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Underwhelmed by these new KT77's, break-in needed?

jmitchnh said:
I recently decided to try a little tube rolling in my Cayin A-50T. It came with JJ EL34's which I thought sounded really nice, but wanted to try something different. After much online research, I settled on a quad of Cryoset matched Gold Lion KT77's given their numerous positive reviews.

I installed all four, set them at the factory bias, .325 mv and let them sit for about 30 mins and re-checked. Powered up the system and gave a listen. Unfortunately I did not experience the distinct improvement in sound others have. Actually my system sounded worse. Very bright sounding, no low end and very high listener fatigue, to the point I couldn't listen to them anymore.

This seems so opposite of what most users of this tube experienced. Now I'm wondering if there's something I'm doing wrong? Bias is holding steady. I know these tubes had a 24 Hr. burn-in from the dealer, am I expecting too much too soon? Before I give up on these and put the JJ's back in, just curious if anyone else has had this same experience?
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If your system is pretty revealing, then the GLs may be a bit too much. Have done the same with GL KT77s. They will break in a bit more, but the Mullard EL34 re-issue is more to my taste.

If a system is on the darker side then the added sparkle the GLs can offer can be nice.
 
mcgjohn said:
If your system is pretty revealing, then the GLs may be a bit too much. Have done the same with GL KT77s. They will break in a bit more, but the Mullard EL34 re-issue is more to my taste.

If a system is on the darker side then the added sparkle the GLs can offer can be nice.
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So, just to see what happened when I rolled the EH 6CA7's back into the Van Alstine Ultravalve...yeah...with the speakers I have (Genesis 700's) the KT77's are a bit much. This is paired with a Schitt Freya with some NOS Canadian RCA tubes and a Holo Audio Spring 2 KTE.

However, I put the KT77's in the WIllsenton R8 I have in my office paired with some ProAc SC1's and this is a MUCH better combination. Someone on the Steve Hoffman forums said the KT77's are dark on the R8 and I don't get that at all. They sound generally lively to me (more so than the Svetlana EL34's I had in there before) and I think this is a pretty good match.
 
I still love the sound of the JJ EL34L in my SEUL amp that uses a 6SQ7 as a driver. I've tried GL KT77 and several flavors of 6CA7 and always end up back with the JJ.
 
I liked how the JJ KT-77's sounded, but I did loose one that didn't have a whole lot of hours on it. So far the JJ KT-88's are holding up. I didn't like how they sounded in my ST-70, but they sound a lot better in the M-125's. They have a nice bottom end without sounding boomy or flabby. People seem to like the JJ
EL-84's in the ST-35. I'll probably try a quad in mine at some point.
 
Are you guys @Lavane @Brice purchasing new production
EH-6CA7, maybe from upscale ? . I read somewhere that Mcshane quit selling these because he was getting very inconsistent quads and couldn’t guarantee them.
I’ve had similar experience with the GL KT77 in my Eico HF-60s, initially thought they were ok maybe a bit bright and thin and didn’t have the bottom end that my mc30’s 6L6 amps did, but after a few weeks of listening to them I realized that they really were sounding nice. I put the mc30s back in and knew the bottom end wasn’t really better, but a little sloppier.
 
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atlvalet said:
So, just to see what happened when I rolled the EH 6CA7's back into the Van Alstine Ultravalve...yeah...with the speakers I have (Genesis 700's) the KT77's are a bit much. This is paired with a Schitt Freya with some NOS Canadian RCA tubes and a Holo Audio Spring 2 KTE.

However, I put the KT77's in the WIllsenton R8 I have in my office paired with some ProAc SC1's and this is a MUCH better combination. Someone on the Steve Hoffman forums said the KT77's are dark on the R8 and I don't get that at all. They sound generally lively to me (more so than the Svetlana EL34's I had in there before) and I think this is a pretty good match.
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@atlvalet , not too much different than my experience. Both tubes are good, but tonal balance is different. If you really want to try some excellent midrange tubes, try the Mullard Re-issue EL34s. Have not tried the JJs so cannot comment on them.
 
Madman1 said:
Are you guys @Lavane @Brice purchasing new production
EH-6CA7, maybe from upscale ? . I read somewhere that Mcshane quit selling these because he was getting very inconsistent quads and couldn’t guarantee them.
I’ve had similar experience with the GL KT77 in my Eico HF-60s, initially thought they were ok maybe a bit bright and thin and didn’t have the bottom end that my mc30’s 6L6 amps did, but after a few weeks of listening to them I realized that they really were sounding nice. I put the mc30s back in and knew the bottom end wasn’t really better, but a little sloppier.
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Yes, I bought new production. I bought mine awhile before McShane started fi ding problems with the EH 6CA7's. It's too bad, I really like them. Infound the JJ KT-77's sounded pretty well balanced in my ST-70. The EH 6CA7's have a bit stronger bottom end. I don't have tone controls and the 6CA7's sound a little better to me. Supposedly the EH 6CA7's are constructed more like a lower powered 6550?
 
Must be the last of the good ones? I didn't have any problems getting them to bias up.
I wonder what McShane meant. Did he have to crank a trimmer close to or all the way up to get them to bias?
 
I haven’t contacted him, but somebody said a week or so ago that they contacted him because they saw them on his site, but he doesn’t actually have any to sell. Audio classics shows them on there site… to cryo or not to cryo, that is the question:eek:!
 
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Old thread- I know.
IMHO , if you can run the GL- KT66, vs the KT77, I would try that.
(Primaluna EVO 300 @ Prologue Premium power amps.)
They have a very detailed dynamic sound with a wide a deep soundstage.
Lots of harmonics, decays etc.
Deep, and tuneful bass. Not dry like a KT88/120.
My other fav is the TS 7581A.
At least with the Prima Luna, your combination of small signals also makes a difference.
I run Gold Lions 12AU7 center 2and GE6189W outer. Same for both amps.
Also went with the Gold Lions in both Van Alstine power amps.
I don’t find GL small signals bright, as some do, but full sounding, dynamic with big bass.
And right now that means helping them save money. I do think in some set ups they probably can sound bright, circuit dependent it seems.
 
Good info although a lot to take onboard. Sounds like something you have wanted to get out of your system for a while.
 
Just saw this get bumped and saw I had posted a few years back so I'll chime in...

The KT77's ended up breaking in very nicely. I ended up selling the AVA Ultravalve and ran them in my Willsenton R8.

I sold the R8 to pay for the mods Scott Frankland made to my R800i, but liked the KT77's enough that I kept them and will pick up another tube integrated at some point to run them again.
 
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