Detail 01
Matched quartet
Four tubes selected to draw similar current. Keeps the push-pull sections balanced and reduces hum and uneven wear.
Product detailSKU #1274034486315
Tung-Sol6L6GC STR Matched Power Tubes Medium Quartet
Independent shopping perspective
The Korena take
A matched quartet of 6L6GC power tubes at medium bias rating. For retubing a four-power-tube amp built around 6L6s.
Strong match
Who this is for
- Retubing a four-6L6 amp that has gone weak or muddy
- Amps needing all four power tubes replaced as a set
- Replacing a failed tube where the rest are also worn
Consider the trade-offs
When to look elsewhere
- Amps using EL34, EL84 or 6V6 power tubes
- Anyone who cannot bias an amp or pay a tech to do it
- Replacing a single tube — this is a four-tube set
What matters in use
The specifications, translated
Catalog numbers tell only part of the story. These are the details most likely to change how this product feels, sounds, or fits into a setup.
Detail 02
6L6GC
The higher-plate-voltage version of the 6L6. Firm low end and late breakup — the classic American clean platform.
Detail 03
STR
Special Tube Request — built to a tighter spec than a standard production run of the same tube.
Detail 04
Medium rating
Middle of the current-draw range. Sits between low-draw sets that stay clean and high-draw sets that push harder.
Detail 05
Four tubes
For 100-watt-class amps with four power sockets. A two-tube amp only needs a matched pair.
Final check
Know before you order
- 01Power tubes require bias adjustment after install — budget for a tech if unsure
- 02Replace all four together; mixing old and new unbalances the set
- 03Check whether your amp is fixed-bias or cathode-biased before ordering
Product questions
Before you decide
Straight answers to the questions shoppers most often ask about this product.
01Do I have to bias these?
Yes, on a fixed-bias amp. Incorrect bias can run tubes too hot and shorten their life or damage the amp. Cathode-biased amps self-adjust.
02Can I put these in an EL34 amp?
Not without modification. EL34 and 6L6 have different socket wiring and bias requirements. Some amps have a switch for this — check yours.
03What does the medium rating change?
It sets where the tubes fall on the current-draw scale. It affects bias setpoint and how early the amp pushes into power tube saturation.
04Will this fix my amp's noise problem?
Only if the power tubes are the cause. Hiss, crackle and squeal more often come from preamp tubes. Diagnose before buying a full quartet.
