Yamaha E50 has arrived :-)

Discussions about anything analog, digital, MIDI, synth technology, techniques, theories and more.
User avatar
adamstan
Active Member
Active Member
Posts: 511
Joined: Tue Aug 22, 2006 2:56 pm
Real name: Adam
Gear: Yamaha 2xDX7II|QY-70|PSR-S750|PSR-2000|TYROS|Electone D85|Electone E50
B5 DIY polysynth
KORG Poly61
Vermona DRM
Solton Programmer 24
LEMA EDD-5
Location: Poland
Contact:

Re: Yamaha E50 has arrived :-)

Post by adamstan » Wed Jun 15, 2011 7:20 pm

It would be certainly possible to provide basic MIDI input (Key On/Off). However, poly pressure would be difficult, as my board is going to replace keyscan chip, but leaving old voice assigner (called "Channel processor"/"CLP" by Yamaha). So there is no way to assign pressure value to correct voice. To do that I would have to build replacement for "CLP" as well - and that would mean building much larger board to interface with rest of the circuit.

Why? As you know from the "PAS" manual, it uses time-shared parallel interface working with 1MHz clock cycling through 12 channels. It is really fast compared to 8MHz available on AVR MCU - if it had to generate these signals directly (by feeding that clock to INT pins), it would hardly have time for anything else. The solution is to build array of buffers/latches holding data for each channel, and counter/multiplexer driven by instrument's master clock, connecting these latches sequentially to data lines. It is possible, but makes MUCH larger board - especially considering weird voltage levels used by E-50/70 logic. So for now, I'm going for simpler solution of just replacing K-C chip. But maybe someday... this weird digital interface is really tempting challenge for me ;-)
Man with a tape recorder | Living in the '80s ;-)

dr funk
Newbie
Newbie
Posts: 56
Joined: Sun Aug 31, 2008 1:57 am
Location: Ireland

Re: Yamaha E50 has arrived :-)

Post by dr funk » Wed Jun 15, 2011 9:48 pm

adamstan wrote:It would be certainly possible to provide basic MIDI input (Key On/Off).
Excellent! :D
adamstan wrote:However, poly pressure would be difficult, as my board is going to replace keyscan chip, but leaving old voice assigner (called "Channel processor"/"CLP" by Yamaha). So there is no way to assign pressure value to correct voice. To do that I would have to build replacement for "CLP" as well - and that would mean building much larger board to interface with rest of the circuit.
Ah, I understand. Thanks for explaining it! I've monitored the MIDI out of my Chroma in MIDI-OX, and poly pressure certainly does add a LOT of data!

Please keep me posted about your work on the E50. When you build the new key scan board, would you be interested in building a second one for my E70? I could help to fund your work and get MIDI for my E70! I'd imagine the key scanning is identical on both.

Cheers
Frank

User avatar
adamstan
Active Member
Active Member
Posts: 511
Joined: Tue Aug 22, 2006 2:56 pm
Real name: Adam
Gear: Yamaha 2xDX7II|QY-70|PSR-S750|PSR-2000|TYROS|Electone D85|Electone E50
B5 DIY polysynth
KORG Poly61
Vermona DRM
Solton Programmer 24
LEMA EDD-5
Location: Poland
Contact:

Re: Yamaha E50 has arrived :-)

Post by adamstan » Wed Jun 15, 2011 10:41 pm

dr funk wrote: I'd imagine the key scanning is identical on both.
Yes, that's right, the KCA boards are identical. I can make two boards, why not?
Man with a tape recorder | Living in the '80s ;-)

dr funk
Newbie
Newbie
Posts: 56
Joined: Sun Aug 31, 2008 1:57 am
Location: Ireland

Re: Yamaha E50 has arrived :-)

Post by dr funk » Thu Jun 16, 2011 1:41 pm

Excellent! Vintage Electones with MIDI - I like it! :-)

Frank

DX7Alex
Newbie
Newbie
Posts: 33
Joined: Tue Jun 29, 2010 3:41 pm
Real name: Alex
Gear: Yamaha DX7iiFD
Ensoniq ASR-X
Hammond M-162 chop
Korg Monotron
Korg 01/W FD
Novation Xiosynth 49
Yamaha SY-77
Yamaha P-90
Location: Baltimore, MD

Re: Yamaha E50 has arrived :-)

Post by DX7Alex » Thu Jun 16, 2011 2:29 pm

The pipe organ is great, but the synth sounds demo is spectacular. Best of luck with your mods!
"We beat this thing, we kicked it down, on the ground." Stevie Wonder on ARP 2600 repair techniques.

dr funk
Newbie
Newbie
Posts: 56
Joined: Sun Aug 31, 2008 1:57 am
Location: Ireland

Re: Yamaha E50 has arrived :-)

Post by dr funk » Tue Jul 05, 2011 1:37 pm

Check out what this guy has done to his E70! There are 6 'Son of GX' videos... :)

E70 mods

Frank

Post Reply