Orange Squeezer diagram - What does VCC mean?

[Royalston]

Its amazing - my orange squeezer works perfectly...but now I want more knobs on it....

Im wondering what the VCC means on the orange squeezer mod here:

http://www.generalguitargadgets.com/diagrams/orangesqueezer_marks_variable.gif

Do the Brown VCC marks (in the mod) connect in the same place as the Black ones (parts of the original circuit)?

Thanks for helping a newbie 

Royalston

ps. Im using 2 TL072 ICs (the 2nd one is in the the mod).....is this ok?

[hank reynolds 3rd]

Vcc is the V+ (9v in this case) so you can connect the parts in brown to the same rail on the existing pcb

Sam

[Mark Hammer]

Jeez it would be nice to have a *true* standard, eh?  All those subscripts (cc, bb, gg, dd, etc) give me a headache too.

There are essentially 6 voltages you need to know about in building solid-state pedals:

• The maximum positive supply, usually 9vdc, but occasionally something else like 12v or 15v.  This can be abbreviated as V+, Vcc
• The maximum negative supply.  This is typically the complement to V+ (i.e., -9vdc, -12vdc, etc).  This is very rarely seen in battery operated stuff (with the notable exception of Anderton projects), and more often seen in stuff with an onboard transformer and bipolar supply.
• Ground - 'nuff said.
• "Floating ground" - This is a DC voltage that is generally in the neighbourhood of half the V+, and substitutes for a "true" ground used with bipolar supplies.  This is most likely to be used with battery-operated devices, and since those devices use a 9v battery, half of that voltage will be +4.5vdc.  This will be abbreviated as Vref sometimes, and Vb at others.  The "ref" is for "reference" and the "B" has several origins, one of which is "bias".  It the circuit uses an onboard tranformer, it might still use a single-ended supply and derived Vref/Vb.  There are plenty of things out there that use a 15vdc supply from a wallwart or onboard transformer, and still use a resistor-divider to extract half the supply voltage as a "fake" ground.
• Some chips prefer to work with +5vdc as their supply voltage.  This will include some BBDs, many CMOS chips and just about any digital chip (including digital delay chips).  Because other devices on the circuit are perfectly comfortable with 9v or more, you may see several V+ values in the same circuit, including +5v *and* +9v.
• Non V/2 bias voltages.  Some devices need to have a bias voltage applied to them to get them into an operating range where another voltage (generally AC) can have an appropriate influence.  A good example would be a bucket brigade delay chip, which needs to have whatever AC audio signal you feed it riding on top of a DC bias voltage in the vicinity of 14/15ths of the supply voltage.  Another case would be FETs used in phasers, where the cyclical voltage from the LFO sits on top of a basic steady DC bias voltage so that the FET remains within a certain range of gate voltages, and consequently provides a certain range of drain-source resistance values.

In addition to the aphanumeric indications like V+, Vb, V/2, -9v and so on, yuo will also occasionally see symbolic indicators, like triangles or circles.  For example, a + or a - might appear in a circle.  These would indicate V+ and V-.  You might see filled triangles pointing up and down.  Usually, the one pointing up refers to V+ and the one pointing down refers to V-.  Alternatively, you might see open and filled triangles.  This is usually reserved for referring to V+ and V/2 (though which is which has slipped my mind).

[nelson]

Personally I think Marks post should be added to the FAQ.

Great post.

Edit: I see there is already info in the FAQ about this. 

[johngreene]

http://en.wikipedia.org/wiki/Vcc

And just in case you ever wondered why it's called "B+" in tube amps:

http://www.ac6v.com/jargon.htm

--john

[Sir H C]

Vcc = Vdd = + supply (collector or drain voltage)

Vee = Vss = - supply (emitter or source voltage)

And back in the radio days you had the A, B, and C batteries, so that is where some comes from too.

Often Vss or Vee = ground, well that is something I often see.

[Royalston]

wow
thanks

Im glad I asked!

ps. mark - thanks for the squeezer - its great

[StickMan]

Mark,

In your response, you gave a short list of examples with odd vrefs.  Doesn't the referenced OS mod schematic use a odd non-V/2 bias on the IC1a input?  The voltage divider stuff with the 390K & 470K resistors looks like it biases the non-inverted input of the op amp to about 5v.

dave.