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Moving an A100 • dB vs. Hammond


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Dave's non-working reverb is definitely related to the non-working power amp.

 

The reverb in the A100 is pretty interesting, the speaker-level output from the AO39 is put through a series attenuator (reverb knob). This goes in through a pair of light bulbs that act as a compressor/limiter (for Dave's vintage - AO35). It will still work if one of the light bulbs blows, much not two. Then it goes straight to the tank (this is a really low impedance tank, kind of unusual and may be hard to source). The output of the tank goes to a pretty vanilla power amp, which then goes to a separate speaker - a wet-only only signal.

 

Crazy, eh? :)

 

The reverb level knob is connected between the output of the reverb amp and the reverb speaker. The feed from the AO-39 hits the lightbulb-limiter in the AO-35 full strength. Interestingly, when the reverb knob is turned all the way off, the output of the reverb amplifier is unloaded...the pot goes completely open. Normally this is a no-no for a tube amp but the Hammond reverb amps will run into no load without a peep. I did a double-take when I saw that on the schematic, thought it had to be an error. Then I measured an A-100 reverb pot with the ohmmeter. Sure enough, reverb off = open circuit. These tone clocks can be strange sometimes...

 

TP

---

Todd A. Phipps

"...no, I'm not a Hammondoholic...I can stop anytime..."

http://www.facebook.com/b3nut ** http://www.blueolives.com

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Oiled it today. Thank you, Brad! :thu:

 

Also, I figured out part of the problem with the Leslie's volume. There's a belt controlling the top horn that can be in one of three grooves on a wheel that controls it. Mine was on the middle groove. Changing it to the lower groove made a difference not only in the depth of the trem, but it made the rotation noise I was getting at higher volume levels go away. :cool:

 

I'm thinking the 145 could use a little maintenance as well.

 

Talked to Ken Rich...of course, I need to bring the thing to him. I may wait - I'm not ready to give it up for a while just yet. Definitely wanna get his ECC mod (individual toggle, not half moon) and he does a drive mod and effects loop that I think might be cool.

 

dB

:snax:

 

:keys:==> David Bryce Music • Funky Young Monks <==:rawk:

 

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Dave, not taking anything away from Ken Rich, but Alltek is great, and he comes to your house. Pretty damn handy if you're not in the mood to schlep that thing again right away....

Good tip, brother Mike. Ken costs a bunch, too...and if you add that to moving the stuff there and back... :(

 

I'm definitely not in the mood to deal with moving it again, not to mention that it seems logical that moving an large electromechanical device with that's as old as I am should be avoided as much as possible. :idk:

 

Thanks!

 

dB

:snax:

 

:keys:==> David Bryce Music • Funky Young Monks <==:rawk:

 

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I'm thinking the 145 could use a little maintenance as well.

dB

 

How amenable are you to doing stuff yourself at this point? The Leslie is the place to start imo. You'll need to do periodic adjustments on the motor stacks and oil these as well. Some say to do it 1/year but you can get away with way less.

 

Pull off the back covers and start by observing how the fast/slow (upper/lower or lower/upper depending on which stack) engage with the halfmoon switch settings. Removing the stacks is really easy (couple of hand tightened wing nuts, remove 2 wire twist nuts and pull the belt - that's it). I would want to do a one-time thorough cleaning and oiling of the fast and slow motors on each stack.

 

There's so much info on line and plenty of help around here. I don't see how you could get into trouble for long (if at all). But of course it depends on your desire and time. If you decide to go it with someone else, I recommend watching everything and ask a ton of questions. I wouldn't recommend you recap the amp but just about everything else on the Leslie is just a matter of reading up on it a bit, asking some questions here if need be and giving it a try. I'm really trying to see this through non-geek eyes :hitt: , but seriously, you can do most of this stuff yourself - now!

 

 

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I'm defintely not adverse to digging in. I do wanna learn. I already know way more than I did a few weeks ago from what folks have told me here, vids I've watched, stuff I've read...and just generally poking around the thing. It's part of the reason I got one. Luckily, my instrument came with the original instruction manual - it's actually really great how thorough it is...not just how to do stuff - concepts are covered as well.

 

Videos are such a great resource - it was cool to see the trick of getting the oil into the reservoir behind the presets assembly using a drinking straw - worked really nicely.

 

I'm already poking around the Leslie as well. That's what led me to start messing with the belts.

 

dB

:snax:

 

:keys:==> David Bryce Music • Funky Young Monks <==:rawk:

 

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If you don't know it, another great resource is bentonelectronics.com . George is active on the organforum (or was last I checked, but I don't go there much) and provides lots of great info. He has parts on his site, but also the Service Info and Blog have great stuff too.

 

I visited his shop once, it was hard to not :drool:

"I'm so crazy, I don't know this is impossible! Hoo hoo!" - Daffy Duck

 

"The good news is that once you start piano you never have to worry about getting laid again. More time to practice!" - MOI

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The Leslie is definitely a great place to start. The vast majority of these haven't been probably oiled since Nixon was in the Whitehouse.

 

Start with the bottom stack. Not matter how bad you screw it up, the organ is playable with no bottom motors. :D

 

Wes

Hammond: L111, M100, M3, BC, CV, Franken CV, A100, D152, C3, B3

Leslie: 710, 760, 51C, 147, 145, 122, 22H, 31H

Yamaha: CP4, DGX-620, DX7II-FD-E!, PF85, DX9

Roland: VR-09, RD-800

 

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FYI. - just in case -

 

Don't remove the belt slip. Rotor belts are supposed to slip. It acts as a clutch. Taking slack out of the belts is hard on motors.

"It doesn't have to be difficult to be cool" - Mitch Towne

 

"A great musician can bring tears to your eyes!!!

So can a auto Mechanic." - Stokes Hunt

 

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The belt on the bottom rotor can be tricky to set up. You don't want a taunt belt, and you don't want much slack either. There's a "middle ground" that works. They are intentionally designed with belt slip in the equation. The belt on the bottom rotor acts as a torque converter during acceleration. It takes a couple of hours to set up.

 

I had to replace the belts on my 760 that I restored last year. It had been stored in a barn when I bought it - they not only kept stretching but the belt just no longer worked no matter how I adjusted it. There's a certain coefficient of friction between belt and pulley that is required for the rotor acceleration to work, especially on the bottom rotor.

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On thing with all this stuff is if you don't have enough time to work on this don't inherit a problem.

 

True, restoring a Leslie takes time. Once restored and kept in controlled climates, they'll last a long time. Other than a blown rectifier diode in the power supply and recapping the preamp pedal, my original 760 that I bought in 1981 has never been any trouble.

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Sound system works (speakers groan a bit when I hit the lowest pedals with both bars out).

 

If the Leslie bass speaker is straining, you can replace it with an EVM which is more rugged. They're not made anymore, but can be readily found.

 

The trick is, the ohmage of the speaker has to match the amp. This varies depending on the Leslie model. If they don't match, any Hammond tech can order a replacement cone with the desired ohmage.

 

I chose the EVM for my 2nd 760 that was missing the original bass speaker. My 1st 760 that I bought in 1981 has the original speaker. Those Leslie cabinets are sensitive to resonances and the speaker was chosen for optimal sound. I had my tech change the cone on the EVM to match the amp (it DOES make a difference). When I had the two 760s side by side, the one with the EVM sounded just like the original.

 

EVM speakers can more than handle the power of any Leslie.

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All this talk about Leslies inspired me to fix-up one of my 147s this week. The upper motor was causing a hi pitched whine in slow mode and I figured it was long overdue for an oiling and cleaning. I know a lot of you are very familiar with this stuff but figured some pics might benefit a few. Also I don't claim any tips my own as Todd, Moe, Wes and others have helped me enormously over the years.

 

Here's the upper slow motor still mounted to it's plate but de-stacked from the fast motor.

 

http://i1062.photobucket.com/albums/t490/Markyboard/IMG_3623_zpsoh2grepn.jpg

 

And now removed from it's mounting plate. You can see some of the dirt - not too bad, but it's only been a few years.

 

http://i1062.photobucket.com/albums/t490/Markyboard/IMG_3626_zpse9o5poz0.jpg

 

Totally disassembled I replaced the washers and spring (re-furb kit for a few bucks) and took some steel wool to the rotor.

http://i1062.photobucket.com/albums/t490/Markyboard/IMG_3631_zpsyrzaywwj.jpg

 

Here's the back side of 1 of 2 bearing assemblies. The oil hole is on the opposite side. In order to oil both of these you need to de-stack and remove the mounting plate. The oil soaks into a pad drop by drop. Keep adding drops, rotate the shaft and move it up and down (TWSS) until no more oil is absorbed. Also oiled the rotor and shaft

 

http://i1062.photobucket.com/albums/t490/Markyboard/IMG_3630_zpsblj53b4d.jpg

 

Unfortunately after all that the noise although better was still bugging me. I figured the bearings are worn and so replaced with a new motor. Time to buy another spare.

 

Upper fast motor. This one I completely disassembled as I thought that this too might be a noise contributor. Very important: Mark each piece of the casing with tape or some kind of marker (yellow tape for me) so you know the correct orientation to reassemble. Don't assume photos are sufficient - they're not.

 

http://i1062.photobucket.com/albums/t490/Markyboard/IMG_3635_zpsnf9k5k69.jpg

 

This motor was actually very clean, but extremely dry i.e. no sign of oil anywhere! Oiled the pads on each end of the shaft. Oil absorbing pads are just inside the covers and you can drip oil through the cover holes while rotating the case until the pad is good and soaked.

 

http://i1062.photobucket.com/albums/t490/Markyboard/IMG_3638_zpsvz6szkie.jpg

 

 

Oiled and reassembled. I also changed out the O-ring as the shaft on the new motor is not quite as long as the original and so a good O-ring is even more crucial to correct operation.

 

Did much of the same to the lower motor stack this morning other than I did not disassemble the fast motor- it has been working problem-free. This Leslie is quiet now in slow mode.

 

Yay!

 

 

 

 

 

 

 

 

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I've done that too.

 

It sounds like wooooow wooooow wooooow wooooow click woooooooow wooooooooooow wooooow woooow wooow woow wowowowowoowowowowow

 

Wes

Hammond: L111, M100, M3, BC, CV, Franken CV, A100, D152, C3, B3

Leslie: 710, 760, 51C, 147, 145, 122, 22H, 31H

Yamaha: CP4, DGX-620, DX7II-FD-E!, PF85, DX9

Roland: VR-09, RD-800

 

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It sounds like wooooow wooooow wooooow wooooow click woooooooow wooooooooooow wooooow woooow wooow woow wowowowowoowowowowow

 

What he said. Can we get a Smilie for this? ;)

In other words, it sounds like a Leslie? I was wondering if there might have been a subtle but noticeable difference during transition due to conflicting pressure waves or something.

Whenever you find yourself on the side of the majority, it is time to pause and reflect.

-Mark Twain

 

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It sounds like wooooow wooooow wooooow wooooow click woooooooow wooooooooooow wooooow woooow wooow woow wowowowowoowowowowow

 

What he said. Can we get a Smilie for this? ;)

In other words, it sounds like a Leslie? I was wondering if there might have been a subtle but noticeable difference during transition due to conflicting pressure waves or something.

 

The difference is if you run it long enough like this, the sound will be augmented by the smell of motors burning.

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There are no "conflicting pressure waves". It's just a rotor that stops before it goes. Not much different than briefly transitioning a 3-speed through stop.

 

 

Hammond: L111, M100, M3, BC, CV, Franken CV, A100, D152, C3, B3

Leslie: 710, 760, 51C, 147, 145, 122, 22H, 31H

Yamaha: CP4, DGX-620, DX7II-FD-E!, PF85, DX9

Roland: VR-09, RD-800

 

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There are no "conflicting pressure waves". It's just a rotor that stops before it goes. Not much different than briefly transitioning a 3-speed through stop.

 

My question, which I've come to regret asking, is when the lower rotor - which doesn't just stop before it goes - is getting up to tremelo speed, or slowing back down to chorale, was there a discernable difference in sound caused by the two rotors counter rotating. It seems that the answer is no, but I wanted to make sure I clarified what I was asking.

Whenever you find yourself on the side of the majority, it is time to pause and reflect.

-Mark Twain

 

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Nothing significant. You would have to know that specific Leslie very well to notice the difference. Unit to unit variance is much greater. Condition of tire, stack adjustment, belt condition, and stack position all play a bigger role.

Hammond: L111, M100, M3, BC, CV, Franken CV, A100, D152, C3, B3

Leslie: 710, 760, 51C, 147, 145, 122, 22H, 31H

Yamaha: CP4, DGX-620, DX7II-FD-E!, PF85, DX9

Roland: VR-09, RD-800

 

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http://i.imgur.com/QEa2TyD.jpg

:roll:

 

Today, I got the Leslie amp set just right (not quite dimed - about 3:00) so that when I floor the pedal I get That Sound. OMFG. Balanced with the onboard sound system erfectly, too.

 

The way the percussion breaks up in the lowest octave is clearly one of the greatest sounds ever...but then again, I've known that since the first time I heard Tarkus. :cool:

 

dB

:snax:

 

:keys:==> David Bryce Music • Funky Young Monks <==:rawk:

 

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NICE!!!

 

It's an experience, eh? :) Did you have Ken go over the rig, or are you just getting used to it?

 

Wes

Hammond: L111, M100, M3, BC, CV, Franken CV, A100, D152, C3, B3

Leslie: 710, 760, 51C, 147, 145, 122, 22H, 31H

Yamaha: CP4, DGX-620, DX7II-FD-E!, PF85, DX9

Roland: VR-09, RD-800

 

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