Quad 405 405-2 Upgrade Quad 405GE

This upgrade provides a complete re-build of the amplifier modules along with replacement and upgrade of the main power supply capacitors. All primary and secondary wiring is replaced with silver plated copper cable and input wiring is replaced with OFC screened cable. Output wiring is replaced with OFC speaker cable. This upgrade can be applied to any Quad 405 version as we completely re-build the amplifier modules.

Phono inputs are added and the input sensitivity changed to 1.5V (Optional but recommended items).

New speaker sockets are fitted.

Power Supply:

New 15000uF capacitors (2 off) are fitted along with all new secondary wiring.

Module Re-Build:

All components are replaced and the following modifications are carried out:
Current Limiting Removed. (DC Offset protection is retained.)
TR1 Constant current circuit improved.
IC power supply improved significantly using linear integrated regulators.
Op Amp replaced with Burr Brown OPA227.
Additional power line decoupling added.
Output transistors replaced with MJ21194
Driver transistors replaced with MJE15031
All other transistors replaced with low noise audio transistors.
The inductors are high current EPCOS types.
All resistors are low noise types and all capacitors are either film or polystyrene capacitors or Elna Silmic for electrolytic capacitors.
(The DC Offset protection circuit uses a non-polarized capacitor).

Full bench test.

This amplifier is not suitable for use with un-modified ESL57s, otherwise there are no usage restrictions.

The cost for this upgrade is £400.00 plus £25.00 return shipping for GB. Please enquire for shipping to other locations.

Please refer to our Payments and Shipping pages for additional information.