UralTone SVT Preamp - Kit

SVT Preamp Kit

The SVT Preamp is a bass preamplifier housed in a cast aluminum enclosure and based closely on the original Ampeg SVT circuit (1972 ⇒), featuring the renowned inductor-based selectable midrange control. A tube-driven, transformer-balanced output and footswitchable output selection and boost have been added to the design.

Applications

This preamp works excellently as a bass front end for studio, rehearsal room, or stage use. It serves as a natural step between pedal building and full amplifier construction, offering vintage-inspired tone with modern practicality.

Technical specifications and features

• Controls: Volume, Treble, Middle, Bass, LO Z output level
• Switches: Middle, Ultra LO, Ultra High, GND lift, Boost, Output
• Inputs: Normal / Bright or High / Low; balanced 600 Ω (LO Z) and unbalanced (HI Z) outputs
• Power: 12 V / 1.2 A supply, recommended 1.5 A (2.1 mm, center positive)
• Tubes: 3 × ECC83 / 12AX7, 1 × ECC82 / 12AU7 (Note: tubes are not included in the parts delivery)
• Dimensions: 222 × 114 × 51 mm (excluding protrusions)
• Enclosure: 1550G, drilled by the builder
• High-quality PCBs and a modern reproduction of the classic midrange inductor
• Optional transformer for the balanced output: https://en.uraltone.com/vrsc-600-30k-small-signal-audio-transformer-20hz-66khz-1-8db.html
• Uses 12 V / 1.5 A supply; 300 VDC tube voltage generated by boost regulator
• Kit includes all components; power supply and tubes not included
• Compatible power supplies e.g.: 12 VDC supply, or pedalboard PSUs like CIOKS DC7, SOL, Crux (12 VDC)

Instructions

The kit includes a parts list and wiring diagram. Illustrated build instructions are available at: https://uraltone.com/blog/uraltone-svt-preamp/

Required tools

Assembly requires basic soldering tools, side cutters, needle-nose pliers, screwdriver, wrench, and a multimeter. Drilling the enclosure requires a drill and a set of drill bits or a step bit.

Technical support

Unlimited technical support is offered by email. The builder is responsible for placing components correctly and wiring the unit according to the instructions. When assembled properly, the device will function as intended. Typical faults result from misplaced or reversed components, poor solder joints, or short circuits between pads. Troubleshooting these belongs to the builder. Phone or in-store support cannot be provided.

Difficulty level

The project is manageable with careful reading of the instructions and basic soldering skills. Patience and attention to detail will be rewarded with a high-quality, vintage-sounding preamp. Building is an addictive hobby that saves money, expands skills, and offers a strong sense of accomplishment.