Black Diamond Probe

About Black Diamond Probe

Black Diamond Probe pairs with Black Diamond Distortion. Where Distortion lets you build and edit transfer curves, Probe captures them from real circuits and plugins.

Run audio through a distortion stage — a tube preamp, fuzz pedal, or overdrive — and Probe fits a transfer curve to the input and sidechain. Export as a .tfunc file and load it into Black Diamond Distortion to reuse, refine, or push further.

How It Works

Setup Guide

Black Diamond Probe extracts nonlinear transfer functions by probing before and after the device under test (DUT).

Place BDP immediately after the DUT to read the output.
Route BDP sidechain to read the DUT input.
Pass audio through the device to begin probing.
For best results, start with a simple test tone that spans the full input range (for example a 0 dB sine wave).
For clean captures, bypass filters/EQ in the DUT if possible.
If you see a loop in the plot, use X/Y latency compensation to align input and output.
If the loop doesn't collapse (true hysteresis), the device can't be represented by a single transfer function.

Visualization

New in v1.1, Probe shows the device under test in two real-time views.

Time domain

Input and sidechain waveforms overlaid on the same axis. Useful for matching levels, checking latency compensation, and seeing where in the waveform the device is clipping or compressing.

Transfer function

An XY oscilloscope of input vs. sidechain — every sample lands at (input, output), so the device's transfer behavior draws itself in real time.

A memoryless distortion traces a single clean curve. Time-dependent behavior — hysteresis, EQ phase shift, anything where output depends on past input — shows up as a loop or smear. This is the same view the capture algorithm fits a curve to, so you can see whether a device is going to capture cleanly before committing.

Transfer-function view: XY oscilloscope plotting input against sidechain to draw the device's transfer curve

Use Cases

Learn what your gear is actually doing. See how a tube, transistor, or op-amp stage colors your signal. The same workflow works for hardware and software plugins.
Build a personal curve library. Capture .tfunc files from your favorite gain stages and load them into Black Diamond Distortion to reuse and edit.

Technical Requirements

For an accurate capture, the device under test must be memoryless — its output depends only on the current input, not on past inputs. Most distortion, saturation, and waveshaping circuits qualify. The catch is that they're often packaged with DC blockers, EQ, or other tone-shaping that introduces phase shift, which breaks memorylessness in practice. Bypass those if you can.

Devices with memory — compressors, EQ stages, anything with hysteresis (most tape saturation, magnetic circuits) — can still be interesting to visualize, but they can't be reduced to a single transfer curve. The XY plot will form loops or drift over time, and any export should be treated as a rough snapshot rather than a model.

Don’t write those captures off, though — even physics-based hysteresis models are built around a static transfer curve. The Jiles-Atherton model starts from the anhysteretic magnetization (saturation with the dynamics stripped out), then wraps it in nonlinear differential equations to add the feedback. Black Diamond Distortion’s Hysteresis mode lets you hijack that backbone — feed it any curve you’ve drawn or captured, and the physics rebuild the dynamics around it.

Exported .tfunc files load directly into Black Diamond Distortion’s curve browser.

Formats

Operating Systems