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VTA ST-120 with CCS driver board amp KIT assembly manual

Congratulations on your purchase of the VTA ST-120 amp kit. Every effort has been made to give you

the finest sounding, most reliable and best looking 60 watt per channel tube amplifier kit presently

available. Your VTA amp kit features the following items which are all upgrades from the original Dynaco

kits.

1. A new STAINLESS STEEL chassis that is identical in size, shape and markings to the older original

nickel plated steel frame. This chassis is NON-MAGNETIC and removes any magnetic interference effects

of a steel chassis on the audio circuitry.

2. Quality USA made A-260-120 custom wound output transformers which are interleaved/layer-wound

and incorporate high quality M-6 grain oriented laminations.

3. A more robust PA-060-120 power transformer rated at 120 volts, having 410-0-410 secondaries and a

450 milliamp current transfer capability.

4. All stainless steel screws with zinc plated kep nuts

5. Heat resistant Celanex™ octal tube sockets

6. An 80, 40, 30, 20 uF main power supply electrolytic cap.

7. An all triode VTA driver board made of mil-spec epoxy fiberglass. This board also contains an on board

bias supply for the output tubes.

8. Gold plated input and output terminals.

9. A dual choke system rated at 480 milliamps

10. Triode/pentode switches to allow the amp to run in two modes of operation

11. A supplementary cap module (SCM) with an ESL reduction capacitor

Your KIT comes with a very easy to follow instruction manual and a clear pictorial specific to the VTA

driver board. All you need to complete the kit is a soldering pencil, some rosin core solder, a screwdriver,

pliers and a wire cutter/stripper to build your own VTA ST-120. The kit takes about 10-12 hours to build

depending on your skill level and any previous experience with kit building.

List of Parts

1 - 16 gauge heavy duty stainless steel chassis frame with bottom cover

1 - VTA driver board with parts set

7 – Celanex™ octal tube sockets

7 - grounding lugs (in with tube sockets)

1 – USA made PA-060-120 power transformer

4 - hard rubber isolation washers for power transformer

2 - USA made A-260-120 custom interleave/layer wound output transformers

2 - C24-X chokes

1 - multi section (80, 40, 30, 20 uF) quadruple capacitor

1 - three lug terminal strip

1 - pair of gold plated RCA input jack jacks with mounting board

2 - pair of gold plated 3 post output binding posts with mounting board

1 - rubber grommet

1 - fuse post with 5 amp SLO-BLO fuse (inside the fuse holder)

2 – 11 amp rated SPST slide switches

1 - 13 amp rated AC power cord

2 - .022 Mfd 100 volt capacitors

4 - 1000 ohm 1 watt resistors

4 - 10 ohm 2 watt bias resistors

1 - 4.7K ohm 3 watt resistor for quad cap

1 – Supplementary Cap Module (SCM)

1 – ESL reduction capacitor

1 - hardware kit for amp

1 - 22 foot coil of 20 gauge tinned solid core copper wire

1 – triode/pentode kit (2 DPDT switches, two 2 lug terminal strips, 4 X 100 ohm 1 watt resistors)

OPTIONAL > One tube set – 4 X 6550 output tubes, 3 X 12AU7 (or 12BH7, 5963, 6189, 5814), 1 X 5AR4

rectifier

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The VTA ST-120 with CCS driver board amp KIT is a high-fidelity tube amplifier designed for audiophiles and DIY enthusiasts. This kit provides all the necessary components and instructions to build a 60-watt per channel stereo amplifier, emphasizing sound quality, reliability, and aesthetics. It incorporates several upgrades over original Dynaco kits, making it a modern and improved version.

Function Description:

The VTA ST-120 is a stereo tube power amplifier that takes a low-level audio signal and amplifies it to drive loudspeakers. It features a unique "all triode" VTA driver board, which is a key component in its sound signature, known for its warm and detailed audio reproduction. The amplifier also includes triode/pentode switches, allowing users to select between two modes of operation, offering flexibility in sound characteristics. The "all triode" mode typically provides a more linear and transparent sound, while the "pentode" mode offers higher power output and a different tonal quality. An on-board bias supply for the output tubes ensures optimal performance and longevity of the tubes. The dual choke system further contributes to a clean and stable power supply, which is crucial for high-fidelity audio.

Important Technical Specifications:

Power Output: 60 watts per channel.
Chassis: 16-gauge heavy-duty stainless steel, non-magnetic, identical in size, shape, and markings to the original nickel-plated steel Dynaco frame. This non-magnetic property eliminates magnetic interference effects on the audio circuitry.
Output Transformers: USA-made A-260-120 custom wound, interleaved/layer-wound transformers with high-quality M-6 grain oriented laminations. These are critical for accurate sound reproduction and power transfer.
Power Transformer: Robust USA-made PA-060-120, rated at 120 volts, with 410-0-410 secondaries and a 450 milliamp current transfer capability. This ensures ample power delivery for demanding audio signals.
Electrolytic Capacitors: Main power supply features an 80, 40, 30, 20 uF multi-section quadruple capacitor.
Driver Board: All-triode VTA driver board made of mil-spec epoxy fiberglass, incorporating an on-board bias supply.
Tube Sockets: Heat-resistant Celanex™ octal tube sockets, ensuring durability and stable connections for the power tubes.
Terminals: Gold-plated input and output terminals for superior signal conductivity and corrosion resistance.
Chokes: Dual choke system rated at 480 milliamps.
Fuse: 5 amp SLO-BLO fuse (located inside the fuse holder).
Wiring: 22-foot coil of 20 gauge tinned solid core copper wire.
Optional Tube Set: 4 x 6550 output tubes, 3 x 12AU7 (or 12BH7, 5963, 6189, 5814) driver tubes, and 1 x 5AR4 rectifier tube.

Usage Features:

DIY Assembly: The kit is designed for self-assembly, providing a rewarding experience for hobbyists. The estimated build time is 10-12 hours, depending on skill level.
User-Friendly Manual: Comes with a very easy-to-follow instruction manual and clear pictorials specific to the VTA driver board, simplifying the assembly process.
Triode/Pentode Switching: Includes switches to select between triode and pentode modes of operation, allowing users to tailor the amplifier's sound characteristics to their preference or the music being played.
High-Quality Components: Utilizes premium components, including custom-wound transformers, mil-spec fiberglass PCB, and gold-plated terminals, contributing to excellent sound quality and reliability.
Aesthetic Customization: The manual suggests optionally painting the transformers for a better appearance, recommending semi-gloss paints like Krylon "Fusion" Satin black or automotive engine enamel. This allows users to personalize the amplifier's look.
Easy Maintenance: The design, with its accessible components and clear wiring diagrams, facilitates future maintenance or modifications.

Maintenance Features:

Component Accessibility: The internal layout, as depicted in the pictorials, shows a well-organized structure, making individual components accessible for inspection, testing, or replacement.
Clear Wiring: The detailed wiring instructions and diagrams aid in troubleshooting any connection issues that may arise during or after assembly.
Robust Construction: The heavy-duty stainless steel chassis and heat-resistant tube sockets are designed for long-term durability, minimizing the need for frequent repairs.
Bias Adjustment: The on-board bias supply for the output tubes simplifies the process of setting and maintaining optimal tube bias, which is crucial for tube longevity and performance.
Transformer Painting (Optional): The manual provides detailed steps for painting the transformers, which not only enhances aesthetics but can also offer a layer of protection to the transformer bells. This process involves careful sanding, cleaning, and spraying.
Standard Tools: Assembly and maintenance require only basic tools such as a soldering pencil, rosin core solder, a screwdriver, pliers, and a wire cutter/stripper, making it accessible for most DIY enthusiasts.