Earthquaker Devices Hoof: Noise Gate?

[cichra]

Hi all... new to the forum and happy to be here.

Has anyone here noticed that the Earthquaker Devices Hoof is relatively squeal and feedback free compared to other Muff-inspired pedals? When I play through it, it almost seems to have a gate function... guitar signals below a certain threshhold create no response whatsoever from the pedal.

I'm building a muff clone and would love to build my pedal to be just as noise-free. I've looked for muff mods like this, and have found two mentioned: (1) wire a 100k trimpot parallel to the 100k resistor going to ground from the second gain stage and (2) reduce the values of the 470k negative feedback resistors.

Has anyone looked at the Hoof closely enough to figure out how its gate-like response is created? Is it one of these two methods or something else?

Thanks everyone for your help. Apologies if this has been discussed before, but I searched around a bit and didn't find it.

[nocentelli]

Germanium transistors and red LEDs instead of clipping diodes, according to the "other place": Not sure if this is the secret to the gated sound, though. If you've got one, why don't you open it up and have a peek?

[cichra]

If you've got one, why don't you open it up and have a peek?

Yea that would be the reasonable and logical thing to do, but I was wondering if someone else has already done this for me   

I did have a quick look inside the Hoof and notice the germanium transistor cans and the LED's but didn't put the effort into figuring out what might be causing the gate-like response. Not sure if I have enough knowledge and skill to be able to spot how this is being done in the circuit. But I don't get any responses here, I may put the effort in and report back if I have any luck.

[Mark Hammer]

I've often wondered if series diodes could be used as quick and dirty gates to keep low-level noise out of the output.  The problem is that they would produce crossover distortion (clipping of the rise and fall of waveforms), which may not be desired.

[cichra]

I've often wondered if series diodes could be used as quick and dirty gates to keep low-level noise out of the output. 

I think something like what you're talking about is used in the Peavey 5150 amplifier.
http://music-electronics-forum.com/t21936/

Wonder if anyone knows whether or not something like this is used in the Hoof.

[azrael]

The insides look like pretty much a bog standard muff. My muffs are relatively quiet, perhaps you need to use shielded cable, a good layout among other things, to keep noise down?

[cichra]

The insides look like pretty much a bog standard muff. My muffs are relatively quiet, perhaps you need to use shielded cable, a good layout among other things, to keep noise down?

You could be right, and I could be asking about special circuitry in the Hoof that doesn't exist. But I've A/B-ed the Hoof with many other high-gain muff clones (Supercollider, Pharaoh, Musket, a BMP with Tone Wicker) and would insist that the Hoof is unusually well-behaved and noise free compared to those pedals. More specifically, to me it seems to respond in a gated fashion... no response with guitar signals below a certain threshhold and immediate crazy high-gain response to signals above a certain threshhold. This makes me think there's something special going on.

Just wondered if anyone else noticed this and had some idea how this is created. If not I'll have to attempt to look at the Hoof circuit myself or try some of the mods I've found to see if it produces the same effect.

[azrael]

The Hoof, due to the germanium transistors, has a higher capacitance at the base - collector junction. This filters out more highs, gives it that smoother tone.

It is possible to bias the transistors to be a bit more gated, play with the resistor going from the base to ground.

Again, my Muff builds are fairly quiet.

[cichra]

The Hoof, due to the germanium transistors, has a higher capacitance at the base - collector junction. This filters out more highs, gives it that smoother tone.

It is possible to bias the transistors to be a bit more gated, play with the resistor going from the base to ground.

Again, my Muff builds are fairly quiet.

Thanks for this. A few questions:

1.) Are you saying I could possibly get this gated effect by messing with the bias resistors on the standard muff silicon transistors too? Or is this response unique to the Hoof's germanium transistors?

2.) For which resistor to mess with, are you referring to the 47k and 100k resistors to ground? Which of the four stages might be best to try first... the first gain stage, one or both of the clipping stages, or the final stage? (Ram's Head Muff schematic below for reference)

3.) What might be some good resistor values to try to start with?

This suggestion seems similar to the mod in which you wire a trimpot in parallel to one of these 100k resistors.



Thanks for your help!

[azrael]

Yes, that mod is the same idea.

And it can be done with any transistor type, just be aware that it lowers a bit of gain. With the Hoof, it's not a big deal because it's not a high gain muff circuit in the first place.