Fidele Audio

Analogue from Vinyl to Speaker

Quad 405-2 Upgrade Quad 405-2GE

This upgrade provides a complete re-build of the amplifier modules along with replacement and upgrade of the main power supply capacitors. All secondary wiring is also replaced with solid core OFC cable and input wiring is replaced with screened OFC cable.

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

New speaker sockets are fitted.

Power Supply:

New 22000uF 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.
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 ELNA 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 £370.00 including return tracked and insured shipping to the UK. Please inquire for shipping to other locations.

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

 

 

 

 

 

 

 

 

 

 

 

Quad 405-2

405

Upgrade List