Hammond, Leslie, Apache, and Kiowa

Dr. Kemp was kind enough to offer a membership to this group, although I am not a professional organ/Leslie technician.  I have learned what I know from owning a Hammond A-100 and Leslie 142.  I am adept at wiring and soldering, but I have no professional electronics bench with an oscilloscope or expensive meter.  I have novice tools, but I have two, almost three college degrees in music.  Once I was a college lecturer.  After the contributions of this group this is what I have deduced about my HUM.  Firstly, "Is the hum coming from the organ or the Leslie?"  Ground the GG terminals to the amp chassis and if the hum goes away, it is the organ.  The benefit of owning an A series organ is unlike the B or C models, which always I have wanted, the A has its own cabinet and amplification system.  There is wide and diverse opinion about the best use of an A series Hammond.  Often they are used as cheaper alternatives to B and subsequently are chopped, cut down into the more portable B cabinet.  Whether  B is actually portable is debatable.  My overall sentiment about my A-100 was if you want to sustain or increase its value, why wouldn't you keep it stock?  This is what I chose, although this opinion has been met with staunch and almost violent opposition, especially from one Hammond dealer in New Jersey whose facility was damaged in the hurricane a few years ago.  Openly he mocked me for keeping the internal amplifiers and speakers.  I was determined to prove him wrong, and that effort began with figuring out how best to utilize an external Leslie speaker and the internal amplification of the A together.  "Pull the tubes!"  "Disconnect the speakers and add resistors."  Instead I was forced to understand Don Leslie's system for switching between the two systems.  Unlike a 147, the 122 amp is a balanced system.  Call it low impedance.  Call it two channel, not a great description.  The 122 amp receives two signals from the organ console, not one.  It comes from the preamplfier, not the signal level output used to drive a 147.  In some respects the 147 is a better solution.  Certainly it is easier, but because our family owned a spinet first which drove our 145, this was the kit we had.  When we purchased the A-100 our technician set it up as easily as possible.  Therefore the "balanced" capability of the A-100 was ignored.  Some people seem to prefer the 147 and its high impedance signal, possibly because the 122 has a reputation for receiving RF interference.  The 122 will pick up certain radio stations if in close proximity.  There are two "death caps" in female amphenol plug in the 122 which are designed to filter this noise.  Evidently fifty plus years later they drift in value and can leak the 120 volts of AC into the chassis of the amp.  Hence they have been nicknamed "death caps."  We have a plethora of both RF and EMF energy around our house.  RF is just a high frequency of EMF energy.  The low stuff is what really causes problems.  Whence does it come?  It would seem I am a conspirator to even mention such a thing, but my almost three college degrees have allowed me to be able to deduce such a thing.  When an arc forms in your home, and you can get shocked by simple 60 Hz 120 volt wall current without touching either side, then you have an arc forming in the air.  This happens from time to time.  It is not good for any kind of electronic equipment, and certainly not for what could be considered primitive.  Drifting caps and growing dendrites, the stuff of lore.  There is no question in my mind that this energy, which can cause our AC to arc, also makes it dirty.  I have bought and installed Furman power conditioners in my stereo system, my musical instruments, and for my computers.  It has helped considerable, but a line level power filter will not filter static electricity in the air, nor will it eliminate EMF's in the low range.  There are expensive ways to insulated your home for such things, and it is involved.  I would rather not live in a government office building with shielded walls and floors, so I must make due the best way possible.  All of this aside my HUM never was a huge issue until now.  My 122 amp has worked well.  Always there was a bit of hum in the organ and the Leslie, but it was not distracting.  Now it is.  The beauty of choosing to keep an A-100 stock is it can operate independently from an external speaker.  While the A-105 actually is better at this than the 100, both can be used as stand alone organs.  It was not until I had both that I could learn the differences.  What are they?  The 105 is a larger cabinet.  It is deeper and thicker and so its internal amplification sounds louder than the 100.  The enclosure is more efficient as a speaker box.  Once  I tried putting a solid plywood back on my A-100, and promptly the bass pedals began to distort.  I worried about the amps overheating, so I removed it quickly.  Eventually it dawned on me that three twelve inch speakers facing the organist would not suffice as sufficient amplification for a room, hence they are best used as monitors for reinforcement of a Leslie.  They provide a small amount of bass frequency on the organist's feet.  What doesn't make sense is a very good sounding reverb amp hidden there as well.  The solution was adding a 1/4 inch plug to the speaker wire, so you can plug in any speaker you like and place it wherever you like.  Wouldn't this be a good idea for the internal speakers as well, if you happen to have an a series organ?  A better designed, more efficient, better sounding speaker enclosure than a box for a tone generator and a bunch of amps?  I put my reverb speaker on top the Leslie, and I was criticized.  "The top panel of the Leslie is supposed to be free to resonate, so placing a cabinet up here impedes its ability to vibrate."  Everyone has an opinion.  The opinions openly which were solicited for my HUM problem are summarized as such.  Again the beauty of an A series Hammond organ is you have a separate system with which to experiment.  If your Leslie becomes possessed for some reason, flip your MEE switch, IF it is wired correctly for the A-100 and a 122, and the Leslie will be ignored.  In this case the HUM is minimal in the organ sound.  When the switch is in the middle position, which is how I choose to use it giving me tube/spring reverb in addition to the dry Leslie sound, the hum is louder in the Leslie.  I didn't discover this until just the past few days.  While I realize a 57 year old preamp could use a rebuilt, it is not causing me any real problems.  What I have been experiencing I believe is from the Leslie.  What is the easiest thing to change on a tube amp?  Of course the answer is tubes.  I received feedback that HUM was not a product of a bad tube, so why was I looking at them?  One member said that eBay auctions often are places to unload junky tubes.  I got two, and both are the 12au7's in my Leslie 122 amp.  I ride my bike to the local 7/11 and use their tube tester.  It seems like a logical choice.  Check your tubes.  I did, and both are crap.  In no way trying to diagnose a loud hum is a bad thing.  Evaluating your amp and its components certainly is necessary.  My amp has been working fine.  Because this excessive external interference is present, I understand the need for good filtering in both the organ and Leslie.  I am inclined to replace the "death caps" with the X Y safety caps Dr. Kemp suggests.  Of course any failing components should be replaced as well, but we must operate in a linear path.  I am inclined to replace the CE can cap with a new one, because filtering is necessary.  As one member suggests something is causing my tubes to fail.  I believe dirty AC was responsible for killing my Space Generator, seeing as the literature in their repair manual state several specific transistors are responsible for protecting others from "static discharge"  Is like pussy discharge?  Pus.  Static energy, energy that manifests itself through the air or more specifically through space.  Air has nothing to do with it?   In terms of a course of action, don't use the 450v can.  They fail.  Wait for two replacement 12au7 tubes and try them first.  See what happens.  If I still have a hum, replace the can at around $55.00.  Then under the hood assessments must begin.  What other than a full rebuild could be appropriate?   In short.  In one of my first posts a member said "microphonic tube."  Yes I have that, but it is not easily discernable.  When I flip my MEE switch to Main, although there is a minimal amount of HUM, the problem is not there.  It is in the Leslie.  The 122 amp has performed well until this snafu.  I don't think cataclismic events have transpired either.  I think we have dirty 60Hz 120V AC and a boatload of low frequency EMF from the military.  In their arsenal of tools less than five miles away are Apache and Kiowa helicopters, drones, the Compass Call Aerial Command jet, and other various aircraft used for surveillence and gunnery.  Many of these have jamming systems which are designed to disable enemy communications.  From this milleau of classified weaponry, how is a musician to discern their effect on vintage musical instruments?  We can't.  Only can we treat their symptoms.  What doesn't kill you makes you stronger.