A liquid dispenser comprising: a manifold (2, 102, 202, 302, 402, 600) comprising a pressure channel (4, 146, 246, 346, 612, 614), a vacuum channel (5, 148, 248, 348, 616, 618), a plurality of pressure cross-channels (6, 150, 250, 350, 620), each pressure cross-channel beginning at the pressure channel and terminating at an external surface of the manifold, a plurality of vacuum cross-channels (7, 152, 252, 352, 622), each vacuum cross-channel beginning at the vacuum channel and terminating at the external surface of the manifold; two or more pipette channels (8A-8C, 110, 210, 310, 410) coupled to the manifold, each pipette channel comprising a dispense head, a pressure port (10, 156, 256, 356) configured to receive gas under pressure from one pressure cross-channel, a vacuum port (11, 157, 257, 357) configured to receive a vacuum pressure from one vacuum cross-channel, and a valve (12, 158, 258, 358) in simultaneous fluid communication with the pressure port and the vacuum port, the valve operable to selectively divert gas under pressure and vacuum pressure to the dispense head; and electrical connections (14, 174, 274, 374) configured to transmit control signals from the manifold to the two or more pipette channels, operation of each valve regulated independently of any other valve by the control signals transmitted from the manifold, wherein each dispense head is moveable along a vertical direction relative to the manifold independently of another dispense head coupled to the manifold. a manifold (2, 102, 202, 302, 402, 600) comprising a pressure channel (4, 146, 246, 346, 612, 614), a vacuum channel (5, 148, 248, 348, 616, 618), a plurality of pressure cross-channels (6, 150, 250, 350, 620), each pressure cross-channel beginning at the pressure channel and terminating at an external surface of the manifold, a plurality of vacuum cross-channels (7, 152, 252, 352, 622), each vacuum cross-channel beginning at the vacuum channel and terminating at the external surface of the manifold; a pressure channel (4, 146, 246, 346, 612, 614), a vacuum channel (5, 148, 248, 348, 616, 618), a plurality of pressure cross-channels (6, 150, 250, 350, 620), each pressure cross-channel beginning at the pressure channel and terminating at an external surface of the manifold, a plurality of vacuum cross-channels (7, 152, 252, 352, 622), each vacuum cross-channel beginning at the vacuum channel and terminating at the external surface of the manifold; two or more pipette channels (8A-8C, 110, 210, 310, 410) coupled to the manifold, each pipette channel comprising a dispense head, a pressure port (10, 156, 256, 356) configured to receive gas under pressure from one pressure cross-channel, a vacuum port (11, 157, 257, 357) configured to receive a vacuum pressure from one vacuum cross-channel, and a valve (12, 158, 258, 358) in simultaneous fluid communication with the pressure port and the vacuum port, the valve operable to selectively divert gas under pressure and vacuum pressure to the dispense head; and a dispense head, a pressure port (10, 156, 256, 356) configured to receive gas under pressure from one pressure cross-channel, a vacuum port (11, 157, 257, 357) configured to receive a vacuum pressure from one vacuum cross-channel, and a valve (12, 158, 258, 358) in simultaneous fluid communication with the pressure port and the vacuum port, the valve operable to selectively divert gas under pressure and vacuum pressure to the dispense head; and electrical connections (14, 174, 274, 374) configured to transmit control signals from the manifold to the two or more pipette channels, operation of each valve regulated independently of any other valve by the control signals transmitted from the manifold, wherein each dispense head is moveable along a vertical direction relative to the manifold independently of another dispense head coupled to the manifold.