St. Luke's San Antonio Installation Update, part 1
We’re into our sixth week here of the 55 stop, 74 rank organ at St. Luke’s Episcopal Church and School; the organ is now roughly 90% assembled. The delay in installation — originally planned for last Spring — was due to an increase in the scope of work that nearly doubled the size of the project and some unexpected delays from suppliers.
The restored windchets are now long since set now set in place with new Heuss pulldown motors, winding system closed and pressures set, and flue pipes planted. The original wind reservoirs were not only restored, but had al their control valves and weighting systems replaced, as each of them had failed in different ways over the years. As is our custom, reed stops and mixtures will go in after the larger flues are done, and we will be using this opportunity to rectify the tuning issues that have plagued the Great division since the organ was built because of the higher temperatures at the top of the organ.
The new console is fully up and running, wired in to the organ and the control system panel in the chamber. The Positive facade is back in place, minor dents, hand marks and corrosion all worked out by yours truly. (The main case pipes will be getting similar treatment in due course.)
The console's construction is well documented on our FaceBook page, but it is worth noting its unique design features: terraced jambs with concentric radii (as opposed to simple circles) side case cheeks angled in, and our customary version of the classic Skinner style toe piston bolsters. All the hardware is from Harris Precision and keyboards and pedalboard from P and S in the UK, both considered leaders for the components they produce. All the stop knob and tablet engraving was done for the first time in house with our new laser engraver, with careful attention paid to both nomenclature and typography to make for an elegant but instantly readable look.
Brad and Mike have returned Connecticut to prepare the second load, which will include the the mobile console platform and the planned additions to the organ: the 16’ Open Wood, the new slider windhest for the 5 stop lower Swell, along with its separate expression and the supplemental winding system to run them: a 0.75 Ventus and two new Odell single fold reservoirs. When they are installed we will run as much wooden wind line as possible, as this makes for better volumetric efficiency and less turbulence.
The action system for the lowest notes of the Open Wood are Bradley’s design; we wanted something reliable and responsive that would be easy for future maintainers to rebuild: The primary system is the well known (and somewhat difficult to obtain) Compound Magnet made by Kimber-Allen in the UK. It is known for its prompt action and ample excursion, which makes it the best candidate for operating the large valves for these pipes. There is also an electronic 32’ flue extension, a privately funded addition.
As this second load is prepared, I will be fine tuning the slider motor system: this was the Achilles Heel of the organ in its previous incarnation, where motors often froze or failed. The original chest construction made it optimal to keep 48 of the original 62 Laukhuff motors, which ran from an SSOS controller rack designed to control 2 motors per card. This original rack and its wiring harness were installed with not much care as to good wiring practice. What is key here is first that the motors are supplied with adequate power and the correct gauge of wiring. Any given motor will draw a current of up to 4 amps at full power running on 12 volts DC. That would have been 200 amps when all motors are fired simultaneously.
As originally installed, the organ was fitted with only three 50 amp Astron power supplies, hence even if wired correctly, there was still a power deficiency of 50 amps. This issue was compounded by incorrectly wiring the tandem acting Pedal motors to single driver card outputs, thus only providing the pedal motors half the power they needed to operate; in retrospect it was remarkable the arrangement worked at all.
Our solution for the slider motors was three threefold. First, we established a properly sized distributed DC power system, running heavy gauge wire down from the 3 original 50 amp rectifiers to the two Pedal towers and up into the Great, then distributing the power from there to the individual motors from termination blocks. While, in the shop we repaired, replaced and upgraded the Laukhuff motors using their new universal controllers, which will allow is to dial in the performance of each motor so they will operate properly, but as quietly as possible; for future maintenance it will be easy to adjust the performance of any of the motor in the system, and there will be no concern about a lack of power.
For the Swell and its addition, we took different tack and went with Heuss 24VDC slider motors and their ET-40 control cabinet. Part of the decision made here was because the organ layout leaves no easy path for access to motors in the upper Swell, but more because the Huess system is known for its superior design, quiet operation and reliability. Running at the higher voltage allows for slightly lighter gauge control able and the ability to dial in their performance from the control cabinet, which has its own internal power supply; there is actually an individual transformer for every motor in the system. This makes the cabinet heavy and the was surprisingly the only item the riggers groused over on day 1; the ET-40 is in a large steel enclosure and weighs a good 300 pounds or more. The Poistive retains its Laukhuff motors, but runs now on its own own separate 75 amp power supply to run the both the pulldown motors and the sliders.
Tonal finishing will begin once all mechanical systems are up to 100%. I’ll be working directly with Russell Jackson to help realize his vision for our subtle but important transformation of the instrument that will make it far more suitable for Episcopal worship.
Warren Blyden will return on assist March 9; we will switch out with Brad and Mike around March 25 and we expect to have most or all of the organ running and tonally finished for Easter 2017.