Copland CTA401 Upgrades

This amp had seen better days. One of the EL34s had blown, taking out the cathode ‘fuse’ resistor and the main power supply caps were running hot, a sure sign they had dried out and aged. In addition to new psu caps and replacement cathode fuse resistors, the opportunity was taken to upgrade the coupling caps, replace some loose input sockets and swap the valves to Sovtek military spec 5881s, which to my ears are better sounding, and which have also proven to be highly reliable.

The amp is beautifully designed and a joy to work on. As always, care must be taken desoldering and soldering to the pcbs, as the glue holding the tracks onto the board tends to dry out over time allowing the track to become loose.

Coupling caps were swapped for Mundorf ZNs, a great sounding cap, and a new find Leclanche Swiss caps. Both are tin foil /film caps and I prefer the Mundorf ZN tin foil film types in sound quality to Mutdorfs more expensive /exotic metallised film variants.



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