Thursday, April 28, 2016

Korg 770 Synthesizer Troubleshooting Intermittent Pitch Problems



This is a concise, technical, and hopefully well-presented account of how to resolve an intermittent problem on a vintage synthesizer. I learned a lot, and hopefully others could as well. As with all electronics projects take the necessary precautions to prevent electrocution, injury and death.

This old Korg 770 synthesizer was having intermittent pitch problems.
Intermittent problems are the mother-of-all problems to resolve.
Like finding a needle in a haystack...
if your needle is made of glass...
and the haystack takes half a city block.

The keys to the game are four D's:
- Dumping vast amounts of time into the project
- Drawing a map (schematics, diagrams), and marking the places you have already explored.
- Discipline and persistence.
- Deploying the right tools: Voltmeter, Oscilloscope, Iron, and a good rework gun like the Hakko 808.

Other things not covered in this video I dealt with during this restoration were:
- Replaced 3 broken keys
- Re-aligned a bent keybed frame
- Replaced a broken pot and broken switch
- replaced DOZENS tiny pot metal screws that were stripping out.
- Installed a 3-prong AC Power Entry module
- Added an Earth Ground to the chassis

I would like to send special thanks to cykong.com for taking to time to provide graphically enhanced schematics available. Without this I may have not been able to resolve this extremely difficult situation.

Friday, April 8, 2016

Korg 770 vs Volca Bass - Synthesizer Filter Comparison


Quick comparison of the Volca Bass filter to the Korg 770 lowpass filter. Different settings for the peak are explored.

The Volca Bass takes its filter design from the diode ring filter of the 700/700S miniKorg synths of the 70's. The Korg 770 has the identical filter design except replaces matched diodes for a diode array. Do the filters sound the same? To me they sound darn close, but you be the judge.

However the oscillators themselves sound different to me. The Volca Bass has a lot more bottom end than the 770, listen with headphones or a nice set of powered monitors.

Friday, April 1, 2016

AKAI AX73 Analog Synthesizer Ad Infinitum


In this video I share some helpful tips and info on the Akai AX73.

All synthesizer audio comes from the AX73 using all original patches. No outboard effects were used, only a few instances of the built-in chorus. Rhythm provided by a Roland TR-8. Thanks for watching. Be sure to subscribe, like and comment.

Monday, March 14, 2016

Alesis Andromeda Analog Synthesizer Ecstasy



In this video the Andromeda deploys an onslaught of non-stop analog sensory bombardment.

All synthesizer audio coming from the Andromeda comprising over 40 original patches. No outboard effects were used, only a few instances of the built-in delays and reverb. All sequencing and arpeggios also from on-board. Rhythm provided by a Roland TR-8.

The rarer red panel version of the Andromeda A6 is featured.

Wednesday, February 24, 2016

Sunday, February 14, 2016

Oberheim Matrix-12 Synthesizer Nebula


Happy Valentines Day. Here is my love letter to the Oberheim Matrix-12, my most favorite synthesizer. All audio comes from the Matrix-12 with TR-8 providing beats.

I had to use some lo-cut EQ recording a couple of tracks, hope you don't mind. Some use of the Big Sky and Timefactor.

Friday, February 5, 2016

Programming State Variable Filter Behavior on the Oberheim Matrix-12 and Xpander


This is NOT a step-by-step tutorial. This DOES show how I set up a couple of patches to get STATE VARIABLE filter behavior on FIXED filter synthesizers like the Oberheim Matrix-12 and Xpander. To be clear, I leave out all the programming steps where I save and rename the patches as you must.

This method works on most any programmable, multi-timbral, polysynth where different filter modes are configurable. The downside to this method is the overall polyphony will be cut in half. On the Xpander this means 3 voices. But hey, on the SEM it uses only one voice.

0:10 Intro, what is a State Variable Filter
0:55 How the State Variable filter works
1:22 My settings for two Single patches
1:58 My setings for the Multi patch
3:12 So you want to sweep the filter cutoff, too....don't you?

Some modern synthesizers allow you to do this within one patch, but they MUST have TWO configurable filters PER PATCH. Waldorf Blofeld, Novation Ultranova, Elektron Analog 4 and Analog Keys, Dave Smith Prophet-12, Access Virus and TI Snow, and more.

Wednesday, February 3, 2016

Waldorf Blofeld Synthesizer Archnemesis


All tracks generated using custom patches I made on the Blofeld with a TR-8 providing rhythm backing. I sent the choir sounds through a JH Triple Chorus module I built.

Big Sky and Timefactor effects used here and there. All tracks recorded direct to Cubase SX3 via E-mu 1616. NO additional eq, compressors, etc. were used.

Sunday, January 17, 2016

Korg PolySix Mojo Machine



This is the Korg Polysix with the Kiwisix upgrade. This demo features both original patches and factory presets. The main advantage of the Polysix is the 3-BBD chip ensemble effect, which shares the likes of ARP Solina and many others.

Another really cool feature is the external filter control input. No, it cannot filter external sounds. But it can take voltages from external devices like a sequencer and use that to step-modulate the filter.

The Polysix is also good at arpeggios and bass. What's better than bass?...more bass!...you can stack all six voices in unison mode for insane bass action.

There is a trick you can do to achieve filter high-resonance self-oscillation, and nothing else. To defeat the main oscillators, set the OSC to Pulse Width and set the Width to maximum. Make sure the sub osc is also turned off.

0:00 Choir sound, filter self-oscillation FX
0:28 to 2:24 Filter is being modulated, via the external filter control jack, by a control voltage coming from the Beatstep Pro
2:24 to 3:22 String Ensemble

ALL synthesizer sounds originate from the Polysix. A Volca Beats provided rhythm backing, Big Sky and Timefactor for effects. All tracks were recorded direct to Cubase SX3 via E-mu 1616. NO additional production, eq, compressors, mastering, etc. was used.