Archive for category Info: Peripherals
There is a Mac-only Audio Unit (AU) plugin called Volta that’s been out since early 2009 which allows a person to send CV from an audio interface box equipped with DC-coupled outputs. There is a lot of information on the web about this plugin, many people are using it to control the more common analog modulars like EuroRack formats, but the only information up to this point I’ve read about controlling the Serge is a quick mention regarding the NTO and PCO. Volta calibrates well with other Serge sections, allowing effective control over a much wider range then the MIDI to CV converter i’ve used.
In MIDI to CV conversion, tuning the oscillators is an intensive process and requires a separate tuner. Using the scaling and fine tuning adjustments on the converter box I have, I got 3 Variable Q filters to track over 3 octaves and create polyphony. Overall, it’s a lot of work to create a simple polyphonic setup. If the temperature in your studio drops or if you change anything in the signal flow, it requires repeating the intensive tuning process, which can take one hour.
With Volta tuning is very easy. The user just turns up the volume, and clicks Calibrate; Volta detects the pitch of the oscillator and adjusts the voltage accordingly to bring the oscillator in tune. Some Serge sections can be patched to oscillate but have only “VC IN” (not “1v/oct”). That’s OK, just turn the knob to the 2 o’clock position and calibrate, volta figures it out; this works for all the sections I’ve tested.
The sections I’ve tested with Volta, and their calibrated range according to Volta are:
VC TimeGen OSC: both right and left side calibrated 5 octaves, however Volta doesn’t detect pitch on the left side easily; I had to either patch the left side’s red output into it’s gate input and take the blue output, or send through the LO of a Variable Q patched to take the same 1v/oct
VC TimeGen Clock: left side calibrated 6 octaves, right side calibrated 5 octaves
Two DSGs: both calibrated 5 octaves
3 Variable Q filters: one calibrates 6 octaves, the other two calibrate 5 octaves
So that’s 9 oscillators that will all track across a much wider range then anything I’ve seen reported anywhere for these same oscillators, and much wider then my observations with MIDI to CV. I have not verified Volta’s reported calibrated range with a tuner, but they did sound in-tune to me.
Also with Volta I can get new timbres that I haven’t achieved before. Tuning a variable Q filter then setting it up to receive the same midi notes, but transposed (a midi effect in ableton live can do this) while piping in an oscillator can precisely emphasize a specific harmonic regardless of the note played. Harmonic distortion can even be added to this concept to have a Variable Q filter emphasize odd harmonics in the same way.
Volta also offers other interfaces to the control voltage like trigger and pitch sequencers, MIDI CC, automation ramps, clock, and lfo.
Here’s a couple noisy demonstrations of Volta being used with a controller and then as a sequencer.
Polyphonic Serge + Monome + Polygome Max/MSP + Volta in Ableton Live 8 + 100W all tube guitar amp
Serge + Volta + Kaossilator
This post will cover some of the multitude of electric and mechanical components that an owner ought to have on hand if they ever plan to DIY a repair.
I haven’t been able to confirm that every one of these is correct or current but the list comes from people who have more intimate knowledge of the STS Serge and Tcherepnin circuits.
Finally, it would be wise to contact Rex first before attempting any troubleshooting or repairs. In the past he has been exceedingly generous with advice, information, and even parts.
So, let’s get to the specifics.
LM3900N – Used in NTO, DTG, TWS, WMX and many older modules
CA3080AE – Used in PCO, NTO, WMX, SSG and old filters and VCAs.
CA3280AE – Used in ACPR, UAP, 2VCA, RING, QUO, WAD.
CA3046 – Used in NTO, PCO, WAD, PRNV, PHA and old UPAP & NEG.
CA3096 – Used in 2VCA, PRNV
LM711(?) – Used in NTO/PCO
There were some secondary sources of some of the ICs. For example, an LM3080 is a National Semiconductor version of the Intersil CA3080. Same for the LM3046, which was made by several other companies. Only Intersil made the 3280, and they’re gone.
Here’s a resource for ordering some of these:
The common opamps in Serges are still available at the moment:
LM324N – CV opamp
LF353 – FET opamp
NJM4559D – audio opamp
NE5532 – audio opamp
741 – opamp (NTO, SSG)
All of these are inexpensive. Make absolutely certain sure you get the DIL versions.
NP4250s and 2N5089s are the common PNP and NPN.
From what I’ve read, most faults on Serges are down to wires and pots.
Pots are 16mm Alpha. 50K lin for CV and 50K log for audio.
STS use Mogami for all internal cabling, Rex tells me.
Banana jacks are
E.F. Johnson, as far as I know, and all 3.5mm and 1/4″ jacks are Switchcraft.
Last but not least, keep an eye out for the Reticon SAD 1024 BBD which is a critical component in the WAD and very difficult to obtain, and the Phasers (PHA and 2PHA) contain VACTEC Vactrols but I’m not sure what the part number is.
This list is by no means exhaustive and there may be and probably are some inaccuracies. Some of these components may have been updated or replaced with the M-odules but I have seen a large number of these components in my own Oakland and Hartland panels.
Without some Pomona cables, your Serge will be sad and hungry. The best deal on the web right now for Pomona cables is www.testpath.com
The Pomona PVC Stacking cords are the ones your Serge wants and they range in price from $4.40-$4.80 per cord depending on length.
Sound Transform Systems, Cynthia and Modcan all provide package sets of Pomona Cables for your system as well, but then you’re stuck with whatever colors/sizes they have in stock. Testpath provides a resource for you to assemble your cords a la carte based on your specific needs and color choices.
They also carry the very sexy Pomona 1508 Test Lead Holder and believe me, it’s been a real necessity for keeping the music room nice and tidy. The last thing you need to worry about is slipping on a banana…cable. Bah dum dum
And while you’re there make sure to pick up a Pomona Adapter with the spade head for all your grounding needs. They’re only $1.57 and allow you to interface your Serge with other systems. That my friends, is priceless! Stay tuned for an in-depth grounding tutorial coming soon!