Here’s a short little bass line I recorded while reacquainting myself with my Maxi-Korg yesterday. I love the gritty sound of this instrument, one of the most well known of the duophonic synthesizers. Sometimes I find myself reaching for the non-existent pitch or modulation wheels, but the limitations of these vintage devices are part of their charm and might encourage the musician to come up with new ways to play (or rediscover old ways).
Another thing that I love about vintage gear is the lack of presets. When I come up with a sound I like I simply say to myself, “you’re never going to get exactly that sound ever again”. You can always jot down the settings, but I never do. This way you’re forced to learn how to control the device and approximate the sounds that you have created in the past if necessary.
Maxi Korg Bass Line
I literally dusted off my 
I have been using my Sequential Circuits Pro-One in the studio pretty often recently, so I decided to use it instead of of a newer keyboard for a recent performance. Unfortunately it did not work the way I had planned. Although I crave unpredictable behavior to stimulate the creative process, it is not exactly as pleasing during a live performance. The aging instrument did not stay in tune for very long and I was having trouble with the keyboard action. I imagine that it’s time for a thorough cleaning of the potentiometers and keyboard contacts. Despite these troubles, while scanning through clips recorded during the set, I came across this nice low frequency filter sweep and ran it through a ping pong delay. 
Old monophonic synthesizers have had all sorts of ways to sequence notes; from fairly complex programmable sequencers to simple arpeggiation. Arpeggiators are nice because they sequence the notes that are played on the keyboard in realtime, allowing the performer to improvise while taking advantage of the capabilities of the machine at the same time. Based on the speed of the LFO, the arpeggiator on the Sequential Circuits Pro-One will sequence all the notes in a chord in either ascending order, descending order, or both. Other synths offer a feature to play the notes in a random sequence. In this example the notes are played in ascending order. I cranked up the LFO and added some delay so that the notes blend into each other so you can hear the harmony in the sequence. With this technique you can sort of simulate polyphony on a mono-synth. 
Here’s another sound that I would label as “Pro-One Dub”. I guess all that really means is knob turning and delay, but when you get good results with this instrument you know it. I love the fact that you cannot store presets on old analog gear. It makes you create a new sound every time you turn it on. I had the knobs in a pretty good position to start this time, but after a few more adjustments I got this great modulated effect with the LFO near top speed and at maximum amount. Just tapping a key gave me this nice squirty raygun effect, so I dropped that in the track before getting my sound for the melodic line I needed for the piece. Here’s a chunk of it pitched down a bit and running through a short delay with lots of feedback to create a vintage raygun effect.