[Escott1377]

Can anyone please comment on their experience with these tubes?  I have read mixed reviews on the Internet.

A lot of focus of quality control, but these were old articles and from what I understand, the quality has improved.

The price makes these attractive, so I am not interested in the Gold Lion reissues.

Please respond with comments based on sound and durability.

Thanks!

[Captainhemo]

When I contacted the tube store  about a year ago and asked about the quality isses,  they  assured me that  the QC was pretty much a thing of the past,as outlets cleared old stock, you'd start hearing less and less about the failures.  On the whole, I'd say that seems to be true. Yeah,  you are going to still have the odd failure, you're going to get that with  any tube pretty much.

I received a 15% off coupon form the tube store ealier this month and wanted to use it beofe expiring at the end of April so I ordered a quad on Monday night.  They are  supposed to arrive tomorrow.
I'm anxious to compare them  to my Canada Fuller EL34G's which  I love but are significantly more  $$  (I finally had to make a bias adjustment to the CF's after about 14 months), wondering if it could be a sign   

Lots of reviews I read on the JJ KT77's cited them as having a very strong mid ragne  with a more extened top and bottom end as compared to the GL KT77 RI.  I'd also read the JJ's produce a wider, more open sound stage.

jay

[mjosef]

Bought a quad about 16 months ago, though the 'sound' showed promise I had 'problems' with a couple of the tubes keeping bias... 

But a couple months ago tried their 'new' 5751, and really liked it, might just be my new fav. 12AX7 type new issue tube.

[Captainhemo]

Bought a quad about 16 months ago, though the 'sound' showed promise I had 'problems' with a couple of the tubes keeping bias... 

But a couple months ago tried their 'new' 5751, and really liked it, might just be my new fav. 12AX7 type new issue tube.

Did you have issue with them  holding bias right away  ?  Or was it something that  crept  in after some time ?   
I didn't even realize they had released a 5751,  might have to try a pair myself one of these days.  Let us know if they last for you

jay

Tubes arrived  this am.
figured I'd grab a few  pics to show the difference betweent eh  Canada Fuller EL34G and JJ KT77 .  The pins are wimpy on the JJ's and are a much looser fit in the sockets.... actually, they aren't loose,  they are just   less snug.  The CF seems to be a far better quality, just feels   much more solid to handle., gold pins, ceramic base, thicker glass etc, but again,  fair price  difference ($250+ / quad vs $80/quad)
Sorry about the pic quality, just can't  take pics of tubes 









No impression yet, amp is warming up before setting bias

[mjosef]

Did you have issue with them  holding bias right away  ?  Or was it something that  crept  in after some time ?   

Right away...well, it took a couple hours for the 'drift' to show up, and day2day there were fairly big swings. I would set the bias one day ( after the hour or two warm up), and check it again just before power off, level them all again, power off...next day repeat. One tube would show +8-10mV swing (bias set @ 35mV.) day to day. After about 6 weeks, I gave up.



Those CF tubes look like bling compared to the JJs.

[Escott1377]

Curious if you have had a chance to break in the KT 77's and your impressions?

Thanks -

[Captainhemo]

Curious if you have had a chance to break in the KT 77's and your impressions?

Thanks -

Not a whole lot of hours on them yet, maybe 12-15.   At first, I was  disappointed with the top end, it really didn't compare with the Canada Fullers but even after only  a few hrs, they do seem to be coming around.  So far,  I wouldn't say they are as "rich" as the  CF's were but it is very early....they're coming around
If your amp has  loose sockets , I'd shy away from the  JJ 's(the 77's anyway).   Sorry the pics were so ppor,  not sure  how  well  you  can  note the differences in the pins.  The 77's slip right in, not  loose, but not  overly snug either,  the CF's were  tight.
 bias seems to be holding fine thus far.
The tube store  does offer a 3 month warrenty so  if  a tube or  2 starts drifting all over the place, I'l lbe sending  it/them back

I can let you know  how  they are doing in a week or  two if you like

jay

[sebrof]

If your amp has  loose sockets , I'd shy away from the  JJ 's(the 77's anyway).

Not all tube sockets are the same, but most I have had you can use a small / sharp (preferably plastic) tool to very slightly bend the connection and make it tighter. I've done this several times and it always worked. In fact, if they are loose it's probably from wiggling the tubes as you take them out, in effect doing the opposite of what you do with the tool.

Of course - Turn the amp off, disconnect power.

[E55l2]

Break in?

After the manufacturing process i would suppose that break in isn't really necessary, just small changes.
If you know how they make the getter active and the tube vacuum bias should be almost perfect for a long time.

btw i had some JJ EL34 and at least 25% had problems. The shop which i visit regularly stopped buying JJ because they had to much problems.

Curious if you have had a chance to break in the KT 77's and your impressions?

Thanks -