Amplifier Tube (T-KT77-JJ-MP)

I bought these to replace the power amp tubes in my Marshall Guitar amplifier. The amp came stock with four EL34 Winged C tubes. I put in a set of JJ EL34 tubes and it "freshened up" the amps tone. I then put these KT77's in and the amp just came alive. It's not that the EL34's sound bad, they sound great. But the KT77's sound better, at least to my ears. The bottom end is tighter, the mids are more punchy and the highs are smoother. It sounds like these tubes shifted the overall sound up in the frequency range a little.The price was reasonable and the shipping was super fast. Would buy these again from this seller in a heartbeat.

I read in several message boards that KT77’s are a great “drop-in replacement” for EL34’s in Guitar amplifiers because they sound like “HD”.While they did seem to lend themselves well to the clean channel on my amplifier (Carvin V3), they made the gain channels sound fizzy. The Mids and Highs were simply too bright and no amount of tweaking the tone stack seemed to help.I took it to my local amp tech and he rebiased the amp for the tubes and it still didn’t help. He told me that KT’s are great for HiFi systems, but rarely seem to translate well in a guitar amp.JJ’s makes a great Tube. They functioned exactly as they should have, but ultimately I swapped back to EL34’s and have learned my lesson about these alleged “Drop-in” replacements.They might work great if you don’t use high gain amps and choose to get your drive from pedals, but they don’t seem to play well with amp gain.

This tubes really surprised me. I was not expecting them to sound as good as they do. I compared the JJ KT77 with Gold Lion KT66, winged =C= 6L6GC, and Tung Sol 7581A (really great tubes also) in my VTA ST 70 HI-FI amp and the JJ's are my favourite. Also the Apex matching and burn in process used by this seller is really good! You pretty much get the best set of tubes you can possibly get, for more info go to their site. I'm very happy with this tubes and I will be purchasing more in the future.

Perfect for my JCM 2000 DSL

These went in a 1987 Marshall Silver Jubilee. I really wanted a bigger more glassy sound than I was getting with EL34 tubes. 6550 would have been my first choice, however since they're 35w tubes they would require modifications to the bias circuitry. These were described to me as the closest you could get and stay 25w. They sound amazing! Extended eq range, especially on the low end. And has that bigger glassy tube sound I was looking for. I'm definitely sticking with these now.

one tube was bad

Best sounding EL34 compatible tube I've found yet. Has tighter bass and more airy sounding high frequencies than the EL34's and 6CA&'s I have tried (New tubes, not old stock). My JJ KT77's didn't last as long as the Shuguang EL34's I have used several times, but the JJ's sound better in the TAD-60 amp I was using them in. Guess you can't have it all. I gave it four stars because of questionable long term endurance. Sound quality is five star performance.

Apex Matched Quad purchased from AmplifiedParts via Amazon. AmplifiedParts is the sister company to Antique Electronics Supply (tubesandmore.com). They were running a discount on Apex Matched tubes, so I picked up a pair to compare with my Tung-Sol KT120 in a Hi-Fi amp. Rich, smooth, warm sound with a slightly narrow but deep sound stage. Bass has some bloom and high frequencies have a noticeable sparkle.