HCFX PEDAL POLL

[V]

 

I wouldn't mind a sick-nasty octave fuzz

 

 

This can be arranged.

[onyxrhino]

you mean like a bit crusher that was described earlier in this thread as sounding "exactly like" another one that has been built already found in a old clip on the web?

 

 

wait...where was this? everything I've heard about amp_surgeon's design is that it's pretty original.

[macadood]

do not want octave fuzz.

and onyx, robo is refering to that Duck pedal, just some other bit crusher / sample rate reducer. no thing to do with amp surgeon's design, just does similar sounds.




and the new HCFX pedal is officially now.... an envelope filter!!!

[Stevenglass]

Warp Sound clone I don't think anyone has done it before. Unobtainium

I'm actually okay with this!!

[V]

do not want octave fuzz. and onyx, robo is refering to that Duck pedal, just some other bit crusher / sample rate reducer. no thing to do with amp surgeon's design, just does similar sounds. and the new HCFX pedal is officially now.... an envelope filter!!!

 

We're talking about me, here. The octave would be switchable. I love switches.

[pelliott]

 

This can be arranged.

 

 

Yippee!

[macadood]

 

sounds good to me is it just an env filter or does it do fuzz too?

 

anyone know what the circuit is like?

[V]

sounds good to me is it just an env filter or does it do fuzz too? anyone know what the circuit is like?

 

7wSnQC8iBZ8

[pelliott]

 

 

 

It's... beautiful.

[WeStartToDrift]

sounds good to me is it just an env filter or does it do fuzz too? anyone know what the circuit is like?

 

These don't sound good. The local guitar shop had one a few years ago and we messed around with it for a while and couldn't get a decent sound out of it. Just get a Q-zone and a fuzz.

[Urinate Forever]

what's the envelope knob actually do?? go wah?

[WeStartToDrift]

 

what's the envelope knob actually do?? go wah?

 

 

From what I remember its just a sweep control. Its basically a wonky fixed wah circuit.

[V]

Seems pretty extreme.

[slushpup96]

I voted reverb because tremolo wasn't an option and if I chose chorus, I'd get lumped in with the flanger people.

[mmolteratx]

Didn't think of a filter in the last thread. Something funky would be pretty cool.

[V]

Ok, so a little update. I have not heard anything more about fixing the problems with the sample rate reducer but last I heard the only way to get rid of the noise would be a noise gate of some kind.

 

Anyway, in the meantime, Drift and I have been working on the design of a nice fuzz based on the black box concept and we've now got a PCB design that's pretty much ready.

 

It's a full-featured fuzz/octave fuzz and, depending on how much gain you have going, can also do overdrive and distortion type sounds. The latest version I breadboarded also has extremely low self-noise.

 

So, the controls would be laid out like this:

Volume, Boost Level, Octave (Switch), Gain

 

Bypass Footswitch, Booster Footswitch

 

Boost in this case could maybe use a new name. It is, in fact, not just a volume boost at all. It is a 3rd gain stage for the fuzz and (in the latest version) uses an AC187 germanium transistor that sounds super thick and warm. Almost in big muff territory but with a lot more dynamics and clarity and a nicer breakup. It also provides a ton of extra volume, hence the control for its output level (this would be switched in only when the boosted mode is activated).

 

The un boosted mode is MOSFET-based and also breaks up very nicely. It's less saturated than the other mode and works equally well for chords and soloing. This one is also very touch sensitive and you can get into clean/overdrive territory pretty much with picking dynamics alone. The Gain knob helps you there as well.

 

The octave is silicon differential-transistor pair based and is switched into the circuit between the first two gain stages. It's capable of some wild sounds (especially in conjunction with the booster mode, where you can get some synth-like sounds) but you can also get pretty clean semi-ring modulated and sitar-like sounds out of it. Playing single notes and very simple chords lower down on the neck will also net you some very heavy pseudo sub-octave sounds.

 

Hopefully later on I can get a clip together from the circuit I have breadboarded.

 

Now, the one consideration is the germanium transistor used for the third stage is readily available but, being germanium, is not all that cheap. It's not ridiculously expensive, but they do cost around 5 bucks each. In comparison, a silicon transistor would be around 10 cents. On the plus side, there'd only be one per pedal so it would literally only raise the cost by five dollars. Now, we can also just as easily use a silicon transistor for the booster stage and it does also sound good in a different way. I have found, though, that the silicon transistors I've used in that stage have pretty significant self-noise. It's not anything you wouldn't be used to from a fuzz pedal and it's not particularly annoying but it's a consideration. It could be a matter of using a different kind of silicon transistor, of course. There are a few common ones i haven't tried yet. But is five dollars an amount people will care about if the resulting pedal sounds significantly better? I present the question to you guys.

 

More experimenting to come.

[ambient]

Sounds like you've got something cool goin V, is it octave up or down?

 

Dunno about the transistor...I personally think we should try to keep parts as cheap and standard as possible. Though if it really does improve the circuit I guess it's worth it. I'd leave it up to the two of you to decide.

[V]

Sounds like you've got something cool goin V, is it octave up or down? Dunno about the transistor...I personally think we should try to keep parts as cheap and standard as possible. Though if it really does improve the circuit I guess it's worth it. I'd leave it up to the two of you to decide.

 

It's mainly octave up but, depending on where or what you play, sometimes you also get undertones as well. Sort of like the Moonrock if you're familiar with that pedal. I believe it's based on an ampeg scrambler (the moonrock, not this circuit). It's easier just to hear it, really. I'll have to do a clip later today.

[spentron]

I'm working on a clip of the sample rate thingy ... erm didgitizer. Just a little longer.... The noise issues are reduced to the point not too bad, for something so noticable when you play through it. No noisier than a Metal Zone just more annoying. Or with clean mix it gets low enough you don't notice it unless you finish playing and leave it on.

[onyxrhino]

I'm working on a clip of the sample rate thingy ... erm didgitizer. Just a little longer.... The noise issues are reduced to the point not too bad, for something so noticable when you play through it. No noisier than a Metal Zone just more annoying. Or with clean mix it gets low enough you don't notice it unless you finish playing and leave it on.

 

 

cool. interested to hear it.

[spentron]

 

 

All neck pickup, a bit stratty. Noodling of course. Still hitting my camera with too much level.

 

And here's the otherwise mostly redundant bridge humbucker version:

[video=youtube;walwk5wYr-4]

[youngpedals]

Sounds very similar to what i achieved, but without the blend (which sounds great BTW). Did you also go with op-amp buffers?

 

What kind of oscillator did you use? Mine is a simple one op-amp square wave oscillator with frequency and duty-cycle/ pulse duration controls. I also tried the envelope detector, but it was too complicated for what we are going for. I ended up increasing the sample capacitor to 0.047uF and the noise went down.

[spentron]

Here's my schematic: http://spenceramps.com/misc/samplerate_schem.gif

... camera refused to give a good pic of a white page, I guess next time I'll have to use a white marker on black paper ;(

 

I used the 555, but the purpose of the 555 was to not use an oscillator limited to 50% duty cycle, yet the circuit still was (typo?), with a pulse generator at C3-R3-CR1. I changed that. Only problem, this is a narrow LOW pulse, a P-channel Q1 could be used but the threshold voltages are higher which is bad for this application, vs. I used a J201 which is excellent. So added an inverter of a 10K resistor into an NPN (only, using a TLC555 which is rail-to-rail). R8 (1M) becomes the pullup. When I added 1M to ground also at Q1's gate, limiting the voltage to 4.5V, a lot of the noise stopped. I also increased C5, though there was loss above .0047 uF.

 

I added a 6 dB boost to reduce noise but also allow an anti-volume drop effect on the mix, which is just passive, problems with mixing with gain are not present here. It doesn't quite go to 100% wet or dry.

 

And yeah, clean mix (or some kind of non-didgitized mix, anyway) seems essential, big loss of potential without it. One thing is the Frequency adjustment is touchy, could be better to limit the range, change the taper, or add a fine tune. Also for bypass the osc should be killed, for example by grounding C1/TRIG (I'm ready to get the thing out of my setup until I add a bypass switch at least . )

 

Almost forgot my guts pic:

[V]

Ok, so I recorded some clips. Not my most stellar recording quality ever, but here are four different modes:

http://soundcloud.com/cjmventer/hcfx-fuzz-proto-clips

First is the basic mode.

1:30 is about the start of the Germanium Booster Section

4:15 is The Unboosted Mode with Octave

5:22 to the end is the Germanium Boosted Mode with Octave

 

Now, keep in mind I don't have any knobs hooked up to the breadboard so the thing is always on at full (very loud) volume and gain is controlled via guitar volume knob and picking dynamics.

[driverhasabomb]

That sounds great V