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Splitting Electric Guitar Signal Effects Pedals, Units & Accessories
Old 19th December 2010
  #1
Gear Nut
 
Subsonic's Avatar
Splitting Electric Guitar Signal

Hey all -

I think I need a little help on this one...what I'm trying to do is simple. I want to record electric guitar, and split the signal. Channel one is the miced amp sound, channel two is a direct signal into my DAW so I can re-amp or use Guitar Rig later if I need a different sound than what I got live.

The way I'm doing this is by using a Radial JDI, the thru jack into the amp, and the DI signal into the mic pre. The issue is that when I place a DI in the chain, and I've tried 3 different ones, it changes my tone at the amp. It dulls the highs and makes the tone muddy. Even with the JDI which is supposed to be very transparent, it's still obviously changing the tone I'm getting.

I'm playing a Fender American strat with Bill Lawrence pickups into a '65 Deluxe Reverb reissue.

Is there any way I can do this without any change at all to my amp tone? And why is that happening? I'm just not quite understanding the reason for the change in tone when all I'm doing is simply inserting a di in the chain...

Thanks for the help in advance! thumbsup

Subsonic
Old 19th December 2010
  #2
Registered User
I use JDI DI's, but I would never use them to split the signal - for that reason. It is the same with any passive transformer DI - and the problem is with the passive guitar pickup:

An audio signal is all about a varying Voltage. But electron flow requires both Voltage and Current. Voltage x Current = Power.

A simple analogy is to compare electron flow with water flow. Take your garden hose and open the tap. Put your finger against the end, and you can feel the maximum Pressure. Your finger is basically "high resistance" or "high impedance" to the water flow. This is like Voltage. As you take your finger off (which is basically 'lowering the resistance' or 'lowering the impedance') then you get a flow of water, but the pressure drops. You will notice that you can spray a much farther distance if you restrict the flow of water.

What we are seeing here is a FIXED AMOUNT of POWER. You can have maximum Pressure - with minimum Flow, or you can have maximum Flow - with minimum Pressure.

Electrical devices that use electron flow have the same issues. A passive guitar pickup has a very small amount of Power available. So if you load it with a very high Impedance, the Current is restricted, and we can enjoy maximum Voltage. Voltage defines the audio signal - not current.

BUT - if we LOWER the IMPEDANCE - by connected more loads to it, we are placing a much greater DRAIN on the available Power. The pickup struggles to deliver the current being demanded of it, and the Voltage suffers. Which means the tone suffers.

The solution is 'buffering'. Either get an active DI box with a high impedance. OR - buffer the pickup some other way.

For example - you could insert a nice pedal compressor before the JDI. Any active pedal will buffer the pickup, as the necessary current is then provided by the pedal battery.

A trick that I like to use involves taking a split from the mic preamp output. This will be at Line level, so I use my Reamp box to drop it back down to guitar level to drive my amp. This means I can track the cleanest short path DI signal, and essentially add a clean boost to your amp. It changes the amp response (I think in a favorable way), and it means that you are hearing a very similar tone to what you will actually get when reamping.
Old 19th December 2010
  #3
Lives for gear
Its much easier than that

Guitar to DI box, DI box 1/4 jack (thru) to Amp input, XLR out of DI box to channel 1 on interface, Mic in front of amp to channel 2. Done!
And you are not splitting anything.
Old 19th December 2010
  #4
Registered User


Read the original post, and my reply to it, and you might learn something today.
Old 19th December 2010
  #5
Registered User
Although somehow I doubt it.

I expect I will have to spell this out, to avoid the inevitable ...

The OP has already done what you propose: Guitar to DI box, DI box 1/4 jack (thru) to Amp input, XLR out of DI box to ...interface ...

This is OBVIOUSLY splitting the signal. one in, two out ....
And the OP can HEAR the damage done to the tone, as can anyone with good ears.

I have given the reason. And some solutions.
Old 20th December 2010
  #6
Lives for gear
 
slaves666's Avatar
I have an Avalon U5 and I have no changes in tone.

The pedal as a buffer is a great way to keep things tight as well. I used to put one in front of my Wah, back with the original Dunlop ones.
Old 20th December 2010
  #7
Lives for gear
ohh SORRY

I was in too much of a hurry and missed some details.

Thank you for curtiously pointing that out and then insulting me and assuming I was not capable of ascending to your level, before I had a chance to man-up and admit my mistake.
Old 20th December 2010
  #8
Gear Guru
 
FFTT's Avatar
 

You'll need a large housing TS plug for one end, but
you can split the signal direct out of your guitar, by
making up a Y jumper cable.

On the guitar end, both pairs of cable wired TS
Then each cable has a single TS jack on the other end
into both channels of your amp or split between an amp input
and a DI input.

It helps to use some heat shrink tubing to keep the dual cable manageable
on the guitar end.
Old 20th December 2010
  #9
Lives for gear
 
Unclenny's Avatar
This might work.......

Voodoo Lab - Amp Selector
Old 20th December 2010
  #10
Gear Nut
 
Subsonic's Avatar
Thanks for the replies everyone, I appreciate all of your input!

@ Kiwi - Thanks for your detailed reply, that's exactly what I was looking for...If I understand correctly then, we're dealing with an impedance mismatch, which then causes the highs to roll off...I had a hunch that was what was happening, but I'm not educated enough on that particular topic to have been sure. I'll give the post-pedal di solution a shot, I'm assuming it would work with any pedal?

So I guess the next question then would be this: If a passive DI is not the best solution for this particular situation, what would everyone recommend in terms of an active DI?

I might also try the split at the preamp as Kiwi suggested, that would then also allow me some flexibility in the amount if gain I'm feeding the amp input, right?

Thanks again guys!

Subsonic
Old 20th December 2010
  #11
Registered User
Quote:
Originally Posted by Manfrensengensen View Post
ohh SORRY

I was in too much of a hurry and missed some details.

Thank you for curtiously pointing that out and then insulting me and assuming I was not capable of ascending to your level, before I had a chance to man-up and admit my mistake.
Sorry about that. I miss details all the time. No insult intended - just a bit hung over after a concert ...
Old 20th December 2010
  #12
Registered User
Quote:
Originally Posted by FFTT View Post
You'll need a large housing TS plug for one end, but
you can split the signal direct out of your guitar, by
making up a Y jumper cable.

On the guitar end, both pairs of cable wired TS
Then each cable has a single TS jack on the other end
into both channels of your amp or split between an amp input
and a DI input.

It helps to use some heat shrink tubing to keep the dual cable manageable
on the guitar end.
This method is basically adding the same 'loop out' wiring that is already in a passive DI. It doesn't solve the basic impedance mis-match problem, and should be avoided for the same reason.

These tricks work fine if you have active pups, or an active DI, or buffer with an active box of any sort.
Old 20th December 2010
  #13
Lives for gear
 
AndyFromDenver's Avatar
So if I'm following correctly, the Avalon U5 (got one too and love it )
doesn't create a discernible change in tone because it's active?

*edit* oops, I now see that that is exactly what Kiwi just said...
Old 20th December 2010
  #14
Gear Guru
 
FFTT's Avatar
 

The Framptone Amp switcher, might solve your problem.

Peter Frampton Framptone products - Amp Switcher
Old 20th December 2010
  #15
Lives for gear
 

There are several options, the best passive one being a Lehle P Split, for active solutions, in addition to the Avalon mentioned above, you could try the Creation MW1 or Littlelabs RedeyeII or PCP. If you're on a budget, a stereo pedal in bypass will work (with a DI).

You may also want to consider recording the preamp out instead of the pure guitar. You wouldn't re-amp the pre-amp tone but instead either virtually or with a real amp, recreate the tone from the f/x return on (obviously, this requires an amp with a loop). The advantage is that it is easier to get those levels in and out of the daw. Impedance matching is also less critical.

Another great tool for this is the Suhr Iso-line out which grabs the speaker out and converts to line.

Those who know me, know my company sells some (but not all) of these products but also know I don't spam very often and always respecting the original poster's interest.

Andy
Old 20th December 2010
  #16
Gear Nut
 
Subsonic's Avatar
Thanks for the suggestions guys...I'm a bass player first, a guitarist a distant second, so maybe a U5 would be the ticket. The U5 would make for a killer bass DI in addition to (hopefully) solving my guitar splitting needs!

Off to check the classifieds...hehheh

Old 20th December 2010
  #17
Lives for gear
 
Barish's Avatar
You need a Lucas Deceiver.

B.
Old 20th December 2010
  #18
Lives for gear
 
Johnny Favorite's Avatar
 

The U5 is great, I love mine, but you can split your signals with an A/B Box.

AB-Selectors at zZounds
Old 20th December 2010
  #19
Registered User
Quote:
Originally Posted by Johnny Favorite View Post
The U5 is great, I love mine, but you can split your signals with an A/B Box.

AB-Selectors at zZounds
Unless your A/B box is active, it achieves nothing more than a Y-cable or the Loop out on the passive DI which is causing the problem in the first place.

A passive pickup has limited POWER output. If you try to extract more current by connecting more devices, the voltage WILL suffer.
Old 20th December 2010
  #20
Gear Nut
 
Subsonic's Avatar
Hi JF -

I do have an A/B box, I've had a Morley ABY stomp box for years, works great switching between my active basses on gigs...but when I used it with my strat, the tone was clearly affected, I believe due to the nature of passive pickups as Kiwi described.

I've also got a L.R. Baggs ParaAcoustic DI I use for acoustic guitars and sometimes upright bass, but the same problem occurs when I try to use it with my strat. The tone changes...and the L.R. Baggs is active too!

Subsonic
Old 20th December 2010
  #21
Lives for gear
 

The old saying that says "you can't measure something without changing it", really applies to a simple guitar--> cable---> amp setup. Just adding a tuner can mess the whole thing up.

Andy
Old 20th December 2010
  #22
Lives for gear
It's actually kind of cool, the pickups/control pots/cable/amp input form a resonant filter which changes if you add anything to it. The changes aren't entirely predictable (there's an article on here somewhere using spice modelling to determine what difference the tone pot/cap can make and it's not simple), but in general decreasing output impedance by splitting the signal loses highs. An active buffer in line disconnects the pickups from the downstream impedance and solves the problem, but may change the sound from plugging straight into the amp because the impedance and other parts of the network change, maybe better, maybe worse. You have a couple of choices:
1. High quality buffer before a passive split: even Boss/Ibanez pedals have a buffer, but not super high quality. A Klon, Cornish pedal, some Barber stuff, the Antelop MDEQ all have higher quality (read, more transparent) buffers. Try it and see what you like. As someone pointed out, a pedal with stereo outputs like a delay or chorus will inherently function as a buffered out put and splitter for you.

2. Buffered splitter: something like the Radial Switchbone or the Lehle pedal. The Switchbone adds a transformer isolation for the secondary output, reducing ground loop problems, not an issue with a DI box but it does have the "drag" control which varies output impedance of the guitar to take advantage of the resonant changes to tailor your guitar sound to more closely match the "direct into the amp" sound.

3. You could record just with the DI and reamp, although you lose some interaction with the guitar amp that way.

4. You could use a guitar amp with a line level output or modify your amp to have one, and record that for later processing (this is actually the way that's going to most closely match the sound of guitar directly into amp, if you tap the preamp just after the first tube).

5. You could use one of the pedals that's essentially a tube amp in a box, with both direct and "guitar amp" outputs: Stage Hog, Mesa Vtwin, Siegmund Missing Link, Sansamp, most rackmount preamps...
Old 20th December 2010
  #23
Lives for gear
I'm curious now. I'll pull out my multimeter and take some
Readings off the guitar lead before and
After the different DI's a have kicking
Around my tool box and do some learning.


I wonder if a fx send On an amp would work.
As long as the amp can send that way without
Needing a return patched back in. But then again
It would not be clean. I know some amps have a slave
Output but still is post pre amp.
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