G2 > Technical details

[Electromagnetic Wave]

Hi

Some useful information about technical details for G2 users with source gathered in a topic.

The G2 numbering system
- G2 the internal sample rate of a signal can be either 96kHz for red and orange signals or 24kHz for blue and yellow signals.
- The G2 has a ‘12 units/Oct’ normalization. A single ‘unit’ is the exact equivalent of 1/12 Volt on a purely analog synth, but more importantly a single unit now also represents a key on the keyboard.
- Actually there are another 32768 subdivisions between two consecutive unit values. Meaning that a half note step is subdivided into 32678 additional sub steps.
- In practice the internal frequency resolution of the G2 is 0.0057 Hz, which is about 4000 intermediate steps between two half notes at the middle of the keyboard.
- The clipping level of the whole system actually lies at +256 and –256 units.
source : http://rhordijk.home.xs4all.nl/G2Pages/index.htm

G2 patch calculation :
- A chain of modules in the G2 system will have only one sample of delay, just as one single module, as they will be calculated sequentially and pass their result values on to the next module to be calculated within the same 96kHz time frame.
source : http://www.electro-music.com/forum/post-420373.html#420373


G1 / G2 - CV signal (DC coupled)
http://electro-music.com/forum/post-399362.html#399362

- the stereo headphones outputs can pass DC signal levels
source : http://electro-music.com/forum/post-395462.html#395462

G2 modifiés / CV :
- http://www.electro-music.com/forum/topic-65263.html (3phase)
- http://www.electro-music.com/forum/topic-12266.html (varice)
- http://www.electro-music.com/forum/topic-67269.html (mush)

Pedal > CV
- ...the Pedal inputs of both the NM and the G2 accept LFO and CV signals from ± 15V analog systems. I don't know if this is actually in the official specs, but I used these signals and the synths survived.
- The G2 has one single CV input, the Pedal input. Plus one input for a gate, the Sustain input. I never tried the sustain input, so from my side no warranty it will work.
source : http://www.electro-music.com/forum/post-10536.html#10536


Tell me if you have other relevant information associated with this topic. I will update it if needed.

[Electromagnetic Wave]

Others useful information. Old users here know probably all that but I think it could be good for new G2 user or old G2 users but new here to have all this information in one topic with source link (of course!) to dig more.

The G2 outputs can deliver a signal of almost 8 volts peak to peak before clipping!
http://electro-music.com/forum/post-86417.html#86417

Internal signals in the G2 are between -64 and +64 'clavia units'. I believe +64 clavia units relates therefore in G2 terms to 0 db. However, the G2 has headroom up to 256 clavia units before clipping takes place... as this would be a signal of 4x '0 db' in clavia units.
Blue Hell > Fozzie is right, and with 4 x 0 dB he means 4 times the level equivalent to 0 dB, which corresponds to +12 dB.
http://electro-music.com/forum/post-98479.html#98479

modules resolution :
whatever has to temporarily stored in the external ram memory is reduced to 16 bits width.... My guess is that the comb filter and the stringosc both use the ram and so run at 16 bit. The clocked delays don't as apparently they do use the full 24 bit.
http://electro-music.com/forum/post-29690.html#29690

the delays and the reverb is 16 bit
http://electro-music.com/forum/post-46043.html#46043

the internal busses are 20bit only, (including FX) while the normal, in-area signals have 24bit width.
http://electro-music.com/forum/post-72906.html#72906

the G2 uses Motorola DSP chips which are 24 bit fixed-point machines
http://electro-music.com/forum/post-97599.html#97599

The G2 uses 256K X 16 bit SRAM chips - one for each DSP chip (four on the main board, four on the expansion board). As far as I can tell, the DSP chips can use 24 bit external RAM, but for whatever reason, Clavia used 16 bit RAM.
The Manual and Online Help state that the Comb Filter "uses DSP audio delayline memory".
***external memory (for delay) is 16 bits
http://electro-music.com/forum/post-226322.html#226322

For memory external to the DSP the G2 system uses a SRAM SMD IC (one per DSP) organized as 262,144 words x 16 bits (I've seen an Alliance AS7C34098-12TC part used). That memory chip (and the main and expansion board layout) only has 16 I/O data lines connected to the DSP data buss. That number of words divided by the G2 96KHz sample rate gives you about 2.73 seconds of data storage, which matches the 2.7 second max time of the delay modules.
http://electro-music.com/forum/post-281859.html#281859

Note that on a new patch, the default is for the output to be set at -7.3 dB
http://electro-music.com/forum/post-40417.html#40417


G2 Hardware :
Control System:
1x Freescale ColdFire MCF5407 @ 162MHz (233 MIPS)
1x Philips 11818B USB1.1 Interface (parallel interface to ColdFire)

Audio System:
+/-5 volt (dual rail, not single supply)
2x CS4392K (2ch 192kHz/24bit DAC, 114db Range)
2x CS5341CZ (2ch 96kHz/24bit ADC, 105db range)
LM833 (used in preamp for mic input, line in, and amp for DAC output

DSP System:
4x Motorola 56367 @ 150MHz
4x 256Kx16 SDRAM (10ns=100MHz)
http://electro-music.com/forum/post-73022.html#73022


I will create another topic soon with all tools (NMG2, Nord Virtual Modular, tools from ian-s and other old tools from Blue Hell, etc..) for the G2 that I found over the time

[varice]

A nice gathering of technical details

Maybe a site mod should make this a “sticky” post.

Regarding the various undocumented details of the I/O levels of G2 modules; I had thought about posting such a document, but never got around to it Oh well...

[Electromagnetic Wave]

Thanks Varice !

[Electromagnetic Wave]

more :

the interslot buses having a tiny amount of latency... it's 24 samples of latency (@96 kHz)
the interslot conections are in fact a real hardware connection between the dsps
http://electro-music.com/forum/post-280718.html#280718

even with the better calculation order of the G2 you still have the issue that control-rate signals only get calculated every 4th sample with no way of knowing which sample
http://electro-music.com/forum/post-188207.html#188207

The G2 only has the one poly key assign mode, which will always trigger a new 'voice' every time a key is pressed.
http://electro-music.com/forum/post-366101.html#366101

[Modularmind]

Thanks for all this info! Nice to see there is still some activity on this forum!

[ersatzplanet]

Someone should add to the hardware specs that the Headphone out is DC coupled while the standard outs are not.

[Electromagnetic Wave]

@ersatzplanet I added a link in my 1st post about the headphone is DC coupled. But it is not specified before the URL. I will clarify it better. I also have other details in my .txt file. I will try to add them soon in this topic.