PYRAMID AUDIO

Quality Service for Quality Equipment

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STK0050+

Replaces STK0050/30/40 in Pioneer SX-780 or Marantz SR4000

This module is listed for individual sale.

Ready to use module replaces the Sanyo STK0030/40/50, but more robust. The STK0050+ fits these models and probably a lot more:
SX-780, SR4000, KR-5010, RS-2004A, JA-S44, JCX-2050

NOTE: The STK0030/40/50 family is smaller than the STK0060/70/80 family.

STK0050+
STK0050+
STK0050+
STK0050+
STK0050+

Compact design, with the same mounting holes as the original Sanyo. With just six solder connections, it takes a professional tech about 10 minutes to replace this module in a Pioneer SX-780. Typical current gain 8,000-20,000 vs original 5,000. 15 amp, 160 volt transistors INSTEAD of the original 5 amp, 110 volt part. These same power transistors are used in the 140 watt per channel Marantz SR8012, Denon AVR-X7200W, and the Yamaha RX-A3070.

  • NO bias adjustment, preset during testing.
  • NO paste needed, we supply silpads.
  • NO drilling or grinding to fit, only 4mm wider than the Sanyo.
  • NOT 35 years old or counterfeit. Sanyo quit making these in 1983.
  • YES, every module tested in our Pioneer SX-780 or Marantz SR 4000.
  • YES, gold-plated PCB. PCB Finish, ENIG (Gold), compliant with IPC-4552.
  • YES, 4 ohm speakers. We use 15 amp outputs vs original Sanyo 5 amp devices.
  • YES, free USPS shipping in the USA.
SX-780 typical performance into 8 ohms with the tone controls bypassed:
45 watt 1k 0.0039% 20k 0.0051%
4.5 watt 0.5k 0.0029%
1.0 watt 1k 0.0047% 20k 0.0177%
Performance into 4 ohms:
88 watts 1k 0.0095% 20k 0.0290%
1 watt 1k 0.0036% 20k 0.0934%
Noise -80 dBv 22-22k BW Audio Precision P1+DD test set
S/N 106 dB 22-22k
S/N 116 dB A-wtd

Hand tools and simple solder skills required. Technical knowledge required. No returns and limited support, this is not for beginners. We do supply instructions and helpful test tips.