Detail 01
Duet
Two tubes, matched to each other. Covers a two-socket power section, or half of a four-socket amp.
Product detailSKU #1274034469315
Groove TubesGold Series GT-E34L-S Matched Power Tubes Medium (4-7 GT Rating) Duet
Independent shopping perspective
The Korena take
Two matched E34L power tubes, an EL34-type octal. For retubing an amp that runs a pair rather than a full quad.
Strong match
Who this is for
- Two-power-tube EL34-class heads and combos
- Replacing a failed pair in a working amp
- Anyone wanting matched tubes instead of two loose singles
Consider the trade-offs
When to look elsewhere
- Four-tube amps — one duet only covers half
- Amps built around EL84, 6L6 or 6V6
- Preamp positions; these are output tubes
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
E34L type
Octal EL34-family power tube. Drops into EL34 sockets, so the amp's tube layout decides whether this fits.
Detail 03
Matched pair
Both tubes pull similar current, which keeps the two sides of a push-pull output stage even.
Detail 04
Medium, 4-7 GT rating
Groove Tubes' middle band on their own soft-to-stiff scale. Note it so you can reorder the same feel.
Detail 05
Made in Slovakia
One production source for both tubes in the set, rather than pairing from different factories.
Detail 06
$84 for two
About $42 a tube. Retubing a four-socket amp with two duets runs roughly double that.
Final check
Know before you order
- 01Most EL34-class amps are fixed-bias — budget for a bias adjustment by a tech
- 02Two duets are not matched to each other; order a quartet for a four-tube amp
- 03No preamp tubes in the box; this covers the power section only
Product questions
Before you decide
Straight answers to the questions shoppers most often ask about this product.
01Will these work in my EL34 amp?
E34L is an EL34-type octal tube and uses the same socket. Confirm your amp's spec calls for EL34 rather than 6L6 or 6CA7 before ordering.
02Can I buy two duets for a four-tube amp?
You can, but the two pairs are not matched to each other. A matched quartet is the better choice for a four-socket power section.
03Do these need biasing?
Fixed-bias amps need the bias set after any power tube change. Skipping it can run the tubes hot and shorten their life.
04What is the 4-7 GT rating?
Groove Tubes' own scale describing where the tube falls in their range. Medium sits in the middle. It helps you match future replacements.
Reference
Full specifications
The complete catalog record, organized around the decisions musicians make when comparing gear.
2 detailsBody & build
- Color
- Gold
- Country of Origin
- Slovakia
