Sent Mon, Oct 9th 1995, 18:37
> >> I finally found a Korg ES-50 "Lambda". It will be shipped > >Can you tell me/us more about this beast? I've never heard of it. My lambda arrived on Friday, and first I was a little dissapointed. It didn't sound as good as I remembered. Then I found that one of its oscillator banks didn't work. (It has 3 HF-VCO's and 3 complete TOS / Divider chains.) I found that one of the TOS IC's was blown. It's an S50241, and I was quite desparately looking for it on the weekend. Then, after scanning loads of documentation in the archieves of TBS, I found that I could also use a 50240, the one I got from an old Crumar Performer many years ago. As I have no datasheet for either I was saved by finding one strange string synth ("String Melody", maybe this was a Hohner) which could use either the '41 or rthe '40, according to its service docs. So I went home, desoldered the '41 and put a socket and the '40 in, and everything was just fine. What a great sound! ================================================================ I'd really be interested in the difference of the 50240 and 50241 IC's. So if anybody knows something about these, please do tell! ================================================================ Now here's a brief description of the ES-50 "Lambda". 49 Keys, but only 48 working (the 49th would have eaten up another divider chip (;->) ). Fully polyphonic. Two (!) discrete envelope generators for each (!) of the 48 keys (hundreds of diodes used as voltage controlled resistors). 96 voltage controlled Envelope Generators !! Mixing of different footage rectangles, supposedly to get staircase-type saw waves. The three oscillator chains are controlled by a 60 degree / 120 degree / 360 degree LFO to get the basic string-ensemble chorus sound. You can also manually detune two of the HF-VCO's, and two LEDs on the front panel nicely show the beating of the oscillators, caused by detuning and by the complex LFO modulation.There are formant filters for String and Choir sounds, and finally the wole thing can be routed thru a BBD chorus. You can change the chorus speed by a Joystick left to the keyboard. This "Ensemble Section" I have described so far has also a Brass and an Organ Preset, but I don't think they are worth that much. I get this great lush ensemble sound with "Chorus" (=Choir) + "String I" + "String II" switched on simultanously. Attack and Release are switchable from fixed to variable, and unlike the global envelope on a Solina You get a real AR contour for each individual note. In addition, there is a "Percussive" Section which uses the second set of envelope generators. These are AD-types with a fixed and switchable Sustain level and Release switchable from short to Release = Decay. The Presets are E-Piano, Clavi, Piano and Harmonics. Forget about the names - but E-Piano plus Harmonics make a nice bell-like sound that fit to the ensemble section very well. There is a pot for "Key Click", but what it really does is adding a nice attack sound to the E-Piano preset. The Percussive section has a nice Tremolo (AM) feature with modulation rate adjustable. You can route the Percussive and the Ensemble section seperately or both thru the BBD chorus sections - Yes, it's actually two BBD's, one for each section, but they re modulated from a common LFO. The reason for separate signal chains in the chorus is that You both sections go to VCAs and can be mixed together with an expression pedal. Speaking of mixing: There are a (rather effective) tone control and a master volume slider for each section. This was my brief description - sorry it was all mixed together, inside and outside of the beast, hope You enjoyed it anyway. As I posted before, one of the Lamda's greatest features is its flat top, so it Dousn't actually take much space as You can stack anything above it. You shold see my nice keyboard stack: Kawai Piano, Lambda, MS-20. Ah, and routing the Lambda thru the MS-20's filters is nice, too. Besides being a great ensemble machine, the lamda will be the main basis (sonically and physically (;->) ) for my Vocoder, when it will be ready. Oh and I don't know it I will do it, but as each key just switches between 15V and ground (Key contacts go to GND, and there are 4.7k pullups), It would be very easy to get both, Midi In and Midi Out, with Doepfer kits. JH.