what does this schematic symbol mean?

[FWALS]

I'd like to build this, but I'm not sure what the  arrow with 'Vb' above it means.
Any help would be appreciated. Here's a link to the schematic

http://www.experimentalistsanonymous.com/diy/Schematics/Fuzz%20and%20Fuzzy%20Noisemakers/Analog%20Bit%20Crusher.gif

[cloudscapes]

it's a voltage reference. in this case half of the power supply generated by the two resistors and capacitor on the left. just connect all 5 Vb points together and you're good to go.

[FWALS]

Great thanks!

[ayayay!]

Wow!  I don't think I've seen a pedal with so few grounds...  That alone begs it to be built.  Should be really easy!  What the heck is this anyway?  Something synth-y?

[tiges_ tendres]

Wow!  I don't think I've seen a pedal with so few grounds...  That alone begs it to be built.  Should be really easy!  What the heck is this anyway?  Something synth-y?

It's a sample rate reducer.  Kind of sounds like a ring mod.  I built one but was largely unimpressed.

[ayayay!]

I'm a derp.  I don't know what a sample rate reducer is unless it's one of those online mortgage calculators. 

[Gurner]

Wow!  I don't think I've seen a pedal with so few grounds... 

They're there in spades... albeit virtual ones!

[tiges_ tendres]

I'm a derp.  I don't know what a sample rate reducer is unless it's one of those online mortgage calculators. 

Sounds like this:

[ayayay!]

They're there in spades... albeit virtual ones!

Oh yeah I know, I just mean the literal components to earth.  Don't see that too often in pedals. 

[EATyourGuitar]

also fair to say that it can be called a sample&hold that goes up to audio rates. hence, therefor, hereto ::strokes beard:: why its a analog sample rate reducer and not the traditional analog>digital>analog converter with variable clock frequency.

[FWALS]

Wow!  I don't think I've seen a pedal with so few grounds...  That alone begs it to be built.  Should be really easy!  What the heck is this anyway?  Something synth-y?

It's a sample rate reducer.  Kind of sounds like a ring mod.  I built one but was largely unimpressed.

Hey what part did you use for the op amps?

[MikeH]

They're there in spades... albeit virtual ones!

Oh yeah I know, I just mean the literal components to earth.  Don't see that too often in pedals. 

They dont show it on the schematic, but you'll obviously need to ground the opamps.  It's really not that different than other designs of similar complexity.

[tiges_ tendres]

Wow!  I don't think I've seen a pedal with so few grounds...  That alone begs it to be built.  Should be really easy!  What the heck is this anyway?  Something synth-y?

It's a sample rate reducer.  Kind of sounds like a ring mod.  I built one but was largely unimpressed.

Hey what part did you use for the op amps?

2 4558's  Any dual will do.