. Its an acknowledged .... "trait".

 

[Samuel Groner]

You don't need any signal on the ring to make a balanced out on a TRS. Search for "impedance balanced".

Samuel

 

[Pbassred]

Thankyou
This is a whole different direction. I did some reading arround but came up against a brick wall.

How do I know if its working If I can't measure a signal?
If I was to parallel out to an XLR, would I still be able to use a 1/4in jack in the original TRS socket at the same time? I imagine that even if it didn't short the ring to ground, it would unballance the impeadance.

Still screwed! :?

 

[clintrubber]

[quote author="Pbassred"]How do I know if its working If I can't measure a signal?[/quote]

If it's not AC-coupled then you could simply measure the 'balancing resistance' (resistor) with a DMM (between ring & sleeve). It's not likely that this will be broken, so if it's stated to be blanced in some way then I'd believe it and keep the measuring gear stored. How long is your cabling & how hostile the environment ? If there are no disturbances then you're fine.

 

[Pbassred]

I was not thinking that it was broken. I was saying that I am unsure if it is intended to be impeadance balanced.

It is probably better if I just swallow the cost and the extra clutter and buy a good DI box instead.

 

[rotation]

If you can DIY there is a nice DI called Bo Hansen's. Active design, uses one transormer, very nice sounding (i'm finishing it, just need to make holes in chasis) and there is lots of reading about it. And Bo is a really nice guy, always helps if you ask him.
Try it, you won't regret, it's a simple build.

 

[PRR]

> I could revist my past

It has become very hard to find metal film canisters anymore. I think they were all filled with dope and lost under the seats of 1973 Mavericks.

> passive DI out of a transformer, an XLR and 35mm film canister

Works; the issue is that passive guitar pickups may prefer an impedance higher than any affordable transformer can give. Nevertheless, we all did it; also e-bass tends to not care.

For active stuff like Line6, just get Mouser's little 10KCT:2KCT audio transformer. It may even work in a plastic can.