Build your own pedal or preamp

Blocks you can build with

Pick New pedal or New preamp at the top of the circuit menu, then add blocks with the + buttons in Your build, under the schematic. A build can have up to 12 blocks.

Pedal blocks

Transistor gain stage

One silicon transistor with a small emitter resistor, about 26 dB of clean gain (20 times).

Germanium stage

One germanium transistor with its emitter bypassed, using the 1965 treble booster’s values. Its gain is about 37 dB (70 times). Its input impedance is low, about 10 kΩ, so it loads what feeds it, and its bias moves with temperature. Values for Full range or Treble booster.

Emitter follower

A buffer, with no voltage gain, a high input impedance and a low output impedance.

JFET buffer

A source follower, with slightly under unity gain, an input impedance over 1 MΩ and a low output impedance.

JFET gain stage

One JFET with its source bypassed, about 20 dB of gain that clips softly.

Op-amp gain stage

A non-inverting op-amp stage with a Gain knob, from unity to about 39 dB.

Op-amp buffer

An op-amp with its output tied to its − input. It has unity gain, a 1 MΩ input impedance and an output that drives almost anything.

Inverting op-amp stage

An op-amp stage that flips the signal upside down, with a Gain knob from unity to about 34 dB. Its input impedance is low, 10 kΩ.

Transistor stage with a Gain knob

One silicon transistor with a Gain knob in its emitter leg, clean at small signals: about 14 dB (5 times) with the knob down, 21 dB (11 times) at noon and 31 dB (34 times) up full. Its input impedance is about 70 kΩ, so straight from a guitar it trims about 5 dB off 5 kHz. A buffer in front keeps the top.

Gain stage into an emitter follower

The transistor gain stage with an emitter follower straight off its collector, no cap between. The follower brings the output impedance down from 10 kΩ to about 75 Ω, so what comes next can’t pull the gain down. The gain is about 27 dB (22 times). Its input impedance is about 34 kΩ, so straight from a guitar it trims about 8 dB off 5 kHz.

Feedback pair

Two transistors with feedback from the second collector back to the first emitter. The feedback sets the gain as the resistors in an op-amp stage do, 1 plus 10 kΩ over 1 kΩ, or 11 times. With about 125 times of gain to work with, the pair comes out at 10 times (20 dB), flat, and the same way up as the input. The output impedance is about 260 Ω, the input about 130 kΩ.

Bootstrapped emitter follower

An emitter follower with its bias resistor bootstrapped. A cap from the emitter drives the middle of the bias divider, so both ends of the 100 kΩ to the base move together and almost no signal current flows in it. The input impedance comes out about 3.3 MΩ, against 460 kΩ for the plain emitter follower, and the output about 70 Ω. A guitar straight into it keeps its top end.

JFET mu-amp

Two JFETs stacked. The lower one amplifies. The upper one is its load, held at a steady current, so it looks like about 1 MΩ and the gain runs up near the JFET’s limit, about 46 dB (200 times) into 1 MΩ. The output impedance is high too, about 150 kΩ, so whatever comes next sets much of the gain, about 39 dB into the Level knob. Both figures depend on the JFETs’ output resistance, typical of the part, not measured. It spreads from part to part, so a real JFET may come in lower.

JFET mu-amp with a follower

The JFET mu-amp with an emitter follower straight off its output. The follower brings the output impedance down from about 150 kΩ to about 300 Ω, so the Level knob no longer pulls the gain down. The gain is about 47.5 dB at 1 kHz. As in the mu-amp, the gain depends on the JFETs’ output resistance, which is typical of the part, not measured.

Long-tailed pair

Two transistors sharing one emitter resistor, the tail. The signal goes in one base, the other base is held still, and the output comes off the second collector, the same way up as the input. About 23 dB of gain. Pushed hard, the tail’s current swings all the way to one side or the other, so it clips about the same on both sides, at about 4 V peak to peak.

JFET stage with a Gain knob

One JFET with a Gain knob in its source leg: about 11 dB with the knob down, 15.5 dB at noon and 19.5 dB up full. Its input impedance is 1 MΩ, so a guitar can plug straight in. It clips softly and unevenly, more on one side than the other.

Diode clipper

A pair of diodes to ground behind a resistor. It flattens the peaks over about 0.5 V.

Treble cut

A Tone knob that rolls off the top end. Full treble at full rotation.

Fuzz tone control

The four-transistor fuzz’s Tone knob on its own. It’s a low-pass and a high-pass with one knob fading between them. At noon the dip sits near 500 Hz, about 5 dB under the lows and 9 dB under the highs, and the level drops 8 to 18 dB, so a gain stage after it helps. Values for 1970 fuzz or DS-1.

Bass and treble stage

The 1971 three-transistor overdrive’s tone stage. It’s a Baxandall bass and treble network wrapped around one transistor, so both knobs boost and cut. At noon it’s 1 to 2 dB down and close to flat. Bass end to end runs from about +6 to −7 dB at 100 Hz, treble from about +21 to −24 dB at 5 kHz. Its input impedance is about 5 kΩ, so drive it from an emitter follower or an op-amp stage.

Volume

A pot as a divider, to set the level going into the next block.

Two-transistor fuzz

Two silicon transistors with feedback between them, the 1966 fuzz with BC108C and BC109C parts. Put it first: it loads the guitar hard, and that’s part of how it cleans up with the guitar’s volume.

Four-transistor sustainer

The whole 1970s four-transistor fuzz without its Volume. It has a boost, a Sustain knob, two clipping stages with diodes in their feedback, the Tone stack and a recovery stage, with the same parts as the four-transistor sustainer on the bench.

Op-amp overdrive

The core of the 1979 op-amp overdrive, without its buffers. It’s the clipping stage with diodes across its feedback and a Drive knob, the 720 Hz low-pass, and the Tone stage. Add Volume or Emitter follower blocks around it for the buffers and level.

Octave up

The octave side of the 1969 octave fuzz, without its clean blend. A gain stage runs flat out, diodes split the wave into its two halves, and a Darlington pair turns one half over, so both come out the same way up an octave higher. A Texture knob sets how evenly the halves match. Its input impedance is low, about 4 kΩ, so put a buffer in front. Its output is small, about 0.35 V peak to peak however hard it’s driven, so a gain stage after it helps.

Op-amp distortion (Rat)

The 1978 op-amp distortion without its output buffer and Volume. It has an LM308 stage with the Distortion knob, two ground legs that roll off the lows, 1 kΩ into a pair of silicon diodes to ground, and the Filter knob’s low-pass after them. With the knobs at their default settings, the gain is about 42 dB at 1 kHz and 28 dB at 100 Hz, and the diodes hold the output near 1.2 V peak to peak. With Filter at full, 5 kHz drops about 19 dB. With the Filter up, the output impedance runs past 100 kΩ, so a JFET buffer after it, as in the pedal, keeps the next block from loading it.

Op-amp distortion (Distortion+)

The 1978 op-amp distortion without its Volume. A 741 stage has a Distortion knob that runs the gain from 1 to about 40 dB at 1 kHz, and a 47 nF cap that holds the lows back at high gain. Then 10 kΩ feeds a pair of germanium diodes to ground with 1 nF across them. With the knob at its default setting, the gain is about 18 dB, and the diodes hold the output near 0.35 V peak to peak. In the pedal the 10 kΩ Volume pot loads that 10 kΩ, so the pedal runs about 3.5 dB quieter than this block into the 100 kΩ Level knob.

Op-amp overdrive with clean blend (Klon)

The 1994 overdrive without its treble stage and Level: an input buffer, a gain stage into two germanium diodes, and two clean paths summed back in by an inverting op-amp. The dual Gain pot turns the gain stage up and the clean paths down together. With the knob at its default setting, the gain is about 23 dB at 1 kHz, 18 dB at 100 Hz and 9 dB at 5 kHz. At full it’s up to 46 dB at 1 kHz. The output is upside down. Add the Klon treble stage block after it for the whole pedal. In this block every op-amp runs on the battery, where the pedal runs the summing stage on a charge pump. Many parts return to the 4.5 V reference, so the reference cap matters in the lows: the build’s 10 µF passes about 1.6 dB more at 30 Hz than the pedal’s 47 µF.

Discrete two-stage overdrive (Blues Driver)

The 1995 discrete overdrive without its tone and output stages. It has a JFET buffer, then two gain stages, each a discrete op-amp (a JFET pair driving a PNP transistor). The dual Gain pot is in both feedback paths, and two pairs of diodes go to ground between the stages. With the knob at its default setting, the gain is about 41 dB at 1 kHz and 28 dB at 100 Hz. It runs from about 30 dB at zero to 65 dB at full. The second stage swings close to the full supply, about 8.5 V peak to peak, so turn the Level knob down or put the BD-2 tone block after it. The pedal runs all this on a regulated 8.2 V with a 4.1 V reference. In this block it runs on the battery and the 4.5 V reference.

One-transistor distortion (MPC)

The 1970s one-transistor distortion module without its Volume. It has one silicon transistor with collector-to-base feedback, then a pair of germanium diodes to ground. At the starting settings the gain is about 15 dB at 1 kHz and 10 dB at 100 Hz. That’s not much gain, so the diodes clip hard only with a hot pickup or a boost in front. A 1 V note comes out near 0.5 V peak to peak.

Op-amp fuzz (Muff Fuzz)

The 1979 op-amp fuzz without its Volume. It has an inverting stage with a gain of about 4.7, then a second inverting stage with two silicon diodes across its feedback. Below the diodes’ knee that second stage runs almost open loop, so small signals get about 72 dB of gain at 1 kHz, and anything played comes out squared off near 1 V peak to peak. The 10 nF input cap against the 100 kΩ input resistor cuts the bass below about 160 Hz, as in the pedal.

Two-stage blend fuzz (Fuzzrite)

The 1968 two-stage fuzz without its Volume. It has two silicon transistors with collector-to-base feedback, each on a 470 kΩ load, so they run on a few microamps. The Depth knob blends between small caps off the first and second collectors. With the knob at its default setting, the gain is about 41 dB at 1 kHz and 32 dB at 100 Hz. Depth runs it from about 22 dB to 47 dB at 1 kHz. The output is near 2 V peak to peak and its impedance is high, so a buffer after it helps.

Two-op-amp LED distortion (Guv’nor)

The 1988 distortion without its tone network and Level. It has a first op-amp stage whose Gain knob boosts the treble, two coupling caps and a resistor between the stages, a second inverting op-amp stage, and a pair of LEDs to ground. With the knob at its default setting, the gain is about 44 dB at 1 kHz and 31 dB at 100 Hz. The Gain knob runs it from about 13 dB to 65 dB at 1 kHz. The LEDs hold the output near 3.7 V peak to peak, louder than silicon diodes. Put the Guv’nor tone network block after it for the whole pedal.

Two-stage op-amp overdrive (Bluesbreaker)

The 1991 overdrive without its Volume. It has a first op-amp stage with the Gain knob and a leg to the reference that favors the mids and highs, then a second stage with two silicon diodes each way in its feedback, and the Tone control. With the knobs at their default settings, the gain is about 14 dB at 1 kHz and 10 dB at 100 Hz. The Gain knob runs it from about −2 dB to 36 dB at 1 kHz. With Tone down the gain at 5 kHz is about 4 dB, and with it up about 24 dB. A 1 V note comes out near 1.5 V peak to peak.

Transistor-boosted distortion (DS-1)

The 1994 boosted distortion without its input buffer, tone control, Level and output buffer. It has a 47 nF cap into a transistor booster, the op-amp stage with the Dist knob, and a pair of silicon diodes to ground. The booster’s input impedance is only a few kΩ, so the 47 nF cap cuts the bass, and a buffer in front keeps the guitar from being loaded. With the knob at its default setting, the gain is about 56 dB at 1 kHz and 40 dB at 100 Hz. Dist runs it from about 35 dB to 62 dB at 1 kHz. The diodes hold the output near 1.3 V peak to peak. For the whole pedal, put the Fuzz tone control block after it and pick DS-1 under Values.

Three-transistor overdrive (Overdriver)

The whole 1971 three-transistor overdrive. It has a two-transistor feedback pair with the Gain pot in the first emitter, then a bass and treble network wrapped around a third transistor. It has no volume control. With the knobs at their default settings, the gain is about 31 dB at 1 kHz, flat from 100 Hz to 5 kHz with the tone knobs at noon. Gain runs it from about 11 dB to 57 dB at 1 kHz, nearly all of that in the last bit of the turn, since the pot is linear. A 1 V note comes out near 5 V peak to peak, so turn the Level knob down. The Bass and treble stage block is its tone stage on its own.

Op-amp overdrive with Spectrum (ODR-1)

The 2000 op-amp overdrive without its input buffer, Level and output buffer. It has an op-amp stage with diodes in its feedback and the Drive knob, and a second pair of diodes to the reference. Then come a stage whose Spectrum knob raises or lowers the treble and the low mids together, and a last stage that rolls off the top. With the knobs at their default settings, the gain is about 28 dB at 1 kHz and at 100 Hz, and 20 dB at 5 kHz. Drive runs it from about 8 dB to 47 dB at 1 kHz. A 1 V note comes out near 3.6 V peak to peak. Its 220 nF input cap is inside the block. In the pedal a buffer drives it, so put a buffer in front.

Two-stage distortion with fixed EQ (MT-2)

The 1991 distortion without its input buffer, its three-band EQ and output. It has a first op-amp stage with the most gain near 950 Hz, the Dist stage with a gain of up to about 250, and two silicon diodes to ground. Then come a stage that lifts about 105 Hz and 4.9 kHz, and an inverter. With the knob at its default setting, the gain is about 50 dB at 1 kHz, 36 dB at 100 Hz and 23 dB at 5 kHz. Dist runs it from about 27 dB to 73 dB at 1 kHz. A 1 V note comes out near 1.5 V peak to peak. Its 15 nF input cap is inside the block, against 100 kΩ, so put a buffer in front. For the whole pedal, put the MT-2 low and high EQ and the MT-2 parametric middle after it.

Transistor and op-amp distortion (HM-2)

The 1983 distortion without its input buffer, EQ and output. It has two transistor stages, an op-amp with uneven diodes in its feedback, then germanium diodes in series with the signal and silicon diodes to ground. The Dist pot works on two stages at once. With the knob at its default setting, the op-amp’s output is about 48 dB up at 1 kHz and 41 dB at 100 Hz, and Dist runs that from about 24 dB to 59 dB. The series diodes pass almost nothing until the signal tops their knee, so quiet playing gets gated, and a 1 V note comes out near 1.1 V peak to peak. Its 47 nF input cap is inside the block. For the whole pedal, put the HM-2 two-band EQ after it.

Three-transistor germanium fuzz (Tone Bender Mk II)

The 1966 three-transistor germanium fuzz without its Volume: a first stage running on its own leakage, then the two-transistor feedback pair with the Fuzz pot as its emitter bypass. The pedal is PNP on positive ground. This block turns the circuit round, with germanium NPN parts on the same model values, so it shares the build’s negative-ground battery. At full Fuzz the gain is about 51 dB at 1 kHz, 29 dB at 100 Hz and 48 dB at 5 kHz, and Fuzz runs it from about 24 dB. A 1 V note comes out near 0.55 V peak to peak. The pedal has no supply cap, so a little of the output gets back to the first stage through the battery. The build’s 100 µF supply cap stops that, so this block runs about 5 dB under the pedal at 1 kHz.

Three-transistor germanium fuzz (FZ-1)

The 1962 three-transistor germanium fuzz without its Volume: an emitter follower, two stages that each clip one side of the wave, and a 3.3 nF output cap into 56 kΩ that passes almost nothing below about 860 Hz. It runs on its own 3.1 V supply, as the pedal did, since on 9 V its bias would end up somewhere else. The pedal is PNP on positive ground. This block turns the circuit round, with germanium NPN transistors on the same model values. With the knob at its default setting, the gain is about 45 dB at 1 kHz, 27 dB at 100 Hz and 48 dB at 5 kHz. Attack runs it from about 25 dB to 46 dB at 1 kHz. A 1 V note comes out as spikes near 5 V peak to peak.

MOSFET booster

A clean booster, one BS170 with feedback bias and a Gain knob, from unity to about 35 dB. In a preamp it runs on its own 9 V supply, like a pedal built into the amp.

James bass and treble

The James bass and treble network at pedal values, with 10 kΩ and 100 kΩ pots and caps ten times the amp values. Both knobs boost and cut, close to flat at noon. Drive it from a buffer or an op-amp. With a 100 kΩ Level pot after it and the knobs at their default settings, it drops the level about 18 to 20 dB from 100 Hz to 5 kHz, so a gain stage after it helps.

Tone network from a pedal

The tone controls of a pedal on the bench that the other tone blocks don’t cover, part for part. Pick the pedal under Values. Values for Electro-Harmonix Hot Tubes, Fender 6G15 Reverb or Marshall Bluesbreaker pedal.

TS808 tone stage

The 1979 op-amp overdrive’s tone stage on its own. It’s a fixed 720 Hz low-pass, then an op-amp stage whose Tone knob boosts or cuts the treble. At noon it’s about 1 dB down at 100 Hz, 5 dB at 1 kHz and 16 dB at 5 kHz. Tone up, the top comes back to about 4 dB down at 5 kHz. Tone down, it’s 20 dB down there.

Rat filter

The 1978 op-amp distortion’s Filter knob on its own. It’s 1 kΩ, 1.5 kΩ and a 100 kΩ pot in series into 3.3 nF, a first-order low-pass. Its corner falls from about 30 kHz to under 500 Hz as the knob goes up. At its default setting, about a third of the way up, it’s close to flat to 1 kHz and about 2 dB down at 5 kHz. At full it’s about 21 dB down at 5 kHz.

Guv’nor tone network

The 1988 LED-clipping distortion’s passive three-band network: a 4 nF treble path and a 1.5 kΩ low path, with Middle and Bass pots that shunt parts of the low path to ground. Drive it from a low impedance, such as an op-amp or a buffer. It drops the level a lot. With the knobs at their default settings it’s about 15 dB down at 100 Hz and 1 kHz and 22 dB down at 5 kHz, so a gain stage after it helps.

BD-2 tone

The 1995 discrete overdrive’s tone section. It’s a fixed low-pass, 5.6 kΩ with 5.6 nF across it and 5.6 nF to ground, then a 10 kΩ pot between two 18 nF caps. At noon it’s about 7 dB down at 100 Hz, 9 dB at 1 kHz and 12 dB at 5 kHz. Tone up, it’s about 6 dB down from 1 kHz to 5 kHz. Tone down, it’s 21 dB down at 5 kHz.

Klon treble stage

The 1994 overdrive’s active treble control. It’s an inverting op-amp stage with unity gain in the mids, and the Treble pot swings a 3.9 nF cap between its input and its feedback. At full it’s about 16 dB up at 5 kHz, at zero about 7 dB down. At noon it’s about 0 dB at 100 Hz, 2 dB up at 1 kHz and 3 dB up at 5 kHz. It flips the signal upside down.

HM-2 two-band EQ

The 1983 distortion’s EQ stage, a non-inverting op-amp with Low and High pots between its inputs. The Low wiper feeds a gyrator branch tuned near 90 Hz, and the High wiper feeds two tuned near 960 Hz and 1.3 kHz. Low boosts or cuts about 20 dB near 90 Hz, High about 22 dB near 1.3 kHz. At noon it’s flat, 0 dB at 100 Hz, 1 kHz and 5 kHz.

MT-2 low and high EQ

The 1991 distortion’s first EQ stage, with Low and High on one op-amp. Low is a gyrator branch near 105 Hz and High is a shelf above about 7 kHz. Both boost and cut, about 19 dB at 100 Hz and 16 dB at 5 kHz. At noon it’s flat, 0 dB at 100 Hz, 1 kHz and 5 kHz.

MT-2 parametric middle

The 1991 distortion’s second EQ stage. A dual Freq pot tunes a band-pass network from about 240 Hz to 5 kHz, and the Middle pot adds it to the signal or subtracts it, about 15 dB either way. At noon it’s flat, 0 dB at 100 Hz, 1 kHz and 5 kHz. It flips the signal upside down.

RC filter, one pole

One resistor and one cap with a Frequency knob, as a low-pass or a high-pass. Pick the shape under Values. Values for Low-pass or High-pass.

RC filter, two poles

Two RC sections in a row on a dual-gang Frequency pot, as a low-pass or a high-pass. Pick the shape under Values. Values for Low-pass or High-pass.

RLC filter

A resistor, an ideal 500 mH inductor and 100 nF, as a low-pass, high-pass, band-pass or notch at 712 Hz, about where a wah’s inductor sits. A real inductor’s winding resistance lowers the peak. Pick the shape under Values. Values for Low-pass, High-pass, Band-pass or Notch.

Bridged-T mid scoop

Two 10 nF caps in series, a resistor from their junction to ground and 220 kΩ bridging both: a mid notch with no inductor and no loss outside it. The Depth knob moves it from about 1.6 kHz at zero to about 330 Hz at full, getting shallower as it goes down. At noon it sits near 880 Hz. It only reaches full depth with a light load behind it.

Sallen-Key filter

A two-pole active filter on one op-amp, unity gain, fixed corner, as a low-pass or a high-pass. Change the parts to move the corner. Pick the shape under Values. Values for Low-pass or High-pass.

Op-amp Baxandall

Bass and treble that boost and cut around one op-amp, flat with both at noon. Bass runs about ±14 dB at 100 Hz, treble about ±16 dB at 10 kHz and ±7 dB at 3 kHz. Its input impedance drops to a few kΩ, so drive it from a buffer or an op-amp stage. It flips the signal upside down.

Preamp blocks

Diode clipper

A pair of diodes to ground behind a resistor. It flattens the peaks over about 0.5 V.

Volume

A pot as a divider, to set the level going into the next block.

Triode gain stage

Half a 12AX7 with a bypassed cathode, about 35 dB of gain.

Triode stage into a cathode follower

A gain stage whose plate drives the next half’s grid directly, as in a Marshall. The follower drives a tone stack from a low impedance.

Volume with bright cap

A volume pot with a small cap from its top to its wiper. Turned down, the cap lets treble skip past the top of the track, so the sound gets brighter as the volume goes down. Full up, the cap is shorted and does nothing. The voicings are the bright caps of ten amps, 47 pF to 5 nF. Values for Fender AB763 Deluxe Reverb, Fender 5F6-A Bassman, bright, Fender 6G7 Bandmaster, Marshall 1959 Super Lead, volume I, Marshall JCM800 2203, preamp volume, Vox AC30 Top Boost, brilliant, Vox AC15, EF86 channel, Mesa/Boogie Mark IIC+, volume 1, Soldano SLO-100, gain, Mesa/Boogie Dual Rectifier or red gain.

Interstage divider

null Values for JCM800 2203, with treble cap, SLO-100, no cap, Mark IIC+, treble cut, JCM800 2203 or second (grid stopper).

Pentode gain stage

An EF86 pentode as in the Vox AC15: 220 kΩ on the plate, 1 MΩ to the screen. About 45 dB of gain into a 500 kΩ volume, as in the AC15. One tube has as much gain as two triode stages. The plate idles low, near 100 V, and the screen sags when it’s driven hard, so it compresses and breaks up softly. Values for EF86, as in the AC15, EF86, more headroom, EF86, triode-wired or 5879 in the same circuit.

MOSFET booster

A clean booster, one BS170 with feedback bias and a Gain knob, from unity to about 35 dB. In a preamp it runs on its own 9 V supply, like a pedal built into the amp.

Tone stack

The passive treble, middle and bass stack most tube amps have. Once it’s in, pick one of 10 sets of amp values under Values. It starts with the Twin Reverb’s values. Values for Fender AB763 Twin Reverb, Fender AB763 Deluxe Reverb, Fender 5F6-A Bassman, Marshall early, Marshall lead, Vox AC30 Top Boost, Mesa/Boogie Mark IIC+, Soldano SLO-100, Mesa/Boogie Dual Rectifier or Peavey 5150.

Marshall 18 W tone control

The 18 Watt’s single tone control. It has 5 nF from the plate to the output, and a 500 kΩ pot with its wiper grounded between 10 nF and 100 kΩ. In the amp a 500 kΩ volume follows it. After a triode stage, with the knob at its default setting, it drops the level about 3 dB at 100 Hz, 5 dB at 1 kHz and 5 dB at 5 kHz.

Tweed tone and volumes (5E3)

The 5E3 Deluxe’s one tone knob and two volumes, all meeting at the next grid. The signal comes in on the volume’s wiper, and the mic channel’s volume hangs on the output too. After a triode stage, with the knobs at their default settings, it drops the level about 14 dB at 100 Hz and 15 dB from 1 kHz to 5 kHz.

Brownface tone and volume (6G3)

The 6G3 Deluxe’s tone knob wrapped around its volume pot, as one block. Pick the normal or the bright channel under Values. It starts with the normal channel’s values. Values for Fender 6G3 normal channel or Fender 6G3 bright channel.

Treble and bass, no middle

A two-knob treble and bass network with no middle control: 250 pF or 220 pF to the treble pot, 100 kΩ under it, and a bass pot below. Pick the Bandmaster or the Sound City version under Values. It starts with the Bandmaster version. Values for Fender 6G7 Bandmaster or Sound City Lead 105.

Hiwatt tone stack

The DR103’s stack, with separate treble and bass feeds from the plate and a middle pot bridged by 1 nF. In the amp 22 kΩ into a 220 kΩ master follows it. After a triode stage, with the knobs at their default settings, it drops the level about 18 dB at 100 Hz, 17 dB at 1 kHz and 11 dB at 5 kHz.

James bass and treble

The Graphic’s James-type stack: bass and treble that each boost and cut, close to flat with both at noon. In the amp a 1 MΩ volume follows it. After a triode stage, with the knobs at their default settings, it drops the level about 20 dB at 100 Hz, 1 kHz and 5 kHz alike.

Tone network from an amp

The tone controls of an amp on the bench that the other tone blocks don’t cover, part for part. Pick the amp under Values. Values for Ampeg B-12-NC Portaflex (1964), Ampeg B-15-N Portaflex (1968), Ampeg Mercury M-12, acc tone, Ampeg Mercury M-12, inst tone, Ampeg Reverberocket R-12-R-B (1966), Ampeg Rocket R-12-A, Ampeg SVT, Ampeg V-4, Dumble Overdrive Special #102, Dumble Overdrive Special #124 (1984), Dumble Overdrive Special #183, Dumble Steel String Singer #002 (draft drawing), Dumbleland 150 W (Sleepwalk redraw of #009), Fender 5B3 Deluxe, Fender 5C8 Twin, Fender 5D8 Twin, Fender 5E4-A Super, Fender 5E6-A Bassman, Fender 5E7 Bandmaster, Fender 5F11 Vibrolux, Fender 5F2-A Princeton, Fender 5F4 Super, Fender 5F8-A Twin, Fender 6G16 Vibroverb, Fender 6G6-A Bassman, bass bass, Fender 6G6-A Bassman, bass treble, Fender 6G6-A Bassman, normal treble, normal bass, Fender 6G7-A Bandmaster (vibrato channel), Fender 6G8 Twin (vibrato channel), Fender 6G9 Tremolux, Fender 6G9-A Tremolux, Fender AA165 Bassman, Fender AA764 Champ, Fender AB165 Bassman, Fender AB763 Super Reverb, n. treble, n. bass, Fender AB763 Super Reverb, treble, bass, middle, Gibson EH-150 (6SQ7 version), Gibson Falcon (EL84 version), Gibson GA-18T Explorer, Gibson GA-19RVT Falcon, Gibson GA-30RV Invader, Gibson GA-400 Super 400, treble (i), bass (i), volume (i), Gibson GA-400 Super 400, treble (ii), bass (ii), volume (ii), Gibson GA-400 Super 400, treble (iii), bass (iii), volume (iii), Gibson GA-50, bass, Gibson GA-50, volume (instrument), volume (mic), treble, Gibson GA-50T, Gibson GA-75 (1960s), Gibson GA-77 Vanguard, tone (lower), Gibson GA-77 Vanguard, treble, bass, Gibson GA-77RVT Vanguard, treble 1, bass 1, Gibson GA-77RVT Vanguard, treble 2, bass 2, Gibson GA-80 Vari-Tone, Gibson GA-85, bass (i), treble (i), volume (i), Gibson GA-85, bass (ii), volume (ii), Gibson Hawk, Gretsch 6152, Guild Masteramp, Harmony H415, Kalamazoo Model One, Kay 703, Kitty Hawk M1, lead treble, lead bass, lead middle, Kitty Hawk M1, treble, bass, middle, Magnatone 110, Magnatone M10A, Marshall 1959 Super Lead, Marshall 1987 Lead (plexi), Marshall JCM800 1992 Super Bass, Marshall JCM800 2205, lead treble, lead middle, lead bass, Marshall JCM800 2205, normal bass, normal treble, Marshall JTM45, Marshall Silver Jubilee 2550, Redbear MK120, presence, Redbear MK120, treble, bass, middle, Rickenbacker M11, Selmer Constellation 20, Selmer Stadium (TV19/T), Silvertone 1483, Sovtek MIG-100H, Sovtek MIG-50, Sunn Model T, Sunn Sorado (and 200S), Supro S6424, Supro Thunderbolt S6420, Trainwreck Liverpool, Vox AC50 (Mk III or 1965).

RC filter, one pole

One resistor and one cap with a Frequency knob, as a low-pass or a high-pass. Pick the shape under Values. Values for Low-pass or High-pass.

RC filter, two poles

Two RC sections in a row on a dual-gang Frequency pot, as a low-pass or a high-pass. Pick the shape under Values. Values for Low-pass or High-pass.

RLC filter

A resistor, an ideal 500 mH inductor and 100 nF, as a low-pass, high-pass, band-pass or notch at 712 Hz, about where a wah’s inductor sits. A real inductor’s winding resistance lowers the peak. Pick the shape under Values. Values for Low-pass, High-pass, Band-pass or Notch.

Bridged-T mid scoop

Two 10 nF caps in series, a resistor from their junction to ground and 220 kΩ bridging both: a mid notch with no inductor and no loss outside it. The Depth knob moves it from about 1.6 kHz at zero to about 330 Hz at full, getting shallower as it goes down. At noon it sits near 880 Hz. It only reaches full depth with a light load behind it.