Jkaway, I've heard nothing but bad things about the Ruby KT-88's. Their EL-34's are junky, cheaply made tubes with thin glass, and the general consensus is that the Svetlana EL-34 blows it away. I find it very hard to believe the Ruby KT-88 beats the JJ-Tesla KT-88, which, along with the Svetlana KT-88, is the top contender for KT-88, in my opinion.
Another 6550 vs. KT88, 90, et. al.?
Recent listening after having the tetrode/triode switches in my VTL 185's restored by the factory to functioning status (a previous owner removed them) has me reassessing the amps' tonal balance as presently configured (with Svet 6550C's, new last fall). While the tetrode setting I was confined to before the repair holds most of the 'high fidelity' aces (dynamics, space, separation, resolution, articulation, detail, extension, bass definition), my newfound ability to access the triode option has confirmed, and strengthened, my previous suspicions about the overall balance: A little spotlit in the lower treble, a little tight from the lower mid's down through the mid-bass.
The result is a tad hard and lean (for a tube amp), with a bit of glare above and a lack of plushness and body below. Triode corrects this balance toward the warm side, more neutral overall IMO (except at the frequency extremes), and also gives a smoother textural presentation with lowered grain, but at a cost in the other areas mentioned above. In general, the amps pass more info and get better speaker control in tetrode, but are purer and more natural through the heart of the audioband in triode, if also less present and more homogenized.
I know none of this is revolutionary news to many, and obviously questions of tonal balance will be highly system-dependent as well.* And in the big picture the 185's are the most revealing and least colored and distorting amps I've owned. But before plunking down for 12 more power tubes to experiment, and after having read through the archives, I wanted to bring this question back to the forum, especially in the hope that some VTL owners might shed more light on their power tube experiences.
*[Thiel CS2.2's/AZ Satori/VTL MB-185 Signatures (with 60's NOS Sylvania gold pin 6201/12AT7 inputs)/HT Magic Link One/Levinson 380S/HT ProSil/Theta Basic IIIa and Pearl/Shunyata Sidewinders on the amps, HT AC11's on the digital separates/API Power Wedge Ultra 116 on all]
The result is a tad hard and lean (for a tube amp), with a bit of glare above and a lack of plushness and body below. Triode corrects this balance toward the warm side, more neutral overall IMO (except at the frequency extremes), and also gives a smoother textural presentation with lowered grain, but at a cost in the other areas mentioned above. In general, the amps pass more info and get better speaker control in tetrode, but are purer and more natural through the heart of the audioband in triode, if also less present and more homogenized.
I know none of this is revolutionary news to many, and obviously questions of tonal balance will be highly system-dependent as well.* And in the big picture the 185's are the most revealing and least colored and distorting amps I've owned. But before plunking down for 12 more power tubes to experiment, and after having read through the archives, I wanted to bring this question back to the forum, especially in the hope that some VTL owners might shed more light on their power tube experiences.
*[Thiel CS2.2's/AZ Satori/VTL MB-185 Signatures (with 60's NOS Sylvania gold pin 6201/12AT7 inputs)/HT Magic Link One/Levinson 380S/HT ProSil/Theta Basic IIIa and Pearl/Shunyata Sidewinders on the amps, HT AC11's on the digital separates/API Power Wedge Ultra 116 on all]