Aaron’s Synth DIY Datasheet and Ap Note Collection

Aaron’s Synth DIY Datasheet and Ap Note Collection

Aaron’s Synth DIY Datasheet and Ap Note Collection

Some Useful Parts-Related Links

Assorted Notes


  • 2N3904 – general purpose NPN
  • 2N3906 – general purpose PNP
  • Analog
    Devices MAT02
    dual NPN
    matched (MAT02EH $15.05/1 Digikey)

  • Analog
    Devices MAT03
    dual PNP
    matched ($6.96/1000 Analog Devices, $9.45/20 Digikey – but not in stock as of

  • Analog
    Devices MAT04
    quad NPN
    matched (MAT04FP $6.78/1 Digikey)

  • Analog
    Devices SSM2210
    dual NPN
    matched ($2.24/1000 Analog Devices, $4.79/1 Digikey)

  • Analog
    Devices SSM2220

    dual PNP matched ($2.73/1000 Analog Devices, $3.91/2500 Digikey)

  • THAT series:
    300 matched quad NPN, 320 matched quad PNP, 340 matched dual NPN/dual PNP

  • National LM194/LM394
    matched dual NPN (LM394, $3.30/1K Linear Systems, $5.80/1 Digikey)
    (LM194 is improved version of LM394; I’ve usually only
    seen LM394 in synth schematics)

  • Linear Systems LS358
    log conformance dual PNP

  • Linear Systems LS318
    log conformance dual NPN

  • Linear Systems
    dual PNP

  • 2SC1583 NPN pair (5 pin, tied
    emitters) – out of
    production ($1.25/each from

  • 2SC3381 NPN pair (6 pin, separate
    emitters) – out of
    production, similar characteristics to the 2SC1583 (these were
    advertised for $1.25/each from
    Electronix Online, but I tried
    to order some, and they said they’d been backordered for a year!!!)

  • 2SA798 PNP pair (5 pin, tied
    emitters) – out of production,
    ($0.45/each at
    Electronic Surplus Inc.)

  • 2SA1349 PNP pair (6 pin,
    separate emitters) – out of production (Anyone have
    a source for these? I haven’t been able to find them…)

  • NTE42 (2SC1583 replacement) ($1.84/each at Mouser)
  • NTE43 (2SA798 replacement) ($1.98/each at Mouser)

  • Intersil HFA 3xxx
    HFA3046 (five NPN; $3.75/1 Digikey), HFA3127 (five NPN: $4.28/1
    Digikey), HFA3128 (five PNP; $4.28/1),
    HFA3096 (3 NPN, 2 PNP; $3.18/1) (not available in through-hole)

  • CA3046
    five NPN, Q1 and Q2 have emitters tied, substrate is tied to one of the
    other emitters – used in many classic Electronotes
    VCO designs, and the Serge PTO ($0.45/each/25 Jameco)

  • CA3083
    five independent NPN with a separate substrate pin; Q1 and Q2
    are “matched at low current” (a favorite of Ian Fritz; he says
    they have “low Re and
    very good matching (way better than spec.)… still my favorite for NPN
    expo converters (use transistor #3 for HF
    tracking)”) ($0.89/each)

  • CA3096 3 NPN, 2 PNP on a common
    substrate with a separate connection – used as an
    OTA by Sergio Franco in a SVF design



  • 2N7000 N-channel enhancement-mode
    (suggested by Tim Daugard) – general purpose

  • Supertex VN0104 N-channel
    enhancement-mode MOSFET
    (recommended by Ian Fritz for
    sawtooth core discharging)

  • 4007UB
    – “dual complementary pair and an
    inverter with access to each device” – three N-channel and three P-channel
    enhancement mode MOS transistors (but things are wired in a particular way;
    you have to see the schematic in the datasheet to understand)

  • 4069UB
    – hex inverter (these can be
    biased into a linear mode of operation; they’re used in place of op amps
    in the
    Wasp filter


There are a variety of vactrols, but the VTL5C3 is the “magic” one that
shows up in the Buchla designs.

Operational Transconductance Amplifiers (OTA)

Norton Amplifiers

“VCA” chips

Current in, current out, exponential voltage control:

Rumor has it that the
THAT chips may be
used in some of the newest STS Serge VCF designs; I’m not sure
where else they might be used.
The SSM2164 looks pretty nice (it’s an updated variant of the SSM2024,
which appears all over place on the Oberheim OB-Mx schematic).

Four-Quadrant Multipliers


Comparator comparisons and notes by Jim Patchell (sdiy list, 1/1/06) (why
does “comparator” have an “a” and “comparisons” have an “i”?)

  • LM319 (dual) – fast,
    high performance voltage
    comparators ($0.31/each Jameco)

  • LM393 (dual),
    LM339 (quad) – low performance
    voltage comparator ($0.19/each Jameco)

  • LM392 – interesting
    combination of one LM339 type
    comparitor and one LM324 type op amp

  • LM311 – medium performance
    single voltage comparator (takes more careful layout to prevent it from
    oscillating than the LM393 and LM339; also has more flexible output)

Op Amps

  • National Semiconductor
    LM324 (quad) and
    LM358 (dual) – bipolar,
    can run off of a single supply (actually has problems in when used with
    a dual supply; see Harry
    Bissel’s, Jim Patchell’s, and Ian Fritz’s posts
    good for control voltages, not so great for audio (Pat Kammerer recommends
    the MC3403 instead; Mike ??? recommends the MC34074 – “like a supercharged

  • Texas Instruments TL081/082/084 JFET-input
    (giving high input impedance),
    good for audio, in single/dual/quad versions
    (made by other manufacturers as well) (TL081, $0.32/each Newark,
    TL082, $0.38/25 Newark)

  • Motorola TL081/082/084
    sometimes it’s useful to have
    datasheets from different manufacturers

  • National Semiconductor TL082 (strange, National
    doesn’t seem to make the 081 or 084)

  • Texas Instruments TL071/072/074 – lower
    noise version of the TL08x (TL071, $0.32/each Newark; TL074 $0.25/each/25
    Future Electronics, $0.38/each/25 Allied)

  • National LF442 (dual) and
    LF444 – favorites of
    Ray Wilson;
    maybe try them in place
    of TL08x for lower power consumption (LF442 $0.79/each Allied; LF444
    $1.17/each Allied)

  • National Semiconductor ap notes:
  • NE5532 dual,
    single – very high quality audio, although there’s DC offset issues.
    5534 has some “balance” pins not present on the 5532.
    (NE5532 $0.65/each Allied,
    NJM5532 $0.58/each Mouser
    NE5534 $0.78/each Jameco, NJM5534 $0.35/each Mouser)

  • CA3140 (single, $0.52/each at Allied),
    CA3240 (dual, $1.05/each at Newark)
    MOSFET input/bipolar output, insanely
    high input impedances – often used in VCO integrators and in sample-and-holds
    (Pat Kammerer says: “…very good for single supply applications,
    partially due to the voltage swing that includes the – rail, and even a
    bit more. I would replace a 741 with this in most cases, citing higher
    bandwidth, and higher slew rate…” J. Haible says: “…makes a great
    buffer in OTA-based phasers, as it’s high impedance and doesn’t suffer
    from phase reversal as much as the usual BiFET amps.”)

  • CA3160 MOSFET input/CMOS output, capaple
    of rail-to-rail output operation. Out of production; listed since it’s used
    in the Buchla 259 timbre circuitry. Frequency compensated version of CA3130.

  • CA3130 – like CA3160, but uncompensated
  • JRC4558
    or NJM4558
    (dual) bipolar, mediocre specs
    from a modern viewpoint, but
    potentially useful if you’re trying to sound retro – remember these were
    generally chosen because they were cheap, not because they were particularly

  • OP275
    dual bifet, with “Butler amplifier front
    end” – really high performance, good audio
    and DC behavior (datasheet sounds like hype though – “sound quality of
    JFETs?” what the heck is THAT supposed to mean?) ($1.93/each Allied)

  • OPA134/2134/4134
    (single/dual/quad) – also really high
    performance (a favorite of Ian Fritz; he writes that they have
    “super-low distortion (0.00008% for audio amplification, low input
    bias current (5 pA) and voltage offset (0.5 mV) for integtrator
    applications and fast slew rate (20V/us) for cap dischargee
    usage. for lower offset I like the OPA2227.”)
    (OPA134 $2.25/each Newark, OPA2134 $2.37/each Newark)

  • Misc. application notes:
  • Op Amp Circuit Collection (AN-31)
  • Audio Applications of Linear Integrated
    (including “Exponential V-F Converter”)

Electronic Switches

  • DG211
    quad CMOS switch (up to +/- 15 V signals)

  • 4066 quad CMOS switch
    (up to +/- 7.5 V signals)

Voltage Regulators

Suggested by Ian Fritz.

  • National LM336-5 (5 volt),
    LM336-2.5 (2.5 volt)

  • National LM329 (6.9 volt)
  • Fairchild TL431 Programmable Shunt
    Regulator – can be set
    to any value between 2.5 volts and 36 volts with two external resistors

Miscellaneous Interesting Chips

  • LM398 sample and hold
  • LM1894 Dynamic Noise Reduction System

Voltage Controlled Oscillators (VCO)

With the exception of the XR4151, these don’t actually seem to turn up in
synth schematics very often.

“Universal” Filters

These seem to be pretty expensive! I haven’t seen any of them appear
in synth designs…