Synare 3 bipolar supply?

[hoyager]

Hey there, I've been trying to find similar circuits to the ones in the synare 3 to get an answer, thought someone might be able to let me know off the bat..

http://clacktronics.co.uk/wp-content/uploads/2011/09/Clacktronics_Star_Synare_Schematic.gif

Is it just a matter of replacing all the 6v (vref) points with ground and all the grounds with -v?

VCF and VCA are pretty straight forward conversions

But the other parts...

CMOS 4093 oscillators: these should be +v and ground only right?

This would mean if using +/-12v it would use only +12v and gnd.

Would this result in a one-sided wave though?

Envelopes: the grounds marked become -v?

Noise generator: grounds become -v?

Trigger Conditioner: grounds become -v?

The service manual seems to be more correct, as in marks the power points in a bipolar fashion, except the oscillators, which I'm starting to understand wouldn't be able to handle +12v at pin 14 and -12v at pin 7??

Andy

[nd_efx]

18V will become +6V (  Plus bipolar supply)
12V ( removing battery saver switcher ( all 3 transistors and oth parts down right side) tied also to +6V (Plus 6V bipolar )
6V 1/2Ref  - GND (GND  bipolar)
GND tied to  - -6V (Minus Bipolar)

or.
Just skip the bipolar supply ground ( let it floating ) and power the whole circuit with +/- 6 Volts

good is also to add some filtering on the supply for the oscilators and/or the VCF to stop eventual hiss...

is you bipolar supply powering only that circuit or also some other units ?

[hoyager]

Thanks, I'm not sure if you've added anything here?

There are 5 or so circuits which make up the synare, so my question is if the rest of the circuits are bipolar, is it ok for the oscillators to run off +v and gnd?

I haven't ever heard of running circuits without a ground??

Although with the envelope portion this would be the case if making the grounds -v

Opamps need a ground though right? so this would work if any of the circuits involved don't have opamps?

Andy

[slacker]

There will be no difference running OSC1 of +12 volts and ground with the rest of the circuit on a +- 12 Volt biploar supply. It's AC coupled to the filter by the 100n cap after the osc/noise switch, so the difference DC levels don't matter.
OSC2 is directly coupled to the filter though, so in the original its output is 0 - 12 Volts, the filter is referenced to 6 Volts, so OSC2s output is +-6 Volts as far as the filter is concerned, so it's positive and negative. If you run the filter off a bipolar supply so it's referenced to ground then OSC2s output will look like 0-12 volts to the filter, so it's only positive. I don't know if this makes any difference in practice, I'm not 100% sure what OSC2 is doing to the filter. You may need to level shift its output to +-6 Volts.
The OSC2 connection to the filter CV mixer has the same issue, in the original it is centred around half the supply, so you may need to tweak things to keep it there or it might not matter.

Why do you want to do this anyway?

[hoyager]

Awesome thank you, sounds like I might need to make it and see.

I'm making a clone, and don't want to use batteries, already have lots of 12v regulators, and charge pumps, and just figure the vcf section is going to sound better and the whole circuit, possibly even quieter on 'normal' full strength supply?

Also the manual says there will be hum if trying to run it from a power adapter with its current power scheme (vref for ground).

Current draw is supposed to be about 25ma, maybe it'd be ok as it is?

Will this level shifting work for both osc2 and its cv output?

http://img515.imageshack.us/img515/3668/levelshift.png

from this thread

http://www.diystompboxes.com/smfforum/index.php?topic=97949.0

Maybe a redesign of osc2? Will have a look at MFOS snyths

Andy