Author Topic: JJ EL34s?  (Read 7699 times)

Offline richidoo

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JJ EL34s?
« on: April 02, 2007, 12:30:52 PM »
Mike L,
Did you ever get the JJEL34s worked out for your new amps? Since your last post about them I have bought new amps which use EL34, so I am starting to develop nevosa about the stock tubes, which are EH, well matched by the mfg. They aren't even broken in yet and sound pretty good, but I'm always curious what others are hearing and thinking about tubes.
Thanks
Rich

Mike L

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JJ EL34s?
« Reply #1 on: April 02, 2007, 01:45:07 PM »
Yes I did, but I got so many things different it really is difficult for me to offer a pinpoint comparison/opinion vs. the EH6AC7's that my amps previously had.  Since one of the EH's failed on me prior to receiving the JJ's I can't really switch them back to compare.  To further complicate things I have included the BSC Silver ref MKV power cords on the amps and just finished a DIY speaker.  Therefore, I have been doing a fair amount of experimenting/switching and burning/breaking in all at the same time.  I have swapped power cords back and forth a little, but still primarily using the BSC's, which so far aren't really working out for me.

Difficult for me to be really confident in what I may be perceiving, therefore I choose not to comment so as not to be inaccurate in what I am experiencing.

Sorry,
Mike

edit: just to be totally accurate I have the JJ E34L's..........thanks

Offline richidoo

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JJ EL34s?
« Reply #2 on: April 05, 2007, 05:55:54 AM »
I understand. Sounds like you gutted the whole thing! You are very brave. I'm going through it too with new amps, but it is not too bad so far. A borrowed set of BSC silvers did improve both of my tube amps noticably. So I'm looking forward to getting my own from the GB.

Some ideas you may have thought about:
Remove power conditioning and surge suppression on tube amps.
Separate isolated circuit/s for amps/whole system.
Speakers and tubes will take some time to break in. No way around that, and it can be 200 hours before they are totally stable. Thats 2 months of 4 hour listening sessions!
Try different output taps if you have them.

Shane (hometheaterdoc) taught me how to break in speakers quickly, by facing baffles together as close as possible, and reversing polarity. They null each other at all freqs, and can be played at high levels but sound relatively quiet so can be run all the time. The loudness speeds it up a lot due to larger excursion, more stretching. Same with tubes, higher current is by definition more electrons flowing through tubes burning them in faster.

Don't worry, you'll get it!! And it will be better than ever.
Rich

Mike L

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JJ EL34s?
« Reply #3 on: April 05, 2007, 08:31:20 AM »
How old were those BSC power cords as I have had mine for about 4 weeks and they have not opened up.  I do swap them occasionally with my stock cords and in comparison they are a little shut down up top, and the soundstage doesn't extend as far into the room.  With the stock cords the peaks in the music can really jump out at me where as with the BSC's this is not happening probably due to the loss in dynamics.  I will give them some more time, hopefully they will open up.

Thanks,
Mike

Offline richidoo

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JJ EL34s?
« Reply #4 on: April 05, 2007, 09:03:11 AM »
I borrowed them from Shane (hometheaterdoc.com), so they get a lot of use on high power amps (Butler Monads). I think I borrowed them previously about a year ago on a NuForce demo, but not sure how long mk5 has been produced. So I would venture they are fully broken in. They improved the sound, especially the highs in my manley tube amps as compared to their stock molded plastic 12 ga computer cables. I will have a new set of silvers myself soon. I will let you know if they need much break in.

Offline richidoo

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JJ KT77
« Reply #5 on: May 05, 2007, 09:57:07 AM »
I replaced the Groove Tubes GT34LS with JJ KT77 tubes on the Manley Snappers. The harsh midrange is now gone. Hallelujah! [-o<

I noticed the stickers on the GT tubes had "Performance Rated" numbers on each tube. Looking this up on GT website, I found that the scale is 1-10, 1 being the most distortion and wildest dynamics, designed for rock and blues guitarists wanting the most distortion even at low volumes. They have low headroom. The highest rating of 10 is tubes with high headroom, for jazz and bass guitar amps and hifi amps. Lowest distortion, and "Max Headroom"


The tubes that came with my Snappers were marked 4,4,4,1 and 4,2,2,1 as quads in each amp. So it seems (and sounds) like Manley is voicing the amps toward the rocker side, which has given them some good reviews. Mitch Margolis, the designer of the Snapper is also Chief Engineer with Groove Tubes, and designed this special higher power version of the EL34 for production on the JJ assembly line. So naturally he will specify his own design tubes for his own design amp. I wouldn't be surprised if the Snapper was designed around the new tube.  Some hifi tube experts on Asylum have judged the GT E34LS very good, I don't know what performance rating they were using. Good question to ask... :-k

The KT77s are noisy on startup, a loud wind blowing sound and some popping. I hope that goes away during break in. The amps upstairs are much noisier without the dedicated 20A outlet. Not sure if that has to do with the tubes or combination or things. It's bad enough on both Cary and Manley that I will have to bring dedicated power up there.  :roll:

THe JJ KT77s are the only such tube in production now. Previously they were only made by Genelex years ago. NOS is very precious. So the guy from Eurotubes where I bought mine gave a pair to JJ for reverse engineering to make their KT77 copy. People have compared the original to the new and said they are a good copy, some people even prefer the newer ones. Since they are only $16/tube they might be worth checking out. So far I like the sound of them. They have mellowed out the flamethrowing Snappers and cured the midrange, but also lost some of the intense tight bass and crystalline highs of the GT tube. But they are much more listenable, less of a fireworks show. I'm not sure yet which I prefer. Cool thing about tubes, I can choose and change my mind whenever I want!

I may try to get a set of GT E34LS with the performance rating of 10 on all 8 tubes, to see if that gives me the fireworks without the midrange bite.  Also TubeDepot is cryo treating the SED EL34 which is supposed to be the lowest distortion best built EL34 available. That's the latest!
Rich

WEEZ

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JJ EL34s?
« Reply #6 on: May 06, 2007, 04:35:25 PM »
Rich,

As you know, a lot depends on the circuit and tranny's in various amps to actually determine a specific 'signature' for various tubes. But in general, the JJ & SED EL-34's sound mellower than EI's in my experience. Never heard Groove Tubes...but I don't doubt your experience...from what I've read and heard from users.

WEEZ

Offline richidoo

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JJ EL34s?
« Reply #7 on: May 06, 2007, 05:51:02 PM »
You're right WEEZ. The circuit and the tubes together make the sound, no one tube is right for every amp, or person.

The JJs are breaking in and getting a bit grainy along the way, but I'm sure that will change again before they settle in. The GTs are great tubes, no doubt about it.

NotoriousBIG_PJ

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Re: JJ EL34s?
« Reply #8 on: June 06, 2007, 07:39:59 AM »
I recommend getting the jj kt77. Its the best el34 type tube I have tried. Better then nos siemens, cryo valve art el34b's, gt el34m's, mullard reissue, sed el34, and sventlana el34.

Biggie.

Offline richidoo

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Re: JJ EL34s?
« Reply #9 on: June 06, 2007, 08:56:28 AM »
Thanks Biggie. I ended up preferring the GTs in the end. I later found out that the same guy (Mitch Margolis) designed the amps around the GT tubes, which he also designed for GT. The output trannies are wound specifically for the higher output power of the GT tube. But the JJs do sound very nice indeeeeeeed!  8)  I still wanna try them in my Cary.
Rich

Mike L

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Re: JJ EL34s?
« Reply #10 on: June 24, 2007, 10:50:32 AM »
Do you know what the GT tubes are?  It is my understanding that GT tubes are just rebranded oem's.  Am I wrong?

Thanks,
Mike

PS.  I haven't been around since the change.....I like it

Offline steve

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Re: JJ EL34s?
« Reply #11 on: June 27, 2007, 02:07:40 PM »
I recommend getting the jj kt77. Its the best el34 type tube I have tried. Better then nos siemens, cryo valve art el34b's, gt el34m's, mullard reissue, sed el34, and sventlana el34.

Biggie.

Hi Nortorious,

     I have heard good things about the KT77 but have also heard about the small pins. I noticed the JJ KT88s also seem to fit loose. Have they corrected that problem? Just wondering.

Thanks.
« Last Edit: June 29, 2007, 12:36:39 PM by steve »
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Offline richidoo

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Re: JJ EL34s?
« Reply #12 on: June 29, 2007, 06:47:40 PM »
Hi Mike,
According to GT, they bought the works from GE to make this tube when GE stopped making tubes. They sent the machines and material to make them to JJ factory. GT (Mitch Margolis) also tweeked the GE tube design slightly for more power, blablabla, dunno what else. JJ's own EL34 is supposedly built alongside the GT, but is a different tube. I cannot confirm or deny, YMMV, etc. hehe They have signed of JJ build quality, crooked glass, etc, but are screened for Manley by GT and again by Manley's in house regimen, and have performed flawlessly. Quite a dramatic burn in, lasting all of 100hours + Very sweet and powerful now. I'm glad I stuck it out. Snapper's a great amp.

The JJ pin thickness problem has been resolved about 2 years ago. New power tubes are all 0.091" or so.

I think the JJ tubes are pretty good, especially for the money. A lot of great tube equipment deigners are using JJ small signal tubes. I have 12AT7 and KT-77, and find them both very nice sounding. I think they are also noisy during breaking and when warming up even after break in. I have not swapped tubes around to confirm that the JJs 12AT7s are at fault, but I suspect it, because KT77s were very noisy until warmed up. Once warmed up, the performance is great and I would buy them again.
Rich