Vintage Made In Japan 1970s Pioneer SX-780 recently serviced by DALAUDIO. This is a very clean unit, both inside and out (see photos). This unit has the original Darlington Pair STK- 0050s, tested to spec per the service manual, so we left them in. All selectors, potentiometers and switches have been cleaned and tested. The unit currently meets or exceeds service manual specs. Testing confirmed all inputs including phono are functional and operational - unit was tested at 46.25 WPC RMS @ 8 Ohms with negligible (.052) THD utilizing fixed sine wave generator on the aux input. All backlighting and indicator lamps work including FM Stereo with original style bulbs(not LEDS!). The Nichicon filter caps are on spec as measured with ESR Meter/Huntron Tracker. Power Cord is in very good condition. The units feet are in good functional condition.
Overall the unit shows very minimal signs of use with very minimal light scratching (see photos). The simulated wood cover is very good condition with minimal chips on rear / no major peeling veneer on edges and corners. Please see all photos.
Note 1: If you would like a digital copy of the manul or service manual please bring a USB drive.
Note 2 : DALAUDIO provides STK Darlington Mod Upgrades. With over over a dozen replacements in the past year, the results lead to better than service manual specs for output power, DC offset and amp bias. Again, both the original STKs are running perfectly in this unit, so we did not perform the mod change. Ask us if interested. We only use quality DALAUDIO tested/assembled mods.
About the unit: The SX780 was one of Pioneers' final 700 series receivers. The 780 platform was wildly popular due to its solid construction, "Made in Japan for America" features set, and the attractive $325 list price! Pioneer built quite a few of these for about 2 years between 1978 and 1980. The internal amplifiers are based on high quality Sanyo made Darlington STK-0050 Power Packs in the output stage, and high quality Nichicon filter capacitors. The units were rated conservatively at 45 watts per channel at .05% THD , as previously stated, this unit tested at 47.2 Watts RMS @ 8 Ohms at .052% THD. The crisp FM reception has good selectivity and lock on. The phono preamp and other inputs are all functional. Overall a great receiver for a knowledgeable collecterg, a 60's kid returning to their former glory years (ha), or just getting into exploring the vintage audio advantage.
Features:
AM/FM Stereo Receiver
A, B, and A+B speaker options
4 RCA inputs: Aux/CD, Tape1, Tape2, Phono Inputs (MM type)
RCA outputs: Tape
Tape Monitors Switches
Loudness Contour
Chassis ground for phono
Bass + Treble Tone Controls
15 Hz Low Frequency Filter
Front Panel Headphone Out
Dimensions 18.9" x 5.6" x 12.6"