Hammond/Leslie overdrive/volume decrease

[SamuelBLupowitz]

Hey all,

 

Something I’ve noticed with my A100/147 rig is that sometimes (not all the time) when I start it up, I’m getting a higher volume output, and a much more overdriven sound (which I really like, even if it’s not appropriate for everything). Then after playing for a few minutes — not sure if it’s something I trigger or if it’s just the amount of time the organ runs — the volume drops down and the distortion goes with it. At both levels I can adjust with the normal/soft switch, so I’m not sure yet if it’s the organ or the Leslie or the cable or what… but I wanted to see if any of you more experienced Hammond folks recognized this issue off the bat. 

 

Thanks friends!

[funkyhammond]

2 hours ago, SamuelBLupowitz said:

Something I’ve noticed with my A100/147 rig is that sometimes (not all the time) when I start it up, I’m getting a higher volume output

 

I'm also no expert, but I do remember sometimes getting a bit of tonal difference with mine. I would have thought it's basically the tubes warming up so maybe it depends on the temperature of the tubes and the room when starting up the organ and Leslie. If you don't get a clearer answer, I'd ask on the Hammond organ forum at organforum.com.

[Old No7]

It's been awhile since I had a "real" Hammond, but I would suggest you remove and "re-seat" all the tubes*.  I recall having a similar issue back in the 80's with one of the two Hammonds we jammed with, and I think that did the trick.  I'd watch out for the tubes too, as it could be signs of a tube failure coming.

 

I hope some other more knowledgeable Hammond pros will weigh in on this -- as my advice is anecdotal.

 

Old No7

 

* The Brits call them "valves" -- which they are, for the flow of electrons.

[KuruPrionz]

Old No7 is on the right track. 

If you want to go "all-in" get some Caig De-Oxit and clean ALL of your tube sockets and tube pins. 

That will eliminate that variable at least. If the problem continues it's time to consider that one (or more) of your tubes are well worn and no longer capable of consistent response.

OR, that you have other connections in the system that need to be cleaned, plugs and sockets. De-Oxit will work miracles on those connections as well. 

 

If everything is clean and shiny and any weak tubes have been replaced and it still does it, it's time to check power supply capacitors. All of the above needs done every so often anyway so it's not wasted effort. 

 

And all of this fun is why I no longer depend on tube amplifiers for my guitar playing. Hate to say it but there you go.

Best of luck to you in your search for uniform performance!!!! Cheers, Kuru

[funkyhammond]

Good point, I forgot to mention that. There could be a tube that's starting to go. I used to get a bit of variation until the tubes warmed up but nothing too significant. This sounds more extreme. I totally agree, the simple thing to start with is re-seating all the tubes.

[mate stubb]

What he said. Tube starting to go bad or poor contact in a tube socket. Sometimes a cold solder joint can show this behavior. 

 

You might gently tap around on the preamp and leslie amp when it is exhibiting the problem.

[SamuelBLupowitz]

Thanks all! I will try re-seating the tubes and doing a pass with deoxit. The tubes are all new since I got the A100 in 2020, but I do have backups of everything just in case.

 

Though honestly I wouldn’t mind the extra gain if it were just consistent!

[funkyhammond]

24 minutes ago, SamuelBLupowitz said:

Thanks all! I will try re-seating the tubes and doing a pass with deoxit. The tubes are all new since I got the A100 in 2020, but I do have backups of everything just in case.

 

Though honestly I wouldn’t mind the extra gain if it were just consistent!

 

All tubes in both organ and Leslie are new? Have you been getting this behaviour from the start? Have you tried swapping any of the tubes? Since you have spares, after cleaning and re-seating, I'd also just try out the spare tubes for the Leslie just to see what differences you might notice, starting with just the power tubes, then the rest of the tubes, then the preamp tube of the A100. You might have a bad tube somewhere. Beyond that, you'll have to get more expert advice than mine.

 

Edit: And if you do notice any difference when swapping the pair of power tubes, I'd follow up with just trying to swap one at a time.

[KuruPrionz]

2 hours ago, SamuelBLupowitz said:

Thanks all! I will try re-seating the tubes and doing a pass with deoxit. The tubes are all new since I got the A100 in 2020, but I do have backups of everything just in case.

 

Though honestly I wouldn’t mind the extra gain if it were just consistent!

The extra gain is probably the normal state of things, I used to own an Hammond M1 and at a certain point on the volume pedal it didn't get louder, it got more distorted in a wonderful, overdriven tube amp sort of way. 

All that said, I would check the rectifier tubes in both the Hammond and the Leslie first. The AC power cord that you plug into the wall will terminate near the power supply transformer and there should be a couple of large capacitors and a rectifier tube nearby. Possibly a 5y3 but more likely a 5U4 which is larger. Try cleaning those sockets first and also swapping in your spares. 

If the power supply is fluctuating it could be the rectifier tube or it could be that the power supply filter caps are deteriorating with age - this is very common with older tube gear. 

 

Should be pretty straightforward to tackle those two tubes and it might solve the problem. If not, just systematically go about it one tube socket at a time. If they've already been cleaned and you have all new tubes then that might indicate that the power supply capacitors are not up to spec and need replaced. Be careful, capacitors can hold a charge and shorting one out with your body in the circuit could result in a painful or even fatal shock, or a lovely burned place on your skin or maybe an observer will get to see your skeleton, just like on cartoons. 😳

[Delaware Dave]

Tap from the G-G terminals of the pre-amp into a Powered monitor and play.  If it exhibits a volume drop the problem is on the organ side; if it doesn't then I'd concentrate on the leslie side.

[funkyhammond]

1 hour ago, KuruPrionz said:

The extra gain is probably the normal state of things

 

Just to note that he originally said he's getting significantly more volume and distortion and it only happens sometimes but settles down after a few minutes. But I agree, that might actually be the normal state if the volume is at max.

[HammondDave]

The problem could also be in the Leslie or Tone Cabinet (if you are using one). In any case, like the others say, its probably a tribe going bad...