Genalex - Gold Lion KT66 Power Vacuum Tube (Matched)

12 Reviews

Availability: Usually ships within 24 hours.

USD $‎71.95

Need matched power tubes? Don't worry! Price includes matching in any quantity you need for no extra charge. Need a matched pair? Just order "2" tubes. For a matched quad order "4" tubes. Matched sextets and octets are available as well.

From our reviews ... "At low to moderate volumes you get a big open sound across the guitar spectrum. Very articulate with little compression, excellent touch response and dynamics."

The Gold Lion KT66 power tube is a reissue tube that is made in Russia. From the manufacturer, "Exact copy of the original clear glass KT66 vacuum tube. The tube that created "The Bluesbreaker Tone". Used in 50's - 60's hi-fi favorites such as the Heathkit W-5M and many Leak amplifiers."

Other Genalex - Gold Lion tubesKT66 Tube Types

Additional Information and Downloads

KT66 Tube Review

Tube Matching Information:
Power Tube Matching FAQ
Perfect Pair System

Genalex - Gold Lion KT66 Datasheet (PDF)

Download Adobe Acrobat PDF reader

Warranty Information and Return Policy

Warranty Period: 3 months

All our tubes are guaranteed for 3 months from the date of purchase. (Any exceptions will be noted on that tube's Warranty tab)

If you receive a tube that does not perform to the manufacturer's specifications, please do the following:

- contact us to get a return authorization
- return it via regular mail within 90 days from when we shipped it, and we will provide an exchange or refund of the full purchase price of the tube.

Returns not related to warranty or defect will be considered at our discretion, and are subject to a 15% restocking fee.

We can not accept returns that don't have an authorization, are past 3 month, or are returned improperly.

These guidelines may be updated without notice.

Ratings & Reviews

12 reviews

GENALEX - GOLD LION KT66 | They are awesome.

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These GL-KT66 are awesome. Full with really good midrange which is the best improvement. Higher range is more detailed. What I hear now is music that is completely balanced. It’s big and fat and detailed; it sounds right. This is definitely the right tube for my PrimaLuna Dialogue HP amp.

Genalex - Gold Lion KT66 | Nice Compliment!

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Purchased a matched pair of these GL-KT66's for my Space Tech Labs preamplifier. The more I listen the better they sound. They sound exactly like the description in my system. Definitely looking forward to them as they mature. A great sonic value!

Genalex - Gold Lion KT66 | These Kick Arse


I have a 1960 brown Fender Deluxe. I was gifted a `62 brown Tremolux output tranny which I installed in my Deluxe! I put the Genalex GL-KT66's in this amp and it sounds huge! I was never a fan of 6V6's... I do have about 12 sets of original M.O.Valve/Genalex and these new ones actually have a little bit more clarity on the highs! They standup against the originals in ever aspect. I've used original KT66's for over 30 years in some of my Marshall's and I have to say these are just as good, especially when my amps are on 8 or 9 and being brutally punished by old Gibson PAF's and early Pat.#'s! I have two Marshall Astoria Custom's and side by side the New Genalex hold up against the originals in nearly every aspect and sound great in my Hand built Marshall Bluesbreaker combo!

Genalex - Gold Lion KT66 | One of my favorites


I’ve been using these GL-KT66 tubes for a while. First time I tried them was on an amp I built based on a Marshall jcm800. I replaced a pair of el34’s and I liked them so much more that I’ve tried them on other amps. I like them more than el34’s, 6L6’s, 7581A’s, KT88’s and all other similar to mentioned on must cases. They sound big and full, punchy, clear, defined, articulate. Bottom end is deep and beautiful, mid is very present but not humpy as el34’s and the top end is clear and sweet. What i like most about these tubes is the harmonic complexity. They sound so rich and alive. I love them.

Genalex - Gold Lion KT66 | Reissue Not Worth the Money


Ran 8 of these Genalex GL-KT66 in new Mono Block amps. Burned in for 120 hours. Sound was decent, but not as precise as vintage Made in England tubes. After cool down..I saw that the glass envelope has spider web cracks in it. It is now garbage. No obvious reason for this that I can see. I would not buy these tubes again.