Allen ADC Custom Megathread

[michaelhoddy]

Well, 720 miles later, the Allen ADC Custom is "home" at my church and loaded in. I wanted to start a topic dedicated to the journey of exploring it and getting it up and running. I'll try to add some pictures as well to document the process.

First things first. This thing is MASSIVE once you account for all the parts. I bought it long distance and sight unseen. I thought it might be in the larger "C" console like the other ADC three-manuals, but thankfully, it's in a 35-1/2" deep console. Also, interestingly, the console is nearly empty, since all the TG equipment and amplifiers is in the 3 remote racks. Really just the USCP and USCM boards on a hinged door, a power supply or two, and the various interface boards out to the remote racks. Even with that, and with some good organ dollies, this thing is heavy, and really a 3 or 4-man move to do safely.

The organ connects to the remote racks with a single console multiplexer cable home-running to each of the "A," "B," and "C" racks, terminating on separate molex-style connectors in the bottom of the console. There is also a power relay and mute circuit control cable that runs to the first rack and jumps to the others. Finally, there is a stereo audio send on two shielded single pair cables, and two return cables for expression control for the MIDI interface, which in this case included an audio embed out to two of the speaker channels. Since all the audio is in the remote racks, this all runs to an ADC audio mixer in the C rack.

Speaking of the racks, they are also VERY heavy. They are a variation of the same types we've seen since the MOS era and in the Johnson Ferry organ, which was built I believe the same year (1989). To the contrary of the reports of the cabinets being unventilated, they have vents in the front on the doors and another grille in the center of the top, as well as a grill surface as the top of the cage. It seems like a very adequate setup to facilitate convection airflow. It does however seem a little weird that the ADC amps are on the bottom with the cage right above.

Each rack contains a single full 25-slot ADC cage with 7 channels of audio, and each of the three cages is full with all slots and all 7 audio channels used. Two of the cages have 7 ADC amplifier channels (two doubles and a triple), and the third cage has 8 ADC amplifier channels (4 doubles), as it's the cage with the subwoofer crossover with an extra amp channel for the B-40 sub. Another way to think about them is that each of the (3) remote racks is basically an entire ADC Classic I or ADC 5300 resource wise!

The cages are very simple, being filled with TT-4 cards, and a sprinkling of FG cards for frequency/pitch, and DG cards for envelope generation, one of the unique attributes of the TT-4 system, which has both attack AND release transients.

There are also two of the unicorn-like TT-5 cards for the chimes and Festival Trumpet! This one has 8 Eproms instead of 4, and 512K memory per Eprom. The chimes sound absolutely realistic, far and away better than any of the other TG-2 or similar-generated chimes used in the smaller organs. The festival trumpet also sounds great, although I didn't examine it as closely.

Finally, audio. This one has 22 amplifier channels if you're counting. There was originally double audio installed, as the church it originated in sat 1200 people. I purchased it with single audio and 22 speakers- a mixture of 15 HC9 and 2 HC18 cabinets for the manual stops, and 4 HC15 and 1 B-40 cabinets for the pedal. I have some additional HC15's around and might try doubling things up again once we see how it performs.

[michaelhoddy]

More pictures of the cages and TT-5.

[AllenAnalog]

Congratulations!!! This is really exciting to have a Forum member acquire one of these incredibly special TT-4/5 instruments and document it for the rest of us. Thank you for giving this instrument a new home and life.

Having eight 512K EPROMs for the chimes is outstanding and shows how far the ADC system could go. The Universal System (USxx) was an impressive creation of electronic topology in the days before the ubiquitous microprocessor came into the tone generation world.

Your comment about the DG card providing for both attack and release transients is the first I've heard about that function of this card in comparison to the EG card. Thanks for clarifying that; I've been curious about the use of the DG card ever since I first saw it in association with the brass choir option.

The relatively empty console and the revelation of the multiplexer to connect to remote TG cages is also a new facet of these organs to me.

Looking forward to lots more photos and some recordings of this organ once you have it set up and voiced.

[michaelhoddy]

Speakers and multiplexer connections

[SchnarrHorn]

Awesome!! It will sound great!!

[myorgan]

They are a variation of the same types we've seen since the MOS era and in the Johnson Ferry organ, which was built I believe the same year (1989). To the contrary of the reports of the cabinets being unventilated, they have vents in the front on the doors and another grille in the center of the top, as well as a grill surface as the top of the cage. It seems like a very adequate setup to facilitate convection airflow. It does however seem a little weird that the ADC amps are on the bottom with the cage right above.

Michael,

Congratulations on the acquisition of the organ for your church! I am especially interested in the paragraph I quoted above. It could account for the fact there were 2 different dealers involved with the initial installation of each organ. OTOH, it could have been the case with both organs, and both were well-ventilated. I know my ADC-8000 racks are totally open to the air as well.

What also interests me is your observation that the cages and cards are located ABOVE the heat source, which seems antithetical to common sense. I wonder what Allen's thinking was in creating that design.

Because my ADC racks will be in an attic space, I've thought about reversing the design of the racks when I get mine installed.

Is it possible to post more photos of an amplifier rack from the front & back? You got the top & side great, but I am curious about the amount of airflow from front to back. I would think with the shelves being solid, not much air travels vertically.

Michael

[michaelhoddy]

Michael, I'll get you a photo of the internals of one of the racks once I pull them out far enough so that they can be opened up fully. To be clear, this is a different style rack than an ADC 7xxx or 8xxx amp rack, and much closer to the Johnson Ferry racks or even the old MOS "verticals" on the big custom organs, where the TG hardware was remote from the organ. Each has two hinged doors in the front, a solid back, and a couple shelves for amps and other components, with the ADC cage mounted towards the top and above the rest.

But they are painted the same Allen blue!

I would imagine the amps were at the bottom because of their weight and for center of gravity reasons. But it does mean all that heat is rising up past the cage.

[Larason2]

Looks great, congratulations on the acquisition! It will be a real treat to get it working again. Thanks for posting.

[michaelhoddy]

Here are the "cage charts" (in quotes because they're not quite the same as regular ADC cage charts. This shows clearly the mapping of the FG and DG boards to the TT-4 cards, as well as the amp channel routing (7 channels per cage, with 2 or 3 stops per channel). A few notes:

1. You'll note how the bigger mixtures (IV ranks and above) are mapped with 1 TT-4 board for every 2 ranks, with each 2 rank pair also in a separate amp and speaker channel. This is one of the secrets of why these sound so big and pipelike.

2. The Swell Plein Jeu VI is on 3 TT-4 boards, with a second drawknob that only draws the top 4 ranks to give the option of a smaller mixture.

3. There's one "as built" change from the cage chart. On the chart, the 8' French Horn was on the Choir, and in the Swell, there were discrete 2-2/3' and 1-3/5' mutations on separate knobs. As built, the French Horn is moved to the Swell, the 2-2/3' and 1-3/5' are condensed into a Sesquialtera II (and I'm pretty sure on one TT-4 board rather than 2 as with the discrete to make space for the French Horn), and an 8' English Horn is added in place of the French Horn on the Choir. The "Sesquialtera" in this case is actually made of flutes rather than the more typical principals, so more like a Cornet II.

[myorgan]

Thank you for sharing these cage charts. They are so informative regarding what a TT-4 based organ is set up like.

Michael

[myorgan]

Michael,

I do have a question for you about the stoplist. I've observed no less than four 4' stops on both the Choir and Swell, while the 8' stops are cut back (I LOVE the Erzähler Celeste!). On the Swell, there's no less than 6 Reed stops! I know what it looks like from a stoplist perspective, but I'm wondering how it works in reality? Are you able to register various genre's of music adequately?

Curious minds and all!;-)

Michael

P.S. How appropriate was the name of the church?!!!

[michaelhoddy]

Michael, I haven't spent enough time with it to feel out the limitations yet, but it's a big enough spec to get around limitations in any one division, and all the major effects are there. A shortlist from my short time playing it a couple days ago:

1. I don't really see the need for 2 sets of 4' strings and Celestes. 1 is plenty. The Swell 4' strings provide a really nice shimmer. I'd prefer a real 8' Dulciana and Unda Maris instead of the 4' set.

2. I'd trade the Vox Humana for a third Great 8' mp string or Spitzflote or something instantly. The Great chorus is very vertical. Doing the French 8' fonds (think the opening of the Franck Choral in E) or any quiet accompanimental work there invariably takes coupling in another division. This is the one major foundational weakness I've already seen that really makes your 3-manual organ a 2-manual organ to overcome.

3. The French Horn and English Horn are unexpected nice color stops and solo voices on an organ this size.

4. Not sure how I feel yet about the 2-2/3' and 1-3/5' mutations being packaged together as a Sesquialtera. I like having them separate in the swell to register individually for different color combinations.

5. The two-stage Swell Plein Jeu IV or VI is bananas. I love it! You can register the smaller one as a divisional mixture, and the bigger one with the full Swell reeds to crown the organ.

6. I like the 16' Great reed, and how it's the duplex to the pedal rather than the Swell 16' reed. It's voiced bigger in the bottom, so it can sit under full organ without reeds nicely or for Bach, but then the 16' Bombarde can be voiced bigger to pull when the other reeds come in, and also more appropriately for French music with the requisite reed-heavy pedal.

It's also nice to have a 16' Great reed that's a little more mellow but still a chorus reed.

7. The Swell 8' Principal is really nice because it allows the Swell strings to actually be voiced as strings rather than having to pull double duty as foundation stops for the chorus.

The great thing about the TT-4 voices and all the channels is the fact that EVERY voice is colorful and special and adds to the ensemble. This is in contrast to some of the regular big ADCs (like the ADC 8000 that's sitting at the other end of my church) which has a lot of knobs, but a lot of them don't really contribute much.

Will be interesting to live into this. I do see some kind of MIDI expander as an option to fill in the couple holes, since it's already so well set up to do it in terms of both MIDI and audio- just for a few voices.

And yes- the name of the church!

[myorgan]

Michael,

I wish you had posted your response as a post so I could like it (except for the comment about my ADC-8000)! You make some excellent observations, and it will be quite nice to hear samples when you get it totally installed.

Thank you for sharing your journey!

Michael

[jbird604]

Wow! Just wow! Can't wait to read all about this. Thanks!

[michaelhoddy]

Well, it's loaded in, and it's alive! Took a little bit of troubleshooting to get it up and running, as it originally powered up with NO control- no capture, crescendo, working stops, nothing. Just a random assortment of notes playing from different boards. And the transposer light was on with no transposition.

Since the (working) ADC-8000 here also has a USCM-2 multiplexer board, I experimented with it to duplicate the condition, along with some semi-related reading from old topics here. The USCM is looking from a valid clock signal on its primary bus FROM THE CAGE input to literally do anything, even non-audio console functions. Each cage multiplex connects to the USCM separately. In a regular 1 or 2-cage organ, these are just short jumper runs right from the cage to the USCM, so not a big deal. In this organ, those runs are 100 feet long out to the 3 remote racks.

So, for the organ to work, it's looking for the clock from Cage A/Rack A. It sends multiplex on a 4 pin connector, and receives clock on a different 4 pin connector back from the cage which serves as the master clock for the USCM. I figured this out because Cage A has a slightly different multiplex connection setup from Cage B and Cage C. Cage B and C also synchronize clock and multiplex on a single 8-pin connector each, but can't run the USCM. So if there's an issue with the Cage A clock getting back to the console from the remote rack and Cage A, the whole organ is dead. This is a weak link in the whole ADC remote rack approach, which was probably never an intended implementation in the original design and only affects a small handful of larger ADC custom organs that use more than the 2 cages that fit in a regular console.

I ended up testing continuity of each pin and re-seating everything and finally, the organ came up! Once the clock issue was addressed, everything worked exactly as it should, even after being uninstalled, loaded out and bumped around, driven720 miles in the back of a truck, and manhandled back into a new home. It's a testament to Allen's robustness.

And it sounds absolutely beautiful- literally brings one to tears, and in the exact same way as a good pipe organ.

Once I get a few miscellaneous issues cleared up (a couple dirty pots on boards) and get it balanced and voiced, I'll post some audio clips. I'll also A/B it and the ADC-8000, since they're both in the same room, just as a standard of comparison for the TT-4 system.

[michaelhoddy]

Larry, it was actually your recent discussion about the USCM that got me thinking in terms of it needing an external clock input from one of the cages to run, so thank you for that!

Jumping off of that and a little experimentation with the ADC-8000 got me on the right path (when I disconnected the multiplex cable running from the USCM-2 to the "A" cage only in that organ, it exhibited exactly the same symptoms with nothing working and transpose light lit. But when I disconnected the B cage only, the capture and crescendo still worked as normal).

I owe Michael some pictures of the external racks. I'll get a few of the multiplex interfaces in the racks as well for posterity.

EDIT: And also, no, this console is not a "C" console like the ADC 6000/7000/8000 drawknob versions. It's quite a bit smaller- about the same size as my old ADC5000DK width wise and either the same height or a little taller. This may be one reason there's no coupler rail, with the couplers and MIDI controls on knobs on the right jamb, because of the added height of the third manual in the same smaller console shell. I was expecting a "C" console (bought it sight unseen) and was pleasantly surprised that it wasn't. My back is sure thankful!

I don't know all my Allen console types by heart, so what console would that be? It's much more like the later mid-sized MDS 3-manuals- narrower and less tall- than the earlier ADC 3-manuals with their larger C and D consoles.

You are absolutely right that the ADC-9000 and presumably the ADC-9300 4-manuals had more than 2 cages in the console, presumably, as you say, because they were monsters. But I don't know of any others besides a handful of the larger ADC customs that had remote cages?

[Organkeys Jones]

The custom ADC that Michael has is in the D console. I believe the one in Rapid City (Otispit) is in the F console, larger than the C.

[michaelhoddy]

Larry, a couple pieces of trivia about those remote cage interface boards: The RCLD-1 is presumably the "driver" board that's sending multiplex to the cages- there's one for each cage. They run on the 12 volt turn on delay power. The RCLR-1 board you see is the only one of those in the console, and this is presumably the board that receives the clock signal back from Cage A to synchronize the USCM-2. Interestingly, it runs on the 5 volt supply unlike the others.

[davidecasteel]

Looking forward to the sound clips!

[otispit]

This is the 9000 console.."F?"....wider, no rolltop. . Beautiful interior organization...a masterpiece really.
The 8350 is a "D" with rolltop. Both are approx. the same depth

[myorgan]

I'd dearly love to find an organ like that, but alas, it will probably never happen in my lifetime!

Michael

[michaelhoddy]

Agreed on the interior organization. The ADC Custom is the same way. Impeccably finished and dressed inside, albeit on a smaller scale the the ADC-9000 monster!

[myorgan]

Otis,

What do you do to keep the dust and prying hands out of the organ on the ADC-9000? I wonder if a roll top was an option.
I can only imagine how heavy it would be!

No matter how big the church, there are still prying hands! And on an organ that large, I almost find it humorous they had a card reader.

Michael

[michaelhoddy]

I made some progress today with voicing and balancing, and don't want to keep those of you who want to hear the organ waiting, so here's a run through some of the stops, a hymn building up the chorus starting at the Great 8' Principal, and then some improvisation to show the slushy side of the organ, and how it just keeps getting bigger.

One of the unique things about this one, unlike the Classic and the other 2-manual ADC Custom I played years ago, is that this one is a lot more American Classic/Romantic, and somewhat surprising from the Phelps era, but I guess they had to do something with all those Johnson Ferry samples they'd created! It's really an absolute joy to play, even in this rough demo.

If there's any sounds or combinations you'd like to hear specifically, let me know, and I'll record 'em.

There are still some voicing adjustments to be made, and a couple spots where a dirty pot makes an appearance briefly.

https://www.dropbox.com/s/opddrn4p0e...00001.m4a?dl=0

[michaelhoddy]

Larry, it really would benefit from double audio in this 600-seat room, and you can be sure I'll find a way to pull that off. There are several channels right on the edge of distortion, and some additional air movement and headroom would only make it sound better and less forced.

[Prince Lazarus]

Wow sounds great. Congratulations and thanks for posting.

[davidecasteel]

Terrific! My Fisher XP=18 speaker really loved the bass! It's about 30 years old and still working great! (I've 2 of them, but the other one is in another room conneccted to my audio system there. Don't ask--I have no rational explanation why they're separated.)

David

[michaelhoddy]

Michael 1 (myorgan), I'll swing back around since I've played it a little more with a couple more impressions. The Erzahler and Celeste are absolutely stunning, and some of my favorite sounds on the organ. The improvisation above starts out with them, and the 16' Gemshorn in the pedal. Very unlike any other Allen I've played. And I'm glad the ubiquitous Allen "Flute Dolce II" is banished from this organ, under that name or any other!

The weakest point is the lack of a good accompanimental voice on the Great. It makes it harder to use all the nice color sounds and combinations on the Swell and Choir (and there are a lot) as easily, as those manuals have all the accompanimental stops. I voiced the Great 8' Flute Harmonique with ascending power in the treble and smaller in the bass, to allow it to be the great solo voice that it is, but still be able to accompany with the box closed a bit without losing the Pedal stops (also on the same expression) by having to close it more. It works in a pinch.

But man, is this thing fun! Being able to voice stop by stop with gain, treble, mid, bass, and 4 regions per voice and without a computer is really wonderful. This 32-year-old electronic acquits itself nicely.

Finally, you asked for a better picture of one of the racks. They're in a bit of a tight spot, but here are a few (forgive the angle necessary to get the photo). This is the C rack- full picture, detail showing where the multiplexer interface board comes in, and the hidden parts- ADC audio mixer for the MIDI audio inputs, and the bass lift card for the couple 16' Pedal stops that are in the C rack. The others are similar with some slight variations. The B rack has an extra amp for the pedal subwoofer. The A rack has a couple additional power supplies since it functions as the "master" rack.

[myorgan]

Michael,

Thank you for the photos. It looks to me like there wasn't more than cross ventilation or convection ventilation using the chimney effect. IMHO, that's not enough to keep the temperature down, but then I don't get the pay Allen Engineers do!

That recording traversed luscious, to majestic, to exquisite, to powerful! I LOVE the Erzähler at the beginning of the improv. The individual voices you demonstrated at the beginning of the clip were so nice. I do need to respond to one thing you mentioned in one of your posts about a dirty pot. If you're talking about any of the reeds, I seem to remember that Allen's Trompette on the Swell, as well as a couple of the other reeds, had a particularly "dirty" sound around Tenor C, give or take a 4th. We discussed it in a post years ago and came to the conclusion it's part of the original sample, and Allen simply preserved it. IIRC, it was also present in the ADC Tone Cards when I checked.

Great work so far!!!

Michael

[michaelhoddy]

Michael, the spot I was running into it was in the Great 2' Doublette, which shares an audio channel with part of the IV Mixture. The board pots and the amp channel gain knob both had some scratchiness, and as much as I exercised them, it still was popping up occasionally.

Hard to tell if this Swell 8' Trompette is the same as the other ADC models in source material. I guess I could check against the ADC-8000.

The one interesting crossover stop is that the Great 8' Principal here is the same sound as used in the later MDS organs as their 8' Principal, including the Expander II. It has a little more life and movement here than in the MDS organs, probably because of the TG resources behind it, but definitely the same sound.