📍 Los Angeles County & SoCal
🔧 30+ Years Experience
🎚️ High-End Preamp Specialist
🏢 TEK Media Group
🇺🇸 WE WORK LOCALLY & NATIONWIDE 🇺🇸
Los Angeles • Southern California • Shipping Available Across the United States
📋 TECHNICAL DISCLAIMER: The Mark Levinson No. 380 and No. 380S preamplifiers are sophisticated, fully balanced designs with discrete circuitry, precision volume control, and complex power supply regulation. They require specialized knowledge, documentation, and test equipment for proper restoration. I have the expertise and parts access to restore these units correctly.
⚠️ CRITICAL WARNING – MARK LEVINSON NO. 380/380S SPECIFIC: The No. 380 series uses high-quality but aging electrolytic capacitors in the power supply, audio path, and control sections. Capacitor degradation causes increased noise, loss of transparency, and compromised dynamics. The volume control and input switching relays can also develop issues. I provide a thorough, methodical restoration to factory specifications. The 380S includes upgraded components and circuitry over the standard 380.
About the Mark Levinson No. 380 / 380S & My Approach
The Mark Levinson No. 380 (introduced 1996) and No. 380S (introduced 1999) are reference-grade preamplifiers that defined high-end audio performance for their era. Featuring a fully balanced, dual-mono topology, precision stepped volume control, and a sophisticated power supply, the 380 series delivers stunning transparency, dynamics, and musicality. The 380S added improved components, upgraded power supply, and refined circuitry. Both models remain highly sought after by discerning audiophiles worldwide. I've restored dozens of Mark Levinson preamplifiers over three decades, and I treat each No. 380/380S with meticulous care, using premium replacement parts while preserving the original reference-grade sonic character.
✅ WHY TRUST TEK MEDIA GROUP WITH YOUR MARK LEVINSON NO. 380/380S:
- 30+ Years of High-End Audio Restoration Experience
- Specialized Knowledge of Mark Levinson Preamplifiers
- Complete Dual-Mono Restoration (Both Channels)
- Full Capacitor Replacement: Power Supply, Audio Boards, Control Section
- Volume Control Relay Service (stepped attenuator)
- Input Relay Testing & Replacement
- Precision DC Offset & Channel Matching
- 380S Upgrade Options Available
- 100% Personal Attention – No Assembly Line
- 90-Day Warranty on All Work
- Nationwide Service – Secure Shipping Available
Complete Mark Levinson No. 380/380S Restoration Services
🔍 Full Diagnostic & Evaluation Complete assessment, power supply check, noise measurement, volume control function test, baseline performance
⚡ Power Supply Rebuild Replace all electrolytic capacitors, bridge rectifiers, voltage regulators, and critical resistors
🎛️ Audio Board Restoration (Dual-Mono) Full recap of left and right audio boards, signal path optimization, op-amp or discrete stage service
🔊 Volume Control Service Test and clean stepped attenuator relays, verify tracking accuracy between channels
🔄 Input Switching Service Test all input relays, replace if intermittent or noisy, clean RCA/XLR connectors
📟 Control & Display Board Service Capacitor replacement, display check, microprocessor voltage verification, remote sensor test
🎚️ DC Offset & Gain Calibration Adjust DC offset to near 0mV, match gain between left and right channels within 0.1dB
✨ 380S Upgrade (for standard 380) Upgrade standard 380 to 380S specifications (optional) - improved caps, refined power supply
🏆 COMPLETE FULL RESTORATION All services above – your No. 380/380S will perform to original reference specifications
💡 WHAT MY RESTORATION INCLUDES: Full electrolytic recap (power supply + audio boards) • Volume control relay service • Input relay testing • DC offset & gain calibration • Control board recap • Remote sensor check • 90-day warranty • 380S upgrade available.
Deep Dive: My Mark Levinson No. 380/380S Restoration Process
⚡ POWER SUPPLY (Critical for Low Noise)
- Main Filter Capacitors: Large snap-in electrolytics in the power supply – I replace with high-ripple, low-ESR, 105°C rated types (Nichicon KG, Panasonic, or Cornell Dubilier).
- Regulator Section: I replace all small electrolytic capacitors on the regulator boards, verify voltage rails (±15V, +5V, +5VA, etc.) within tolerance.
- Bridge Rectifiers: I test and replace if noisy, upgrade to ultra-fast soft recovery types for lower noise floor.
- AC Input & Safety: I inspect AC input filter, replace RIFA caps if present, check fuses and IEC inlet.
- Transformer Check: I verify toroidal transformer output voltages and listen for mechanical hum.
🎛️ AUDIO BOARD RESTORATION (Dual-Mono Design)
COMPLETE SIGNAL PATH RESTORATION:
- Electrolytic Capacitors: All coupling and power supply decoupling caps on the audio boards are replaced with audio-grade types (Nichicon FG, Elna Silmic II, or WIMA films for small values).
- Discrete Stage Service: The No. 380 uses discrete transistor gain stages. I test transistors and replace any that are noisy or out of spec.
- Op-Amp Upgrade (Optional): For units with op-amps, I can upgrade to modern low-noise types (OPA1611, OPA1656) if desired.
- Feedback Network: I verify resistor values and replace any that have drifted.
🔊 VOLUME CONTROL (Stepped Attenuator)
- Relay Testing: The No. 380 uses a relay-switched stepped attenuator for precision volume control. I test each relay for contact resistance and proper operation.
- Relay Replacement: I replace any relays that are intermittent, noisy, or have high contact resistance.
- Resistor Ladder Check: I verify the precision resistor ladder values, replace any drifted resistors.
- Channel Tracking: I verify volume tracking between left and right channels within 0.5dB across the entire range.
🔄 INPUT SWITCHING & CONNECTORS
- Input Relays: The No. 380 uses high-quality relays for input switching. I test and replace any that show increased contact resistance or intermittent operation.
- Connector Cleaning: I clean all RCA and XLR connectors with DeoxIT, tighten any loose jacks.
- Balanced Line Driver/Receiver: I verify proper operation of balanced input and output stages.
📟 CONTROL & DISPLAY BOARD
- Microprocessor Supply Caps: Replace electrolytic capacitors on the control board to ensure stable operation of the logic circuits.
- Display VFD Check: I verify the vacuum fluorescent display for brightness and missing segments. Replacement displays are available if needed.
- Front Panel Controls: I clean the volume encoder and button contacts, ensuring smooth operation.
- Remote Control Sensor: I check IR receiver operation, replace if weak.
Common Mark Levinson No. 380/380S Problems I Solve
#1 Capacitor Aging in Power Supply
Symptom: Increased noise floor, loss of transparency, hum, reduced dynamics.
My Solution: Complete recap of all electrolytic capacitors in the power supply and regulator sections.
#2 Volume Control Issues (Relay Noise / Skipping)
Symptom: Clicking or popping when changing volume, uneven channel balance, steps not tracking correctly.
My Solution: Test and replace faulty relays in the stepped attenuator, verify resistor ladder, recalibrate volume mapping.
#3 DC Offset Drift
Symptom: Output relay protection triggering, audible thump on power on/off, DC at outputs.
My Solution: Replace aging input differential pair transistors, recalibrate DC offset to near 0mV.
#4 One Channel Distorted / Low Output
Symptom: Imbalance between channels, distortion on one side.
My Solution: Check audio board components, replace capacitors, test discrete transistors, verify relay contacts.
#5 Input Switching Issues
Symptom: Input not switching, intermittent connection, noise when switching, no sound on certain inputs.
My Solution: Replace input relays, clean contacts, check control logic.
#6 Display Dim or Missing
Symptom: VFD display dim, flickering, or not working.
My Solution: Check filament voltage, replace driver capacitors, replace VFD if necessary.
#7 Remote Control Not Working
Symptom: No response to remote commands.
My Solution: Check IR sensor on front panel, replace electrolytic caps on control board, verify remote transmitter.
Mark Levinson No. 380/380S – Component Overhaul Database
⚠️ Typical restoration: 60-80 electrolytic capacitors replaced, 10-20 relays tested, bias/offset calibrated to factory specs.
POWER SUPPLY SECTION
| Component |
Original Type |
My Restoration Replacement |
| Main Filter Caps (4-6 pcs) |
4,700-10,000µF @ 35-50V |
High-ripple, 105°C (Nichicon KG / Cornell) |
| Regulator Board Caps |
47-1000µF @ 16-50V |
Low Impedance, 105°C (Panasonic FC / Nichicon PW) |
| Bridge Rectifiers |
Standard silicon |
Ultra-fast Soft Recovery (IXYS or Vishay) |
AUDIO BOARDS (Per Channel)
| Section |
Capacitor Count |
My Replacement |
| Power Supply Decoupling |
10-15 caps |
Low ESR, 105°C (Panasonic FC / Nichicon PW) |
| Signal Path Caps |
8-12 caps |
Audio Grade (Nichicon FG / Elna Silmic II / WIMA) |
| Feedback / Compensation |
4-6 caps |
Polystyrene or C0G/NP0 Ceramic |
VOLUME CONTROL & INPUT SWITCHING
| Component | Action | Specification |
|---|
| Volume Control Relays (30-40 pcs) |
Test & Replace |
Low signal relays (Omron, Panasonic, or equivalent) |
| Input Selection Relays (8-12 pcs) |
Test & Replace |
Low contact resistance, hermetically sealed preferred |
| Resistor Ladder |
Verify Values |
0.1% tolerance metal film if replacement needed |
Precision Calibration & Performance Testing
🎛️ MY CALIBRATION & TESTING PROCESS FOR NO. 380/380S:
- Power Supply Verification: I measure all voltage rails (analog ±15V, digital +5V, etc.) to within ±1% tolerance.
- DC Offset Adjustment: Using a precision DMM, I adjust DC offset at main outputs to <±1mV.
- Gain Matching: I verify gain between left and right channels within ±0.1dB across the entire frequency range.
- Volume Control Tracking: I test volume step accuracy and channel tracking from minimum to maximum, ensuring <0.5dB tracking error.
- Distortion Measurement: I measure THD+N at various frequencies and levels, targeting <0.001% at 1kHz.
- Noise Floor: I verify signal-to-noise ratio >110dB A-weighted.
- Frequency Response: I measure response from 5Hz to 100kHz, ensuring ±0.1dB flatness.
- Input/Output Impedance: I verify input and output impedance specifications.
💡 NOTE: Proper calibration requires precision test equipment (DMM, oscilloscope, distortion analyzer, audio generator). I have all the tools and 30+ years of experience to restore your No. 380/380S to reference-grade performance.
No. 380 vs. No. 380S – What's the Difference?
| Feature |
No. 380 |
No. 380S |
| Power Supply |
Standard regulation |
Upgraded regulation with lower noise |
| Audio Path Capacitors |
Standard electrolytic |
Upgraded audio-grade capacitors |
| Volume Control |
Stepped attenuator |
Refined stepped attenuator with better tracking |
| Noise Floor |
>105dB |
>110dB (improved) |
| Upgrade Path |
I can upgrade standard 380 to 380S spec |
Factory S version - no further upgrade needed |
💡 UPGRADE NOTE: I offer 380-to-380S upgrade services for standard No. 380 owners. This includes upgraded capacitors, power supply refinements, and calibration to 380S specifications.
Mark Levinson No. 380/380S Specifications
| Parameter | Specification |
|---|
| Frequency Response |
±0.1dB, 5Hz-100kHz |
| THD+N |
<0.001% (20Hz-20kHz) |
| Signal-to-Noise Ratio |
>105dB (380), >110dB (380S) A-weighted |
| Channel Separation |
>100dB (1kHz) |
| Gain |
12dB (balanced), 6dB (single-ended) approx |
| Volume Control |
Stepped attenuator, 0.5dB steps (approx) |
| Inputs/Outputs |
Balanced XLR, Single-ended RCA (multiple) |
| Dimensions (WxHxD) |
17.8" x 4.5" x 15.5" |
| Weight |
Approximately 25 lbs (11.3 kg) |
Frequently Asked Questions – Mark Levinson No. 380/380S
❓ What's the difference between No. 380 and No. 380S?
The 380S features an upgraded power supply, improved audio path capacitors, refined volume control, and lower noise floor. I can upgrade standard 380 units to 380S specifications.
❓ How long does a full restoration take?
Typically 3-4 weeks due to the complexity of the volume control and dual-mono design. Rush service available.
❓ Do you offer nationwide service?
Yes! I serve customers nationwide. You can ship your No. 380/380S to my Los Angeles facility securely. I provide detailed shipping instructions and insurance guidance.
❓ Can you upgrade my standard 380 to 380S?
Yes, I offer a 380-to-380S upgrade service that includes upgraded capacitors, power supply refinements, and calibration to 380S specifications.
❓ Do you have spare relays for the volume control?
Yes, I stock replacement relays for the stepped attenuator and input switching sections.
❓ Do you warranty your work?
Yes, 90-day warranty on all parts and labor. I stand behind every restoration.
❓ How do I ship my preamplifier safely?
I provide detailed packing instructions. Double-boxing with adequate padding is essential. I recommend insurance for high-value shipments.
My Service Area – Local & Nationwide
🇺🇸 NATIONWIDE SERVICE AVAILABLE 🇺🇸
Ship your Mark Levinson No. 380/380S securely to my Los Angeles facility – I serve customers across all 50 states
Local Service: Los Angeles County, Orange County, Ventura County, Riverside County, San Bernardino County, and surrounding Southern California areas. Local pickup and delivery available.
Nationwide Service: For customers outside Southern California, I offer secure shipping options. I provide detailed packing instructions and work with fully insured carriers to ensure your valuable No. 380/380S arrives safely. I've restored equipment for clients across the United States.
Los Angeles County: LA Burbank Glendale Santa Monica Hollywood Pasadena Beverly Hills
Orange County: Santa Ana Anaheim Irvine Costa Mesa Newport Beach
Nationwide Shipping: New York Texas Florida Illinois Colorado Washington All 50 States
TEK Media Group — High-End Audio Restoration Since 1994
📞 (818) 244-4440 | ✉️ service@tekmediagroup.com
Serving Los Angeles, Orange County, Ventura, Riverside, San Bernardino, and nationwide via secure shipping
Specializing in Mark Levinson, Krell, Audio Research, McIntosh, and High-End Reference Components
Mark Levinson No. 380/380S Preamplifier Specialist • Nationwide Restoration Expert • 380 to 380S Upgrades Available
