hammond l 100 amp issue

[Guest]

HI everyone!</P>


i have a situation with my hammond that i just recently uncovered. I have been gigging alot lately and JUST recently discovered my hammond is no longer functioning adequately. I run my hammond through leslie 122...the problem occurs when i increase the volume of the organ, i get this buzzing hum sound coming through the leslie and creates some pretty bad distortion...i just had the amp recapped and retubed awhile back.I cant seem to figure out the issue, i thought it might have somethign to do with the amps for the vibrato or percussion? maybe output transformer? any ideas? thank you</P>
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[fredy2]

Re: hammond l 100 amp issue



I found a similar problem with a friend's that was traced to ground loops between the organ and Leslie... The net problem was improper grounding of a modification of a switch to turn Leslie effect on. After getting that corrected, some hum still remained.</P>


It turned out that the Leslie had a switch to simulate a speaker load and the setting of the switch had to be changed. As I recall, the switch on the Leslie had three positions. Changing the switch position fixed the remaining hum problem. Look for this switch, and if it exists on yours, try different setting.</P>

[tonewheel1966]

Re: hammond l 100 amp issue



Fredy is talking about the load selector which is found on a 147. The 122's do not have this as they are supposed to be used with a console Hammond with balanced GG output. I used my 122 with my Hammond L100 until I got an RT3. The only hum I had there on the L100 was traced to a cap in the power chassis.</P>


Have you had the Leslie serviced? I get occasional hum through mine and crackles of static now and then. The RT3 that it is connected to has had the pre amp rebuilt and retubed like your L100. I was advised by Hammond101 to connect headphones to the Hammond to see if I could eliminate that as the source and it sounded fine. He has advised me to replace the 6550 tubes in the Leslie. I am going to recap it's amp at the same time.</P>


Have you experimented with low organ output and Leslie volume high etc?</P>


Hope this helps.</P>


Dave</P>

[fredy2]

Re: hammond l 100 amp issue



I will revisit an important thing in regards to hum, ground loops, and safety of equipment.</P>


ALWAYS power all the system from a single receptacle !!!</P>


Plugging power into different receptacles CAN resullt in ground loops in the building's wiring... this can even lead to damage of equipment due to ground loop surges.</P>

[Guest]

Re: hammond l 100 amp issue



thank you so much guys</P>


the hum does not seem to change whether i try low output on the organ and high volume on the leslie, ive tried several leslies and i get the same result, NASTY distortion when organ output is high. </P>


I plugged headphones into the organ and the source of the problem IS the organ</P>


Fredy2 you brought up a point about groundloops, my organ is a chop...could the steel chasis it is built in be an issue? i also use a groundlift before going into the leslie it DOES help a bit but the problem is still pretty noticeable.</P>


any other suggestions? tube? cap? </P>


thank you</P>

[tonewheel1966]

Re: hammond l 100 amp issue



This sounds like the problem I had on my L100. Try playing the G on the pedal board if you still have one on it. If it sounds the same as the hum you have (experiment with volume on pedal drawbar) then it is a mains hum. I think andyg brought this to my attention. If you look at the main amp in your L100 you will see the two Mallory capacitors (big cans). My organ tech bridged the underneath of one of these with a new capacitor and the hum virtually went. I can still get hum if I more the wiring around behind the amp but that is the nature of the beast. If you did not have it before (even though you have a chop) I would bet this is where you should start lookng. These amps store high voltage and the job I described above is best left to an expert who knows how to discharge them. I think my tech had the amp on until he had found the problem!!! and just turned it off while he soldered in the cap.</P>


Cheers</P>


Dave</P>

[Guest]

Re: hammond l 100 amp issue

awesome man ill check into that, i was assuming a problem with a cap since its been a year since i had it recapped and have been gigging quite a bit this whole year...ill look into replacing the caps. thank you