JJ KT77

Escott1377 · « **on:** 29 Apr 2016, 12:17 pm »

Anyone have experience with this tube? I have read good reviews in regards to performance, however quality seems to be an issue. Talking to Tube Depot, JJ has supposedly improved their quality standards.

For reference, I run a bi amp set up w/ a pair of Prima Luna Dialogue 6 mono blocs on the mids / tweets. I currently am using KT 88's, but own a pair of the New Sensor NOS Russian subs for the 6L6.

I am also considering the EH KT90 and Tung Sol EL34B.

My musical tastes run from classical to 60's rock and anything in between, however I rarely push my amps past a quarter turn on my pre.

Thanks in advance -

rotarius · « **Reply #1 on:** 29 Apr 2016, 01:52 pm »

I think you should be fine with JJ tubes that are burned in and properly selected. Quality is still a concern as far as I can tell. I got a quad of JJ 6CA7 that were Apex matched and all that but they all had a rattle which does not inspire a lot of confidence. They sound GREAT though!! One of the best sounding current production tubes imo. I did not care for the Tungsol EL34B, mids were lacklustre, nice bass though.

Escott1377 · « **Reply #2 on:** 29 Apr 2016, 02:32 pm »

It's tough reading thru reviews regarding performance since I do have a bi amp set up and bass is not really a concern.

The JJ's are cheap, I will give them a try.

Thanks -

datman · « **Reply #3 on:** 29 Apr 2016, 03:32 pm »

I am using the JJ's in a custom KT77 amp built by Dennis Had of Cary Audio fame. The JJ's are much better than the Gold Lion Reissues.

The JJ's have delicate, detailed and correctly sized midrange with clean extension at the extremes. They actually sound better than the NOS M-O KT77's that I have to compare them to. They are a really sleeper tube and at $35/pair, a total steal.

I purchased mine from The Tube Store in Canada and have had no problems with them or the tubes they supply.

trackball02 · « **Reply #4 on:** 29 Apr 2016, 04:32 pm »

I purchased a quad set of JJ6CA7 3 years ago, which I assume is kind of similar to the KT77.
1 tube failed within one month, and was replaced under warranty. Two tubes failed after 9 months, out of warranty. Unreliable product. The JJs sounded fine when working, but not worth the hassles and dollars.

I switched to Gold Lion KT77, and have not had any problems.

Escott1377 · « **Reply #5 on:** 29 Apr 2016, 04:42 pm »

Quote from: trackball02 on 29 Apr 2016, 04:32 pm

I purchased a quad set of JJ6CA7 3 years ago, which I assume is kind of similar to the KT77.
1 tube failed within one month, and was replaced under warranty. Two tubes failed after 9 months, out of warranty. Unreliable product. The JJs sounded fine when working, but not worth the hassles and dollars.

I switched to Gold Lion KT77, and have not had any problems.

Thanks for the info. I have been told specifically that quality control has improved since the time frame you referenced. I'll be the guinea pig I suppose...

FullRangeMan · « **Reply #6 on:** 29 Apr 2016, 05:44 pm »

Quote from: Escott1377 on 29 Apr 2016, 12:17 pm

For reference, I run a bi amp set up w/ a pair of Prima Luna Dialogue 6 mono blocs on the mids / tweets. I currently am using KT 88's, but own a pair of the New Sensor NOS Russian subs for the 6L6.

I am also considering the EH KT90 and Tung Sol EL34B.

If you are running KT88 you are very well deserved, mainly w/Gold Lion, KT90 are only more power, harmonic content are poor, 6L6 are irrelevant in SQ over the KT88.

rotarius · « **Reply #7 on:** 29 Apr 2016, 06:15 pm »

Quote from: Escott1377 on 29 Apr 2016, 04:42 pm

Thanks for the info. I have been told specifically that quality control has improved since the time frame you referenced. I'll be the guinea pig I suppose...

FYI, my JJ 6ca7 were purchased a few months ago.

Escott1377 · « **Reply #8 on:** 29 Apr 2016, 06:18 pm »

Quote from: rotarius on 29 Apr 2016, 06:15 pm

FYI, my JJ 6ca7 were purchased a few months ago.

I was responding to the post regarding a past purchase of KT77.

The JJ's are so cheap that if 1 fails after its 30 day, I can replace it. I've been thinking of pulling the trigger for a while on these. Thanks!

Captainhemo · « **Reply #9 on:** 30 Apr 2016, 06:59 am »

I bought a quad of the JJ KT77's form John at The Tube Store as well after he assured me the QC issues had pretty much been resolved. They give you 90 days warranty.

Pretty good sounding tubes especailly considering the price. As posted above, very extended at both ends with lots of detail.

I also ran a set of Canada Fuller EL34G's (OEM'd by Shuguang) that I bought from Parts Connexion back when they stocked them. These were a better souinding tube, best EL34 family tube I've heard but they were approx 3 x the cost. Chris at PC told me he could still supply them but he'd have to bring them in, I am not sure if he'd still offer teh 1 year full warranty or not. On top of them sounding great (tighter bas, richer mids, and just as clean and extended highs), they are one gorgeous tube !

I racked up a lot of hrs on these tubes and they sounded as good as new when I sold the amp
jay

Escott1377 · « **Reply #10 on:** 30 Apr 2016, 04:44 pm »

I pulled the trigger on these. If anyone is interested, Tube Depot is running a 20% discount right now on all JJ tubes and they match for free.

Octet ran me a whopping $125 with free shipping - less than a nice dinner out with the wife.

avahifi · « **Reply #11 on:** 30 Apr 2016, 05:01 pm »

I tried the JJ KT77 tubes a few years ago and found unfortunately had smaller diameter tube socket pins than normal. This caused intermittent connections in the power amplifier.

If someone can assure me that this issue has been fixed, I will try them again.

I still can't recommend JJ 5AR4 tubes, too many failures.

By the way, a forward biased 1N4007 diode in series with each power transformer HV secondary lead to the 5AR4 socket will extend that tube's service life.

Frank Van Alstine

rlee8394 · « **Reply #12 on:** 30 Apr 2016, 08:30 pm »

I understand that the small diameter pin issue was solved a couple of years ago. I just ordered a quad of the JJ KT77 last night. Frank, I'll let you know how they fair in the U70.

Ron

Captainhemo · « **Reply #13 on:** 1 May 2016, 08:35 pm »

Quote from: rlee8394 on 30 Apr 2016, 08:30 pm

I understand that the small diameter pin issue was solved a couple of years ago. I just ordered a quad of the JJ KT77 last night. Frank, I'll let you know how they fair in the U70.

Ron

I was told the same thing , when I got mine about a yr ago there were no issues with the pins or anything else for that matter.

jay

rlee8394 · « **Reply #14 on:** 6 May 2016, 03:50 am »

The JJ KT77s showed up today. The pins are the same size as the EH 6CA7 tube give or take 0.001" or so. JJ seems to have remedied the thin pin issue. They fit snug in both vintage and modern ceramic octal sockets. Been listening for a couple of hours in an Audio by Van Alstine Ultra 70. Initial results are quite positive. Well controlled low bass, great midrange, and extended highs. All of the attributes that you've heard about this tube. I'll continue to listen throughout the weekend to allow for break-in and see how they fair. If they end up reliable over the long run, I'd say that they're a keeper. Don't know how they would compare to NOS or the new Russian Gold Lion KT77, but for the money, a great tube and tremendous value IMHO. Give 'em a try.

Ron

Wind Chaser · « **Reply #15 on:** 6 May 2016, 05:05 am »

Quote from: trackball02 on 29 Apr 2016, 04:32 pm

I purchased a quad set of JJ6CA7 3 years ago, which I assume is kind of similar to the KT77.
1 tube failed within one month, and was replaced under warranty. Two tubes failed after 9 months, out of warranty. Unreliable product. The JJs sounded fine when working...

I switched to Gold Lion KT77, and have not had any problems.

Tim Smith at 6 Moons concurs with the above. He says the hype surrounding the Gold Lion KT-77 "is well deserved... It is fast and capable of turning on a dime but is also super quiet—quieter than the coated Shuguang black bottles that rattle for several minutes upon start up—and therefore it shocks with its ability to sort out the highest highs and lowest lows in the blink of an eye."

Escott1377 · « **Reply #16 on:** 6 May 2016, 11:01 am »

My octet showed up yesterday as well. I only had time to listen to the new Bill Evans release. For my purpose, they sit to fit well in between the KT88 and 6L6 that I have to compare.

I have the ability to switch from UL to triode on my mono blocs, triode seemed a little muddled to me, but again, I have not given them fair time yet.

I paid less than $130 for 8 tubes, that's a deal that is hard to pass up.

ASMAN · « **Reply #17 on:** 6 May 2016, 01:28 pm »

I bought a quad of JJ's for my Cary SLI-80. I don't remember where I got them. I was not impressed. I was (and am currently) using TS KT120's. Maybe I will try them again giving them longer to break in.
I don't think it necessarily the JJ brand but KT77's in general that I didn't like. No balls like the KT120 tubes. Frequency extremes seemed dull and lifeless.
Just my take on KT77's.

Escott1377 · « **Reply #18 on:** 6 May 2016, 01:48 pm »

You have to remember though from my original post that's these are feeding tweeters / mids so power is not what's I am after. I want a nice top end and great mid range, all of which I have read are attributes to the 77. I've got 400 W SS going into a 4 ohm load on my woofers.

richidoo · « **Reply #19 on:** 6 May 2016, 05:02 pm »

I tried matched octet of them in Manley Snappers about 6 years ago, based on hype I read on asylum or somewhere. This was after the undersized pins issue was resolved. I, too, was not impressed. Actually, they were the worst EL34 type tubes I've ever heard. At that time my favorite EL34 type was Groove Tubes E34Ls, a copy of old GE tube, mfg for GT by JJ, but they messed up a batch and there was nothing as good on the market so I sold the amps. Don't know if they ever fixed the GTs. Today I'd try Gold Lion KT77 first.