Allen ADC question(s)

[Guest]

Hello All,</P>


I finally have my organ all in one piece and in a clean cool locationafter a drawn out shipping/delivery/set-up story. It sounds lovely and is more than I ever expected for what I paid... However, as you will see, I do not have the most accoustic of settings and am looking to improve the sound quality of my little organ. I have been researching two digital reverbs - being the Alesis Nanoverb and the Lexicon MX-200. I don't really want or need 1,000 different algorithims and computer pragammable presets etc. just some basic, clean reverb. I have read positive reviews of both brands, any recommendation on which way to go with this? </P>


Secondly, I have a pair of home HI-FI speakers that arein pretty good condition that I was thinking of possibly connecting to the organ. They are full range speakers with 12 inch woofers, 6 inch mid range and a tweeter. Is this advisable? I have attached pictures of the various connections on the amp and some kind of relay that is on the bottom of the console. I can hear an audible relay click when I flick the console speaker control tabs (External Speakers Off &amp; Console Speakers Off). I am not sure where I would connect speakers to - the relay or the amp? Your advice/criticisms welcome! I can't find an Allen technician easily, so excuse my hands on approach to this.</P>


My apologies for the TERRIBLE pictures, I rushed and took all of these quickly with my cell phone camera.</P>


Console...</P>


<U><FONT color=#0000ff>http://i276.photobucket.com/albums/k...05-08_1214.jpg</FONT></U></P>


Accutronics Spring Reverb...</P>


http://i276.photobucket.com/albums/k...05-08_1145.jpg</P>


Amp...</P>


http://i276.photobucket.com/albums/k...05-08_1143.jpg</P>


Relay? (sticker above reads 'remove jumpers if external speakers are used')</P>


http://i276.photobucket.com/albums/k...05-08_1154.jpg</P>


Audio/Expression cage (I think)</P>


http://i276.photobucket.com/albums/k...05-08_1150.jpg</P>
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[fredy2]

Re: Allen ADC question(s)



Home HiFi speakers are not rated to take the continuos power that an organ can generate, so drive them with say1/4 the power they had rated them for. You can put a resistor pad to reduce power if the Allen amp puts out too much for the speakers. Consumer speakers just won''t take the power they are rated for home use if the audio sent to them is continuos like from the organ.</P>


Also make sure the impedance is NOT LOWER than what Allen had designed the amp to drive.</P>

[jbird604]

Re: Allen ADC question(s)



Mike,</P>


Looks like the jumpers have already been removed from the relays. You can test this by flipping the tab marked "console speakers off" -- if they actually do go off (hold down notes to see), then the jumpers are out and the relay is ready to use. </P>


Just hook up your external speakers to the terminals marked "main speaker 1" and "main speaker 2" .. Use color coded speaker wire and connect the + terminal of one speaker to the "main 1" terminal and the other terminal of that speakerto common. Do likewise with speaker #2, connecting its + terminal to "Main speaker 2"</P>


I wouldn't try to play really loud using ordinary hifi speakers as you might burn them up rather quickly. The Allen amps can put out 100 watts RMS and will really heat up the voice coils on low 16' pedal notes if played loudly. But they might last for a while and then you could buy some better quality Eminence 12" drivers to put into the boxes.</P>


To keep from damaging those speakers, turn the two volume knobs on the amp down by about the same amount each to keep the channels in balance.</P>


Reverb units -- I use Alesis and think they are great. Other people swear by other brands. You can replace that spring directly with an Alesis (using only one channel, of course, since the spring is mono and the reverb circuitry in the organ is too), but you'll need to make up a special cable for that purpose.</P>


Basically, you need to insert 1 meg-ohm of resistance between the plugs that you remove from the spirngs and the input and output jacks of a digital reverb. The resistance is needed on the INPUT to keep the organ from drastically overdriving the digital reverb, as the signal that the organ is sending to the spring is a pretty high level, meant to drive the spring actuator. And the resistance is necessary on the OUTPUT line because the digital reverb is going to put out a fairly hefty ("line level" or about 1 volt) signal, but the reverb recovery amp in the organ is expecting to receive only a few milli-volts from the pickup end of the spring reverb.</P>


You may need to adjust the little mini-pot marked "reverb level" on that audio assembly. You'll have to tinker with the input, output, and mix controls on the Alesis, as well as selecting the type of reverb you want.</P>


Good luck!</P>


John</P>
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[Guest]

Re: Allen ADC question(s)



To follow up, thank you for your advice gentlemen, I ended up hooking up my HI-FI speakers and they are holding up OK for now, I put the channel controls both at about a hair before No. 7. and avoid playing at full tilt with the swell pedal all the way in. Oh it sounds SOOO much better not having the sound screaching right inmy ears from under the key desk! Actually the higher pitch harmonics sound much better through the HI FI's, maybe the console speakers really do not do justice to the sound generation capabilities - it'smore pleasant to listen to now. The woofers are pretty well built Mitsui's - they don't compare to thebassresponse of the main 15" woofer in the console, but until I get a pair of real Allen speakers, they will do. I will be getting a reverb of some sort on the weekend, as far as the resistors go, these only need to go on the positive side(centre pole of RCA connector) right? Oh I wish I did pay more attention during physics class [8-)]. </P>


I amon the look-out for a pair of HC-12, HC-14 / 15 if anyone should know where I can look toget a pair on the cheap, I would be most grateful.</P>


PS JBird: The WD-40 cleared the crescendo pedal right up! - Mike</P>

[jbird604]

Re: Allen ADC question(s)



Mike,</P>


Yes, the resistors are to be in the "signal" wire (the center of the RCA plug) and not the ground or shield.</P>


Congrats on getting it up and running with the externals. I'm sure they do sound better than just those console speakers. The ADC sound, especially in the 3-digit models, is rather grainy when heard up close, but getting it away from your ears helps immensely.</P>


Please report after you add on the reverb unit.</P>


John</P>
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[Guest]

Re: Allen ADC question(s)



Alright,not to bore you all too much withe my little reverb saga, but here's where I am at...</P>


I now have a Lexicon MX200 twin processor reverb. I tried the the reverb directly in place of the spring tank with the 1 K resistor in series with the signal wire on the output. The results were terrible... Looks like the recovery circuit that was disigned for the spring verb is just too sensitive,over amplified or something... I put (5) 1K (1/4 watt) resistors in series and that still didn't bring the level down enough, it plays times louder than the actual dry signal and it distorts badly with more than one note played. </P>


My other option that I am thinking might give better results is to put the line level signal (pre-amp) going into the reverb unit utilising both audio channels and then running another RCA cable from the reverb output into the the amp, one good thing is that I can keep the channels seperated and run them as dual mono channels, mix them or whatever.Does anyone think this might have any inherent problems? The reverb algorithimswere nice when I tested playing just one note onthe original reverb loop, but I could only play one note at a time without distortion occuring (plus the volume problem).</P>


Seems many other forum members have done this with MOS I / MOS II organs with great results and that this is just a snap on the ADC series organ, not so maybe, but anyone have some idea what I might be doing wrong here? I am going to try the pre amp lines tonight and hope for better results than the reverb loop circuit. At any rate,the organ has affordedme alot of practise time for pedal technique, I can play scales, some appregios without looking now! </P>

[jbird604]

Re: Allen ADC question(s)



OK, Mike, go for plan B.</P>


Instead of just subbing in the lexicon for the spring -- which as you have discovered does not work, and it IS because the reverb recovery circuit in the Allen is extremely sensitve, expecting only a few millivolts of signal instead ofthe volt or more that it's getting from the lexicon -- here's a better plan:</P>


Where the RCA cables plug into the Allen amplifier, pull them out of the jacks. Run the signal that was going into the amp into the line input of the lexicon. Then come out the outputs of the lexicon and go directly into the Allen amps. (You may need to visit Radio Shack and get the appropriate adapters for the cable ends.)</P>


This will work, because the lexicon expects to both receive andsend out aline level signal, and that's what the Allen system uses at the point where the signal enters the amp.</P>


Now, you can use the controls on the lexicon to select the type of reverb you want, set the wet/dry mix, etc. This is actually the way the lexicon was intended to be used. You will want to tinker with the input and output levels of the lexicon to that it will not overload or clip even when you draw all the stops and play at full volume. Then set the amplifier knobs to suit yourself.</P>


Sorry I didn't suggest that at the beginning. I do think the lexicon might work as a direct plug-in replacment for the spring if you'd used 1 MEG resistors instead of 1 K, and you need to use a resistor on both the input and output cables.But possibly not, as from your description I'm guessing that the outputs of the lexicon are really hot.</P>


So try my plan B. It will work.</P>


Another alternative is to use the reverb signal meant for the spring to drive the lexicon, then run the output of the lexicon into a dedicated amp and some well-placed ambience speakers. I've known of people doing that and they say that it works beautifully. Keeps the reverberated sound separate from the original, and you can place the reverb speakers where they give the most realistic illusion.</P>


Good luck. Please report your findings!</P>


John</P>
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[Guest]

Re: Allen ADC question(s)



Ah yes John, Plan B did the trick! WORKS LIKE A CHARM now, Ihave the input level on the lexicon all the way up,as the organ's line level seems quite low for the lexicon,but it is working.I haven't even tried all of the settings on the it yet, although I did find one neat feature, I can detune/pitch shift one of the channels in relation to the next. The stops are split between the channels somewhat haphazardly, but mostly all the principles and 16 ft. stops (plus the 8' trumpet) are onchannel 2, with everythingelse on channel1 (strings, flutes, mixtureandoddly the 16' Bassoon) At any rate, the organ sounds much lesssterilenow and I can pretend I am in some huge cavernous building with physically impossibleabsurd amounts of reverberation [H]. There's a tremolo and rotarysetting wiht adjustable speedson the unit that made it sound (almost) like a Hammond, not necessary, but its a neat distraction.</P>


You are right about the resitors, I had the wrongvalue - Iwas thinking 1 meg meant 1K (1,000) ohms, anyway I will leave the spring verb intact. Itcould have worked if I had done it right. Iwill keep this in mind if I ever want to have seperate reverb speakers. Thank you for all the help and troubleshooting advice. </P>

[jbird604]

Re: Allen ADC question(s)



Wonderful! Enjoy!!</P>


John</P>