The TCguitar blog

Field notes, comparisons, and real bench-tested research.

Four new posts a week on dating, identifying, maintaining, and understanding vintage Fender tube amps — built on the foundation of the original 1997–2000 Gagliano research and decades of community knowledge.

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Fender Pro Junior IV and Blues Junior IV amplifiers side-by-side catalog illustration
Comparisons

Fender Pro Junior vs Blues Junior: Same Wattage, Different Voicing

You’re standing in a guitar shop with a budget around $600 and two amps on the floor in front of you. One is small, black, almost alarmingly simple.…

August 15, 2026 · 15 min read
ecc83 vs 12ax7 overview diagram
Tubes

ECC83 vs 12AX7: Same Tube, Different Name, or Real Difference?

You can drop an ECC83 into any socket that calls for a 12AX7, and vice versa, without touching a single solder joint. The tube is the same. The…

August 13, 2026 · 14 min read
12AX7 and 12AU7 dual-triode tubes side-by-side comparison
Tubes

12AU7 vs 12AX7: Gain Differences in Preamp Tube Substitution

That roughly six-to-one gain ratio is the whole story in miniature. Both tubes slot into the same Noval socket. The heater current is identical. But the circuits around…

August 12, 2026 · 17 min read
Fender Hot Rod Deluxe and Blues Deluxe 40-watt combo amplifiers front view
Comparisons

Hot Rod Deluxe vs Blues Deluxe: Twin Brothers, Different Eras

Both amps share the same chassis, the same output section, the same series effects loop, and the same basic signal architecture. What separates them sits in the preamp:…

August 9, 2026 · 14 min read
5881 and 6L6GC power tubes side-by-side octal beam tetrodes
Tubes

5881 vs 6L6: The Military-Spec Tube’s Second Life in Guitar Amps

Most forums will tell you the 5881 and 6L6 are the same tube with a different label. That’s wrong. Close, but wrong. The distinction matters the moment you…

August 7, 2026 · 14 min read
EL84 and EL34 power tubes side-by-side size comparison illustration
Tubes

EL84 vs EL34: Smaller British Class-A vs Bigger British Class-AB

Most players assume the EL84 and EL34 are just different wattage versions of the same British sound. They’re not. The wattage difference is real, but it’s the operating…

August 5, 2026 · 19 min read
6V6GT and 6L6GC vacuum tubes side-by-side comparison Fender amplifiers
Tubes

6V6 vs 6L6: The Two Power Tubes at the Heart of Fender’s Lineup

You’re standing in a music store comparing a Princeton Reverb and a Twin Reverb. Same brand, same reverb tank, same basic circuit topology, but they don’t sound remotely…

August 4, 2026 · 15 min read
12AT7 and 12AX7 dual-triode preamp tubes side-by-side catalog illustration
Tubes

12AT7 vs 12AX7: When to Use Which Preamp Tube and Why

That mu difference gets quoted everywhere. The plate resistance difference almost never does, and it’s the number that actually explains why you can’t just swap these two tubes…

August 2, 2026 · 17 min read
fender deluxe reverb 65 reissue and 68 custom side-by-side vintage amplifier illustration
Comparisons

Fender Deluxe Reverb ’65 vs ’68 Custom: Reissue Comparison

This guide covers the circuit differences, full specs, tonal character, controls, pedal platform behavior, and recording considerations so you can make the right call the first time. Quick…

July 30, 2026 · 17 min read
blackface fender deluxe reverb aa763 and twin reverb ab763 front panel comparison
Comparisons

Deluxe Reverb vs Twin Reverb: 22W vs 85W and What That Really Means

Blackface Deluxe Reverb (left) and Twin Reverb (right) showing relative cabinet size, speaker configuration, and control layout differences. Quick Specs Comparison, Deluxe Reverb vs Twin Reverb Before getting…

July 29, 2026 · 13 min read
vintage fender princeton reverb deluxe reverb blackface amplifiers side by side
Comparisons

Princeton Reverb vs Deluxe Reverb: Which Blackface Belongs in Your Studio?

Quick Reference: Princeton Reverb vs Deluxe Reverb at a Glance Princeton Reverb: AA1164 circuit, ~12–15W, 2x 6V6GT, 5U4GB rectifier, 10″ speaker, ~26 lbs Deluxe Reverb: AA763/AB763 circuit, ~22W,…

July 26, 2026 · 18 min read
6L6 and EL34 power tubes side-by-side vintage amplifier comparison
Tubes

6L6 vs EL34: The American vs British Tube Tone War Explained

Two tubes. Two continents. Decades of argument. The 6L6 versus EL34 debate runs through every corner of guitar culture, from the blackface Fender Twin Reverb to the Marshall…

July 25, 2026 · 16 min read