Fuzz splitter for guitar

[martthie_08]

tricky one:

although it seems today anything is possible with technology and interfacing, this is a tough nut to crack:

I'd like to split a direct bass guitar signal and send one signal to a fuzz pedal and the second one to a clean di in order to get a nice parallel blend of the two signals.

While this may seem trivial, the fuzz pedals I am using (Big Muff and Wooly Mammoth) have a special way of interacting with guitar pickups. Putting a buffer before the fuzz pedal alters the sound in bad way (compressed and loss of low end). If the signal is split without a buffer, the fuzz signal is fine, but the DI signal sounds crappy.

What I already tried was sending the DI'd and preamp'd signal back to the fuzz using a reamp box, but this also alters the sound in a bad way.

There is just some "magic" in the way the fuzz pedals interact with the pickup where the last resort I can think of would be to use a stereo cable from the bass wiring both pickups on individual outputs. But there must be a better way (or not?).

any ideas? I guess I need some sort of a real pickup simulator box...

 

[Joechris]

Hm..what about going  streigth into the dist, but splitt the signal into a very hi imp booster before the di? 10M or so..

 

[Gus]

The BMP input and FF like effects interact with passive guitars and basses
This is because the input stages are inverting amps

With the BMP the 470k  feedback/bias C to B  divided by the 33K series resistor (or what ever value resistor) and the input cap and the cable capacitive and the guitar or bass LRC's

With the FF at less than max gain the is the feedback bias 47k, 100k etc divided by the the stuff before it
The above is if the gain is infinite the transistor open loop gain reduces this and adds more to the interaction by the input not being a perfect summing node

So there is no way to do exactly what you want. A pickup sim box is not like a guitar or bass because the setting of the volume control(series resistance from top of the control to wiper changes the interaction) a volume control is also a tone control

One way I can think of is a pickup to the fuzz and a pickup to the clean channel with a dual potentiometer volume control

 

[joaquins]

A reamp box should do it, but not any... I've been looking to build one but I never needed one and would be quite easy and quick to do it so never got there till I need it. I'm talking of a series mic winding with level and tone control as the instrument, I do have a pickup I salvaged from a bin in a friend's music store, lucky me I found the cut wire quite fast, resoldered and call it a day, I kept it around just in case. Wasn't a particularly good mic but should do the trick of adding the series impedance I want. I could just use an LRC network but starting from a mic should be a nice way. Adding a switch for single, series, parallel of both windings should help emulate different mic configs, then a couple of 500k pots working as level and tone, and feed the signal in the right level to start with, maybe adding an attenuator and/or a buffer before if needed.

That should interact quite closely to the pedals, not as usual reamp boxes which are usually more similar to a DI TX wired backwards.

JS

 

[martthie_08]

thanks for your replies!

One way I can think of is a pickup to the fuzz and a pickup to the clean channel with a dual potentiometer volume control

yes, that is probably the excuse I've been looking for to finally get that Rick-O-Sound 4003 

I'm talking of a series mic winding with level and tone control

do you mean a pickup coil?
any schematics?

 

[joaquins]

I don't have any schematics by hand but in your case would be just a copy of the wiring in your bass, but instead of connecting the other end of the pickup to ground connect it to the a signal source. So, signal source, pickup, level, tone, fuzz.

The closer the pickup you use to the one in your instrument the better. Maybe using the same instrument as a reamp box adding connector at the proper place?? But I guess using the same mic configuration would be good enough.

I don't know what bass are you using, what mics, in guitar it doesn't get much more complicated than SC/2SC/HB, so with two SC, connecting them in series or parallel you are good to go for most situations. But let's say you are using a precision, get a really cheap precision mic and call it a day, you should get the impedance close enough so the interaction with the input impedance of the box you are using is close enough. The other important thing which is not as easy as it might seem is to get the proper level, isn't the same to have a higher level going into a fuzz and a lower gain that a lower input level at a higher gain.

You probably want to do something to deal with the noise, since a pickup will pickup noise, so having it in a nice shielded can would be ideal.

JS

 

[martthie_08]

Joaquins, thanks for your reply, I've been using standard stuff, Jazz Bass and Precision for the most part.

so I'll see if I have any pickups laying around that I can use to test your idea!

 

[Gus]

joaquins

Read my post again.

 

[joaquins]

joaquins

Read my post again.

I think I've done it right, I'm talking about a proper matching in impedance, not just a first order approximation, that's why using a pickup itself to do so. If you want a good model of a pickup a voltage source in series with it's output impedance will do it quite nicely, I guess that could be close enough. Adding the level and tone controls after that would emulate the complete instrument. Here distributed parameters are ignored, but I'm guessing is not a big deal. You'd need a lot of tiny sources and a lot of taps splitting the winding to get it better, I don't think it worth it. Feeding the magnetic circuit of the pickup would be another way of doing so but finding a proper way and getting the proper signal to do so (replicating not the signal of the instrument but the strings movement)

What I'm trying to say here is this is the best way of doing what he's asking without having to use two different signals from the bass, since he doesn't have an Rick 4k it may be easier to test this than the splitting idea which needs to change all the wiring inside the instrument.

JS

 

[jensenmann]

I didn´t read the whole thread since I´m in hurry, so sorry if it had been said before. The additional load of the DI isn´t a problem in theory if it´s as high Z as possible. Radial has a DI box with 10Meg input Z, called PZ DI. Give it a try, Marten. If you want to check it out give me a call, I have a few of them.

 

[martthie_08]

Jens, thanks so much for your reply (and generous offer), but I think that the input impedance of the DI is a non-issue here.

the Fuzz already puts a whacky load on the pickup(s) that gets the signal distorted BEFORE the Fuzz and I can't seem to isolate the pickup output to have a clean direct signal without using a buffer that destroys the sound of the Fuzz.

 

[joaquins]

The problem is the load of the fuzz on the signal going to the DI, not the other way around.

As I said, I'd try splitter->{DI->ADC & Buffer->SeriesPickup+vol/tone->Fuzz->ADC}

JS

 

[jensenmann]

Ok, then I misunderstood your problem.

 

[martthie_08]

joaquins,

I've built up a little circuit, but I am getting no signal at all.

Just to be sure, I got your plan right:
the buffered signal goes to the pickup ground connection (lifted).
The other end of the pickup coil goes to the Volume / Tone section and that'll be my output?

 

[Gus]

Look up inverting opamps.  Note the input of the opamp is a summing node trying to be 0 ohms

A FF first stage is a inverting amp the 100k(or whatever bias feedback value used) from Q2 emitter to Q1 base is the feedback resistor(Q2 E tracks Q1collector one Vbe apart)
The pickup resistance and inductance and capacitance along with the rest of the guitar RCs is like the input resistor of an inverting opamp circuit you see in textbooks

This along with the fact the first transistor stage has limited openloop gain(much less than a opamp) cause the interaction you get with a FF. 

Things also change as more of the gain control is bypassed by the capacitor connect to the wiper

The BMP has less interaction because of the series 33K the first stage has a 470K C to B part of the bias feedback resistor

I don't think this is trivial

A fuzz that you might want to try is a Lovetone Big Cheese it has opamp buffers and it a crazy sounding fuzz

 

[Gus]

You could also try a 10K or higher value in series with the input of the Zvex after a buffer.  Not exactly the same as  guitar cable to FF but closer and costs very little

 

[joaquins]

joaquins,

I've built up a little circuit, but I am getting no signal at all.

Just to be sure, I got your plan right:
the buffered signal goes to the pickup ground connection (lifted).
The other end of the pickup coil goes to the Volume / Tone section and that'll be my output?

  If you are getting no signal at all there might be something wrong with the wiring, if the signal is very dim or way too much LF loss try this: I'd have to review the physics but try to add a shorted winding over each coil of the mic, thick wire, few turns shorted (uninsulated wire could be used) That way you only leave the parasitic inductance in series, not the inductance of the entire coil.

JS

 

[martthie_08]

thanks for all the suggestions, I'll have to see when I find some time to try out some of your ideas.

I never heard the Lovetone Big Cheese, but I'll see if I can find one.

I already have a really great old green Russian Big Muff that sounds better than any other Big Muff that ever came to the studio, and the Wooly Mammoth is very special too. But if I could just get the same tone out of them after a buffer as when I plug into them direct I would surely find a place in tone heaven

anyways, good night and thanks again!