Lexicon MX400 help

[gebohmusic]

Hey,

I am trying to use a Lexicon MX400 with my Allen (M)ADC 3100 organ.

I have it connected and it is working -- but the change is subtle and not blowing me away like I thought that it would.

I know each set up is different -- how do some of you that use a Lexicon have it set up or programmed?

My Allen 3100 has the early USRM-2 board -- not the board that was used later on in the 3100's.

If anyone out there has pictures of your connections at the USRM-2 board --- that would be awesome!!!

Thanks,
Geoffrey

[Leisesturm]

I'm kind of idle at the moment so, knowing nothing more about it I did some Google searches based only on information you have provided. You say "I have it connected and it is working". Well, could you take some pictures of 'your' connections so we can see what you have done? Have you been to the Lexicon site and downloaded the setup .pdf for the MX-400? It is pretty informative as to what the different settings accomplish. Finally, what is a USRM-2 board? Closest I can get to that is: USMA -2A board. What is interesting however is a board: 904-5803-3F Audio Mixer board. Is there one of those in your instrument? Seems to me that is where I would be trying to insert an MX-400 if I had that situation. Nothing more I can do until Jbird or myorgan see your post and offer insights. HTH.

[gebohmusic]

Here is a pic of what I have:

[jbird604]

Best I can tell, you have it hooked up correctly, per the Allen tech site. The USRM-2 does not have stereo inputs for the digital reverb. It was the later USRM-3 that had stereo inputs. So you can only connect one of the outputs from your Lexicon to get mixed into the Allen amps and speakers. That's ok, probably not as good an effect as you'd get if you could return a stereo signal to the mix. You could try using a different output and see if one of them happens to work better than the others.

A really superb way to do this would be to run the outputs of the Lexicon into their own amplifiers and speakers. Then you could of course place them wherever they sound best, and you could adjust the level and tone and so on just to suit the reverberated sound.

But that costs money and takes up space, so may not be what you want to do. The row of seven mini-pots are there to regulate the amount of each channel's signal that gets mixed into the reverb, so you might try turning all of them up to about 3/4 of full rotation. You could even try putting them all at max if you want to, as long as it doesn't create distortion, and I doubt that it will. That alone should increase the amount of signal that gets reverbed, and may make the effect more pronounced.

The only other thing you can do is to regulate the input and output controls on the Lexicon itself to adjust the amount of reverb being returned to the USRM. There is bound to be a limit of some kind to the level of signal the USRM would accept without overload, but you can certainly try turning up the Lexicon as high as you like to see what happens.

I assume the Lexicon has an overload indicator on the input level, and you should adjust that level by turning on the tutti and the couplers, pushing expression pedals wide open, then holding down a big two-handed chord and two pedal keys. Turn up the input level on the Lexicon until the overload indicator flashes, then turn it down just a tad so you will be sure never to get overload on the loudest playing you might ever do.

As I said, the perfect solution is to give the reverb its own two-channel or even four-channel speaker system, but that may not be practical. I hope you're able to get the desired effect by tweaking the controls as outlined above.

[JohnBoyDeere]

Geoffrey, I hooked up my MX400 basically this way: ADC computer outputs 1 thru 6 go to the Allen Audio Mixing board inputs. 1 thru 4 are the four main channels out with 5 and 6 being the card reader outputs. (someone correct me if this is a wrong observation?) From the Allen Audio Mixing board these 6 channels are combined into the 4 channel outputs which on my 3100 originally went to the 4 input channels on the amplifier. My MX400 is connected between these 4 Audio mixing board outputs and the 4 channel Allen amplifier inputs. I highly recommend that you completely bypass any of the Allen reverb equipment and wire as suggested thoroughly documenting your stock setup with notes and copious amounts of pictures.

I recommend setting up your MX400 as a free standing system and as I can see from your picture, you only have one channel hooked up and it is wired back into the Allen reverb components? There is no logic in having reverb wired back into another reverb. This is self defeating:)

My MX400 is wired dual stereo surround hall with 4 channels in and 4 channels out. I am very happy with the MX400 Stereo Surround Hall effect. My settings are as follows as found on the MX400 screen to screen: Pre:5ms, Mid RT:1.522, Size:24ms, Shape:5, Spread:50, RT High Out:6.30kHz, High Out:6.30, Bass Freq:250Hz, Bass Boost:.8X, Diffusion:50, ER Time:50ms, ER Level:45 Imput knobs are both set to the 12 o'clock position.

In review: ADC3100 computer to Allen Audio Mixing Board to Lexicon MX400 (4 input/4 outputs) into the Allen 4 channel amp.

With regard to voicing... There are 4 pots per channel basically a high freq., mid high, mid low and bass pots. They all interact one to another. I traced all my voices to the various channels with channels 1 and 2 being pedal and Great stops. Channels 3 and 4 being Swell stops with the Swell Viola II on the Great and the 8' trumpet in the pedal. I spent several days carefully balancing the various stops one to another intra and inter manually. My adjustments got down to a very minute tweak here and there. I have a very discerning ear from my pipe organ days and know fake from realistic pipe sounds and I can say though not perfect, my 3100 sounds fabulous thanks to the Lexicon MX400!

My Allen is labeled: ADC-3100-DKT T1880 Picture is of my Audio Mixing Board which is different than yours. Maybe Mr. Jbird604 can help us here:)

Lastly, read the manual very carefully with regard to saving settings as well as the different nuaunces of the various functions. Once understood, it really is easy to set up. Blessings!

[gebohmusic]

Thank you so much for the help and information!!

She’s up and running with the Lexicon — hallelujah!!

One thing I am still unsure of — and it may be because it’s late and it has been a long day. Will the Alterables run or sound through the Lexicon?

Thanks!
Geoffrey

[AllenAnalog]

The mixing board on JohnBoyDeere's organ looks much more complex than the USRM-3. I too am curious about what model it is and its full capabilities since there are many unused RCA jacks on it. I presume the expression is done on this board rather than in the cage since it has those two connectors on the bottom of the board. Are the switches combining switches like on the USRM-3?

[jbird604]

Yay! Geoffrey, I woke up in the middle of the night and it occurred to me that you could do exactly what JohnBoy did. Bypass the USRM completely. Just take the four audio signals that are currently going into the USRM-2 (the four RCA plugs at the top of your USRM) and run those four signals straight into the four inputs of your Lexicon.

Then take the four outputs of your Lexicon and run them straight to the four inputs on the Allen ADC amp (removing the four RCA plugs that currently go into the amps). That will give you completely control of the reverb on the Lexcion's knobs, and will give you fully quadraphonic reverb.

Now........ As to the confusion and to Larry's question about the various Allen mixer boards......

The USRM-2 was the old standby reverb mixer for a long time, and appeared on many ADC and MADC models. It has provisions for using either a spring or digital reverb, but only in mono mode. It was replaced by the USRM-3, which has stereo inputs for a digital reverb, and in order to use it with a spring reverb, there are jumpers that have to be moved. Normally it would only be used with a digital reverb though.

The "ADC Mixer" shown in the pic supplied by JohnBoy is a different unit altogether. It was designed at some time during the latter ADC era and was used primarily for the MADC-3 models. It incorporates many functions necessary for those organs, such as built-in bass boost and cut (to simulate the Leiblich Gedeckt and Bourdon stops in the pedals), and it provides inputs for the expression pedals, since expression must be done post-cage on those organs.

It was also pressed into service in certain other models, but it was made just for the 3100, 2160, and 3160. It functions as a mixer, expression processor, bass booster, and reverb handler. And yes, it has DIP switches that can be used to combine the channels in various ways. For example, the 3100 and 3160 use all four inputs and all four outputs, so the DIP switches are set for no mixing. But the 2160 only has two amplifiers, so some switches are set to mix certain inputs together on certain outputs. I'd have to look up the chart somewhere to tell you which switches do what.

[gebohmusic]

Thank you so much !!

To connect the Lexicon up and bypassing the Allen reverb altogether— does it matter if the 3/4” inch plugs going to the Lexicon are mono or stereo?

If bypassing the Allen reverb unit - how many total cables do I need?

Will the alterables also have reverb/Lexicon effects?

My F#/Gb at middle C on the great is sluggish or sometimes does not sound — how can I remedy this?

My chimes stop is holding / sustaining out continuously — any ideas to fix this?

Thanks SO much for your help and input!!!

[JohnBoyDeere]

Here is my YouTube arrangement of "Where You There?" from last spring. It is early on in the MX400 install but very satisfactory. I have fine tuned the -400 even further. Hope you like it as I went for dynamics and tones directly related to the wording of each verse:) https://youtu.be/WHsK9NV3gLY

[jbird604]

You need 8 cables. Four to carry the signal to the four inputs of the Lexicon and four more to bring the four outputs of the Lexicon to the ADC amplifier inputs. I'd get cables that are about 10' long so you have plenty and can put the Lexicon anywhere you want it for ease of adjustment and control.

It may be helpful to get cables with RCA plugs on one end (to interface with all the Allen connectors) and 1/4" plugs on the other end (since the Lexicon probably only takes 1/4" plugs. You'll also need four of the male-to-male RCA couplers so you can connect your new cables directly to the RCA plugs that you are going to be removing from the top four jacks of the USRM-2 board.

All the plugs need to be MONO, as each one carries only a single channel.

The key that is giving you trouble may need to have the key contact cleaned. Use a $100 bill (or a dollar bill will do). Slip the bill between the two parts of the switch (between the contact points), then depress the key lightly while gently moving the bill back and forth to clean any dust or corrosion off the contact points.

I don't know about the chime malfunction. That is odd. Have you exercised the two sustain length pots on the TG board? Also, there are some diodes involved in the chime. I think they are arranged in a little matrix, possibly 3 or 4 of them, right above the CM-1 or CM-2 board on the back of the swing-out panel. Look to see if one of them has gotten broken, and if so, replace it.

[JohnBoyDeere]

I bought my cables and 1/4" adapters from: https://www.parts-express.com/ 10' cables are great as John said as you can sit the MX400 on top and fiddle with all of the various settings. I didn't install it inside until I was sure, sure, sure of the correct settings:)

FWIW, the "A" channels in and out are mono or stereo. The "B" side is mono only on the Lexicon.

I eventually went with mono to stereo inputs as this allows greater versatility with the unit. Now I get 16' and up through all 4 speakers instead of just 2. (see 3rd picture) I stereo imputed channels 1 with 4 and 2 with 3 as the-400 Lexicon is in reality 2 reverb units in one hence the term "dual stereo". Dual stereo really is the bomb diggety but can only be accomplished vie dual stereo inputs...

Picturer #1 is 4 mono in, 4 mono out.

[gebohmusic]

Great!!! Sounds wonderful!! I had listened to it when I was thinking about buying the Allen 3100.

[gebohmusic]

Hello,

Ok..............I tried bypassing the USRM-2 and using the Lexicon.

I guess I may be crazy -- but to me the sound was better going through the USRM-2???

I tweaked the Lexicon settings and modes in many ways --- when I would get it somewhere like I like it --- some of the organ stops were just barely audible.

When I did get all of the stops sounding -- I did not like the Lexicon setting/sound.

Could it be that my Allen (M)ADC 3100 and USRM-2 configuration is not the best for bypassing the Allen reverb (USRM-2)?

Ideas? Thoughts?

Thanks!

- - - Updated - - -

I forgot to mention that I tried using the stereo, dual stereo, surround modes on the Lexicon and tried the different routing options............

[Leisesturm]

Hello,

Ok..............I tried bypassing the USRM-2 and using the Lexicon.

I guess I may be crazy -- but to me the sound was better going through the USRM-2???

I tweaked the Lexicon settings and modes in many ways --- when I would get it somewhere like I like it --- some of the organ stops were just barely audible.

When I did get all of the stops sounding -- I did not like the Lexicon setting/sound.

Could it be that my Allen (M)ADC 3100 and USRM-2 configuration is not the best for bypassing the Allen reverb (USRM-2)?

Ideas? Thoughts?

Thanks!

- - - Updated - - -

I forgot to mention that I tried using the stereo, dual stereo, surround modes on the Lexicon and tried the different routing options............

It could never, absolutely never, be the case that the built in reverb of a legacy early digital instrument like an ADC model Allen would outperform a dedicated reverb like a Lexicon MX-400. It would be pointless in any case to still use the stock reverb in parallel with the Lexicon. Maybe you need a tech to set things up for you, because for certain you are doing or setting something(s) incorrectly. Levels can be important. The fact that some sounds are inaudible means that pre-amp stages are not feeding the proper levels to subsequent stages. I would start all over again. Get things sorted properly without the Lexicon in the audio chain. Then try again, bypassing the built in Allen reverb. Or use the Allen reverb and call it good. In this instance, John is correct: folding the output from the Lexicon back into the Allen pre-amp/amp/speaker chain is not the best way to use the Lexicon. Lexicon recommends you buy an outboard audio mixer to loop it, and all their schematic diagrams make this assumption. If you are using the Lexicon without an outboard mixer I have little doubt that the Lexicon is not receiving proper 'line level' voltage signals to do its best work for you. FWIW.