📍 Los Angeles County & SoCal
🔧 30+ Years Experience
🎚️ Tube Audio Specialist
🏢 Tek Media Group
📋 TECHNICAL DISCLAIMER: The H.H. Scott 355 is a vacuum tube receiver that operates with potentially lethal voltages. Capacitors can retain dangerous charge even after power-off. I strongly recommend that only qualified technicians perform internal service. I have the expertise, test equipment, and tube-era knowledge to restore these units safely and correctly.
⚠️ CRITICAL WARNING – VINTAGE TUBE EQUIPMENT: The H.H. Scott 355 uses selenium rectifiers, wax/paper capacitors, and carbon-comp resistors that degrade with age. These components MUST be addressed before safe operation. I provide a methodical, safety-first restoration approach to preserve both the equipment and the listener.
About the H.H. Scott 355 & My Approach
The H.H. Scott 355 is a legendary all-tube AM/FM stereo receiver from the golden age of hi-fi (circa 1962-1965). Known for its lush, warm sound, excellent tuner section, and robust construction, it's a favorite among collectors and vintage audio enthusiasts. The 355 features a sensitive FM tuner with a 6BL8 multiplex decoder, a capable preamp section, and a power amplifier using 7591 output tubes delivering about 35-40 watts per channel. I've restored countless Scott units over three decades, and I treat each one with the respect it deserves, using modern high-quality components while preserving the original sonic character.
✅ WHY TRUST TEK MEDIA GROUP WITH YOUR H.H. SCOTT 355:
- 30+ Years of Tube Audio Restoration Experience
- Specialized Knowledge of H.H. Scott Circuitry & FM Tuners
- Complete Safety Restoration: Selenium Rectifier Replacement, Capacitor Reforming/Replacement
- Full Tube Testing on Hickok & Precision Testers
- Precision FM Alignment with Sweep Generator & Oscilloscope
- Upgrade Options: Premium Coupling Caps, Safety Modifications, Bias Adjustment
- 100% Personal Attention – No Assembly Line
- 90-Day Warranty on All Work
- Local Service Throughout Southern California
Complete H.H. Scott 355 Restoration Services
🔍 Full Diagnostic & Evaluation Visual inspection, tube testing, initial power-up with variac, performance baseline
⚡ Power Supply Rebuild Replace selenium rectifier with silicon diodes, replace all electrolytic capacitors, add safety resistors, upgrade multi-section cans
🎛️ Full Capacitor Replacement Replace ALL wax/paper, bumblebee, and electrolytic capacitors with high-quality film and modern electrolytic types
📏 Resistor & Component Testing Measure and replace out-of-tolerance carbon-comp resistors, check ceramic caps, test switches and pots
💡 Tube Testing & Replacement Test all tubes on Hickok tester, match output tubes (7591), replace weak or noisy tubes
📻 FM Tuner Alignment Complete FM front-end and IF alignment, multiplex decoder alignment for optimal stereo separation
🔊 Amplifier Calibration Bias adjustment, balance, phase inverter check, distortion measurement
✨ Cosmetic & Mechanical Service Clean controls, lubricate tuning capacitor, replace dial lamps, clean faceplate
🏆 COMPLETE FULL RESTORATION All services above – your Scott 355 will sound and perform like new, safely
💡 WHAT MY RESTORATION INCLUDES: Selenium rectifier elimination • Full electrolytic recap (power supply & cathode bypass) • All paper/wax coupling capacitors replaced with film • Out-of-tolerance resistors • Tube testing & biasing • FM alignment (if tuner issues) • Control cleaning • Safety modifications • 90-day warranty.
Deep Dive: My H.H. Scott 355 Restoration Process
⚡ POWER SUPPLY & SAFETY (Critical First Step)
- Selenium Rectifier: I replace the original selenium rectifier (a common failure and toxic hazard) with a modern silicon bridge diode, adding a dropping resistor to maintain proper B+ voltage.
- Multi-Section Filter Caps: The original "twist-lock" electrolytic capacitors are rebuilt or replaced with modern high-temperature, high-ripple units. I either restuff the cans or discreetly mount new capacitors for reliability and safety.
- Bias Supply: I rebuild the negative bias supply with fresh capacitors and diodes, ensuring stable output tube bias and extended tube life.
- Safety Modifications: I add a fused IEC power inlet, replace the two-prong cord with a grounded cord, and install safety caps across the AC line.
🎚️ AUDIO & COUPLING STAGES
COMPLETE SIGNAL PATH RESTORATION:
- Coupling Capacitors: I replace all bumblebee, black beauty, and wax/paper capacitors with high-quality polypropylene film caps (Auricap, Illinois, or similar). This eliminates leakage, restores bass response, and eliminates distortion.
- Cathode Bypass Caps: All electrolytic cathode bypass capacitors are replaced with low-impedance, high-reliability types.
- Resistor Replacement: Carbon composition resistors drift high over time. I measure and replace any resistor out of tolerance (typically >10% drift) with carbon film or metal film for improved noise performance.
- Tube Socket & Pin Cleaning: I clean all tube sockets and pins for reliable contact.
📻 FM TUNER & MULTIPLEX ALIGNMENT
- Front End Check: I verify oscillator and RF section performance, replace weak tubes (6AQ8, 6AU6, etc.).
- IF Strip Alignment: Using a sweep generator and oscilloscope, I perform a full 10.7MHz IF alignment to restore sensitivity and selectivity.
- Multiplex Decoder (6BL8): I align the 38kHz oscillator, adjust separation and stereo blend for proper stereo performance.
- FM Detector & Ratio Detector: I calibrate the discriminator for lowest distortion and correct center tuning.
💡 TUBE TESTING & OUTPUT SECTION
- Tube Testing: I test every tube on a calibrated Hickok tube tester for mutual conductance and gas. Weak or microphonic tubes are identified and replaced.
- Output Tube Matching (7591): The 7591 output tubes are critical. I match them for transconductance and bias current to ensure balanced operation and lowest distortion.
- Bias Adjustment: I modify the bias circuit to include individual bias adjustments or matched pairs for optimal performance and tube longevity.
- Phase Inverter Balance: I check and balance the phase inverter for symmetrical drive to the output tubes.
Common H.H. Scott 355 Problems I Solve
#1 Selenium Rectifier Failure
Symptom: No power, low B+, burning smell, hum.
My Solution: Replace with silicon diodes, add dropping resistor, rebuild bias supply for reliability and safety.
#2 Leaky Bumblebee / Paper Capacitors
Symptom: Muddy sound, low volume, distortion, output tube red-plating.
My Solution: I replace ALL paper and bumblebee caps with modern film caps, restoring proper frequency response and safety.
#3 Weak / No FM Reception
Symptom: Poor stereo separation, hiss, inability to tune stations.
My Solution: Full FM alignment, tube replacement, and multiplex decoder service.
#4 Hum & Ripple
Symptom: Audible 60Hz or 120Hz hum.
My Solution: Rebuild power supply filter caps, replace cathode bypass caps, check grounding, add or replace can capacitors.
#5 Noisy Controls / Scratchy Pots
Symptom: Crackling when adjusting volume or balance.
My Solution: Thorough cleaning with DeoxIT, lubrication, replacement if necessary.
#6 Output Tube Red-Plating
Symptom: Plates glowing red, distortion, blown fuse.
My Solution: Rebuild bias supply, replace coupling caps, match output tubes, add bias adjustment mod.
H.H. Scott 355 Restoration – Component Overhaul
⚠️ Typical parts count: 40+ electrolytic & 50+ film/wax capacitors replaced. I use premium audiophile-grade components.
POWER SUPPLY & BIAS
| Component | Original Type | My Restoration Replacement |
|---|
| Selenium Rectifier | Selenium Stack | Silicon Bridge + Dropping Resistor |
| Filter Capacitor C1 (multi-can) | 40/40/20/20 µF @ 450V | Rebuilt can or discrete high-temp caps |
| Bias Supply Caps | 50-100µF @ 50V | Nichicon / Panasonic 105°C |
| AC Safety Caps | Ceramic/paper | X1/Y2 safety capacitors |
COUPLING & SIGNAL CAPACITORS
| Circuit Location | Original | My Replacement |
|---|
| Phase Inverter to Output Grids | .1µF / .047µF Bumblebee | Polypropylene Film (Auricap/Illinois) |
| Preamp to Phase Inverter | .022µF / .047µF Wax/Paper | Polypropylene Film or PIO (upgrade) |
| RIAA Equalization | Ceramic / Mylar | Polystyrene or Polypropylene (tight tolerance) |
TUBE COMPLEMENT & TESTING
| Tube | Function | My Action |
|---|
| 7591 (x4) | Output Tubes | Test, match, replace if weak. Provide bias adjustment. |
| 12AX7 / 12AU7 | Preamp / Phase Inverter | Test for noise, microphonics, replace with low-noise. |
| 6BL8 / 6AU6 / 6AQ8 | FM Tuner / Multiplex | Test, replace as needed, realign tuner. |
FM Tuner & Amplifier Calibration
📻 PRECISION ALIGNMENT & CALIBRATION:
- FM IF Alignment: Using a sweep generator (10.7MHz) and oscilloscope, I align each IF transformer for maximum gain and correct bandwidth.
- FM Detector / Ratio Detector: I adjust for minimum distortion and correct center tuning using a distortion analyzer.
- Multiplex Decoder Alignment: I adjust the 38kHz oscillator and separation controls for maximum stereo separation (>30dB) and minimal crosstalk.
- Amplifier Bias & Balance: I set bias current per channel and balance phase inverter for symmetrical output.
- Power Output Check: I verify power output and distortion using an audio analyzer.
Frequently Asked Questions – H.H. Scott 355
❓ What makes the Scott 355 special?
The 355 is a classic all-tube receiver with a warm, detailed sound, a superb FM tuner, and robust 7591 output tubes. It's highly sought after for its musicality and build quality.
❓ How long does a full restoration take?
Typically 4-6 weeks depending on parts availability and required alignment. Rush service available.
❓ Do you offer pickup and delivery in Southern California?
Yes, for Los Angeles, Orange County, Ventura, Riverside, San Bernardino, and surrounding areas.
❓ Do you have replacement tubes and parts?
Yes, I stock quality tubes (7591, 12AX7, etc.) and all necessary passive components for the Scott 355.
❓ Is it safe to use after restoration?
Absolutely. My restoration includes a grounded power cord, safety capacitors, and replaces dangerous selenium rectifiers and leaky caps, making it safe for daily use.
❓ Do you modify the circuit or keep it original?
I focus on safe, reliable restoration that preserves the original sound. I can do subtle upgrades (bias adjustment, premium caps) if desired, but always reversible.
❓ Do you warranty your work?
Yes, 90-day warranty on all parts and labor. I stand behind every restoration.
My Service Area – Southern California
I serve Los Angeles County, Orange County, Ventura County, Riverside County, San Bernardino County, San Diego County, and surrounding areas. Local pickup and delivery available.
Los Angeles County:
Los Angeles
Burbank
Glendale
Santa Monica
Hollywood
Pasadena
Long Beach
Torrance
West Hollywood
Culver City
San Fernando
Palmdale
Lancaster
Whittier
Downey
Orange County:
Santa Ana
Anaheim
Irvine
Costa Mesa
Huntington Beach
Fullerton
Garden Grove
Newport Beach
Mission Viejo
Orange
Ventura & Inland Empire:
Ventura
Thousand Oaks
Oxnard
Camarillo
Riverside
San Bernardino
Ontario
Rancho Cucamonga
Corona
Redlands
Chino
San Diego County:
San Diego
La Jolla
Carlsbad
Oceanside
Escondido
Chula Vista
El Cajon
Tek Media Group — Vintage Tube Audio Restoration Since 1994
📞 (818) 244-4440 | ✉️ service@tekmediagroup.com
Serving Los Angeles, Orange County, Ventura, Riverside, San Bernardino, and all of Southern California
Specializing in H.H. Scott, McIntosh, Marantz, Fisher, and Vintage Tube Equipment
H.H. Scott 355 Specialist • Tube Tuner Alignment Expert
