Quad 303 Full Upgrade
This full amplifier upgrade is based on the original Net Audio 303 upgrade. Fidele worked with Net Audio on 303 upgrades by providing a build and test service for Net Audio when required. There is a link to Fidele from the Net Audio web site.
For this upgrade the amplifier and power supply modules are completely re-built with all new components. The power supply and output capacitors are replaced and increased in capacitance. The output configuration is changed to a 'push-pull' design and the output transistors replaced with high quality audio transistors.
This upgrade provides the following:
- Replace Power Supply capacitors with 2 x 4700uF
- Replace output capacitors with 2 x 10000uF
- Add by-pass film capacitors to main output capacitors
- Replace amp module electrolytic capacitors with Elna Silmic
- Replace input capacitor with film capacitor
- Add Constant Current diode sources for TR101 and Bias Circuit
- Replace trimmer pots
- Replace the output inductor with high current type
- Reduce output current limiting (except for use with ESL57s)
- Replace all amp module transistors with modern audio transistors
- Replace all amp module resistors
- Convert the output to 'push-pull' drive
- Replace output transistors with complementary On Semi MJ series audio transistors.
- Replace the rectifier bridge module with a modern bridge rectifier
- Completely rebuild the power supply module including small modification to increase temperature stability.
- Replace the power supply output transistor with On Semi MJ series power transistor.
- Replace the speaker connectors with new binding posts
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Full alignment and bench test
The cost for this upgrade is £285.00 plus £25.00 for return shipment to the UK. Please enquire for shipping to other locations.