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Quad 405


Example 4: Quad 405 (405-2)  Amplifier Repair & Refurbishment


A standard Quad 405 service from 110.00 includes; 

Fault diagnosis & rectification. Replacement of out of tolerance (OT) components including all decoupling electrolytics. Sensible modifications*. Performance test( frequency response, distortion test, listening test)
Soak test. (running for a prolonged period of several hours into a dummy load to locate any short term failures). Safety test.  (Earth leakage and insulation breakdown test).

The standard 'from' price does not include replacement of faulty mains transformers.


valve amplifier  

In this Quad 405 repair example, after fault rectification,  fitting a new set of electrolytics on both PCBs, and replacing a faulty class A transistor on the right channel, it is about to be performance tested on dummy loads, prior to carrying out a listening test. It will then be soak tested for several hours, followed by a Portable Appliance safety Test. (PAT).

If your smoothing capacitors have deteriorated we will replace them with new high quality Cornell Dubilier 'snap in' 10,000uF 63V 105 degree capacitors. To orientate them correctly (lugs down), we add a bolt-on  PCB. (see the image above). Alternatively at an additional cost of 30.00, (no audible performance gain) we can fit Computer grade screw terminal types that fit in the same orientation as the originals.


* What we call sensible modifications involves changing certain components for higher performance types where a genuine improvement in performance will be perceived. Where necessary we may also re-route wires/cables. For example,  we move the left  & right Zobel network on certain boards to the correct output earth plane.

Modification options:

On older 405s, for a nominal extra charge, we can fit  RCA (phono) sockets in parallel with the DIN socket and/or fit professional loudspeaker binding posts in place of the push to connect types. The extra charge for supplying and fitting 2 x gold plated phono sockets and 4 x gold plated  LS binding posts is 40.00 when included in a full service.



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Last modified: Monday, 27. April 2015 12:57