In 1991, after twenty-eight years of splendid service, the organ was again fully restored, this time by the organ builders N P Mander Ltd of London. Ian Bell, Managing Director of Manders, summarised the aims of the 1991 rebuild:
“The work on the organ in 1991 has included the renewal of all the low-voltage electrical equipment installed in 1963, both in the console and in the organ itself. The system is now entirely solid-state, and the opportunity has been taken to upgrade the controls available to the organist, to bring the instrument into line with present day standards. The outer cladding of the console, and all of the ivory fittings, have been retained and refurbished, but all of the internal equipment is new.
“Up in the organ, again all electrical equipment and cabling has been renewed. All of the delicate leatherwork in the key mechanism has also been replaced, and several of the large reservoirs which store the wind pressure have also had their leatherwork renewed. The action of the stops, which was entirely operated by human power until 1963, was converted to a pneumatic system at that time. This has now been upgraded to powerful and silent electric solenoids.
“The large soundboards which support the pipes, and supply them with wind-pressure, have all been taken back to London and completely overhauled. The access ladders and walkways have been improved, and the humidification system enhanced.
“The organ has once more been left completely unchanged tonally; damaged pipes have been carefully repaired and cleaned, but the sound has been jealously preserved. Only one modification has been undertaken – the loudest solo stop, the Tuba, has always received criticism for being uncharacteristically modest. In a Willis organ the Tuba normally balances the Pedal reed in power, but at Truro this has not been the case, since the pipes were rather buried in the depths of the instrument.
“It was therefore decided not to alter the Tuba, but to move it to the front of the organ where it could be heard to rather better effect. This has resulted in a considerable improvement, but all of the original mechanism has been left in place in case anyone wishes to move the pipes back in future. In every other respect the instrument sounds exactly as it did when first built 103 years ago.”
The organ in St Mary’s Aisle was built by John Byfield in 1750.
When St Mary’s Church was largely pulled down in the 1880s the Byfield organ was thoroughly repaired and “abridged” from 3 manuals to 2 manuals. The instrument was re-installed in St Mary’s Aisle by Messrs Brewer and Son in 1888.
A four stop chamber organ was specially built for the Cathedral by Kenneth Tickell in 1997. It is housed in the Quire of the Cathedral.