Allen ADC 2160

[DonS]

BTW, the Allen 2160 is a pefectly decent organ and can be upgraded to send its audio into four or even six channels (if you put the card reader on its own channels). The audio system has extra inputs on the mixer board, so it's easy to pipe in the audio from an external device and have it express with the existing organ stops.</P>


My partner and I just finished putting MIDI on his church's ADC 3100 (very close to your 2160) and we ran his expander boxes into the organ's own audio with good results.</P>


John</P>
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Hi jbird. Thanks for your extremely helpful sharing of knowledge. I've spent hours reviewing the archives to glean knowledge about Allen MDS, ADC, MDS Expander II and Hauptwerk integration. Of course other member posts have been very helpful too.

My church is contemplating the purchase of an Allen ADC 2160A. The purchase is contingent on my ability to successfully install an Allen MDS Expander II on the ADC 2160A. Can you please comment a bit more regarding if divided expression translates correctly when plugging the Expander L/R audio outputs into the existing extra inputs on the ADC 2160A mixer board. In other words, will the configuration recommended above result in the Expander division expression being divided as it is for the native Allen voices?

Also, if it makes a difference, are you able to comment specifically on which mixer board inputs to use to get divided expression for the Expander audio.


DonS

Church #1: Allen MDS-8
Church #2: Baldwin A240 draw knob (by Viscount) Likely to be replaced with Allen ADC 2160A very soon
Home: Allen MDS 16 with external MDS Expander II

[jbird604]

Don,

I'm attaching a block diagram of the mixer in the 2160A, in case you don't have it. It appears that there is only one spare input that goes through the expression stage, and that is J508, called "Chan 4A In". That input gets mixed with the adjacent input and goes through the great expression engine on its way out. So you could send the Mono signal of the expander into that jack and have it express with the great (and come out of only one of the speakers).

Another idea would be to do away with the Card Reader and then use the two inputs -- J503 and J506 -- that are now used by the Alterable Voices (channels 5 and 6 coming out of the cage). These inputs go through the swell expression engine, and have the advantage of going into both amp/speaker channels, so you can use the stereo outputs of the expander (and have it come out of both speakers).

On that old 3100 that I mentioned in the old post you quoted, Allen hadn't yet come out with this neat little all-purpose mixer, and they put that 3100 together using a pair of the old original MADC two-channel mixers. That was a clunky setup, of course, but it did have several unused inputs, since a board called a USEM-2 was used to blend the Alterables into the swell (and the USEM-2 had some unused inputs on it), and the original MADC mixers had dual Rhythm inputs on each mixer which were expressed. So there were a multitude of ways to do it with that old organ. As I recall, we had the MIDI box wired so that it went into all the amp channels, and one channel expressed with the great, the other with the swell. That was odd, of course, but it made it "seem" like the MIDI voices were expressing along with the other stops, regardless of which manual you were playing it on.

So, unfortunately I guess, you can either do away with the Card Reader and have stereo for your Ensemble, or you can use the Mono output and have it express with the Great.

Of course, it's possible to do more extensive modifications. A good tinkerer could make up a customized resistor matrix to feed the Ensemble signal directly into the inputs that are already in use. That would of course "void the warranty" ...

EDIT ........ A third possibility would be to attach the Ensemble to J498 and 499, which are the Rhythm inputs. These inputs do not go through either expression engine, but they do go into both amps and speakers for full stereo. Then you'd have to use the volume knob on the Ensemble itself to set your volumes, and the Ensemble would be a "floating unexpressed" division.

[DonS]

Hi jbird,

I went with the option to disable the card reader and use the J503 & J506 inputs with swell expression.
If worked wonderfully. Thanks for your help. I purchased the organ for $1000 and will be installing it in the church next week.

I have two additional questions:

1. Would it be possible to use RCA "Y" adapters to simultaneously feed the expander and card reader audio input into J503 & J506?

2. The organ came with 4 speakers. They appear to be HC-15Us, however one speaker has a very different looking crossover circuit on the back (two rather large coils) while the other three have several smaller coils. When testing the larger coiled speaker using the Handbell expander voice, I noticed a significant drop in volume when I played notes on the high end of the keyboard. That makes me think the speaker is a subwoofer, even though it has a mid-range speaker and tweeter in addition to the 15" bass speaker. Does this assumption appear to be correct? It seems odd to have three regular speakers and a subwoofer rather than two pairs and a subwoofer.

[jbird604]

Hmmm.... I don't know what that odd speaker would be, though it could just be a later or earlier version of the HC-15 than the others. The drop-off in treble makes me wonder if it's actually an HC-12, but I don't think the HC-12 ever has the crossover on the rear of the cabinet. And the HC-12 would be obvious with its dual midrange drivers instead of the single midrange in the HC-15.

Maybe the tweeter control on that one is just turned way down. Or the tweeter could be defective or not even connected at all for some reason. There should be a label on the rear of the box to identify the speaker model. It's surely not a subwoofer, as there wouldn't be any kind of crossover on one of those.

As to your question about using "Y" cables to connect both the Card Reader and the Expander to the same inputs on the mixer -- you can try it and see what happens. In a pinch, I have gone so far as to use "Y" cables to temporarily mix two organ channels into the same amp, when there is a bad amp and the organ has to be used anyway. So it might work.

My preference, when mixing two inputs like that with a "Y" cable is to install a resistor in series with each branch of the Y, so that there is at least some electrical isolation between the two devices that you are feeding into the same jack. This will slightly reduce the level of the sources, but not much, and you have plenty of volume range on the volume knob of the expander and on the gain controls of the Card Reader board. If you decide to try it with resistors, cut the Y cables and put the resistor into the signal (center) wire of each leg, and then re-join the two parts of the shield with a jumper wire soldered to each piece.

What value resistor? I think about 10K would be a good value to try, as that ought to give enough isolation to prevent any interaction between their circuits without reducing the level much. I have actually used as high as 100K resistors for this purpose, when I was really worried about possible interactions, as when piping the output of an external device into the organ's audio system.

Let me know how that works out.

[toodles]

Just using a Y cable will probably not work--the ADC mixer has an input impedance of 100K ohms, so the two outputs will likely load each other--sometimes motorboarding results (parasitic oscillation) and sometimes you just get a dramatic drop in volume of the two sources. So if you try this, make sure the volume is set very low in case it does motorboard.

Typically when running two outputs into one input you need a mixer--it keeps the two outputs from seeing each other. There is nothing at all unusual about the ADC input circuits, so standard line level mixers should be fine. This looks like it would work fine and is quite reasonably priced: http://www.nady.com/products/compact-mixers/mm-242/

It requires a wall-wart power supply. You can probably find the mixer for under $20--the power supply seems to be about $20 also.

[jbird604]

I concur with toodles. Small investment to do the job right!

[DonS]

Hi jbird,

I'm reporting back on what I feel is a very successful installation of an ADC 2160A in our church. THANK YOU, and others, for all your help! (However, I do have a remaining MIDI switch problem I hope you can help me resolve.)

1. I am successfully using "Y" cables to connect the MDS Expander II to the J503 & J506 inputs used by the card reader (no resistors or mixer were needed for a clean sound). The card reader and Expander can be used simultaneously and both are expressed by the Swell pedal. I'm very happy with this arrangement because everything on the organ works as it should. (by the way, mixing Arco Strings and cello on the Expander with a full organ registration for hymn singing results in a marvelously full sound worthy of the Mormon Tabernacle Choir. While playing the call to worship last week, the Pastor said "that sounds so good, let's sing it again".)

2. Regarding the speakers, I mounted two Allen HC-15 cabinets to the rear wall of the sanctuary. Mounted at the front are two smaller non-Allen speakers (Mid-range and tweeter, without crossovers) that were used with the old organ. I experienced some distortion from these when they were hooked up in parallel with the rear speakers. They were also much louder than the rear speakers -- not a good sound. I solved the distortion and balance problem by first passing the front speaker wires through a non-powered Optimus 10" subwoofer with crossover circuitry that I purchased for my home theater many years ago. What a difference that made! The distortion disappeared and the front speakers were reduced in volume to a level where they balance nicely with the rear speakers. One parishioner told me last week that the sound from the pews made him feel like he was floating in the sound of the organ. The surround effect in the sanctuary is truly wonderful.

3. Voicing the 2160A was tricky with the original bad speaker arrangement and I ended up paying the local Allen technician for a service call to help me with that issue. That was a good thing because the technician also provided me with advice on how to separate the divisions so I can control MIDI keying On/Off for each manual and the pedal separately using two un-used stops in the 2160A console. My console does not have internal or antiphonal speakers attached. However, it does have two fully functional blank tabs prepared for Console Speakers Off/On, and Antiphonal Speakers Off/On. These blank tabs are conveniently located adjacent to the existing MIDI tab. The Allen technician showed me that the blank tabs were pre-wired to control certain terminals in the speaker wiring block, and that I could connect separate wires from the MIDI board to these speaker terminals and thus control the MIDI On/Off keying for two more divisions of the organ using these blank tabs.

So I finally did the MIDI wiring project last night with some success. The original MIDI tab controls the Swell division On/Off, the first blank tab now controls the Great division MIDI On/Off and the last blank tab controls the Pedal division MIDI On/Off.

The original MIDI tab works flawlessly. However, the two blank tabs I hijacked are giving me some trouble. The tab controlling the pedal always comes on when activated, however, sometimes it will not turn off without exerting some extra pressure by lifting the tab manually. The tab for the great always turns on but has the same problem turning off as the pedal division for the first 2 or 3 times it is used. After that it will not turn off at all, regardless of the amount of pressure I use lifting the tab. Once it's stuck on, I have to turn the organ off then back on to cancel the MIDI on the great division.

I've noticed that the blank tabs I hijacked are different than the other stops, the blanks appear to have double the number of contacts. I wonder if this difference has anything to do with the problem.


Do you have any ideas about how to resolve this MIDI On/Off problem?

[jbird604]

Congratulations on the good setup and the fine reception by the church. It's great to know that folks appreciate good organ sound when they hear it!

As to the stubborn tabs, I'd take a close look at them mechanically. The only thing required by the MIDI adapter board is that the control line for each division gets grounded when you want MIDI to play from that division. That's fairly easy to do on MADC organs like the 2160, because the stop rail itself is at ground, and the tabs simply short the wire that's connected straight to the frame or ground when the tab is pressed down.

So, either the faulty tabs are not working just right, which should be apparent from a mechanical point of view if you look at them closely and watch what happens as you depress each one. In order to see this happening, you may need to remove the roll-top cover from the console. That is pretty easy to do on the "T" style console of the 2160. The back edge of the roll-top will exit through some alternate slots and roll right out the back of the console if you direct it into those slots. You do have to untie and move the music desk light zip cord out of the way to allow this to happen, and you will need an assistant to help you catch the roll-top when it goes out the back!

Once you have the roll-top out of the way, watch closely to see what the tabs do and make sure they do nothing other than close the switch to ground out the wire. The contact points on the small leaf parts could be dirty or corroded, so wipe them with a Q-tip dampened in alcohol or even WD-40 if there is a stubborn material that needs to be dissolved and removed.

There are two switches per tab because one of them goes to the capture action memory board to "sense" when the tab is down, so it can be captured by the DM-3 board when you set combinations. Every tab should have a secondary switch for that purpose. The other leaf of the switch is for grounding the control wire of whatever you desire to turn on with that tab.

It's possible that these two blank tabs actually go somewhere else in the organ, and that they are somehow connected into a board or other component in such a way that they don't act right, don't simply ground the wire. You could fix that problem by remove the small white wire that goes off somewhere else (NOT the one that goes to the capture board; the OTHER one) and then solder your MIDI control wire directly to the terminal on the back of the stop tab.

There's always a chance that the MIDI adapter itself is not working properly. You can verify its operation by physically grounding each control wire, one at a time, with a clip lead. The MIDI voice associated with each division should turn on and off just like any other stop as you ground and un-ground the control wire.

That's about all I can think of. Hope that will help.

[DonS]

Thanks for your suggestions jbird.

I looked closely at the mechanical action of the misbehaving tabs and noticed that pushing the tab down (on position) makes a small magnet at the rear move down and moving the tab up makes the magnet move up. This moving magnet appears to activate a reed switch when in the down position. Since the reed switch was still activated while in the up (off) position it was an easy fix to bend the metal stem the magnet is attached to upwards to get it out of the range that activates the reed switch. I now have reliable on-off action from these blank tabs. I couldn't be happier! All I need to do now is make labels for the blank tabs.

I love this forum! I'm beginning to like this ADC 2160A more than the MDS-16 I have in my home.

Thank you all for your help!!!

[jbird604]

Good detective work. I had forgotten about the reed switches. It was MOS organs and possibly a few very early MADC models that had simple open-air on-off switches. ADC/MADC models typically have magnets and reed switches, which accomplish the same thing but do it in a sealed environment less likely to be affected by humidity and air pollution.

I enjoy my 2160 too, though I currently have neither MIDI nor card reader, so I'm limited to the native stops. I do have a third-party digital reverb (Behringer MiniFex800) installed, and when using headphones I mix in a LOT of reverb to make me feel like I'm playing in a vast cathedral! That makes it more fun.

[DonS]

A new problem has cropped up with this ADC 2160. Sometimes there is no sound after turning on the organ. When this happens, all lights turn on, the capture pistons work, the crescendo pedal position indicator lights display properly and the MDS Expander II powers on. I may have to turn the organ off and on six or more times before I finally have sound. Many times, thankfully, it has sound the first time I turn it on.

Unfortunately, this problem is happening more frequently now. Any ideas for a self service fix for this problem?

[jbird604]

A no-sound condition is very often the result of the amps failing to un-mute. This is caused by a problem with the delayed voltage gate, which is on a small pc board down inside the AC distribution box. On the top of that box you'll see three terminals marked something like +12, ground, and "delay" IIRC. The little pc board inside has a capacitor that has to charge up which then triggers a transistor switch to close, thus sending out the voltage required to trip the relays inside the ADC amplifier cage and open the mutes.

(The mutes are there to keep you from hearing thumps and pops that would come out of the speakers as the computer system boots up in the first few seconds after turn-on, and it also instantly mutes the audio when you flip the power switch off, so you don't get a loud "whomp" in the speakers as the computers shut down.)

Next time this happens, leave the organ on, and open up the back of the organ and attach a clip lead between the +12 and the delay terminals on the AC dist box. Be sure not to let the clip lead touch the ground terminal or anything metallic, or you'll blow a fuse in the 12 volt supply!

The instant you attach the clip lead, the audio should un-mute and you will have sound as normal. You can leave it attached and get through the service without a problem as long as you don't turn the organ off again. After the service, BEFORE you turn off the organ, remove the clip lead. Otherwise, if you turn off the organ without removing that lead, you'll get the big whomp in the speakers, which is unpleasant and might eventually damage the woofers.

That delay circuit has caused a lot of problems in my experience. It is one of the weakest and most vulnerable components in an Allen digital and is usually the first thing to be damaged when the organ takes a power surge. I developed a vastly simplified replacement circuit that is impervious to lightning or surge damage because it has no transistor switch in it. My circuit is just a string of parallel capacitors separated by resistors, and with a relay at the end to instantly kill the voltage when the AC is switched off. It's rather big and clunky and won't fit down into the AC box, but I've never had one fail. I guess I need to publish a diagram of it for anyone who needs to build one.

[DonS]

Thanks jbird!!! I'll test the circuit tomorrow. I would like to see your schematic for the replacement circuit. Sounds like I'll be building one soon...

[DonS]

Of course you were right again jbird!

I shorted the connection between the +12 and the Delay terminals and the amps were immediately un-muted.

I installed a pair of wires on the terminals and ran them outside of the console, taping them to the side of the organ so I can short them together when needed without opening the back.

This will be my solution until you post a schematic of your solution. Hopefully it's something I can build and install myself.

[jbird604]

Roll Your Own delay circuit for the amplifier mutes on an Allen organ

Here's the circuit. Download and print the PDF so you can see it as you read my description.

Parts you need:

2 -- 1000 to 5000 mfd electrolytic capacitors rated for anywhere from 25 to 50 volts

2 -- 50 ohm resistors rated for 5 watts or more

1 -- 10,000 ohm resistor rated for 1/2 watt or more

1 -- Relay with 120 volt AC coil. There should be a pair of terminals you can use which are "normally open" but which make contact when the coil is energize and the armature is pulled in. One of these terminals may be marked "common" and the other one "NO" for "normally open." There may be two pairs, so be sure that you choose two terminals that conduct only when the coil is energized.

You can get such a relay from RadioShack or from an on-line source. A diagram should come with it to show you how to connect to a pair of terminals that will close when the coil is energized.

Here's how it works.

(1) When your turn on the organ, the relay coil is energized immediately, since it draws power from one of the switched AC outlets on the organ's AC distribution box in the floor of the console. The organ's 12 volt power supply also powers up quickly and provides +12 volts to the input of the circuit. The two 50 ohm resistors and the two 1000 to 5000 mfd caps are a "time delay" circuit that will take a second or two to charge up to a voltage high enough to unmute the amps. This gives the organ's tone generators a couple seconds to boot up and stabilize before you hear anything, thus preventing unwanted startup noises. Larger caps make the delay time longer. I find the 1000's sufficient, but just to be safe you can get larger ones. They don't cost much anyway.

(2) When you turn the organ off, the AC voltage is instantly removed from the relay coil, which allows the armature to relax, thus opening the contacts and shutting off the 12 volts to the mutes. The amps instantly go silent, and you won't hear the turn-off thump that would be present in the speakers if it weren't for the muting system.

(3) As soon as the organ is off, the 12 volt power supply stops supplying 12 volts to the circuit, but some power will be stored in the large caps. The 10K resistor "bleeds off" any voltage that might otherwise linger on the 1000 mfd caps, preparing the organ for the next turn-on event.

I build this clunky setup on a piece of plywood about 6" square and attach it to the inside of the organ somewhere. Parts can be mounted using hot glue or cable ties or whatever you have. Small nails can be driven into the wood to serve as tie points for the various components, with bare copper wire strung between them. (Do NOT use bare copper wire for the 120 volts of course!)

Be aware that you have DANGEROUS 120 volt AC on the coil, so be sure to invent a cover of some kind to put over it. Older organs used to have stiff cardboard box-shaped covers over such things as this. Organs today always have a sturdy metal cover over any AC wiring that might otherwise get touched by accident. You must provide a safe way to cover up this AC so that nobody gets hurt! People shouldn't be poking around inside an organ console, but you have to make allowances for the foolish!

This little circuit is a bit clunky, and the delay is only a second or two instead of the four to six seconds the original Allen device provides. But it is all you need, and it is almost impossible to destroy it with lightning or a power surge.