Question on XLR

[Gullplayer]

For performing, I am currently running my acoustic guitar 1/4 cable to a LR Baggs Para DI, and then to my Ultrasound acoustic amp. I have always used a 1/4 cable for the output from the DI to the amp. I am confused, though, on whether an XLR cable should be used from the DI to the amp for the DI to be effective in matching impedance levels. My question: In order for a DI to do its job, does an XLR cable instead of a 1/4 inch cable need to be used to run from the DI to an amp or mixing board?

[Rudy4]

Originally Posted by Gullplayer

For performing, I am currently running my acoustic guitar 1/4 cable to a LR Baggs Para DI, and then to my Ultrasound acoustic amp. I have always used a 1/4 cable for the output from the DI to the amp. I am confused, though, on whether an XLR cable should be used from the DI to the amp for the DI to be effective in matching impedance levels. My question: In order for a DI to do its job, does an XLR cable instead of a 1/4 inch cable need to be used to run from the DI to an amp or mixing board?

If your amp has a combo input jack or separate 1/4" / XLR jacks then the impedance matching is not an issue. In that case the only thing the XLR will offer is a bit higher immunity to RF interference. If it's under 10' (or the length of a quality 18' cable) then 1/4" is OK, longer distances will normally be better for noise immunity for the PA input. That's why the instrument inputs via snake are always balanced cable (XLR).

[lschwart]

Just to add to what Rudy4 says: right now, strictly speaking, you are not using the Para DI as a DI at all, but only as a preamp/EQ unit. Impedance matching is irrelevant in this particular situation. You should be able to plug just about any kind of pickup into the Ultrasound amp using a regular 1/4" instrument cable and have no problems due to impedance.

The only reasons to use a Para DI in this situation would be:

1) It offers better EQ and feedback notching than the amp on its own.

2) The pickup you're using has such a weak signal that for some reason the preamp in the Ultrasound is not strong enough to amplify it adequately to drive the power amp stage sufficiently.

3) You need to split your signal between the amp and a PA system's mixer and the mixer is some distance away (in which case you'd send a signal to the amp from the 1/4" output of the Para DI with a relatively short instrument cable and a signal to the PA from the XLR DI output with a long mic cable).

4) You need to run a long cable from the Para DI to the amp (in which case you would use XLR DI output of the Para DI into the XLR input of the amp).

I hope that helps!

Louis

[Gullplayer]

Thanks for responses. Yes, I use the Para DI primarily for its EQ functions. So, if I'm understand it, a DI is only really needed if the guitar is run straight to the PA mixing board, and not needed if run to an amp.

[lschwart]

Originally Posted by Gullplayer

Thanks for responses. Yes, I use the Para DI primarily for its EQ functions. So, if I'm understand it, a DI is only really needed if the guitar is run straight to the PA mixing board, and not needed if run to an amp.

Yes. Most (maybe all) combo amps designed for acoustic guitars have 1/4" inputs designed to accommodate most common pickup systems. That is, the impedance is sufficiently high to let you plug in a passive piezo system directly.

Amps that have XLR inputs have them primarily to allow you to also plug in a mic for either your guitar or for vocals. Since most people play fairly near their amps, it's pretty rare for someone to need to use a DI to go into the XLR input, although in some cases it can help with noise (ground loops, for example).

Given the distances often involved and given the nature of the inputs you usually encounter, a DI is often, however, necessary for plugging an acoustic guitar into a PA mixer. Certainly with most passive piezo pickups, but often also with active piezo systems, magnetic pickups (active or passive), and hybrid systems of various kinds. On stage, balanced signals offer advantages, and a DI gives you that.

Louis

[ljguitar]

Originally Posted by Gullplayer

For performing, I am currently running my acoustic guitar 1/4 cable to a LR Baggs Para DI, and then to my Ultrasound acoustic amp. I have always used a 1/4 cable for the output from the DI to the amp. I am confused, though, on whether an XLR cable should be used from the DI to the amp for the DI to be effective in matching impedance levels. My question: In order for a DI to do its job, does an XLR cable instead of a 1/4 inch cable need to be used to run from the DI to an amp or mixing board?

Hi Gp

• ¼" is for short runs (under 25 feet)
• XLR is for long runs (think 250 feet via a snake to a PA board at the back of the room)

Your ¼" guitar cable is all you need on stage to your UltraSound. The XLR will not give you any benefits or improvements in tone or function.