Quad 405 405-2 Module Rebuild

This upgrade can be applied to any Quad 405 version as we completly re-build the amplifer modules.

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).
Each module is bench tested.

The original power and input / output connections are retained to allow easy re-fitting of the module.

The module can then be re-fitted without further changes to the standard 405-2 chassis with either the original power supply or other dual mono power supplies.

These modules are not suitable for use with un-modified ESL57s, otherwise there are no usage restrictions.

The cost of this rebuild is £300.00 per pair of modules, including return shipping to GB via Royal Mail Special Delivery.

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