📍 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. 326S reference preamplifier is a sophisticated, fully balanced design with separate external power supply, discrete circuitry, and precision volume control. It requires 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. 326S SPECIFIC: The No. 326S uses a separate external power supply (the 326S Power Supply Unit). Both chassis require restoration. Capacitors in the power supply and audio chassis degrade over time, causing 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.
About the Mark Levinson No. 326S & My Approach
The Mark Levinson No. 326S reference preamplifier (circa 2004-2012) is one of the finest solid-state preamplifiers ever made. Featuring a fully balanced, dual-mono topology, a precision stepped attenuator volume control, and a separate external power supply, the No. 326S delivers stunning transparency, dynamics, and musicality. The "S" suffix denotes the upgraded version with improved power supply and refined circuitry. I've restored dozens of Mark Levinson preamplifiers over three decades, and I treat each No. 326S 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. 326S:
- 30+ Years of High-End Audio Restoration Experience
- Specialized Knowledge of Mark Levinson Reference Preamps
- Complete Dual-Chassis Restoration (Power Supply + Audio Chassis)
- Full Capacitor Replacement: Power Supply, Audio Boards, Control Section
- Volume Control Relay Service (precision stepped attenuator)
- Input Relay Testing & Replacement
- Precision DC Offset & Channel Matching
- 100% Personal Attention – No Assembly Line
- 90-Day Warranty on All Work
- Nationwide Service – Secure Shipping Available
Complete Mark Levinson No. 326S Restoration Services
🔍 Full Diagnostic & Evaluation Complete assessment of both chassis, power supply check, noise measurement, volume control function test
⚡ External Power Supply Rebuild Replace all electrolytic capacitors, bridge rectifiers, voltage regulators, and critical resistors
🎛️ Audio Chassis Restoration (Dual-Mono) Full recap of left and right audio boards, signal path optimization, 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 XLR and RCA connectors
📟 Control & Display Board Service Capacitor replacement, display check, microprocessor voltage verification
🎚️ DC Offset & Gain Calibration Adjust DC offset to near 0mV, match gain between left and right channels within 0.1dB
🔌 Power Supply Umbilical Service Check umbilical cable and connectors for wear, clean contacts
🏆 COMPLETE FULL RESTORATION All services above – your No. 326S will perform to original reference specifications
💡 WHAT MY RESTORATION INCLUDES: Full electrolytic recap (power supply + audio chassis) • Volume control relay service • Input relay testing • DC offset & gain calibration • Control board recap • Power supply umbilical service • 90-day warranty.
Deep Dive: My Mark Levinson No. 326S Restoration Process
⚡ EXTERNAL POWER SUPPLY (Critical for Low Noise)
- Main Filter Capacitors: Large snap-in electrolytics in the external 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.
- Power Supply Umbilical: I check the umbilical cable and connectors for wear, clean contacts.
🎛️ AUDIO CHASSIS 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. 326S uses discrete transistor gain stages. I test transistors and replace any that are noisy or out of spec.
- Feedback Network: I verify resistor values and replace any that have drifted with 0.1% tolerance metal film.
- Gain Stage Biasing: I verify and adjust gain stage biasing for optimal linearity.
🔊 VOLUME CONTROL (Precision Stepped Attenuator)
- Relay Testing: The No. 326S 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 with 0.1% tolerance types.
- 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. 326S 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 XLR and RCA 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.
- 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. 326S 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 external 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.
#8 Hum / Buzz (Power Supply Umbilical)
Symptom: Audible hum or buzz, especially at low volume.
My Solution: Check umbilical cable connectors, clean pins, verify ground integrity, replace cable if damaged.
Mark Levinson No. 326S – Component Overhaul Database
⚠️ Typical restoration: 60-80 electrolytic capacitors replaced across both chassis, 20-30 relays tested, bias/offset calibrated to factory specs.
EXTERNAL POWER SUPPLY
| 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 CHASSIS (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 (40-50 pcs)
| Test & Replace
| Low signal relays (Omron, Panasonic, or equivalent)
|
| Input Selection Relays (10-15 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. 326S:
- Power Supply Verification: I measure all voltage rails from the external power supply (analog ±15V, ±24V; digital +5V, +3.3V) 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 ±0.05dB 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 <0.0008% at 1kHz.
- Noise Floor: I verify signal-to-noise ratio >115dB 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. 326S to reference-grade performance.
Mark Levinson No. 326S Specifications
| Parameter | Specification |
|---|
| Frequency Response
| ±0.1dB, 5Hz-100kHz
|
| THD+N
| <0.0008% (20Hz-20kHz)
|
| Signal-to-Noise Ratio
| >115dB (A-weighted)
|
| Channel Separation
| >110dB (1kHz)
|
| Gain
| 12dB (balanced), 6dB (single-ended) approx
|
| Volume Control
| Precision stepped attenuator, 0.5dB steps
|
| Inputs/Outputs
| Balanced XLR, Single-ended RCA (multiple)
|
| Power Supply
| External (separate chassis)
|
| Dimensions (WxHxD) per chassis
| 17.8" x 4.5" x 15.5"
|
| Weight (both chassis)
| Approximately 45 lbs (20.5 kg)
|
Frequently Asked Questions – Mark Levinson No. 326S
❓ What makes the No. 326S special?
The No. 326S features a fully balanced, dual-mono topology with an external power supply, precision stepped attenuator volume control, and stunning transparency. The "S" version has improved power supply and refined circuitry over the standard 326.
❓ How long does a full restoration take?
Typically 3-4 weeks due to the dual-chassis complexity and volume control service. Rush service available.
❓ Do you offer nationwide service?
Yes! I serve customers nationwide. You can ship your No. 326S (both chassis) to my Los Angeles facility securely. I provide detailed shipping instructions and insurance guidance.
❓ Do you have spare relays for the volume control?
Yes, I stock replacement relays for the stepped attenuator and input switching sections.
❓ What's the difference between No. 326 and No. 326S?
The 326S has an upgraded external power supply, improved components, and refined circuitry for even lower noise and better performance.
❓ Do you have spare parts for the 326S?
Yes, I've accumulated a stock of capacitors, relays, transistors, and other components for the 326S over 30 years.
❓ Do you warranty your work?
Yes, 90-day warranty on all parts and labor. I stand behind every restoration.
My Service Area – Local & Nationwide
🇺🇸 NATIONWIDE SERVICE AVAILABLE 🇺🇸
Ship your Mark Levinson No. 326S (both chassis) 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 for the dual-chassis system and work with fully insured carriers to ensure your valuable No. 326S 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. 326S Reference Preamplifier Specialist • Dual-Chassis Restoration • Nationwide Service
