Black Ice?

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I messed around with one or two schottky and germanium diodes, single or back to back, sometimes with a resistor in series. Im pretty sure that out of what I tried, the hidden contents of a black ice was covered. It was interesting and not horrible, but even tbe simplest active OD circuit was way better.
 
...hidden contents of a black ice...
Just the fact that the contents are hidden is enough to make a person's BS detector ring loudly. There are probably only two reasons for a manufacturer to conceal what's inside their new device:

1) He/she has come up with something so clever and original that nobody else could come up with it on their own. So, by hiding the details, he/she will be the only one who can make this magical product. (This is rather unlikely. And why not just take out a patent, if you really did invent something revolutionary?)

2) He/she is trying to cover over the fact that he/she is peddling something quite ordinary, and charging way too much money for it.

The odds are strongly in favour of (2). Electronics is a mature engineering field that is over a century old, there will not be many revolutionary new products at this stage of the game.

The Standels and Dumbles of this world may fill their products with black epoxy, but the truth tends to come out eventually, and the truth is usually "Geez, that was nothing special, after all!"

It was interesting and not horrible, but even tbe simplest active OD circuit was way better.
Thank you for doing the experimenting, and sharing your results!

-Gnobuddy
 
I vote #2. How cosmic can a passive circuit be? Anyone wanting to steal it can chip away or dissolve the potting. Patents don't stop circuit thieves.

When I was in another industry, a friend made a speed-up module for PacMac games. A black epoxy filled box had a half dozen wires training out, each a different color. You soldered two wires to the circuit board, and a couple to the FAST button on the panel. Hold the button and the game speeds up.

I chipped it open to find the various colored wires just soldered to one another inside. the whole circuit was the button shorting two points on the circuit board. For this he was asking $100.
 
Have you actually TRIED one? Or just speculating?
I have tried them, of course, when the idea was new, around 1976 or so.
Do the math ;)

Dissappointed, junked it.

If you have weak pickups, it does nothing.

If you have powerful pickups, which comes at a price: lots of magnet, complex magnetic path,thousands of turns of very fine wire, usually double coil, you throw all that overboard in exchange of cheesy weak slight distortion.

If you have active pickups, then you are missing the boat and them some.

If you want distortion, an Op Amp is WAY better used in a real Distortion pedal, driven by classic passive pickups, rather than hving active pickups and adding cheesy farty uncontrolled diode clipping.

Did I miss anything ;)
 
I have tried them, of course, when the idea was new, around 1976 or so.Dissappointed, junked it. If you have weak pickups, it does nothing. If you have powerful pickups, ................. you throw all that overboard in exchange of cheesy weak slight distortion.If you want distortion, an Op Amp is WAY better used in a real Distortion pedal, driven by classic passive pickups, rather than hving active pickups and adding cheesy farty uncontrolled diode clipping.
Did I miss anything ;)
Nope. I think "cheesy farty" about covers it!!
 
I´m talking Black Ice ..... what are you talking about? :confused:

:)
Active pickups - didn't you say they make "cheesy farty" sounds in post #8, or did I misunderstand you?

Active pickups do often sound to me as though they have built-in semiconductor clipping, with some accompanying harshness. Maybe just not enough headroom.

Zakk Wylde does a good job of playing something beautiful even with active pickups (I think) in the first clip. The second clip is a stock Les Paul, and I like the guitar timbres in the second clip better.

-Gnobuddy
 
The Standels and Dumbles of this world may fill their products with black epoxy

The Standels that I opened all had colored epoxy in plastic boxes like fishing lures came in.

If you want distortion, an Op Amp is WAY better used in a real Distortion pedal

Nah, germanium transistors.....AKA Vox Tone Bender or Dallas Arbiter Fuzz Face. Both of the originals had the same circuit until Vox added a third transistor. I made dozens of these things in the late 60's with transistors out of dead radios.

I have seen a Black Ice module and briefly played with it. I am convinced that it contains a pair of diodes and a series resistor. I could not get a similar sound from any combination of SMT silicon with a series pot that I had on hand, although I did not have both together at the same time. The Ice did not hard clip (hence my belief that it had a resistor). I could still get almost 1 volt P-P by blasting on all 6 strings as hard as I could on a flea market quality Squire Strat with all 3 pickups on full. The guitar without the Ice can make almost 2 volts into an open circuit (scope probe).
 
since Ge transistors are becoming scarce.

The flea markets and hamfests are running out of old electronics to mine for their germanium. I still have a few NOS RCA SK3008's still in their poly bags from 1972. I also have the Tone Bender that I built for myself in the 60's. It has "Sony" transistors in it. Out of an old radio, I believe.

Note, don't build a Fuzzface INSIDE a tube amp. The tone goes all over the place as the amp heats up, and gets nasty when real hot. I learned back in the 60's not to paint the stomp boxes black if they will be used outside in the Florida sun.
 
I also think Schottky's are thd best way to optmise this idea (though not quite to the level of making it a really good idea!).

The Vf figure is s good quick way of describing a diode, and a low value suggests that more will happen when clipping a guitar signal. But a much better characterisation is to note the logarythmic voltage to current relationship for a diode. This gives a better characterisation at the very low currents tbat are relevant. This is from wiki and shows an ideal diode equation for a silicon diode.(with a simple linear model too)

450px-PWL_diode_characteristic.PNG


With that one can look at the slopes and so derive an effective 'variable resistance', changing with voltage. I did that a few years ago from measurements, and if I remember right, a silicon diode gets to many mega-ohms of forward resistance as current falls to zero. Hence we get no audible effect in a guitar until a very loud transient suddenly causes a nasty dirty clip.

But the schottky is changing its resistance, on a similarly shaped curve, but rising only into the range around 80 to 100k at zero current, and more with reverse signal. This range is right where it will significantly affect tone, all through the volume range as a note decays.

A pair back to back with a fixed R in series is a credible design for such a passive clipper.
 
With that one can look at the slopes and so derive an effective 'variable resistance', changing with voltage.
Silicon diodes follow an exponential current-to-voltage relationship very accurately over many decades of current, so you can calculate the "dynamic resistance" simply by taking the derivative (calculus).

The result is that, at room temperature, the dynamic resistance of a silicon diode is (26/Id) ohms, Id being the diode current.

In other words, 26 ohms at 1 mA of current, 52 ohms at half a milliamp, 260 ohms at one-tenth of a milliamp, 2.6 kilo ohms at ten microamps of current, and so on. At zero current, the resistance predicted by this equation is infinity. Open-circuit.

I don't know if Schottky diodes follow the same equation or not - they weren't in my textbooks back when I was studying semiconductor physics!

I agree with you about the sound of semiconductor diode clipping - I've never managed to extract a sound I like from them. But David Gilmour and Eric Johnson certainly do!

-Gnobuddy
 
I never did the formal study, but when I tested I saw an offset in the log (or exponential) relationship of I and V, such that there is a non infinite dynamic resistance through zero, with tendency to infinite being with some reverse voltage. It matched tbis type of plot:

images


All my diodes followed that type of curve and I think the value of R though zero is the key to wether this idea, squashes all tone, does nothing except on transients, or does somthing useful to the tone.
 
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