Is there a a mixer circuit that doesn't change your tone?

[Loose]

Hi,

I'm interested in building (or even buying) a parallel looper pedal that splits your signal and then mixes the two signals back together.

From what I've read, such circuits require a buffer and an active mixer circuit.

My experience with buffers is that they always change your tone for the worst.

Is there such a circuit that doesn't change your tone? I've read good things about Lehle, any opinions about their parallel looper?

Thanks!

[Derringer]

Not all buffers are bad. Bad buffers are bad. Good ones are good and don't mess up your tone. 

If you're a builder, I suggest you make one of these:
http://runoffgroove.com/splitter-blend.html

and save yourself a ton of money over that Lehle product.

[PBE6]

The documentation on Lehle's website mentions high input impedance on both the Input and Return channels, JFET technology and 9V battery use. All of these indicate the use of active electronics (including buffers and active mixing). Virtually all splitter/mixer boxes use active electronics because of predictable operation and low noise.

It might be possible to find a box that uses transformers instead, but it would probably cost hundreds of dollars to purchase and only slightly less to design and build. It would also colour your tone, although the colour action might be more to your liking.

A simpler and cheaper option might be to design a box that has a direct path for your original signal from the input to a passive mixer, but uses buffered send and return channels. That way your original signal is largely intact and uncoloured, but the split signal can still play nicely with outboard gear.

[PBE6]

+1 to Derringer, I built a slightly modified version of ROG's Splitter/Blender and it works great!

[Loose]

Thanks guys.

Does the Splitter Blend just changes the ratio between the two signals? Because what I need is a dry signal at 100% and then to mix in a wet signal like a reverb or delay.

[blackieNYC]

This might be better

One op amp stage:
http://www.muzique.com/schem/mixer.gif
Or if you want mix controls:
http://www.generalguitargadgets.com/pdf/ggg_mixer_sc.pdf
I believe the ROG includes the Geofex Polarity Reverser, which you should look into.

These are great. And if you think about it, they can help your tone, if you are blending in effects. Pitch shifters, delays, some modulators - if you don't have a splitter mixer, your whole signal passes thru all of them. With a mixer, you send signal out to the crap, give it a fairly strong setting, and then blend a small amount of it into your dry signal.

[karbomusic]

My experience with buffers is that they always change your tone for the worst.

The majority of the time, assuming it's a well designed buffer, ^that sometimes happens because it is doing it's job and allowing more highs to come through. However that can be rectified in the design as well.

I've read good things about Lehle, any opinions about their parallel looper?

Thanks!

I purchased a Lehle ABY box about a year before I started DIYing my own stuff. Looking back, I think they are overrated and my Lehle has been in the closet ever since. I also recommend the splitter-blend circuit mentioned above, I use sections of that circuit in several other circuits I've built for various uses.

[ashcat_lt]

This might be better

One op amp stage:
http://www.muzique.com/schem/mixer.gif
Or if you want mix controls:
http://www.generalguitargadgets.com/pdf/ggg_mixer_sc.pdf
I believe the ROG includes the Geofex Polarity Reverser, which you should look into.

If those (especially the second) don't change your tone, IDK what will! 

[blackieNYC]

How so? My mixer is like the GGG or the Geofex Adjusticator , and was very flat up to 16k, which I can roll back a little.
Edit:Ah- geofex has 100k pots instead of 10k. Go with 100k

[Derringer]

Thanks guys.

Does the Splitter Blend just changes the ratio between the two signals? Because what I need is a dry signal at 100% and then to mix in a wet signal like a reverb or delay.

As far as I know, yes, the splitter blend changes the ratio between the signals. This is basically what's going to happen when you mix signals. Each signal automatically becomes a fraction of the summed signal. If we do a math thought experiment, let's say you have your unaltered signal and it's at 100%. If you then add 25% of the "wet" signal to it, you now have a sum total of 125%, which in turn means that your unaltered signal is now 4/5 of the total and the wet is 1/5. This signal may be a bit louder than just using a plain old blend, but volume isn't what you're after here.

If you do want a volume boost, you could either tweak the opamps in the circuit or just add a booster at the end.
See what I mean?

[Hatredman]

My experience with buffers is that they always change your tone for the worst.

If buffers are that bad, nobody would use a Mixing Desk. But they do.

[Loose]

Thanks for the replies guys.

Hatredman- My experience with buffers has been that they add too much highs, reduce bass and make the tone more hi fi and thinner.

Do you know of a buffer circuit that doesn't alter your tone like that?

And is there a tonal difference between opamp and jfet buffers?

[mth5044]

Buffers can't add anything. They could boost frequencies and cut others, but they aren't going to give you anything you aren't giving it. Here is a buffer page you might find interesting. There is a statement that IC buffers sound more 'sterile' than transistors; however, I can't tell a difference.

http://www.muzique.com/lab/buffers.htm

[R.G.]

Hatredman- My experience with buffers has been that they add too much highs, reduce bass and make the tone more hi fi and thinner.

Unbuffered guitars lose treble to both cable capacitance and loading. Buffers present the guitar with a higher impedance and stop the losses, so with more of the original treble left, it sounds - um, more treble. A good buffer adds nothing; it stops losses that would otherwise have happened.

Of course, it is always possible to design a not-so-good buffer that will do what you say. But much of your description is from a buffer doing what it's designed to do. If you don't like the sound of buffers, don't use them. Or add in the losses, then buffer *that* lossy signal, which will then appear pristine after the buffer, properly lossy like you like.

Do you know of a buffer circuit that doesn't alter your tone like that?

No good buffer alters your tone like that. You're describing what NOT using a buffer does.

And is there a tonal difference between opamp and jfet buffers?

Yes. Opamp buffers are generally more clean and less inaccurate. JFET buffers add their own slight distortion; but some people like this particular kind of distortion.

[Hatredman]

Hatredman- My experience with buffers has been that they add too much highs, reduce bass and make the tone more hi fi and thinner.

Do you know of a buffer circuit that doesn't alter your tone like that?

In fact it's the opposite. Your guitar HAS the Highs you despise. The buffer preserves that. When you don't use a buffer, you lose the highs.

So the buffer does not alter the tone. It's the LACK of the buffer that alters the tone.

That being said, it is possible to EQ your buffer to mimic the tonal loss of a non-buffered system. This way you retain all of the advantages of a buffered signal but still get the treble loss you love.