Our full service includes replacing the following : • All out of tolerance (OT) parts discovered during the diagnostics check • Replace full complement of electrolytic capacitors (unless very recently changed). • Smoothing capacitor replacement: If the ESR, value, or physical condition is below standard we replace the two main smoothing capacitors with high quality 10,000uF 63V 105 o C types. Option1: When available, we can fit, high grade 10000uF 100V screw terminal capacitors that fit the original large clamps, see the above image. This will add an additional charge. Currently (May 2023) add £80.00. Option2: If your 405 has the original Quad 405 transformer, we can modify your PSU arrangement to provide individual ac rectification and smoothing for each channel. This can offer better performance when BI-amping etc. CLICK HERE FOR MORE DETAILS > IRSUGD Currently May 2023 add £100.00. • L & R IC1 301 changed to a low noise counterpart. • L&R +ve feed resistors R7 replaced with 1W types • On early 405s, we correct the LS Zobel network earthing point to go to the output ground. The incorrectly shorted stand-off resistor R2 is reinstated in circuit by removing the erroneous input-ground to chassis-ground s/c. • Finally we carry out a listening test followed by a soak test for several hours, followed by a Portable Appliance safety Test. (PAT). The smoothing capacitors Quad 405 full service & LS and DIN socket Upgrade (Q405FSSU) On older 405s, for a nominal extra charge, we can fit RCA (phono) sockets in parallel with the DIN socket and fit sturdy dual-connect 4mm loudspeaker binding posts in place of the push-to-connect types. * What we call ‘sensible modifications’, involves changing certain components for higher performance type, where a genuine improvement in functionality and/or performance is achievable. Where absolutely necessary, we may also re- route wires/cables. For example, we move the left & right Zobel network on earlier boards, to the correct output earth plane.