Curtis chips (integrated circuits made by Curtis Electromusic Specialties) are a common component in vintage synths. Unfortunately, these chips went out of production decades ago and have become hard er and harder to find.
In June, CES announced that it was planning to re-release these rare chips in production volumes, starting with the CES 3340 VCO.
The above video, via Gregory Cox, captures a comparison of new vs old CES 3340 VCO chips, running in a Oberheim OB-8 synthesizer.
Here’s what Cox has to say about the video:
This video is a demonstration of the newly manufactured Curtis Electromusic CEM3340 oscillator IC. A comparison is achieved using the Oberheim OB-8 with half of its 3340s replaced and setting the keyboard in dual mode. Voices 1-4 are the original CEM3340s and 5-8 are the Revision Gs. By assigning the same sound to both splits in dual mode, a comparison can be made by fading between both sounds using the program balance knob.
The signal chain is OB-8 / Neutrik patch bay / Apogee Symphony / Headphone Output / Canon 5D mkiii mic input.
CES says that “there is currently no timeline or concrete plan to offer others in the Curtis Electromusic signal processing family. We are evaluating demand and are very interested in new designs that our chips might foster.”
Check it out and let us know what you think about the prospect of new CES chips!
Excellent news, now if only we could get consistent versions of the old SSM2040s..
making chips again???
yahooooooooooooo
there are so many old designs based on them
It is about time chip makers realized that there is a market for theses specialized chips, after all they have been making all kinds of other special chips
(I work with electronic boards
Great job calibrating the voices perfectly for an excellent comparison. Convincing.
Wow! Great news!
Is this in honor of Tom’s 80th? 🙂
Honestly can’t tell the difference. Great news.
I hear no difference. Thank the lard for these.
Thanks for the video, but honestly, the quality of even the best videos on the web are really not great (due to compression and output devices, etc) o’scope waves comparisons might have compensated…
I had to open a spectrum viewer to pinpoint any difference.
The newer filters are slightly cleaner than the old ones, with the older one showing more harmonics on the first notes of the triangle wave than the second ones. But only in the lower frequencies oddly. And this observation gets thrown out the window when he plays notes slightly higher, as the newer filter adds more harmonics than the old one.
The jury is pretty much out for the Saw wave. Other than the newer filters sounding SLIGHTLY more open than the old ones, I couldn’t see or hear any difference even after closing my eyes and squinting at my graph.
And on the Pulse waves, I mean I guess the newer filters sound “fizzier” than the old ones? There is definitely harmonic difference between the two filters in the low range again for the Pulse wave, but it’s so slight that it’s almost indistinguishable.
If I had to give an ultimate observation, I’d say the newer one sounds more “analytic” than the older one. Slightly cleaner and more modern sounding, but to a point where you’d need to pay attention to any differences if you were to compare them side by side. And unless you’re actively trying to point those differences out as we see here, such small variations would be immediately drowned out in a mix.
Probably one of the best reproduction filters I’ve ever heard. If I could only spot differences by looking both deep in myself and at a microscope, I’d say they accomplished their job perfectly.
the CEM3340 is a VCO, i don’t think the filters are different.
There are no new filters. The filters are the same old filters for everything you hear.
These are new VCO chips only.
kinda makes you wonder why so much “analysis” was undertaken, and differences cited, when an apple (filter) was compared to an apple (same filter) and a difference was found…
Some “purists” take this shit a bit too far.
Well as it figures I can’t read.
Meaning it’s all good!
Thanks, the detail you’ve provided is certainly weighing on how soon and how many of these I pursue ..
I can hear the difference but the new chips are of more than acceptable quality. I will certainly be purchasing a set of these.
Where can you buy the new chips?
This is bad news, the Curtis chip in the 80’s made analog easier to make, but in the process made synthesizers sound bland (many keyboard companies used this same chips), which lead the rise of the digital monstrosities of the 90’s. The pursuit of synthesis should be based on sound quality and innovation not cheaper price points and lackluster uniformity.
i have no idea what the hell you just said Vo1t. Makes no sense whatsoever.
so happy to see these remade! so all our old and unique sounding synths (that can not be touched with new synths) can finally be guaranteed an even longer future!
While I somewhat understand where you’re coming from, you’re way off.
SSM and Curtis chips made it possible for companies to produce affordable polyphonic analog synths. It’s true that they because extremely popular and had a distinctive sound in many cases, but to claim that Curtis made synthesizers “sound bland” is utterly false.
The industry runs in fads, and during a particular period from 1979-1985, the “golden ticket” keyboard from Roland/Korg/Siel/Everyone else was a decent sounding 6-voice analog or analog hybrid that sold for about $1395.
At the same time, we saw the rise of very different sounding instruments like the Emulator II sampler and PPG Wave 2.X digital synths (using Curtis VCFs and VCAs paired with digital oscillators). There was nothing bland about those instruments, but they were priced out of reach of most musicians.
The “rise of the digital monstrosities” of the 1990s had everything to do with dramatic advancements in microprocessor technology throughout the 1980s and 1990s. Polyphonic digital voice and filter chips from companies like E-mu and Ensoniq brought the price of samplers, romplers and digital synths down to the point that anyone could own them. As a result, we were inundated with unimaginative regurgitation of fairlight voice samples, orchestral hits and all manner of cliche string sounds. None of this had anything to do with Curtis chips.
The fact that people love the sound of Curtis-based instruments three decades later speaks to their quality. It’s good to see them back in production, and I hope they end up in many quirky and original modern instruments.
It (the CEM 3340) is a building block. A stable and reliable one at that. Anything can potentially sound bland – it’s the context that counts and the context is the rest of the instrument built around it. Whilst there is something quaint & pleasant in a drifting oscillator for some there’s a heap of value in a stable poly synth that stays put.
Arguably the filters set a good bit more in the way of character (- I preferred the CEM 3372 to the 3320 … ) but that is well understood by all
Yup.
It is the VCO chips that tend to go out the most on these synths, which is why they are so sought after.
I paid about 70 dollars a pop for a couple a year ago for a repair, well, the customer did.
The best part is that many older synths will not be cannibalized for spare parts now, they may get repaired and played again.
impressive!