Hammond X77 Owners Corner

[MihevicB3]

Thanks Admin!

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Hi John,
Some of the functions are hard wired. For instance, #1 is for the Midi sustain, #2 is in/out control for the Chord Comp feature (kind'a like Lowrey's AOC), #3 is in/out control for MIDI channel 1, which is hard wired to the internally installed Roland JV-880 synth module, #4 is in/out for MIDI channel 2, which is a 5-pin DIN mounted on the organ's accessory panel, and #5 and 6 are 1/4" jacks also mounted on the acc panel. There are 2 jacks for each, one is for a normally open contact and the other for normally closed so that a variety of effects units or drum machines can be accommodated. The controls for the kick switch are mounted on the lower right cheek block...
[ATTACH=CONFIG]25513[/ATTACH]
(The other panel shown is the upper right block used for power.)
Here's the schematic for the kick switch...
[ATTACH=CONFIG]25514[/ATTACH]
The momentary button, SWM1, cycles the 4017 sequencer chip which steps through the 6, 4PDT relays. The 555 is for the debounce circuit.
I use expresspcb.com's free schematic and pcb design programs for everything, and futurlec.com produces the pc boards. If you're interested in anything else let me know.

Thanks for the info. The attachments (25513 & 25514) don't display.

John M.

[bnelson218]

That's odd...they were displaying just fine yesterday. Here's the cheek block and the schematic.

[MihevicB3]

Thanks, the photos are visible now. You sure will have a unique X-77. Where will the public demo be when you have it finished?

John M.

[bnelson218]

Thanks, the photos are visible now. You sure will have a unique X-77. Where will the public demo be when you have it finished?

Well, a good friend helps organize the Sunset Jazz Festival, held each August in Grand Rapids, Ohio, and I'm hoping the X might be ready for this year's show, but I've been saying that since the mark II rebuild began in 2011, so who knows. A friend of mine and I put up a website, hammondx77junkies.com, hoping we might attract other X enthusiasts and be able to share ideas on improving and modifying the instrument, but after a year or so there's been absolutely no activity and the site's sat dormant. I'd really like to use it to chronicle all the work I've done on mine but don't know very much about website management, so I just offer up bits and pieces here. She might actually start making noise this spring so I'll keep you informed.

[kkeys]

Great to see the photos of your X-77 project. I remember you mentioning that you were working on this so it is nice to see the progress made.

Is the percussion section left stock?

Surprised to read of the poor quality of build. The price tag on the organ with the X-77L Leslie in Canada was $8,500. This organ is my favourite tone wheel instrument.


There is an interesting section on the X-77 in Scott Faragher's book "The Hammond Organ" on page 89.

In essence, the concept was a joint effort by Hammond engineer Allen Young, main designer of the H-100 series and Don Leslie. Young was a house guest of Leslie while they worked on the development. Both disliked the ramp up/ramp down time of a conventional Leslie so sought an alternative. My hunch is the space generator in the Leslie cabinet replaced the slow speed on the rotosonic drum.

The X-77 was considered as a new entry rather than a B-3 replacement. An interesting quote included in the book from Harvey Olsen, engineer/historian is "Hammond was sick of the B-3".

[bnelson218]

The ordinal percussion system has been discarded. When I decided to incorporate the Trek II SSP3 preamp, it opened a few doors. I didn't have to build a reverb system, I'd have the drive and recovery circuits for the vibrato scanner and line box, and I didn't have to develop a percussion circuit. I did, however, redo the voicing. I prefer the footages rather than the preset Banjo or Marimba, etc. The percussion section offers 8 voices: 5 1\3, 4, 2 2\3, 2, 1 3\5, 1 1\4, 1, and 10\12. Should be fun. The overlay for the perc section also has the Decay Long/Short switch, the Level pot, and a Behringer Slow Attack effects unit.

[bnelson218]

Here's another pc board that arrived yesterday. It's the Percussion Select pcb. Notice the original X77's percussion matching transformer onboard. This board allows me to select the 8 drawbar footages shown on the control panel in the previous post. More later as the balance of the boards arrive.

[MihevicB3]

The ordinal percussion system has been discarded. When I decided to incorporate the Trek II SSP3 preamp, it opened a few doors. I didn't have to build a reverb system, I'd have the drive and recovery circuits for the vibrato scanner and line box, and I didn't have to develop a percussion circuit. I did, however, redo the voicing. I prefer the footages rather than the preset Banjo or Marimba, etc. The percussion section offers 8 voices: 5 1\3, 4, 2 2\3, 2, 1 3\5, 1 1\4, 1, and 10\12. Should be fun. The overlay for the perc section also has the Decay Long/Short switch, the Level pot, and a Behringer Slow Attack effects unit

Interesting! I added percussion harmonics 4, 5 and 6 in addition to the 2nd and 3rd to my B3 in any combination (polyphonic). My design modification was simple and as a result, if a harmonic is selected for percussion (other than stock 2nd or 3rd) that harmonic is not returned (available) on the drawbar. I usually use the percussion only with the first 3 drawbars, so that isn't a problem for me.

Just wondered, are all the harmonics on your X77 design still available at the drawbars? Also, are they additive (polyphonic)?

Why did you choose the 1 1/4 ft. and leave out the 1 1/3 (6th harmonic)?

John M.

[bnelson218]

Just wondered, are all the harmonics on your X77 design still available at the drawbars? Also, are they additive (polyphonic)?

Why did you choose the 1 1/4 ft. and leave out the 1 1/3 (6th harmonic)?John M.

On the upper manual all 11 drawbars are available and certainly polyphonic. I would never change that. For me, those sassy last 2 drawbars are what I love most about the X. On the lower, however, only the first 5 drawbars are working. That's because I needed 5 sets of contacts for various features. 1 set for the 8' strings and 1 for the 4' strings, 1 set for the arpeggio bar, 1 for Chord Comp, and finally 1 set for trek ii string bass.
As for the percussion, I really didn't want to go beyond 8 voices and just thought the 1 1/4', which is the Chime harmonic, would be a fun and quirky voice to play with.

[MihevicB3]

On the upper manual all 11 drawbars are available and certainly polyphonic. I would never change that. For me, those sassy last 2 drawbars are what I love most about the X. On the lower, however, only the first 5 drawbars are working. That's because I needed 5 sets of contacts for various features. 1 set for the 8' strings and 1 for the 4' strings, 1 set for the arpeggio bar, 1 for Chord Comp, and finally 1 set for trek ii string bass.
As for the percussion, I really didn't want to go beyond 8 voices and just thought the 1 1/4', which is the Chime harmonic, would be a fun and quirky voice to play with.

My question on polyphonic was pertaining only to the percussion; i.e; can you select more than one percussion tone simultaneously? Can you select 2 out the 8 voices together? For example on my B3, the percussive 2nd & 5th together give a nice “twin mallet” xylophone tone. However, if I am using a particular harmonic for percussion, that harmonic is not available (returned) to the drawbar. Of course when I am in “stock” mode the 2nd and 3rd harmonics are returned to the drawbar per Hammond design. So, my other question is, if you select one of your 8 voices say the 1¼ ft; is that voice also available at the 1¼ ft. drawbar?

John M.

[bnelson218]

I see. Yes, the tones are additive and always available on the drawbars.

[bnelson218]

Finished populating and testing the latch pcb for the percussion section. The new control panel has all momentary buttons and each one has its own dedicated latch circuit. Push the button and the relay latches closed; push it again and the relay latches open. Then, the relay's NO / NC contacts operate whatever effect or feature they're tied to. I also use these latch relays for the Leslie motors, which enables me to use the momentary switch on the expression pedal.

[MihevicB3]

Nice looking board & layout. I prefer a momentary kick switch which I mounted on my B3 expression pedal for Leslie tremolo On/Off. The maintain switch would have been easier to install, but I like the "quick tap" low force needed to actuate a momentary. My installation isn't as neat as your PCB. Of course, I only needed to build one latch circuit for the Leslie.

John M.

[Roger Memphis]

Nice looking board & layout. I prefer a momentary kick switch which I mounted on my B3 expression pedal for Leslie tremolo On/Off. The maintain switch would have been easier to install, but I like the "quick tap" low force needed to actuate a momentary.

This is a great relay for that... one pulse latches it "ON" and next pulse latches it "OFF." Inexpensive and very reliable. Works nicely with low voltage foot-switch.
I use a 5 V wall wart to power it.
http://www.--------/itm/1ch-5V-Latch...YAAOSw4GVYS1Yt
Scroll down, too... all sorts of cool stuff.
Roger Memphis

[MihevicB3]

This is a great relay for that... one pulse latches it "ON" and next pulse latches it "OFF." Inexpensive and very reliable. Works nicely with low voltage foot-switch.
I use a 5 V wall wart to power it.
http://www.--------/itm/1ch-5V-Latch...YAAOSw4GVYS1Yt
Scroll down, too... all sorts of cool stuff.
Roger Memphis

Thanks Roger. The price is right. I'm going to order a couple. For me, there are so many applications for a "toggle" output for a trigger/contact input.

John M.