I didn't want my first ever Hammond mp3 to be of a problem, but it turned out that way. Please take a listen, it really appears to be somewhere in the percussion section of the preamp. I don't want to move ahead until I get few pointers.</P>
Thanks .. keep a watch for several other mp3s being posted over the next few hours .. of Hammond mods instead of problems! :)</P>
Re: A102 troubles. Big ol hum, please take a listen.
I do not know exactly why it is making that noise but I am pretty sure is has nothing to do with the TG. To me, it sounds like a 60Hz hum or a harmonic of it. You probably know this already but 60 Hz is very close in frequency to a B. The frequency for B1 is 61.74 Hz. That is very close to 60Hz and could explain the beats you hear when playing a B along with the noise. </p>
Sounds to me like when the audio signal ground is broken somewhere. But what do I know? Not a lot about Hammonds. Perhaps my observation may shed some light on where to look?????
</p>
Re: A102 troubles. Big ol hum, please take a listen.
The link worked for me. Percussion section should be it, the normal/soft part gives it away, I think. That vibrato effect with the low B against the hum was interesting. It definitely doesn't sound like a tonewheel hum anyway, even if it was more in tune with the TWG. Electrical interference of some kind? (But why just in the percussion section?) Maybe components are touching within the preamp? Not being the amplifier expert I'm just shooting in the dark here, but it'd probably be worth checking the inside of the amp out and looking for any physically apparent problems. The bit about the tubes was the fishiest/most compelling evidence. I don't know if the percussion tubes are supposed to get much hotter, so that could be a telling symptom. I'm going to go pull my M3 away from the wall and compare.
1955 M3 (in good hands!)
1962 A100
1942 BC
too many other keyboards...
Re: A102 troubles. Big ol hum, please take a listen.
Kenny Hall: </P>
I was wondering about that. 60hz hum seems to be a common problem as far as interference with Hammonds goes. I didn't know the B was so close, though, that definitely explains it.</P>
Farndurk: What was it/how did you fix it? You can ignore my above post I guess...</P>
1955 M3 (in good hands!)
1962 A100
1942 BC
too many other keyboards...
Re: A102 troubles. Big ol hum, please take a listen.
Yup, 60 cycles is very close to a B. When I was a kid, and needed a tuning reference for my guitar, I found out that if I pulled the cable out of the jack on my guitar and touched the tip of the plug I could tune my B string to that pitch and it was pretty close. At least a lot closer than I would have gotten by ear. B on my mom's piano was almost perfect with 60Hz. I think she may have had it tuned once while I was growing up. Needless to say it was a bit flat.
I forget what the tubes are in the percussion stage--I don't think there's a 12AX7--but the other explanation, about bad contacts, sort of makes sense...except this happened rather suddenly. It's probably worth checking anyway.</P>
1955 M3 (in good hands!)
1962 A100
1942 BC
too many other keyboards...
Re: A102 troubles. Big ol hum, please take a listen.
Arlo Brine!</P>
I yam back, yup, link linked like it was meant to.</P>
Course, I'm only here to throw a little shade on the matter, not ACTUALLY help...</P>
But Ya gotta take a <U>good</U> bunch of samples of that cool Analogue synthesis before you fix it!! You'll never get those sounds again and just when you're about to make the experimental recording of the millenium, you'll remember these sounds you have stashed away on your hard drive....</P>
Re: A102 troubles. Big ol hum, please take a listen.
Getting back to the original problem folks,be aware that 60 cycle hum signals impending doom for electrolytic capacitors. It could be in either the pre-amp, main amp, or reverb amp. You can eliminate the reverb amp by pullingtubes to kill the sound from the reverb speaker first. If you have an external Hammond tone cabinet or Leslie, you can check the organ's main amp the same way. It probably past time for the can caps to fail if they're original, and the other axial electrolytics underneath each chassis should be changed as well. Easy peasy.</P>
Re: A102 troubles. Big ol hum, please take a listen.
I should have mentioned in the begining .. No reverb amp, no power amp, no amp in the Leslie either. I'm running my own voltage divider off of G-red/G-brown into a Marshall JTM45, theninto the Leslie. It is not the Marshall, nor anything downstream of it (no hum using an XK-2 through the same system).</P>
Can the two small tubes next to the crooked transformer be temporarily removed to see if the hum goes away? In any case, I am going to seek out and buy a used AO-28 and rebuild it. With the way my time has been lately I will most likely pay someone to rebuild it for me. Or .. is there anyone of repute that sells already rebuilt or new AO-28s?</P>
See, I know me .. and if I get in there and go to rebuilding it myself, I won't be happy until it is point-to-point artwork of my best effort. In short, that could take me weeks ... months. I know I'll tear it all apart at least twice because I got a 3am revelation on how to do the layout just that much more efficiently. Then I'll decide to tear it all down again .... "because I've only got about 6 hours in it this time and I can tear it down and have the chassis POWDERCOATED FLAT BLACK!!! Yea!! Cooly! Let's do that!". May .... June ... July .... tick tock ... all the while the M3 is getting played and the A102 is sitting there whilst it's owner continues his *road to nowhere...* with the AO-28 repairs. Dang .. truth is harsh sometimes! So my guess is this is about a $600 hum. ~groan~.</P>
I have no time for this! Shucks, I'm in the midst of constructing a 40+ module Modular Synthesizer, as well as remodeling our home, closing our "other business" of 15 years,desiging a new line of *purpose built* Hammond dedicated effects pedals .. oh .. and trying to get my effects pedal business into "career level" status and out of second gear .. and somewhere in there we have to feed ourselves and pay the bills as well. And pet the cats and dog on the spare moment. My stomach hurts. :)</P>
Any recommendations of a good amp rebuilder? I guess I cna poke around a little and find the (most likely) shorted cap, but as already stated above, it's just *time* to have the preamp rebuilt .. y'know?</P>
Thanks for all the responses. Dang the torpedoes, full speed ahead. ...... I'm gonna post the Line Out Box Comparison anyway ... hum and all. None of the line out products I used produced any hum before my machine went kafloots anyhow, so that's no issue. And as for the OD comparisons .. my junk don't hum so all the hum heard is from the crapped out component in the A-102.</P>
Re: A102 troubles. Big ol hum, please take a listen.
If you're needing to find this trouble quickly, then it sounds like its time to enquire of Chris Clifton on Hammond Zone. He's an old time tech in Wales who seems to live on the forum! (during UK hours of course!)</P>
Re: A102 troubles. Big ol hum, please take a listen.
Captain Foldback can do the whole enchilada for $275 US. That is if it doesn't need trxfrmrs or toobs. It was very cool of him (Lars) to write me back on a 3 day weekend. That alone warrants giving him a second look. :)
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