Testing a Hammond M3 before buying . . .

[B3Guy]

Hi, all! I know this is a guitar forum, but I am in a rush to find some information. I have recently come across a Hammond M3 in [my area] for sale for a [steal] price. I know how to test the tonewheel by pulling out one drawbar at a time and playing every key individually . . . but I also know that (unlike my B2), the M3 has no "foldback". Can anyone tell me where the keys stop sounding for the drawbars that have no foldback? (I realize that I am talking a foreign language to anyone unfamiliar to this topic, but those in the know should understand).

IMPORTANT: ON AN M3, WIT ONE TOP DRAWBAR PULLED OUT, SOME KEYS AT THE TREBLE END OF THE KEYBOARD ARE NOT WIRED TO SOUND. I WANT TO KNOW WHICH KEYS DO NOT SOUND ON THIS AND OTHER DRAWBARS.

I realise this might be a shot in the dark, but any help would be great.

 

[Superlizard]

I know about tonewheels and drawbars, but I've never heard of "foldback".

Then again, I'm a wannabe B3 player (I use an emu for my DAW by Native Instruments - B4 II or something).

 

[B3Guy]

Ok, so there are only so many tonewheels, right? and when you pull out, say, just the topmost (highest harmonic) drawbar on a B3 (or equivalent model) . . . and proceed to play one key at a time from the lowest to the highest, you will get to a spot where the notes are very high pitched, and then all of a sudden, when you play the next highest key . . . the pitch "drops" an octave from what you'd expect it to be.  that is foldback. There are no tonewheels to generate the pitches needed to continue increasing pitch all the way up the keyboard for that harmonic drawbar, so Hammond "cheats" . . . they repeat the same octave of notes over and over a few times, on up the keyboard to the high "C". Or at least that's how they do it on a full size organ. :tard:

On a bite sized organ (a spinnet) like an M3, they dispense with repeating, or "folding back" the notes at all. This makes it so that several of the higher harmonics drawbars simply do not "sound" (i.e. make a noise) when keys in the higher register are pressed. The reason for folding back is that it maintains the same number of harmonics per key (nine . . . one for each drawbar), and thus, the same volume. With no foldback, the keyboard gets gradually quieter towards the higher end, especially when higher harmonics drawbars are pulled out.

The easiest and quickest way to test if all of the tonewheels are working is, of course to sound them each individually. this is done by pulling out one (and ONLY ONE) drawbar at a time, and playing all of the keys, but one (and ONLY ONE) key at a time, with that drawbar pulled out. Thus, you are listening to a different tonewheel, by itself, for each key you play. You do this for each drawbar, playing up the keyboard, each key. If one doesn't sound, either the key is bad, or the tonewheel is bad.

My current dilema comes with the foldback. Normally, I would expect every key to sound on every drawbar . . . but with the foldback, on some drawbars, some keys will NOT sound . . . indeed, are not even wired or DESIGNED to sound. My problem is I do not know which are supposed to sound on which drawbars with which keys, and which are not supposed to sound at all.  :tard:

If anyone has an M3, and can run the "one-drawbar-at-a-time-play-every-key-test", and can then let me know where the lack of foldback starts silent notes on which drawbars, it would be much appreciated.

 

[B3Guy]

Bought the M3 for $50, fully functional! :toothy12: 100% Green Onions sound! now all I need is a Leslie hookup kit and a foldback kit . . . :headbang: