17 Reviews

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USD $‎25.95
The JJ KT77 is an alternative to the common EL34 tube.

From our review: "Overall a nice balance of tone in bass, midrange and treble. The breakup is earlier than a 6L6 with more compression but not as compressed as the EL34. If you have a Marshall amp and find EL34’s too compressed and 6550’s too crunchy the JJ KT77 may be just the ticket."

The now rare KT77 tube was introduced by MO-Valve in the late 1950's and has recently been brought back by JJ. They use the same base and biasing as any EL34 tube so they are a great option for substitution in any EL34 amp.

If you are curious about how these fare in a hifi stereo amplifier be sure to read the Wall of Sound EL34 tube comparison for details.

Other JJ Electronics tubesEL34 Tube Types

Additional Information and Downloads

EL34 Tube Review for Guitar Amplifiers
EL34 Tube Review for HiFi Audio

Tube Matching Information:
Power Tube Matching FAQ
Perfect Pair System

JJ KT77 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

17 reviews

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Good Sounding Tubes


Stronger, tighter bass than an EL34 with nicer highs. A bit more tone all around, like others have mentioned a little like a 6L6. I had one develop a bad hiss after a month even though it had been biased correctly. I was told they have a 3% failure rate I was just unlucky. The Tube Store replaced it no problem. Good tubes, good vendor.

Highly Recommended


Tried a pair of these based on the few good reviews at the time. I've been using a pair of these in my Musical Paradise 301 amp for about 6 - 9 months now. I'm very pleased with these, and have stopped rolling tubes. I've found these much more musical overall than the various 6L6 tubes I've tried. Better clarity and depth for the highs, mids, and boy do they produce bass on the little amp. Give these a try, I think you'll like them. They seem to be very reliable so far, many hours on these. And The Tube Store provides very good service.

Very Good Sounding JJ KT77


If you like the sound of the JJ EL34, the KT77 has more headroom and bass than a standard EL34.My Audio Innovations Series 800 SE power amplifier came alive with new life.And The Tube Store provides very good service.Thank you very much.

Great tubes


I bought a pair of these to replace the stock EL34's in my Blackstar HT-50, and they really brought the amp to life. Definitely more crunchy and articulate, with better clarity and rich tones. Very satisfied.

Great tube


What a difference these made to my Jolida 202A. So much better than the original EL34's. Mushy bass is gone. Beautiful highs. My amp used to distort at higher volume. Now it stays clean and clear.