Songs That Use Roland CR-78

[Aloysius]

Not a fan of man buns meself

[vurt]

Not a fan of man buns meself

[WatchTheGuitar]

This is a cheat answer, but
Brooklyn Funk Essentials - The Revolution Was Postponed Because of Rain
as it prominently features a sample of the intro CR-78 part from "Heart of Glass"

[PlantsnMusic]

Some recent examples:
Partners in Motion - Wild Nothing
Green Eyes - Kevin Krauter

[PlantsnMusic]

Kept - Kevin Krauter

[aciddose]

The most distinct thing about the cr-78 has got to be the method used to apply the amplitude envelopes leading to the saturated exponential response... so it's a very steep edge where it goes out of saturation (clipping to 100%) and suddenly drops off fast. If I'm not mistaken they use an NPN transistor base as a gate and apply the filters afterward. So the envelope while above about 650mv is "on", and below that an exponent is applied. The signal passing through the gate is distorted by the exponential function during the decay.

That style of circuit is the same as the diode gates used in divider organs and their associated drum circuits during the 70s and of course sounds the same or very similar.

Thank you. This information is also really helpful. I have to write a 2000 word essay on a piece of equipments impact on a music period through different genres.

This might be useful too:

https://imgur.com/RrQX9OD

From this schematic you should be able to see a few interesting things.

I've used highlight to mark the schematic with:

• RED Trigger/gate inputs and subcircuit names
• YELLOW Envelope circuits (value on capacitor)
• ORANGE Trigger/gate + envelope circuit overlaps
• MAGENTA Generators/oscillators
• BLUE Noise generator and noise path
• CYAN Filters
• GREEN Mixer, VCA and output signal path

I'll just make a rough list of pointers:

1. Most triggers taken directly usually via capacitor and diode with no buffers
2. Sine oscillators are all phase-shift circuits
3. Envelope circuits are negative trigger, some positive cut/stop
4. NPN gates serve dual-purpose as gates/amps/buffers
5. Cymbal, Hi-hat and Maracas are all varied envelopes to the same circuit
6. Clave, Rimshot are LC ("high" Q) filtered pulses
7. Bongo (high/low), Conga and Bassdrum are simple decaying sine oscillators
8. Metallic Beat uses three pulse oscillators
9. Cowbell uses two sine oscillators
10. Output is averaged (edit: see below!) into a resistor and buffered, then passes through an OTA VCA

The snare drum and others use simple high-pass (6 dB/o) RC filters. Others such as clave, rimshot, cymbal, hi-hat, maracas, guiro, tambourine, metallic beat, cowbell use a low/band-pass LC filter to achieve higher Q.

edit: Regarding pt.10, it isn't accurate to say averaged as the input is 1k into an inverting amplifier with feedback gain control. The feedback is 560k and there is a bias point set by 100k to ground at the base. So technically speaking, each input has its output resistance with 1k added due to the series resistor at the amplifier/mixer input. There are in addition multiple points where volume is adjusted, so the level input to the mixer is not solely determined by the input impedance.

[aciddose]

Here's what the hi-hat output + envelope looks like at the base of the transistor:


You can see the envelope (which decays from ~15 v peak) saturates the transistor base initially. After it decays below ~650 mV the output signal fades exponentially. At 600 mV it's already less than -6 dB, and by 400 mV it's less than -60 dB (700 uV.)

Without linearizing feedback the transistor can said to be operating "as a switch". It's either on or off, or in the process of switching quickly between the two.

The older style of "vibrato" (actually a misnomer for tremolo circuits!) sometimes exhibited this style of amplitude modulation in cheaper circuits. The more expensive later circuits usually used opto-resistors called "LDR" driven by a lamp. The first such circuits however used materials which are not at all like modern semiconductor LDRs, a famous example being the LA-2A.

The older style gave a unique timbre with its rapid on/off switching which created a mood very different from modern smooth sine amplitude modulation effects. The older drum tone synthesizer circuits with this style of envelope would be later reproduced in the famous "gated snare" effect, utilizing effects circuits including gates and compressors or other dynamics processing along with reverbs, echos and so on.

One should be tempted to draw the connection between these cheap old synthesizer circuits and our modern heavily compressed sounds, as there may very well be a direct connection between the two; albeit spread over many years.

[chris979899]

Oh my god so helpful. Just seen this. Thank you everybody!!

[WatchTheGuitar]

I caught a bit of a very odd and dated 80's movie named Liquid Sky (it's on Amazon Prime if anyone's interested) and it had this sequence with a girl singing with what looks like a CR-78 bound to her side
https://www.youtube.com/watch?v=yVGOmDMrREU

[Bodhisan]

Wow - I was living in NYC when that movie came out - and did see it. It was playing at the art houses for years. Good catch!

[chris979899]

I can't decide if that's a cr-78 or not? It looks like a modded version? Does it have a screen on it?

If it is the cr-78 this would be great for my essay.

[chris979899]

I thought I would make a playlist for everyone to enjoy. Was heart of glass a cr-78? If I made any errors let me know. Also any more I can add would be ace. Thanks.

https://open.spotify.com/playlist/4s4ZE ... 5xlrL12OvA

[WatchTheGuitar]

I can't decide if that's a cr-78 or not? It looks like a modded version? Does it have a screen on it?

If it is the cr-78 this would be great for my essay.

Even with 1080P Amazon Prime it's hard to get a screengrab of it that isn't completely out of focus, but this is the best I could get



the lettering looks right for a CR 78 to me. If it was a bigger budget movie they may have used a lighter mockup, but I'm guessing they did just gaffa tape and strap a CR 78 to the girl here.

[chris979899]

Excellent those images are so valuable to my essay, thank you so much!

[chris979899]

The Radiohead videos have gone howcome? That tied my ending together nicely