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The GL KT77. A cure for blocked audio ducts?

futureman

futureman

If not now, whenever.
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As good as my Kegger-modded ST-70 could sound, there were times when the highs seemed recessed and the bass a bit "woolly." Music was occasionally veiled, although I could correct this by turning up the treble. I decided to open my wallet and replace the Tung-Sol EL34Bs with the GL KT77s.

Within the first few hours of listening with the new tubes--Steely Dan, Aja; The Police, Zenyatta Mondatta; Pink Floyd, DSOTM--I'm hearing more detail and clearer highs. The bass is tighter although a little less extended. The mids are not *quite* as lush (the EL34Bs' strength, maybe?) but still nice. The tone controls are flat. The overall sound is more open and less clogged.

The music might be a tad bright for some, but I've been listening with the new tubes for only 3 hours. I'm anxious to hear them after proper burn in!
 
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The Genalex reissue KT77 is very nice sounding but it takes a long time to break in fully. Give it at least 50 hours before evaluating sound quality.
 
In two of my amps, the GL KT77 did open up the midrange more so than four other EL34-type tubes that I tried. Someone who likes a very lush, warm tube sound might find it too bright for their tastes but I like them a lot. Very good imaging and instrument & voice separation.
 
The GL KT77 takes some time to open up. It takes around 50 hours before the sound settles.
 
About about 6-7 hours in. Is there usually a lot of sonic ebb and flow in new tubes? The soundstage seems to shift quite a bit, with various changes in how open or veiled the music sounds.
 
My experience with tubes "breaking in" is usually that the highs get clearer. I'm generally not a big believer in the concept of break-in but I've definitely heard it with tubes. Most of the Russian tubes seem to be kind of muddy initially but somewhere in the 20-odd hour range they develop high frequency response that makes things sound normal again.
 
I am a big fan of the Gold Lion K77 tubes. They are well worth the money and time for things to settle in.
 
If I didn't have four sets of EL34-compatible tubes already I'd be tempted to buy a set. 3 are new production matched quads, the other is a mixed lot of old production that work well enough together. Hard to justify what would be a fifth set of tubes when I can only use at most 2 sets at a time. Maybe next time I've got money burning a hole in my pocket I'll do it anyway.
 
futureman said:
Music was occasionally veiled, although I could correct this by turning up the treble. I decided to open my wallet and replace the Tung-Sol EL34Bs with the GL KT77s. . . . I'm hearing more detail and clearer highs. The bass is tighter although a little less extended. The mids are not *quite* as lush (the EL34Bs' strength, maybe?) but still nice. The tone controls are flat. The overall sound is more open and less clogged.
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It's always fun to try a new flavor of tube, glad you're liking them so far.

I'm curious, what preamp are you using? Tube or SS? Many people feel that the preamp has as much, or more, influence on sound than the output tubes. Also, keep in mind that just because the tone controls are at noon position doesn't mean that they are actually flat.
 
Kenwood L-07Cii (solid state). The phono stage is great; line stage is OK; the unit as a whole is well built.
 
Has anyone tried the jj kt77 or compared it to the GL? Would that get a cheap guy like me most of the way to the GL KT-77 sound for less outlay?
 
I was wondering if anyone has compared the gl kt77 against the older swetlana winged emblem c 6l6gc tubes.the reason I ask is since the old winged c tubes are no longer available and command a premium price nowadays my Fairchild 260's can be converted to el34 kt77 6ca7(factory mod) and it would be nice to find a alternative for when my swetlana wear out.i do have one pair of n.o.s g.e.c kt77's but I doubt I'd find another pair of those cheap.
 
mnmmt said:
Has anyone tried the jj kt77 or compared it to the GL? Would that get a cheap guy like me most of the way to the GL KT-77 sound for less outlay?
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I ran a quad of JJ KT-77's in my ST-70. I liked them. One failed though. But I'm not sure it was the tubes fault. At the same time 1/2 of the driver shorted. I'm ordering a new JJ KT -77. I'm using a set of KT-88's at the moment, but the 77's have a more balanced sound to me. The 88's had a stronger bottom end, but the midrange is too layed back compared to the 77's.
 
mnmmt said:
Has anyone tried the jj kt77 or compared it to the GL? Would that get a cheap guy like me most of the way to the GL KT-77 sound for less outlay?
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I have about 90 hours on a quad of JJ KT77s. They're worth a shot, and I like them better than my old favorite new production EL34 variant, the Electro Harmonix 6CA7. The JJs sound clear, detailed throughout the audible frequency range, and completely enjoyable.
 
radioactive said:
I was wondering if anyone has compared the gl kt77 against the older swetlana winged emblem c 6l6gc tubes.the reason I ask is since the old winged c tubes are no longer available and command a premium price nowadays my Fairchild 260's can be converted to el34 kt77 6ca7(factory mod) and it would be nice to find a alternative for when my swetlana wear out.i do have one pair of n.o.s g.e.c kt77's but I doubt I'd find another pair of those cheap.
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I've used both, but in different amps. The 6L6GCs in MC240's and the KT77's in Acrosound ULII's. Different beasts, different roars.
 
That's it, I ordered a replacement KT-77 so I can put them back in. The 88's don't quite do it for me. I tried to like them, but the midrange with the 77's just sounds better to me.
 
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