Simple Instrument to Line circuit.

[tomas1808]

Hi, a recording session has been planned with short notice at my small home recording studio and I will be needing 4 instrument inputs so that I can record guitar and bass straight into my audio interface. Is there a simple circuit that would allow me to interface hi-z signals to line level with relying on the usual DI + mic preamp approach? My existing preamps will be used with mikes so I can't just build a DI.

I dont have time to order parts so I will rely on whatever I have stocked up.  It doesn't have to be particularly high quality and I dont need balanced outputs.

Any ideas? Thanks!

 

[kooma]

fet/opamp buffer?

 

[gyraf]

Repost "Re: Possible DI - Hi Z - input to Mic or Line input ? " 2012

Repost "guitar splitter" 2005:


   

Here's a very simple, yet well-functioning instrument splitter:

    http://img.photobucket.com/albums/v172/gyraf/Splitter.gif

    We have several of these in the studio, and they get used all the time...

    Jakob E.

 

[JohnRoberts]

Hi, a recording session has been planned with short notice at my small home recording studio and I will be needing 4 instrument inputs so that I can record guitar and bass straight into my audio interface. Is there a simple circuit that would allow me to interface hi-z signals to line level with relying on the usual DI + mic preamp approach? My existing preamps will be used with mikes so I can't just build a DI.

I dont have time to order parts so I will rely on whatever I have stocked up.  It doesn't have to be particularly high quality and I dont need balanced outputs.

Any ideas? Thanks!

It sounds like you may need dedicated instrument preamps that put out conditioned line level signals.

Have you ever recorded dry guitar outputs? While bass guitar can often be used that way with just channel strip EQ, lead guitar will be often be too thin sounding without conditioning (like occurs in guitar amps). 

The instrument level preamp is relatively straight forward but I am cautious that you might not be happy with the result of simple (flat) amplification.

I'm sure others here have explored this and can share their experience.

So short answer is yes you can, but I'm not sure you want to.

JR

 

[RuudNL]

That is the reason why I always put a microphone in front of a guitar cabinet.
(Or eventually use the parallel speaker output, if a direct signal is needed.)

 

[tomas1808]

It sounds like you may need dedicated instrument preamps that put out conditioned line level signals.

Have you ever recorded dry guitar outputs? While bass guitar can often be used that way with just channel strip EQ, lead guitar will be often be too thin sounding without conditioning (like occurs in guitar amps). 

The instrument level preamp is relatively straight forward but I am cautious that you might not be happy with the result of simple (flat) amplification.

I'm sure others here have explored this and can share their experience.

So short answer is yes you can, but I'm not sure you want to.

JR

I'll be using an amp sim plugin so it should sound alright. That's why I need the inputs in the first place, I dont have an actual amp  (or amps for that matter) :'(

 

[JohnRoberts]

To just boost up/buffer instrument levels, can be a simple as an op amp stage... I've made active direct boxes with TL07x op amp front ends.

JR

 

[Matador]

If you are going to be using plug-ins for the guitar amplifier/cabinet chain, most (if not all) assume no pre-EQ on the dry pickup signal.

I can attest that Gyraf's schematic posted above works fine.  If you are running in to bridging inputs (with 10k or great input impedance), you can shrink the 22uF caps down to 10uF without any issue.  I used OPA4134's, which are also unity gain stable.  Works great!

 

[tomas1808]

Ok, I'll go with Gyraf's schematic. Thanks everyone.

 

[andre tchmil]

If you are going to be using plug-ins for the guitar amplifier/cabinet chain, most (if not all) assume no pre-EQ on the dry pickup signal.

I can attest that Gyraf's schematic posted above works fine.  If you are running in to bridging inputs (with 10k or great input impedance), you can shrink the 22uF caps down to 10uF without any issue.  I used OPA4134's, which are also unity gain stable.  Works great!

resurrecting this oldie.
could this OPA4132 also work for low impedance / mic preamp inputs ?