Description: PLEASE NOTE - THIS IS A 40+ YEAR-OLD DEVICE. IT IS NOT NEW. IT WAS UPGRADED AND TESTED. THERE ARE NUMEROUS COSMETIC IMPERFECTIONS AS SEEN ON ALL PHOTOS. WHAT YOU SEE IN THE PHOTOS ARE WHAT YOU ARE BUYING. IN ADDITION, THE SWITCHES AND POTENTIOMETERS ON THE DEVICE ARE KNOWN TO NEED OCCASIONAL LUBRICATION AND CLEANING - PLEASE BE PREPARED TO DO SO.While maintaining the designers' original philosophy, this SX-3900 was upgraded and modified to take care of a few design flaws that crept in with this model and to deal with the fact that this is a 40 year-old piece of electronics. In the rebuild, exactly 120 capacitors were changed (48 of them will be WIMA MK2 film), 11 transistors (including 2 current regulator diodes), 5 Zener diodes, 8 transistor sockets to thermoplastic connectors, 12 bulbs to LEDs, and a high current SSR were added/changed. All audio path capacitors are metal film or audio grade capacitors. Nearly all will be upgraded to 105 degree 10,000 hour (originally from 85 degree 1,000 hour). All capacitors, transistors, current regulators, and Zeners were obtained from Mouser Electronics - No counterfeit junk. The power amplifer also had 4 mini-heatsinks added and the trimmers were replaced for added thermal reliabilitiy and longevity.Specifically:1) The receiver has each and every electrolytic capacitor changed to a high-end modern component. All the capacitors used were WIMA MK2 (low value film), Nichicon Gold UFG or UKL for audio path capacitors, Panasonic EEU, Nichicon ULD, Rubycon YXM, United Chemicon EKM (filter caps) and ELE, or similar. Nearly all are 105 degree 10,000 hour (except for the audio electrolytics and main filter caps).2) The two filter caps were upgraded from 15,000 microfarad to 22,000 microfarad for increased power supply stability.3) All 12 lamps were exchanged for LEDs, so no more incandescent lamps to burn out.4) The 2SK34 FETs (that are a known weak point) were exchanged for Current Regulator Diodes that handle much higher voltages, significantly lowering the risk of power supply failure.5) The power supply had all transistors and Zener diodes replaced with modern cooler-running devices. New thermal interface media was applied. Additionally a Pioneer modification was implemented by switching out a certain resistor for a Zener diode (as applicable in older revision SX-3900s).6) The output transistor connectors, which are known to crack and short out the unit, were replaced with thermoplastic connectors.7) A slave Solid State Relay was coupled to the power switch, so no risk of sparking the contacts and burning out the unavailable power switch, especially with the filter capacitor upgraded.8) Wires were rerouted to allow for improved thermal circulation. Additionally, all transistors and diodes on the power supply and the driver transistors on the power amplifier were reflowed to prevent cold-solder joints.9) All switches and potentiometers were lubricated. The big switches were disassembled and physically cleaned.10) The power amplifier was re-calibrated, as were the Flouroscan meters. Trimmer pots were replaced, and 4 mini heatsinks were added. 11) Tracking was adjusted on the FM tuner section and it was peaked.12) All inputs, outputs, functions, switches, knobs, potentiometers, displays, and lights were tested.This is the TOTL (top of the line) Pioneer silver-faced Flouroscan monster receiver, the SX-3900 which was Pioneer’s top of the line Fluoroscan receiver and the last of the silver faced receivers. It’s the big brother to the SX-3800 and was introduced in 1980 at a retail price of about $800.00. It represents Pioneer’s transition from analog receivers to the more contemporary digital receivers. In fact, the SX3900 basically has both analog and digital features. As you can see it has an old school analog tuning dial, the mechanism is mechanical, as well as a five digit digital tuning display. The displays use fluorescent bulbs hence the nick name fluoroscan.The blue fluorescent display is beautiful and one of the more iconic displays in vintage audio. Still, the FM Quartz Locked SX-3900 was not all looks. It pumps out 120 watts per channel with less than 0.005% total harmonic distortion and is built with quality engineering. It also incorporates a non-switching amplifier. You can see from the pictures that the SX-3900 has illuminated push buttons for certain functions as well. Some other features are: 2 high pass filters, Tone turn-over controls for bass and treble, Adapter loop switch, FM de-emphasis, Tape duplicate, 2 phono inputs. Measuring in at 20.7 x 6.9 x 17.8 inches the SX-3900 is pretty big and weighs roughly 46 pounds.
Price: 1900 USD
Location: Lubbock, Texas
End Time: 2024-08-29T02:57:49.000Z
Shipping Cost: 150 USD
Product Images
Item Specifics
All returns accepted: ReturnsNotAccepted
Brand: Pioneer
Modification Description: Recap, LED, transistors, zeners, SSR, connectors. Text 8064415575
Model: SX-3900
Featured Refinements: Pioneer SX
Country/Region of Manufacture: Japan
Modified Item: Yes