Help to Mod an Old Church Organ

Hi all,

I have a Hammond Organ that was given to me by a church. It's not a fancy model or anything, circa 1970's.

Anyways, I don't have much use for the "church" sound it gives, I'd love to be able to turn into a rock organ.

Here is my idea... find out where in the guts of the organ to splice the wires, and solder into a 1/4" audio plug and run into an overdrive guitar pedal then send it back into the organ.

I just don't know enough about where I should do the splicing. I know the organ has tubes, should it be before the tubes, or would that blow the tubes? Should it be at the last stage right before the speaker?

If anyone has any ideas I'd love to hear them!

Thanks
Ryan
 
Hammond mods

The churchiness of a Hammond has to do with the presets (black keys) which can be changed on the screw panel in the back, (to copy the slider setup you like) or the dried up electrolytic capacitors on H , E , L, & T models, which remove highs and lows and should be changed out after 40 years. Pull your model out from the wall and look at the bottom for the label to find the model number. Or post a picture and we can tell from the front. How many pedals is important. Lots of schematics on captain-foldback.com, also H schematic on archive.org. I put 70 electrolytic caps on my 1968 H model and it radically improved the sound and made it about 6 times louder. The H was the top of the line, other models have fewer dried up caps. One reason C's & B's are so expensive, they only have about 2 electrolytic caps.
Look at this thread on organforum.com about zener diode based overdrive units between the mixer and the power amp. Zener overdrive with an AO-63-1.. Most overdrive effects on records were done with the add on Leslie unit in the old days, which sells now for $500-$3000, so you don't get those for free.
 
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A supplementary question:

I did some basic homework to find out what an electrolytic capacitor is. If I find them in my organ (still haven't taken it apart) will changing them affect the tone? If so are there different types of electrolytics that I would specifically want to look for or do they have to be of the same type?

I'm not so much worried about achieving greater volume output as a different tone... live an overdriven tone for rock.

I know that the Leslie speaker is the common route yet as you mentioned they are very expensive. So I'd like to be able to just keep the speaker that's in there and modify something else.
 
Yeah, look at the zener diode overdrive circuit on the organforum thread listed above. Brandon Wright and others have done extensive experiments with it, they like the results. A zener diode box is $5 home built and $20 as a kit from the guy on there that sells them.
Electrolytic capacitors are in aluminum cans, with a plus near one lead, or a minus near the other. They dry out in 20 or more years, sometimes explode after that in power circuits. They can hold a charge and kill you , so especially if your organ has glass vacuum tubes, read the "how to work on tube circuits" sticky thread at the top of the tube forum here. Sometimes the aluminum can has a cardboard or plastic wrapper. One kind made after 1966, the tantalum electrolytic, looks like peanut M&Ms in color. Mark the PCB with a sharpie with plus before changing, as if you get them backwards they explode. Electrolytics decrease in value as they dry out, and can cause missing bass frequencies or missing trebel frequencies depending on how they are are hooked up. The cool thing about Hammonds, all things are available cheaply on tonewheel models except the tonewheel generator, which if lubricated properly, lasts (more than today minus 1930 when they were invented0. Your organ does have a motor, doesn't it?
3022 Doesn't mean anything to me as a Hammond model. Usually they have a prefix like A,B,C,D, E, H,R,T,L,M etc. Sorry. I'm not the most experienced Hammond person, I just know H's, that I bought last year. If you upload picture on the "how much is this worth" forum of organforum.com, somebody can identify it for you. Use the advanced reply button to get the upload button to read your picture off your computer to the organforum.
Does your organ have color (not black and white) tab switches at the top. If so, it is not an alphabet model above. Still, the zener diode overdrive box should work if hooked between the tone generator or mixer output and the power amp.
 
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Wanting to do the Zener Overdrive

Well I heard a demo of what the end result of putting in a Zener Overdrive circuit sounds like. Sounds good to me. Price is right too.

My only question would be, where in the scheme of things should it be installed. I read someone mention to install it between the preamp and the amp. Would that be your recommendation.

I've opened the back up and I'm assuming that the 6 or so circuit boards (with those M&M coloured capacitators) are the preamp.... which then runs down to a base unit, which I'm guessing is the amp, which has the tubes and then goes to the speakers.

From the link you suggested, would you agree that the black and red wires from the preamp are the ones to clip into once I've built this zener overdrive?

A note on the model... the 3022 is in the Everett Series... from what sparse information I gather it was an inexpensive model for people to put in their living rooms. I have no idea if there is a motor in my organ... I have looked at all the parts (not really knowing much about parts but just using some common a to b sense) I don't see anything that looks like a motor.
 

bob91343

Member
2010-03-11 10:43 pm
Don't get picky about capacitors. Replace the old ones with new ones of similar rating and then take a listen. Once the unit works well you can fool with the stops to get the tone you like. If you can't get where you want to go, only then should you consider making modifications.
 
Everett 3022

Okay, if you have an everett 3022, that was made by somebody else. It still may have an eletrolytic problem. The FLAT candy sized capacitors are probably ceramic disks, which do not wear out. The Peanut sized ones, should say "10mf" or something like that, else "105" or bigger. They may also have a voltage rating on them, followed by "V" or "WV" or sometimes just two number "10 25" That would be a 10 mf at 25 WVolts.
When you replace electrolytic caps, you have to get the size about the same or up to 33% bigger. The same rule on the working volts. I buy mine from newark.com because they are fresh, also digikey or mouser. Not e-bay bacause those are usually stale.
Note the names have changed since 1980. What before was "mf" or microfarads, is now "uf"
Capacitors smaller than 684 or 0.68 mf are probably plastic or ceramic and don't need to be changed.
The red wire going down to the chassis with the tubes is probably the one you want to splice the zener diode box into. measure it with a voltmeter to make sure it is not 120 VAC or 350 VDC before you cut into it, as it will blow your box into smoke if it is. Negative of the voltmeter clips to the steel chassis of the power amp with tubes.
The chassis in the bottom with the tubes may also have a few electrolytics. These are the dangerous ones that can kill you if not discharged through a resistor tool. Measure below 25 VDC after discharging and before touching metal with your hand.
Sometimes they are below the chassis, not to hard to change. Sometimes they are in a can that sticks through the chassis with twisted tabs on the bottom. These are very expensive ($30). If you're on a budget, buy some phenolic headers from tubesandmore.com or triodeelectronics.com and solder 3 or 4 axial lead electrolytics of the right ratings under the chassis. This would be a lot cheaper.
Good luck.
 
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gain wire

Member
2004-11-27 4:04 am
NCR
ryryrecords,

Please be careful. These old tube-type amplifiers have potentially lethal voltages.
Since you needed to do some homework to find out what an electrolytic capacitor is, I'm guessing that you have a limited knowledge of electronics.
If you have questions .... this is the place to ask.

I second that statement. And it was well said. By the way, As far as I know Hammond never made any organs with only numbers or letters. This is most probably the serial number.

There is a place in Ottawa called toneonwheels (check the yellowpages) and he specialized in organ and tube equipment repair. It might be worth your while to have him look at it. Replacing electrolytic capacitors in a high-voltage device is NOT a job for a beginner in electronics.

But I love what you want to do with the organ! (Steppenwolf, Deep Purple or Focus, anyone?)

cheers