Amp with 1/4" DI..?

[spantini]

I was checking out bass combo amps at Sweetwater. The VOX VX50BA 1x8" 50W bass combo caught my eye. Looking further revealed it's got a DI.. a 1/4" DI..

This is the first 1/4" DI I've seen. Does this perform like an XLR? Or is it just a lower cost substitute with less functionality?

 

[ChristopherBell]

I was checking out bass combo amps at Sweetwater. The VOX VX50BA 1x8" 50W bass combo caught my eye. Looking further revealed it's got a DI.. a 1/4" DI..

This is the first 1/4" DI I've seen. Does this perform like an XLR? Or is it just a lower cost substitute with less functionality?

Well, the best thing is to pull up the manual and read the specs. But, I have seen it... My OLD POD 2.0 from like 2000 ONLY has 1/4" outs. It always bothered me that it had printed on the top 'Ultimate Guitar Direct Box'. Like you, I always associated direct boxes with XLR.

What I found out when I read the manual was that both outputs were TRS +4 outputs - and all they needed was a TRS to XRL dongle to let it be used like that. Using 1/4" cables only gave me -10 outputs.

Imagine my surprise when I plugged in a TRS cable and went into the XLR input on my audio interface.... All of that glorious headroom and +4 signal that I had never tapped before.

Look into it... The cable was cheap off of Amazon..

 

[spantini]

Thanks The manual says to connect a tuner or PA system to this Direct Out. A 1/4" TRS plug will produce an impedance-balanced output and reduce noise. A TS plug can also be used but will produce an unbalanced output. Flexible..

 

[ecc83]

I get a bit hissed off when I see an XLR connector on a guitar or bass amp labelled "DI Out, unless that is it is balanced and at microphone level. Even better if it is transformer fed and thus earth free.

"But transformer are expensive" you cry. Not really, for a feed at -30 to say -10dBV* almost anything will do and can be found retailing at under $5. How much will a big amp company pay for them?

If you are going to provide a 'Line Feed' use a jack. The XLR is not the natural inhabitant of the gitists gig bag. Sound engineers however generally DO expect an XLR feed at mic level balanced. So the half arsed XLR pleases neither camp!

*In the guitar electronics world, sanity reigns for levels and they are inevitably expressed in dB "V". The rest of the audio world limps along with the archaic dBu, a unit derived from the days of A.G.Bell and his telephones.

Well, that's torn it! Just looked for some cheap traffs to backup my claim and found TEN in a pack for less than seven quid! Ordered them and will do some tests when they arrive. If anyone wants one to play with, PM me.
Dave.

 

[spantini]

And then I see this Blackstar U60 with both 1/4 and XLR labeled as Line Outs.. plus an XLR Cabinet Out.. so I'm supposing both Line Outs are wired the same and it's just whatever is convenient.

 

[ecc83]

And then I see this Blackstar U60 with both 1/4 and XLR labeled as Line Outs.. plus an XLR Cabinet Out.. so I'm supposing both Line Outs are wired the same and it's just whatever is convenient.

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I don't have schematics for the Unity amps* but do for the Series Ones and they provide an emulated output on XLR and TS jack. The XLR out is from a proper, symmetrical drive amp and thus balanced. Pin one in this case is taken to ground but it is presumably switched in the U60 to give ground lift. Not QUITE as good as transformer isolation but better than most?

The U60 is, AFAICT configured to 'slave' to another powered speaker, daisy chained if you will and XLRs are very commonly used on active speakers.

But, I repeat. If a sound tech sees an XLR 3 male on a device announced as "DI" he is well within his rights to expect it to be balanced and at mic level!

*I cannot even download the handbook for the U series, anyone help with that?

Dave.