Schober Organ Notes No. 51

OVERTURE

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NEW HEADMASTER

A Note from Fred Henn
Not long ago I realized that my "more than" enjoyable role, as headmaster of our Schober Orphans Group, was preventing me from pursuing many of my other "projects" such as "interim" completion of my 3 manual Schober. Also... the success of our group suggested the formation of other similar groups such as: an ALTERNATIVE MEDICINE group which would, at minimum cost, disseminate information on alternative medicine procedures, etc. At first the "changeover" seemed simple enough ... just determine who had the best qualifications to assume the role. My selection was Mr. BILL KOHRUMEL. After all ... Bill had an excellent grasp of our procedures since he has been a long time member of our group and additionally has been "format-ting" our newsletter for many years ... plus he was agreeable to idea.

However, after overcoming that initial hurdle ... it occurred to me that I  faced another "bigger" one: We have over 350 members in our group now and a little under half of them receive our newsletter and, of those, about 120 receive the "hard copy". The balance opted for Jack Gildar's kind offer to supply the text of Organ Notes via Email  (at no cost to the recipient). Of course, some folk had no choice (no computer!).. Anyway ... of those receiving "printed" versions of our newsletter ... most have a number of issues that are still due them and most folks haven't supplied SASE's. They originally sent STAMPS (most of which I, not looking ahead, used in my correspondence with folks in the group and if we made the change today ... I'd have to send Bill a large bunch of 1st. class stamps. I owe just a few issues to most folks but I'm asking that everyone will RELEASE me from those obligations. If you have any OBJECTIONS to doing so (hardship, etc) please write to me immediately because I DO WANT TO BE FAIR. If I don't hear from you, I'll assume that you've agreed to release me from those obligations.  In the FUTURE please send  items for our newsletter and/or any info, questions, etc., that apply to the Schober group, to:

Bill Kohrumel
233 Mulberry Court
Warrenton, MO. 63383-5249
Email: bk3@mocty.com

FROM NOW ON I'M ONLY ANOTHER SCHOBER GROUP MEMBER!  However ... if you have any "immediate" questions, etc. please contact me. I'll "pass along" anything that appears to be out of my realm.
 

5mf CAPACITORS

ALEX KRUEDENER phoned Warren Boehling and said they had a very pleasant chat. Alex went on to say; "One important thing he told me which was a surprise is that the 5mf capacitors that dry up all the time in the Schobers should be 25-30 volt rated, not 50! He said that they operate at a very low voltage, and that they will not dry up as rapidly if the voltage rating is kept closer to the actual working voltage!"

COPIES OF SCHOBER PLANS

HAROLD WHIPPS emailed: "I built a Recital years ago and donated it to the church I was a member of at the time. ... The console and speaker cabinet were built from the supplied drawings. I left all the documentation for the organ with the church. I do still have the console, speaker cabinet drawings, and the organ tester. I would consider duplicating the drawings if wanted." If you're interested you can contact Harold at: hmwsr@gte.net

HOW TO MAKE A NEW LDR FOR SCHOBER ORGANS.

MATERIALS NEEDED:

LAMP: T-1 Bi-Pin #8099 18V. (All Electronics #LP-8099)

PHOTORESISTOR: 22 OHM light 2 MegOhm dark (All Electronics #PRE-13) or 30 OHM light 10 MegOhm dark (Hosfelt 24-136) or: most in Radio Shack variety pack work

Housing: Opaque tubing 1/4" !.D. (3/8" O.D.) #4400.05 (Organ Supply Industries) or: Cap from cheap black Paper Mate pen. Cap is 37mm long

Miscellaneous: 5 Minute Epoxy, wire sleeves, wire, Electrical tape: The shiny black type Paint: Fast drying black

The lamp is a tiny lamp that has just about the identical light output as the large lamp in the original Schober LDR and the same current consumption. The output was measured with a special lightmeter designed for that purpose. The photoresistors work in a very similar manner to "good" ones in the Schober 04LDR-1.

PREPARING THE LAMP.

This is somewhat delicate. When ready do not pull or push the lamp in our out of the tubing by  its pins. (Learn from my mistakes).

1) Solder about 11/2" of very thin wire to each of the pins of the lamp.

2) Place a 1" sleeve over each (or at least one) of these wires.

3) Cut a strip of electrical tape to 1/4 inch width.

4) Wrap this thin strip around the white base of the lamp until it becomes just thick enough to fit into the tubing (or pen cap from the large opening side). You will have created about a 1/16" cup at the end of the lamp. 5) Make sure that the sleeve is pushed all the way towards the bulb and place a tiny bit of 5 Minute epoxy into this cup. This will hold the sleeves in place.

INSTALLING THE PHOTORESISTOR AND LAMP.

1 ) Cut a piece of tubing about 25mm (1") long. Push a photoresistor about 5mm into this tubing. If you have trouble, heat one end of the tubing a little.

2) Fill the space behind the photoresistor with 5 Minute Epoxy. Let it harden.

3) Push the prepared lamp into the opposite end of the tubing until it meets the photoresistor.  (This places the filament of the lamp just about the same distance from the photoresistor as in the Schober version which had a rather large lamp).

4) Fill the space behind the lamp with 5 minute epoxy.

5) Paint the epoxy behind the photoresistor with black paint. (Light hitting the rear of the photoresistor, even through the epoxy can make a difference in its resistance).

If you use the pen cap:

1) Cut the pocket clip off the cap.

2) Cut 10 mm off the narrow end of the cap.

3) Push the photoresistor, wires first, through the larger opening of the cap. It will only go in until it is about 7mm from the narrow end.

4) Bend one wire to the right, the other to the left. This will secure the photoresistor.

5) Continue with steps 2 through 5 of INSTALLING THE PHOTORISISTOR AND LAMP above.

I have made quite a few LDR's this way. They work just fine for me. I spoke to Warren Boehling who designed much of the later Schober Organs. He told me that the light to resistance values of the Schober LDR's were "all over the place". They are not critical. I think that hot glue might be used instead of epoxy. To increase resistance for a given light output, put a small space between lamp and photoresistor.

If you have questions or want specifics, call me at 802 874-4894 or email me at Kruedener@Juno.com.

I found that the lamps in the Schober LDR's are usually good and it is the photoresistors of the early times of solid state technology that have failed, these LDR's can be FIXED.  Next time I will describe how to fix Schober LDR's.
 

SCHOBER/DEVTRONIX/PIPES

If you view the overhead shot of the console, the uppermost manual is the Roland D-5 synthesizer. It plays from the organ through a 3 manual and pedal Devtronix midi interface so it functions as a midi sound module which I use for piano, glock, xylophone, traps, pan flute, accordion, etc. The D-5 output goes through expression preamps so level changes with the organ swell shoe.

The organ consists of two Devtronix generator keyers, one three manual and pedal generator/diode keyer, Schober generator for percussion which I use for a poor mans wood bar harp (That's the chrysoglott with a very short sustain). I am using Devtronix voice filters to accommodate the need for level adjustability and stop control from + 15 volts. Some of the voices are the Schober filter circuits on Devtronix cards. I have seven Devtronix tremolo/vibrato generators, nine audio output channels, 600+ watts of amplifier power, two digital delays which take the place of the Reverbatape which I wore out.

Speakers include two Leslies for Tibia and Vox Humana voices and separate systems for strings, pedal/tuba, solo, main, posthorn, bass octaves of tibia and synth outputs. Couplers include solo to great pizzicato ala Wurlitzer and there is a great manual crescendo. The pipe ranks are: Tibia clausa, consisting of a few Wurlitzer pipes among some home modified others.

Vox Humana, Wurlitzer
Harmonic flute, Unknown brand
Open Diapason, Unknown brand
Violin, tuned celeste to the electronic strings.

Johnny Hoffmann
 

Ode to George Wright

I have no idea how many of you saw this "Ode To George Wright" in the latest issue of the ATOS Journal, but I thought it would be a much better "filler" than some of my old, corny humor that I usually use.  Hope you enjoy it as much as I did, because George Wright was one fine organist.

Bill Kohrumel.

Maureen Cross, Bendigo Theatre Organ
Society, Bendigo, Victoria, Australia