Nagra NTA-2S
2-Channel Stereo Reel to Reel Restoration

About the Nagra NTA-2S & My Service

The Nagra NTA-2S is the 2-channel stereo version of the legendary T-Audio series, designed for professional studio mastering and broadcast applications. Produced in the 1980s, this machine represents the pinnacle of Nagra's engineering for stereo recording. With its microprocessor-controlled transport, precision capstan servo, and Nagra's legendary audio electronics, the NTA-2S delivers exceptional sonic performance that has made it a favorite among mastering engineers and audiophiles.

I'm the owner and lead technician at Tek Media Group, and I've been restoring Nagra tape machines since 1994. I have extensive experience with the entire T-Audio series, including the NTA-2S stereo model. I understand the critical requirements for proper stereo alignment, channel matching, and calibration. Every Nagra that comes to my bench receives meticulous attention to preserve its legendary performance and value.

Restoration Services I Offer

The Nagra NTA-2S – Stereo Mastering Excellence

Detailed Repair Information – From My Workbench

• Main Filter Capacitors: Large electrolytic caps – I replace with 105°C rated, high-ripple current types
• Frako Capacitors: Known failure points – I replace ALL Frako electrolytics on sight
• RIFA Suppression Caps: Exploding caps on mains input – I replace BEFORE powering on
• Voltage Regulators: 78xx and 79xx series – I test and replace as needed
• Voltage Rail Verification: I verify all rails (±15V, +5V, +24V, +48V) after restoration

• Capstan Belt: Critical for speed stability – I replace with factory-spec belt
• Pinch Roller: Hardened rubber causes wow/flutter – I replace with new Nagra-spec roller
• Reel Motor Service: I clean and lubricate reel motors, verify torque
• Tension Sensors: I clean opto-interrupters and recalibrate tension settings
• Brake Adjustment: I verify and adjust brakes for proper stopping

• Capstan Servo Board: Full recap and calibration
• Speed Reference: I verify crystal oscillator accuracy
• Motor Driver Transistors: I test and replace if necessary
• Microprocessor Control: I verify logic operation and EPROM integrity
• Speed Accuracy: I verify speed accuracy to ±0.1%

Common Nagra NTA-2S Problems I Solve

#1 Frako Electrolytic Capacitor Failure

Symptom: Missing power rails, blown fuses, dead channels, intermittent operation, noise, hum.
My Solution: Complete replacement of ALL Frako electrolytic capacitors throughout the machine (power supply, 2 audio channels, control).

#2 RIFA "Exploding" Capacitor

Symptom: Smoke, burning smell, loud crack, blown fuse.
My Solution: I replace with X2 class safety capacitors BEFORE applying power – this is step one on any machine that comes to my bench.

#3 Stereo Channel Imbalance

Symptom: Left and right channels mismatched in level or frequency response, poor stereo imaging.
My Solution: Full recap of both audio channels, op-amp replacement, calibration, and precise channel matching within 0.1dB.

#4 Azimuth Misalignment

Symptom: Loss of high frequencies, phase issues, poor stereo imaging, comb filtering.
My Solution: I perform precise azimuth alignment using 10kHz test tape and oscilloscope to ensure proper phase relationship between channels.

#5 Dead or Noisy Audio Channels

Symptom: One or both channels dead, distorted, noisy, or intermittent.
My Solution: Full channel card recap, op-amp replacement, edge connector cleaning, calibration.

#6 Wow & Flutter / Speed Instability

Symptom: Pitch wavering, unstable speed, audible flutter affecting stereo imaging.
My Solution: I replace capstan belt and pinch roller. Clean capstan shaft. Adjust capstan servo.

#7 Transport Won't Engage / Tape Tension Issues

Symptom: Tape won't load, transport issues, tape spillage, tension errors.
My Solution: I clean and recalibrate tension sensors. Adjust reel motor torque. Replace worn belts.

#8 Head Wear & Alignment Issues

Symptom: Loss of high frequencies, increased noise, dropouts, poor stereo imaging.
My Solution: I perform head relapping or replacement, full stereo head alignment, azimuth adjustment, and phase verification.

My Restoration Process

Capacitor Replacement Database

This is a comprehensive list of all electrolytic and tantalum capacitors used in the Nagra NTA-2S, including values and locations. I use only high-quality, reliable capacitors for replacements to ensure long-lasting performance.