Can I adjust the tremulant on my Allen MOS-603? (cross-posted)

[Guest]

Hi all --</p>

I'm cross posting this to the classical and theatre lists.</p>

I have an Allen MOS-603C that will eventually undergo major modification to become a MIDI controller for Hauptwerk/Miditzer. In the meantime, I'm curious about altering the classical tremulant so that it is more theatrical. I've seen the Tremulant Gate circuit area in the organ, but haven't had
it hauled out away from the wall in a while to look more closely -- it
kinda requires tearing up my living room to do so!</p>

Anybody know the technical differences between the theatre and classical trems on the Allen MOS series organs?

</p>

Thanks for any input you can give!</p>

Freddie Brabson,</p>

Knoxville, TN</p>

[Guest]

Re: Can I adjust the tremulant on my Allen MOS-603? (cross-posted)



John H (jbird604) responded:</p>

Your 603 will have 2 identical computer systems inside, and you need
to adjust the trem on both. The tremulant adjustment is on the KBA
(keyboard array) assembly. The so-called "tremulant gate" board is just
a circuit used to pull the tremulant fully sharp and hold it there for
celeste tuning purposes, and I don't think there are any adjustments on
it.</p>


So look for the two KBA boards and find the thumbwheel marked "trem"
or something like that. You'll not find any adjustment for trem depth,
only speed. That's too bad, because if you want to slow the trem down a
lot, you'll find that it is too severe. But the preset unchageable
depth is just fine for normal trem rates.</p>


The only other possibility is that your organ might have the
optional Trem Generators. These are metal boxes marked "Trem II" or
"Trem III" and are placed in the audio path after the DAC boards. If
your organ happens to have these, you can adjust the tremulant in all
kinds of ways and make it sound like a Mighty Wurlitzer! This tremulant
will be engaged by a stop labeled "vibrato" or "chorus" (for the two
speeds).</p>


Hope this helps.</p>


John</p>


</p>

<hr align="left" size="1" width="25%">Rodgers 890 at church
Baldwin D422 at home
The music matters after all!

[Guest]

Re: Can I adjust the tremulant on my Allen MOS-603? (cross-posted)



Thanks, John! Very helpful.</p>

I'm sorry to post a query like
that before actually getting into the organ to check things out, but as
I said, I have to completely rearrange my room to get at the back of
the organ. I'll likely investigate the trem situation this week
sometime. I'll keep you posted on the outcome.</p>

I know that the organ has only tremulant tabs for the great and swell divisions, so no "vibrato" and "chorus" tabs.</p>

If
it's OK, I'm going to cross-post your answer under the church
electronic organs forum so it can be helpful to someone in the future.</p>

All best,</p>

Freddie


</p>

<hr align="left" size="1" width="25%">Freddie Brabson
Knoxville, Tennessee

[Guest]

Re: Can I adjust the tremulant on my Allen MOS-603? (cross-posted)



I'm glad to report that my buddy and I successfully adjusted the tremulants on my Allen MOS-603C today. John, you were right on about the tremulant pot on each KBA board. With two computers in the organ, we had a bit of time getting the trems adjusted to identical speeds. I'm not sure we got it exact, but they're faster and more theatrical than before. We used a metronome to get them each in the right neighborhood...not the most precise approach, but it helped. Hopefully the Tibia cards will sound somewhat like they're supposed to. We'll see...</p>

Thanks again, John, for the help.</p>

Freddie</p>