Using a stomp pedal as a DI box?

[storming heaven]

Yeah, i know it's probably a stupid question but was wondering about this.(Ya i searched the forum and read the reamp sticky) Apparently my m-audio firewire solo's instrument input has less than 1 M ohm impedence (took a year and a half to recognize that d'oh!) and since, for all my guitar tones i plug directly into the interface, there's probably some signal loss when going into firewire solo. Sooo instead of using a DI box, could a stomp pedal (ts7, ts9, or even a tuner pedal?) help me to get most of my signal into the interface? I'm thinking it might help in terms of impedence, but then again i know nothing about electronics so this might be a total bullshit question.

In addition I am wondering about the change in sound quality that a proper impedence input or a di box would allow. Will the difference be like night and day? Or Kirk Hammett to Jeff Loomis? (yeah the tone will be on the fingers, but still..)

Looking forward to your inputs.

 

[colonel kurtz]

probably won't gain anything coming out of a guitar pedal, as its output is still going to be instrument level, as it's still intended to be plugged into an amp from there...

 

[ahjteam]

try it first does it sound ok if you just plug in straight to the interface. if it does, good for you.

 

[hurdy]

A pedal with a buffer will probably help a lil with signal loss. Correct me if I'm wrong someone?

 

[storming heaven]

A pedal with a buffer will probably help a lil with signal loss. Correct me if I'm wrong someone?

Would you elaborate on that? What do you mean by 'buffer'?

 

[hurdy]

Like a boss stompbox, they have a buffered load to prevent signal loss, something like that

 

[TheWinterSnow]

Yes the buffers in pedals help prevent signal loss in low impedance inputs. But unless youare having distortion issues with teh DI, then the input impedance is good enough, and if you have enough gain on the interface to get your trackin levels, you relaly don't need a DI.

 

[storming heaven]

ok thanks guys. gotta get my hands on some pedals for testing.

 

[bryan_kilco]

I've used my Boss NS-2 to split my signal.... Guitar -> Input, Output -> Amp.....Send (from NS-2) -> Interface. Never noticed a significant signal loss.

 

[Omega_Void]

Input Z is normally set by a single resistor. Any competent electronics service/repair tech should be able to swap it out for you. Benefit is you don't introduce an extra gain stage of noise and distortion into the signal chain. Downside is goodbye warranty.

A stomp box should have low enough output Z to connect to a 10k line input instead of the instrument in. Try it both ways if you use a stomp.

Connecting to a different input Z may change the frequency response of the guitar if you're using passive pups, because the inductance and capacitance of the coil combine to create a peaking response, and altering the resistance in the circuit changes the peaking frequency and amplitude.

Active pups frequency response is not affected, since the electronics in the pup will buffer the coil from the soundcard input.

(A buffer is any circuit which reduces interaction between the stuff connected to its input and the stuff connected to its output.)

If you are using active pups, check their output impedance specs -- it may be low enough to connect to the instrument input you have, perhaps even a to 10k line input (i.e. 100 ohms or so).

 

[>>>GENZ<<<]

I've had exactly the same configuration, FW Solo,
Guitar input on that thing is not really hi-z,it's just 480k
so I run stompbox in bypass mode(NOT true bypass box) into guitar input,
and it sounded way better then plugging straight into guitar in
Using line-in gives the same result,but you can't control input level.

 

[storming heaven]

I've had exactly the same configuration, FW Solo,
Guitar input on that thing is not really hi-z,it's just 480k
so I run stompbox in bypass mode(NOT true bypass box) into guitar input,
and it sounded way better then plugging straight into guitar in
Using line-in gives the same result,but you can't control input level.

wOOt! Thanks for the info.

 

[Omega_Void]

I've had exactly the same configuration, FW Solo,
Guitar input on that thing is not really hi-z,it's just 480k

By "not really hi-z" do you meant "not very" or "not truly"?

480k counts as a high-Z input. Plenty of stompboxes have 470k Z-in, although 1Meg is better and more common. TS808 is only 510k input.

But Firewire Solo's instrument input is actually 270k according to the spec in the user guide. So this won't even perform on a par with a 470k stompbox.

There's no advantage making it this low for a passive pickup, because the reduction in Johnson noise from the resistor is more than offset by the reduction in pickup output.

(And no point in making an active pickup with a High-Z output, but that don't stop it happening.)

 

[>>>GENZ<<<]

it's 270k indeed
I beleive true Hi-Z input should be at least 1M

 

[hurdy]

I used to plug into my Boss GE-7 as a DI when I had the Firewire solo
Sounds mint with it in bypass mode like mentioned here before

 

[valdiorn]

it's 270k indeed
I beleive true Hi-Z input should be at least 1M

Actually, not necessarily. For the first time in many years I was let down by my trusty M-Audio Delta 44, turns out the input impedance isn't much over 50k I tried plugging a Proco Rat clone direct into the card. It worked OK but there was a noticable drop in high frequencies, enough that I decided it was not usable for recording.

Using a stompbox as DI depends on two things: the output impedance of the stomp and the input impedance of the interface. the volume output of most stomps will be enough so it'll be usable.

 

[Omega_Void]

ProCo Rat schematics show the output pot is placed after the last active buffer, which makes the pedal's output dependent on the pot setting and the impedance it's driving.

I don't see any advantage in that, most stomps put the last buffer right on the output so the pedal's sound is independent of what it's connected to.

Delta 44 has line inputs, meaning 10k minimum and few line inputs will be 50k or above. Considering the Rat's "innovative" (by which of course I mean "stupid") output scheme it's no wonder you had problems.

At 27 times the line-level spec, the FW Solo's instrument input can justifiably be labelled "hi-Z" and for some sources this will be okay. But I agree with GENZ, that practically speaking a high-Z input should be 1M or over, since this will accommodate pretty much any source for which 10k is not enough.