The TDA 0470 D chip contains a 12-transistor array that's particularly suited for use in electronic organs.

[ It's an improved, pin-compatible version of the TDA 0470. ]

It's 12 parallel transistors can replace up to 12 mechanical key contacts beneath an organ manual key ( 10 contacts are not uncommon ).

Each transistor's emitter is fed its own tone signal and the combined signal is available at the chip's common collector (pin 14) whenever the transistors are gated ‘On’ via pin 7.

Clamping diodes on the emitter inputs reduce capacitive crosstalk among the transistors.

This now discontinued chip generates a four-stage sound envelope (ADSR) in response to four analog input voltages representing:  an Attack time (AT), an initial Decay time (ID), a Sustain level (SUS) and a final Release time (FD); and to a trigger pulse and a gate.

This genuine RCA CA3080 operational transconductance amp is used in scores of vintage synthesizers and music gear.

A ‘transconductance’ amplifier is a voltage-controlled current source — a change in its input voltage causes a linear change in its output current.  ‘Transconductance’ is defined to be the ratio Δ I_Out  / Δ V_In

This OTA also has a ‘bias’ input.  The op-amp's transconductance is directly proportional to the input bias current.

The bias current can be used for gain-control and for gating applications like sample-hold and multiplexing.

This original, Intersil op-amp has the same 8-lead pinout of industry-standard op amps like the ‘ 741 ’.

However, the ‘3140’ contains a high-voltage pMOS FET differential input stage to provide very high input impedance, very low input current, and high speed performance.

The single-ended, push-pull, class A output stage uses bipolar transistors and includes protection against damage from shorted loads.

A ‘Strobe’ input is also provided that can be used for added frequency roll-off.

This vintage chip generates a four-stage sound envelope (ADSR) in response to four analog input voltages representing an Attack time, a Decay time, a Sustain level and a Release time; and to a trigger pulse and a gate.

This is an original 1980s Curtis Electromusic Specialties chip, not a reproduction.

This vintage, four-pole filter chip can be connected to provide a variety of responses such as low pass, high pass and band pass.

Its cutoff-frequency is voltage controllable over a ten octave range.  Voltage controlled resonance is also provided.

This is an original 1980s Curtis Electromusic Specialties chip, not a reproduction.

This vintage VCO chip simultaneously outputs a triangle wave, a sawtooth wave, and a square or pulse wave.

It's used in many vintage synths, including models made by Sequential Circuits, Oberheim, and Moog.

This is an original, 1980s Curtis Electromusic Specialties chip, not a reissued Rev G chip or an Alpha reproduction.

This now discontinued ‘4136’ quad op-amp has a non-standard pinout that makes substitutes hard to find.

Each of the chip's four op-amps is electrically similar to the industry-standard ‘741’ op-amp except that the 4136 doesn't provide offset null pins.

A high common-mode input voltage range and an absence of latch-up make the 4136 op-amps ideal for voltage-follower applications.

These op-amps are short-circuit protected and have internal frequency compensation to ensure stability without external components.

The ‘4727’ is a digital chip containing seven clocked, D-type flip-flops.  Each flip-flop's Q output is wired to its Data input, making it a frequency divider.

Each ‘4727’ has three single flip-flops and two 2-stage flip-flops, making seven dividers in total.  So, including the frequency of the clock, that covers all eight musical octaves.

For example, if the clock frequency is High-C, one ‘4727’ chip can produce every other C-note in the musical spectrum.  Twelve chips can generate the entire musical spectrum from a single top octave of frequencies.