Category Archives: Gear

Gear, Music, Poetry, Repair

Reviving a Vintage Tone Monster:

the Legendary Supro 1616T


After years of soul-stirring service, my Airline 62-9029a (also known as the Supro 1616T and Gretsch G6151) suddenly developed volume fluctuations, low output, and a non-functional tremolo.

Troubleshooting

Initial Checks

  • Tube tester gave all tubes a clean bill of health.
  • Swapped tubes with known good ones, but issues persisted.

Deep Dive

  • Visually inspected the amp’s interior for broken joints, burned resistors, or obvious faults.
  • Performed the chopstick test to detect loose solder joints.
Airline 62-9029a Internal Guts point to point wiring
It’s a wild ride inside this amp. Wires everywhere!

The Culprit?

Electrolytic Capacitors

Original electrolytic capacitors were long overdue for replacement! Before tackling that, I:

  • Safely drained DC voltages through preamp tube 1.
  • Verified zero stored voltage.

Time to replace those expired capacitors and breathe new life into this vintage gem!

Electrolytic Capacitor Replacement

Out went the original can capacitor; in came individual:

  • 10uF/450V
  • 10uF/450V
  • 22uF/450V (replacing 20uF/450V)
  • These are tucked in the corner of the amp on point to point posts.
  • I give them added stability by using Permatex RTV to hold them, so they don’t move or rattle. The amp is a studio amp so it shouldn’t be taking too much of a beating.
Airline 62-9029a New Electrolytic Capacitors tucked in corner
New electrolytic capacitors safely tucked in the corner.

Tremolo Circuit Repair

  • The voltage dropping 6.8K resistor (at 20uf/450 capacitor) was charred and broken, showing infinite resistance. Replaced with 1W metal film 6.8K resistor.
  • Visually inspected the other resistors and capacitors in the circuit, and they all look good.
Broken resistor causing tremolo of Supro 1616T to stop working.
Broken resistor causing tremolo to stop working.

Back to Life!

I prioritized only the essential repairs to maintain the amp’s original character. and tone. After the above repairs, the volume’s consistent and loud; tremolo’s working beautifully! Time to make some soul music!

Future To-Dos:

  • Replace older 35uF/50V electrolytic cathode bypass cap (12AX7)
  • The 330 ohm 2 watt cathode resistor (6v6) looks like it has taken some heat over the years. It measures 356 ohms and is working fine, but should be replaced at some point for longevity.
330 ohm 2 watt carbon comp cathode resistor looks like it has taken some heat over the years.
Future to-do: Swap heat-stressed 330ohm/2W carbon comp cathode resistor (6V6)

Patina & Soul

This vintage gem’s got character. Beautiful patina on the amp, and it smells like an old smoky bar. Full of history and expression. She’s beautiful from years of creation!

Soulful Musings

“This old amp, it’s got stories to tell.
Soulful, like Jimi’s rhythm hand.
Gritty, funky, and worn.
The slow pulsing heartbeat of the tremolo.
Deep breaths of late-night smoke,
sweat and whiskey-tinged t-shirts
untucked on the verge of distortion
Echoes of Bob, Al, Clarence, and Cody
Whispering melodic secrets
to anyone who has a spare moment to listen.”



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