• Opto Tremolo: Optical tremolo (a.k.a. “Photocell Tremolo”) is the effect found in many combo amps of the 1960s. This version of tremolo relies upon a neon light bulb and a light dependent resistor called an "optocoupler." The non-symmetrical aspects of the light and the optocoupler give the tremolo a distinct choppy character. 
• Harmonic Tremolo: This unique effect first appeared in Fender™  “brownface” amps made between 1959 and 1963, which alternately modulated the levels of bass and treble frequencies in the audio signal. The result is a very pleasing and complex tremolo that has characteristics reminiscent of a phaser.
• Bias Tremolo: This approach to tremolo involves using an LFO to modulate the bias voltage of the tubes in an amplifier. This essentially pushes the tubes in and out of saturation. The result is a smooth amplitude modulation with a mild overdrive created by the tube saturation.

Pedal Features

• Three Distinct Spring Reverb and Tremolo Effects.
• Two Modes of Operation – Use the pedal in Standard Mode for a classic (non-preset) stompbox experience or turn on Preset Mode and save a user preset (including reverb/tremolo effects and knob positions) to each of the three toggle switch positions. 
• Flexible Stereo Routing – The True Spring is equally at home in a mono or stereo rig. The pedal’s stereo inputs and outputs offer a variety of routing options such as Stereo to Stereo, Mono to Mono, Mono-to-Stereo, Stereo Sum-to-Mono and External Loop Mode. 
• Universal Bypass — Select Active Analog (Buffered) or True Bypass.
• Secondary Tremolo Controls - Press and hold the CONTROL INPUT button to access the True Spring's tremolo effects (DWELL knob controls tremolo DEPTH / TONE knob controls tremolo RATE / toggle switch selects tremolo type).
• Expression Control — Compatible with Source Audio expression pedals and the Hot Hand 3 Universal Wireless Effects Controller. Assign up to three simultaneous parameters with editable depth and direction.
• External Tap Tempo – Use the Source Audio Tap Switch to tap in the tremolo rate with a choice of four different beat divisions (quarter, eighth, triplet, and sixteenth).
• External Tremolo Engage and Bypass – Use the Source Audio Tap Switch to engage or disengage the tremolo effects on top of an active spring reverb.

Neuro Editor Features

Connect the True Spring Reverb to the Neuro Mobile App (a free download for iOS and Android) or the Neuro Desktop Editor (a free download for Mac or Windows computers) and explore the power of effect downloading, customization, and sharing that comes with every One Series pedal.

• Interchangeable Algorithms — Upload any of the additional reverb or tremolo effects directly to the pedal at no additional charge.
• Customize Effects — Tweak an additional set of parameters including advance EQ, pre-delay, diffusion, reverb modulation, virtual spring length, and more.
• Save and Share Customized Presets — Once you’ve fine-tuned an effect, save it to your personal effects collection in the cloud and share it with the growing community of Neuro users.
• Download Presets — Explore Source Audio’s ever-expanding library of effect presets. Choose from Source Audio Factory presets or presets created and published by members of the Neuro Community.
• Signal Routing Options — Re-route the stereo Inputs and Outputs in a number of different ways including Auto Detect, True Stereo, Mono to Stereo, External Effects Loop, and more.
• Simple Connection — The Neuro Mobile App. connects with the True Spring via the mobile device’s headphone jack and Stereo Input 2 on the pedal. A Neuro App connector cable (1/8” to 1/4”) is included with the pedal.
• USB Connection – Use the pedal’s mini USB port to connect the True Spring to the Neuro Desktop Editor, which can be used to edit presets or download the latest pedal firmware.

Midi Features

The True Spring Reverb also features full MIDI capability and simplicity when coupled with the Neuro Hub (formerly Soundblox Hub).

• Preset Saving – Save up to 128 effect presets.
• Multi Pedal Scene Saving – Connect up to five One Series and Soundblox 2 pedals to the Neuro Hub and create 128 multi pedal scenes, recallable via MIDI program change messages.
• External Expression Control – Connect the Neuro Hub to any Source Audio expression pedal, Hot Hand 3 Wireless Effects Controller or third party TRS (Tip Hot) expression pedal and manually control effect modulation or assign individual or simultaneous expression control to any adjustable parameter.
• MIDI Clock – Sync your tremolo rate with external MIDI clock messages.

Specifications

• Includes 9v DC power supply (300mA / Negative Tip)
• Includes 1/8” to 1/4” cable for Neuro Mobile App connection.
• Power Consumption — 165mA
• USB port — Connects to Mac or Windows PC for firmware updates and the forthcoming in-depth effects editing software.
• Brushed anodized aluminum housing.
• Dimensions: L: 4.5 in./11.4cm x W: 2.75 in./7cm x H: 2 in./5.1cm (including knobs)