π Los Angeles County & SoCal
π§ 30+ Years Experience
ποΈ Monster Receiver Specialist
π’ TEK Media Group
πΊπΈ WE WORK LOCALLY & NATIONWIDE πΊπΈ
Los Angeles β’ Southern California β’ Shipping Available Across the United States
π A NOTE FROM MY WORKBENCH: The Marantz Model 2325 is the most powerful receiver in the 22xx series at 125 watts per channel. It features a massive power supply, a sensitive 5-gang FM tuner, and the classic Marantz gyro-touch tuning. Capacitors and 2SC458 transistors degrade with age and need replacement. This is a complex restoration that requires specialized knowledge. My email is
jt@tekmg.com for direct inquiries.
β οΈ CRITICAL WARNING β MARANTZ 2325 SPECIFIC: The 2325 has a massive power supply with high-voltage rails (65V B+). It uses 2SC458 transistors in the preamp and phono stages β these MUST be replaced. The main filter capacitors are also critical failure points. I provide a thorough, methodical restoration to factory specifications. This is NOT a beginner-friendly receiver.
About the Marantz Model 2325 & My Approach
The Marantz Model 2325 (produced 1973-1976) is the undisputed king of the 22xx series. With 125 watts per channel, a massive dual-transformer power supply, dual heat sinks, and that unmistakable Marantz warmth, it's the ultimate expression of 1970s receiver design. I've restored dozens of 2325 receivers over three decades, and I treat each one with the meticulous care this flagship deserves. I use premium replacement components (including upgraded main filter caps) and follow factory service procedures to ensure your receiver performs to original specifications β or better.
β
WHY TRUST TEK MEDIA GROUP WITH YOUR MARANTZ 2325:
- 30+ Years of Vintage Marantz Restoration Experience
- Specialized Knowledge of the 2325 β The Flagship Monster Receiver
- Full Power Supply Rebuild with Upgraded Main Filter Capacitors
- 2SC458 Transistor Replacement (Noise Elimination β CRITICAL for 2325)
- Precision 5-Gang FM Tuner Alignment
- Amplifier Bias & DC Offset Calibration (125 watts per channel)
- Dual Heat Sink & Thermal Management Service
- Lamp Replacement with Warm White LEDs or OEM-style bulbs
- Every Receiver Gets My Personal Attention β No Assembly Line
- 90-Day Warranty on All Work
- Nationwide Service β Secure Shipping Across All 50 States
- Direct Email: jt@tekmg.com
Complete Marantz 2325 Restoration Services I Offer
π Full Diagnostic & Evaluation Complete assessment, massive power supply check, 5-gang FM tuner performance, amplifier testing, baseline measurements
β‘ Power Supply Rebuild (P800) Replace all electrolytic capacitors, check bridge rectifiers, test voltage regulators, UPGRADE main filter caps
ποΈ Full Capacitor Replacement Replace ALL electrolytic and tantalum capacitors with audio-grade types (80+ caps)
π 2SC458 Transistor Replacement Replace ALL noisy 2SC458 transistors in preamp/phono with KSC1845 β CRITICAL for noise elimination
π» 5-Gang FM Tuner Alignment Complete FM front-end and IF alignment, multiplex decoder alignment for optimal stereo separation
ποΈ Amplifier Calibration Bias adjustment (15-20mV), DC offset calibration (<5mV), 125W power output verification
π‘οΈ Thermal Management Clean dual heat sinks, replace thermal compound on output transistors
β¨ Mechanical & Cosmetic Service Clean controls, lubricate tuning capacitor, replace dial lamps with warm white LEDs
π COMPLETE FULL RESTORATION All services above β your 2325 will sound and perform like new
π Complete Marantz Model 2325 Capacitor Replacement Database
β οΈ TOTAL: 80+ capacitors replaced β 70 electrolytic + 10+ film upgrades. This is the most extensive recap I perform on any Marantz receiver.
β‘ POWER SUPPLY BOARD (P800) β Massive 2325 Supply
| Location | Original Value | My Replacement | Notes |
|---|
| C801 | 10,000Β΅F / 55V | 12,000Β΅F / 63V (Nichicon KG) | Main filter - LEFT channel (UPGRADED) |
| C802 | 10,000Β΅F / 55V | 12,000Β΅F / 63V (Nichicon KG) | Main filter - RIGHT channel (UPGRADED) |
| C803 | 1000Β΅F / 35V | 1000Β΅F / 50V (Nichicon PW) | Regulator supply |
| C804 | 470Β΅F / 35V | 470Β΅F / 50V (Nichicon PW) | Regulator output |
| C805 | 100Β΅F / 25V | 100Β΅F / 50V (Nichicon FG) | Bias supply filter |
| C806 | 100Β΅F / 25V | 100Β΅F / 50V (Nichicon FG) | Bias supply filter |
| C807 | 47Β΅F / 35V | 47Β΅F / 50V (Nichicon PW) | Protection circuit |
| C808 | 47Β΅F / 35V | 47Β΅F / 50V (Nichicon PW) | Protection circuit |
| C809, C810 | 220Β΅F / 35V | 220Β΅F / 50V (Nichicon PW) | Aux supply filters |
π MAIN AMPLIFIER BOARD (P700 β Left & Right Channels)
| Location | Original Value | My Replacement | Notes |
|---|
| C701/C751 | 10Β΅F / 35V | 10Β΅F / 50V (Nichicon FG) | Input coupling |
| C702/C752 | 10Β΅F / 35V | 10Β΅F / 50V (Nichicon FG) | Feedback cap |
| C703/C753 | 100Β΅F / 25V | 100Β΅F / 50V (Nichicon FG) | Bootstrap cap |
| C704/C754 | 100Β΅F / 25V | 100Β΅F / 50V (Nichicon FG) | Bootstrap cap |
| C705/C755 | 100Β΅F / 25V | 100Β΅F / 50V (Nichicon FG) | Decoupling |
| C706/C756 | 47Β΅F / 35V | 47Β΅F / 50V (Nichicon PW) | Compensation |
| C707/C757 | 220Β΅F / 25V | 220Β΅F / 50V (Nichicon PW) | Power decoupling |
| C708/C758 | 220Β΅F / 25V | 220Β΅F / 50V (Nichicon PW) | Power decoupling |
ποΈ PREAMPLIFIER / TONE BOARD (PE01)
| Location | Original Value | My Replacement | Notes |
|---|
| C401, C402 | 100Β΅F / 25V | 100Β΅F / 50V (Nichicon FG) | Power decoupling |
| C403, C404 | 10Β΅F / 25V | 10Β΅F / 50V (WIMA MKS2) | FILM UPGRADE - coupling |
| C405, C406 | 47Β΅F / 25V | 47Β΅F / 50V (Nichicon FG) | Tone control |
| C407, C408 | 100Β΅F / 25V | 100Β΅F / 50V (Nichicon FG) | Decoupling |
| C409, C410
| (Values vary) β replaced with Nichicon FG
| Output coupling
|
π PHONO PREAMP BOARD (P500)
| Location | Original Value | My Replacement | Notes |
|---|
| C501, C502 | 100Β΅F / 25V | 100Β΅F / 50V (Nichicon FG) | Power decoupling |
| C503, C504 | 10Β΅F / 25V | 10Β΅F / 50V (Nichicon FG) | Input coupling |
| C505, C508 | 2200pF | 2200pF / 100V (Polystyrene) | FILM UPGRADE - RIAA EQ |
| C506, C507 | 0.022Β΅F | 0.022Β΅F / 100V (WIMA) | FILM UPGRADE - RIAA EQ |
| C509, C510 | 100Β΅F / 25V | 100Β΅F / 50V (Nichicon FG) | Output coupling |
π» FM IF BOARD (P200) & MULTIPLEX (P300)
| Location | Original Value | My Replacement | Notes |
|---|
| C201-204 | 10-100Β΅F | Nichicon PW | All IF board electrolytics replaced |
| C301-310 | 1-100Β΅F | Nichicon PW + WIMA film for C305/306 | All multiplex board caps replaced |
π¦ CAPACITOR REPLACEMENT SUMMARY:
Power Supply: 10 caps (including upgraded main filters) β’ Main Amp L/R: 16 caps β’ Preamp/Tone: 10 caps (4 film upgrades)
Phono Preamp: 10 caps (4 film upgrades) β’ FM IF: 8 caps β’ Multiplex: 10 caps (2 film upgrades)
TOTAL: 64+ capacitors β 54+ electrolytic + 10+ film upgrades
π§ MY BRAND PREFERENCES FOR 2325:
β’ Main filter caps: Nichicon KG Super Through (upgraded to 12,000Β΅F/63V for improved performance)
β’ General low ESR: Nichicon PW, Panasonic FC
β’ Audio signal path: Nichicon FG (Fine Gold), Elna Silmic II
β’ 2SC458 replacement: KSC1845 (direct fit, lower noise)
β’ Film upgrades: WIMA MKS2, Polystyrene (RIAA)
β οΈ NOTE FROM MY WORKBENCH: I replace every electrolytic capacitor regardless of appearance β they age even if not bulging. I document polarity before removal. After recap, I verify all voltage rails and allow 60 minutes of burn-in before calibration.
π§ Problematic Transistor Replacement β The 2SC458 Issue (CRITICAL for 2325)
| Original Transistor | Location | My Replacement | Notes |
|---|
| β οΈβ οΈ CRITICAL β MUST REPLACE FOR RELIABILITY: 2SC458 transistors are notorious for becoming noisy and intermittent. I replace ALL of them on every 2325 restoration. |
| 2SC458 | Preamp (PE01), Phono (P500) | KSC1845 | Direct replacement, much lower noise, higher gain |
| 2SC871 | Tone control, other sections | KSC1845 or KSC945 | Replaces noisy transistors |
| 2SA493 | Amplifier driver | KSA992 | Matched pair recommended |
| 2SD287/2SB537 | Output transistors (multiple pairs) | MJ21193/21194 | Matched pairs β higher current capability |
π‘ WHY I REPLACE 2SC458 TRANSISTORS: These transistors develop internal leakage and noise over time, causing hiss, crackling, popping, and intermittent operation. Replacing them with modern KSC1845 eliminates these issues and dramatically improves signal-to-noise ratio. This is a CRITICAL part of my 2325 restoration β I never skip this step.
π§ Professional Troubleshooting Tips β From My Workbench
π‘ TIP #1: No Power / Dead Unit β The 2325 Monster Supply
- Check AC power cord and main fuse (15A slo-blo on the back panel)
- Test power transformer β the 2325 has a massive dual-secondary transformer
- Check bridge rectifier diodes β replace with 25A/400V modern types for 2325
- Main filter capacitors (C801, C802) often degrade β I upgrade to 12,000Β΅F/63V Nichicon KG
π‘ TIP #2: Noisy / Crackling Sound β The Classic 2325 Issue
- 2SC458 transistors in the preamp and phono stages are almost always the culprit
- I replace ALL 2SC458 transistors with KSC1845 β this eliminates the noise permanently
- Symptoms: hiss, crackling, popping, especially at low volume or with no input
- This is the most common failure in the 2325 β I address it on every restoration
π‘ TIP #3: FM Tuner Issues β 5-Gang Alignment Required
- The 2325 has a sensitive 5-gang FM tuner β alignment drift is common after 50+ years
- I perform full 10.7MHz IF alignment using sweep generator and oscilloscope
- If stereo light is on but no separation, the multiplex decoder needs alignment
- Dirty tuning capacitor causes intermittent reception β I clean with compressed air
π‘ TIP #4: Amplifier Distortion or One Channel Dead β 125W Power
- Check and adjust bias current β factory spec is 15-20mV across emitter resistors
- Test output transistors (multiple pairs per channel) β replace with matched MJ21193/21194
- Replace all electrolytics on amplifier board (P700)
- Check DC offset at speaker terminals β adjust to near 0mV
π‘ TIP #5: Hum in Both Channels β Massive Supply Issues
- Almost always bad main filter capacitors (C801, C802)
- I upgrade to Nichicon KG 12,000Β΅F/63V for improved ripple rejection
- Also check bridge rectifier and ground connections
π‘ TIP #6: Dial Lamps Dim or Out β The Famous Blue Glow
- The 2325 uses fuse-style lamps (8V/300mA for dial, 6.3V/200mA for meters)
- I offer warm white LED upgrades β brighter, cooler operation, never burn out
- Can also use OEM-style incandescent if you prefer original look
π‘ TIP #7: Overheating β Thermal Management for 125 Watts
- The 2325 has dual massive heat sinks β I clean and reapply thermal compound to all output transistors
- Check bias current β if too high, the amplifier will run hot
- Ensure ventilation β the 2325 needs space around it
β οΈ SAFETY NOTE: The Marantz 2325 contains high-voltage sections (65V B+). Always discharge power supply capacitors before servicing. I use proper safety procedures. This is a heavy receiver β use proper lifting technique.
π Quick Troubleshooting Reference Chart
| Symptom | Most Likely Cause | My Fix |
|---|
| No power, no lights | Blown fuse, dead transformer | Replace fuse (15A slo-blo), check rectifiers, test transformer |
| No sound, lights work | Speaker relay, output transistors | Check DC offset, test output transistors, check protection circuit |
| One channel dead or distorted | Output transistor failure, bad caps | Test outputs, replace caps, recalibrate bias |
| Hiss/crackling/pop | 2SC458 transistors | Replace ALL 2SC458 with KSC1845 β CRITICAL |
| Weak FM / no stereo | 5-gang FM alignment drifted | Full FM alignment, check front end transistors |
| Hum in both channels | Bad main filter caps | Replace C801, C802 with upgraded 12,000Β΅F |
| Tuning knob stiff | Dirty tuning capacitor | Clean with compressed air, fresh lubricant |
| Phono stage noisy or dead | 2SC458 transistors, bad caps | Replace transistors, recap phono board |
| Receiver runs hot | Bias too high, thermal compound dried | Recalibrate bias, replace thermal compound on outputs |
Deep Dive: My Marantz 2325 Restoration Process
β‘ POWER SUPPLY (P800) β Massive 2325 Supply Upgraded
- Main Filter Capacitors (C801, C802): Original 10,000Β΅F/55V β I UPGRADE to 12,000Β΅F/63V Nichicon KG Super Through for improved ripple rejection, tighter bass, and better dynamics.
- Bridge Rectifier: I replace old diodes with modern 25A/400V ultra-fast soft recovery types.
- Bias Supply: I rebuild the negative bias supply with fresh capacitors (C805, C806).
- Protection Circuit: I recap the protection circuit (C807, C808) for reliable speaker relay operation.
- Auxiliary Supplies: I recap C809, C810 for the tuner and preamp supplies.
π MAIN AMPLIFIER (P700) β 125 Watts Per Channel
- Capacitor Replacement: All electrolytics replaced β input coupling, bootstrap, decoupling, compensation.
- Output Transistors: Multiple pairs per channel β I test and replace with matched MJ21193/21194 if needed.
- Driver Transistors: I test and replace if noisy or out of spec.
- Bias Adjustment: I set bias to 15-20mV across emitter resistors (R763/R764).
- DC Offset: I adjust DC offset at speaker terminals to <Β±5mV.
- Thermal Compound: I remove old compound and apply fresh Arctic Silver to all output transistors.
ποΈ PREAMPLIFIER & PHONO (PE01 & P500)
- 2SC458 Transistor Replacement: I replace ALL 2SC458 transistors with KSC1845 β this is CRITICAL for noise elimination in the 2325.
- Capacitor Replacement: All electrolytics replaced. Small-value coupling caps upgraded to WIMA film.
- RIAA EQ: Phono stage capacitors upgraded to 1% polystyrene for accurate equalization.
π» FM TUNER & MULTIPLEX (P200 & P300) β 5-Gang
- IF Alignment: Full 10.7MHz alignment using sweep generator and oscilloscope.
- Multiplex Alignment: 38kHz oscillator and separation adjustment for >35dB stereo separation.
- Capacitor Replacement: All electrolytics replaced with low-leakage Nichicon PW.
Precision 5-Gang FM Alignment Procedure β As I Perform It
π» MY FM ALIGNMENT PROCESS FOR MARANTZ 2325:
- 5-Gang Front End Alignment: I align the RF amplifier, local oscillator, and mixer for maximum sensitivity.
- 10.7MHz IF Alignment: Using a sweep generator and oscilloscope, I align each IF transformer for proper bandpass response.
- Discriminator / Ratio Detector: I adjust for minimum distortion and correct center tuning.
- Multiplex Decoder Alignment: I adjust the 38kHz oscillator and separation controls for maximum stereo separation (>35dB).
- Result: Your 2325 will pull in distant stations clearly, with quiet background and precise stereo imaging.
Marantz Model 2325 Specifications β The Flagship
| Parameter | Specification |
|---|
| Power Output | 125 watts per channel (8Ξ©, both channels driven) |
| Frequency Response | 20Hz-20kHz Β±0.3dB |
| THD | <0.2% at rated power |
| FM Sensitivity | 1.8Β΅V (IHF) β 5-gang tuner |
| FM Stereo Separation | >35dB at 1kHz |
| Inputs | Phono, Tape, Aux, FM, AM |
| Outputs | Tape out, Headphone, Speaker A/B |
| Power Consumption | 600W max |
| Dimensions (WxHxD) | 18.5" x 6.5" x 15" |
| Weight | Approx 55 lbs (25 kg) |
Nationwide Service β We Ship Monster Receivers Across America
πΊπΈ NATIONWIDE SERVICE AVAILABLE πΊπΈ
Ship your Marantz 2325 securely to my Los Angeles facility β I serve customers across all 50 states
- Secure Packaging: I provide detailed packing instructions β double-boxing, secure the gyro-touch tuning knob, foam padding for the 55lb monster
- Insured Shipping: Fully insured shipping recommended for your valuable flagship receiver
- Nationwide Reach: I've restored 2325 receivers for clients from NY to CA, TX to WA
- Direct Contact: Email jt@tekmg.com for a quick quote
Frequently Asked Questions β Marantz 2325
β Why is the 2325 the ultimate Marantz receiver?
The 2325 is the most powerful receiver in the 22xx series at 125 watts per channel. It features a massive dual-transformer power supply, dual heat sinks, and the classic Marantz sound. It's the holy grail for collectors.
β How long does a full restoration take?
Typically 4-5 weeks due to the complexity of the 2325's massive power supply and 5-gang FM alignment. Rush service available.
β Do you offer nationwide service?
Yes! I serve customers across all 50 states with secure shipping instructions for this 55lb receiver.
β What are the noisy transistors you replace?
2SC458 transistors in the preamp and phono stages β these fail and cause hiss/crackling. I replace them with modern KSC1845. This is CRITICAL for the 2325.
β Do you upgrade the main filter capacitors?
Yes β I upgrade from 10,000Β΅F to 12,000Β΅F Nichicon KG for improved performance and reliability.
β Do you warranty your work?
Yes, 90-day warranty on all parts and labor.
My Service Area β Local & Nationwide
πΊπΈ NATIONWIDE SERVICE AVAILABLE πΊπΈ
Ship your Marantz 2325 securely β I serve all 50 states
Local Service: Los Angeles County, Orange County, Ventura County, Riverside County, San Bernardino County. I can arrange pickup for this 55lb receiver.
Nationwide Service: Secure shipping options with detailed packing instructions for heavy receivers.
Los Angeles County: LA Burbank Glendale Santa Monica Hollywood Pasadena
Nationwide: NY TX FL IL WA All 50 States
TEK Media Group β Vintage Marantz Restoration Since 1994
π (818) 244-4440 | βοΈ jt@tekmg.com
Marantz 2325 Specialist β’ 2SC458 Replacement β’ 5-Gang FM Alignment β’ Monster Receiver Restoration β’ 30+ Years Experience
Every 2325 gets my personal attention β I'm the technician who does the work. Email me at jt@tekmg.com.
