Post by myles on Feb 23, 2007 15:38:38 GMT -7
The JJ KT77 is a direct EL34 replacement as is the USA 6CA7 design. The EL34, KT77, and 6CA7 are all a bit different and all have their own cool qualities.
This tube has an 800volt B+ spec as does an EL34 and an 800 volt screen spec vs the 450 screen spec for an EL34. The spec is 25 watts on the plates and 6 watts on the screen. The EL34 has an 8 watt screen rating as a side note. But ... these are just design specs and in actual operation it is clear to many than a duet of EL34 tubes in a "50 watt Marshall" can produce over 70 watts in most cases easily.
Carl Verheyen's two SRZ-65 amps had E34LS tubes installed and he was very happy. We tried the KT-77 as a replacement and he was even more happy. That is one point of view and his thoughts in general on the SRZ-65 are over in that area.
Here is a bit of info from various sources.
From a great guy at www.eurotubes.com - Bob Pletka - comes this:
Factory description: Gold plated control grid for improved fidelity. Special plate alloy to improve plate dissipation. This is a hand aligned Beam power tube resulting in stable performance at higher power levels.
My observation: The story behind this tube is that it was made by JJ at my request after meeting with them. I quietly sacrificed a pair of my original GEC KT77 for them to test and then break apart (while I wasn't looking) to reverse engineer. The result is a stunning new production KT77 that has all the qualities I coveted in the original. The JJ KT77 has a slightly deeper low end than the JJ E34L and they have a nice sizzle on the top end without getting brittle and the mid range harmonic structure is very complex. The clean tone is very fat and full and the when driven to saturation the crunch has more of a chunk to it. These are also great in vintage and current production Hifi applications as you can tell by some of my customer reviews.
and
From: John DeLorme [mailto:small_time_takeover@yahoo.com] Sent: Sunday, August 06, 2006 12:25 PM To: eurotubes@cnnw.net
Subject: KT77s = the missing link!
Thanks so much! I picked up my Marshall DSL 100 from you last friday. You loaded it with KT77s and even matched the grade of the E34Ls you installed for me last time. Thanks for the quick turn around too. Anyway, I was expecting a change for the better but what I heard was amazing! All the gain is still there, yet the overall clarity of every note has improved immensely. The bottom end is bigger, punchier, and no longer muddy. The mids sound killer and are much more present. Didn't notice too much of a change in the highs though I wasn't really looking for a change in that range. These are just my initial observations... I've only actually had a couple hours on them and that was with drums and bass cranked too.
Bottom line is, I've been strugling to get the sound I want and just didn't think it was possible to extract from the JCM 2000. I still don't think I'm there yet... but I'm in no hurry to off this amp now! Thanks again Bob.
John DeLorme
________________
From: Bob Kimball [mailto:B_kimbal@msn.com] Sent: Tuesday, May 02, 2006 5:40 PM To: eurotubes@cnnw.net
Subject: Re: Tubes
Hi Jay,
I've had enough time to let the tubes settle in a bit. I'm using a pair of the JJ KT77 in a Rivera M60 head (60W), replacing whatever the stock EL34s were. The KT77s do everything better than the stock tubes. They have a little more chime/sparkle when driven clean, a nice round and not-flabbly bottom end. They get nicely gnarly when overdriven, real BALLZ! The Rivera can run the output tubes either pentode or triode. The triode setting with the stock tubes was a yawner. It's really nice with the KT77s... articulate and with a touch of reverb, haunting. It's hard to characterize them, they are kind of a cross between the signatures of an EL34 and a good 6L6. They are a welcome addition! Thanks, Bob
As a side note via Myles .... the Rivera normally runs Svetlana EL34's
This tube has an 800volt B+ spec as does an EL34 and an 800 volt screen spec vs the 450 screen spec for an EL34. The spec is 25 watts on the plates and 6 watts on the screen. The EL34 has an 8 watt screen rating as a side note. But ... these are just design specs and in actual operation it is clear to many than a duet of EL34 tubes in a "50 watt Marshall" can produce over 70 watts in most cases easily.
Carl Verheyen's two SRZ-65 amps had E34LS tubes installed and he was very happy. We tried the KT-77 as a replacement and he was even more happy. That is one point of view and his thoughts in general on the SRZ-65 are over in that area.
Here is a bit of info from various sources.
From a great guy at www.eurotubes.com - Bob Pletka - comes this:
Factory description: Gold plated control grid for improved fidelity. Special plate alloy to improve plate dissipation. This is a hand aligned Beam power tube resulting in stable performance at higher power levels.
My observation: The story behind this tube is that it was made by JJ at my request after meeting with them. I quietly sacrificed a pair of my original GEC KT77 for them to test and then break apart (while I wasn't looking) to reverse engineer. The result is a stunning new production KT77 that has all the qualities I coveted in the original. The JJ KT77 has a slightly deeper low end than the JJ E34L and they have a nice sizzle on the top end without getting brittle and the mid range harmonic structure is very complex. The clean tone is very fat and full and the when driven to saturation the crunch has more of a chunk to it. These are also great in vintage and current production Hifi applications as you can tell by some of my customer reviews.
and
From: John DeLorme [mailto:small_time_takeover@yahoo.com] Sent: Sunday, August 06, 2006 12:25 PM To: eurotubes@cnnw.net
Subject: KT77s = the missing link!
Thanks so much! I picked up my Marshall DSL 100 from you last friday. You loaded it with KT77s and even matched the grade of the E34Ls you installed for me last time. Thanks for the quick turn around too. Anyway, I was expecting a change for the better but what I heard was amazing! All the gain is still there, yet the overall clarity of every note has improved immensely. The bottom end is bigger, punchier, and no longer muddy. The mids sound killer and are much more present. Didn't notice too much of a change in the highs though I wasn't really looking for a change in that range. These are just my initial observations... I've only actually had a couple hours on them and that was with drums and bass cranked too.
Bottom line is, I've been strugling to get the sound I want and just didn't think it was possible to extract from the JCM 2000. I still don't think I'm there yet... but I'm in no hurry to off this amp now! Thanks again Bob.
John DeLorme
________________
From: Bob Kimball [mailto:B_kimbal@msn.com] Sent: Tuesday, May 02, 2006 5:40 PM To: eurotubes@cnnw.net
Subject: Re: Tubes
Hi Jay,
I've had enough time to let the tubes settle in a bit. I'm using a pair of the JJ KT77 in a Rivera M60 head (60W), replacing whatever the stock EL34s were. The KT77s do everything better than the stock tubes. They have a little more chime/sparkle when driven clean, a nice round and not-flabbly bottom end. They get nicely gnarly when overdriven, real BALLZ! The Rivera can run the output tubes either pentode or triode. The triode setting with the stock tubes was a yawner. It's really nice with the KT77s... articulate and with a touch of reverb, haunting. It's hard to characterize them, they are kind of a cross between the signatures of an EL34 and a good 6L6. They are a welcome addition! Thanks, Bob
As a side note via Myles .... the Rivera normally runs Svetlana EL34's