The E7→A7 vamp, built from the inside out. The upper-structure triads that live inside each chord — the ones made of the guide tones and tensions we mapped — plus playable riffs that turn the theory into music. The tritone guide-tone slide is the hero: once you feel it, the whole change plays itself.
The two notes that define each dominant chord are the 3rd and the ♭7 — the guide tones. They sit a tritone apart. Here's the magic of E7→A7: both guide tones resolve down a single semitone into the next chord.
E7's 3rd (G♯) drops to A7's ♭7 (G). E7's ♭7 (D) drops to A7's 3rd (C♯). The 3rd of one chord becomes the ♭7 of the next, and vice versa. So the entire tritone shape just slides down one fret. This is the smoothest voice-leading in music, and it's the sound of every dominant resolution ever played.
Play the E7 tritone (G♯ on the G string, D on the B string). When the A7 arrives, slide both down one fret to G and C♯. That's it. Two notes, one slide, and you've spelled the entire chord change. Everything else in this session is decoration on top of this.
E7 (G♯+D) A7 (G+C♯)
e|--------------------|--------------------|
B|--3-----3-----3------|--2-----2-----2------| D → C♯ (down 1)
G|--1-----1-----1------|--0-----0-----0------| G♯ → G (down 1)
D|--------------------|--------------------|
A|--------------------|--------------------|
E|--0-----0-----0-----|--0-----0-----0-----| (opt. low root drone)
the tritone shape slides down ONE fret — that's the change
TARGET · feel the two-note slide as the sound of the change · add the low root drone underneath for weight
Four triads live inside (and just above) E7. Each is a real major or minor triad you already know, but played over the E7 it becomes an upper structure — a slice of the chord's colour. All shown on the top three strings (G, B, e).
The plain triad. Root, third, fifth — home base, the safest sound over E7.
The diminished triad from the 3rd = both guide tones plus the 5th. This IS E7 with no root — pure defining colour. The money triad.
The minor triad from the 5th adds the 9th (F♯). Play Bm over E7 and you get the lush E9 sound. One note off the G♯dim.
The major triad from the 9th = 9, ♯11, 13 — the whole upper structure. This is the E7♯11 / Lydian dominant float. Pure spice.
The exact same four recipes, moved to the A7 root. Same shapes and logic — major from the root, diminished from the 3rd, minor from the 5th, major from the 9th. Prove the system by watching it transfer.
Root, third, fifth. Home base over A7 — the safest sound when the chord changes.
Diminished from the 3rd = A7's guide tones plus the 5th. Rootless A7. Note its guide tones (C♯, G) are the E7 guide tones (G♯, D) each moved down a semitone.
Minor from the 5th adds the 9th (B). Em over A7 = the A9 sound — and it's the open top-three-string shape, dead easy.
Major from the 9th = 9, ♯11, 13 — the A7♯11 Lydian dominant upper structure. The spicy option over A7.
Notice you built eight triads from four recipes. Major-from-root, diminished-from-3rd, minor-from-5th, major-from-9th — apply to E, apply to A, done. This is the chord-building logic from Session 14 in action: the recipe moves, the shapes are consequences. Learn the four recipes and you have upper structures for every dominant chord in every key.
Now turn the triads into music. Six riffs for the E7→A7 loop, each built from the material above. Loop the vamp, learn one at a time, record the lot.
The simplest melodic use of the triads: arpeggiate E major over E7, A major over A7. Every note is a chord tone, so it sounds instantly "right." The two arpeggios share the note E — let it be the pivot between them.
E7 (E maj) A7 (A maj)
e|--0---------------|--0---------------|
B|------0-----------|------2-----------|
G|----------1-------|----------2-------|
E B G♯ E C♯ A
TARGET · smooth arpeggios, notes ringing into each other · hear E as the pivot note
Play B minor over E7 and E minor over A7. Both add the 9th, giving a fuller, jazzier sound than the plain triads. This is the E9 → A9 move — the sound of soul and fusion rhythm guitar.
E7 (Bm = E9) A7 (Em = A9)
e|--2---------------|--3---------------|
B|------3-----------|------5-----------|
G|----------4-------|----------4-------|
F♯ D B G E B
(9 ♭7 5) (♭7 5 9)
TARGET · the added 9th should sound like colour, not a wrong note · keep it smooth
The diminished triads are E7 and A7 stripped to their essence — the two guide tones plus the fifth, no root getting in the way. Comp with these and a bassist fills in the roots; you supply the pure defining colour.
E7 (G♯dim) A7 (C♯dim)
e|--4---------------|--3---------------|
B|------3-----------|------5-----------|
G|----------4-------|----------6-------|
G♯ D B G E C♯
(3 ♭7 5) (♭7 5 3)
TARGET · these are rootless dominants — hear how complete they sound without the root
The Safe Zone scale from The Trip, run up one octave. Because every note is a chord tone of E7 or A7, this exact run works over either chord — play it over E7, play it again over A7, it fits both. The built-in G/G♯ pair is the blues rub.
(works over E7 AND A7 — same notes both bars)
e|----------------------------------|
B|----------------------------------|
G|----------------------------------|
D|--------------------0---2---------| D E
A|--------0---2---4-------------| A B C♯
E|--0-3-4---------------------| E G G♯
E G G♯ A B C♯ D E ← the safe skeleton, one octave
TARGET · memorise this shape — it's your "never wrong" fallback for the whole vamp
The spicy option — major triads a whole step above each root give the Lydian dominant colour (9, ♯11, 13). Beautiful but tense. Resolve it: after the F♯ triad, drop the top note (F♯) down to E, a chord tone. Spice, then home.
E7 (F♯ maj) A7 (B maj) resolve
e|--2-----------0--|--2---------------|
B|------2-----------|------4-----------|
G|----------3-------|----------4-------|
F♯ C♯ A♯ E→ F♯ D♯ B
(9 13 ♯11) resolve (9 ♯11 13)
TARGET · reach for the spice, then resolve the ♯11/9 down to a chord tone · tension then release
The exam. Open with the guide-tone tritone (Riff 1), tag the major triad arpeggio (Riff 2), and when the change comes, slide the tritone down and land on a guide tone. This is the vocabulary as one continuous idea.
E7 A7
e|------------0-------|--------------------|
B|--3-----3----0------|--2--------2\--------|
G|--1-----1----1------|--0--------0---------|
D|-------------------|--------------------|
tritone arp E maj tritone slides down,
(G♯+D) (E B G♯) lands on A7 guide tones (G+C♯)
TARGET · one flowing phrase, no seams · the slide into A7 is the payoff · record it
Broadcast low gain, 9 o'clock. Triads want clarity — you're playing three notes and every one needs to speak. The germanium adds warmth without smearing the intervals. Roll the neck pickup in for the round fusion comp tone, bridge for more bite on the spicy upper structures.
Broadcast noon for the single-note riffs (2, 5, 7) — a touch more grit for sustain and vocal quality on the slides. The tritone slide (Riff 1) especially wants the wet Mesa up: the two notes sustaining through the BigSky while they slide is the sound. Keep the dry Badger present for the pick attack.
These triads and riffs are built from The Trip (Session 12) — the Safe Zone scale (Riff 5), the guide tones from the Spice Map, and the chord-building logic from Session 14. The upper-structure triads are the chord recipes stacked and voiced. It's all one system.