First off, I am NOT a big-time tube roller. Years ago, I did a little tube rolling when I first got my BC21.1 preamp. It was a fun and instructive experience, comparing ElectroHarmonix, Philips, JAN-Philips, and JJ Tesla brand tubes. I chose the JJ Tesla's because they gave me the best bass performance - namely a solid, tuneful, punchy performance - without sacrificing detail or mid-range smoothness. I have since used this brand almost exclusively, and haven't given further tube rolling much thought. But a recent post on the Blue Circle Forum got me back in the groove. So, an order for a pair of matched, high gain Genalex tubes went out to thetubestore, and a few days later they arrived via US Mail.
I used a handful of my long-time favorite songs that also often act as demo tracks since I know them well:
Si*Se, More Shine, "Mariposa En Havana"
Bossacucanova, Uma Batida Diferente, "Essa Moca Ta Diferente"
Tori Amos, The Beekeeper, "Sweet the Sting"
Feist, Let It Die, "One Evening"
Toy Division, Visage II, "Budapest Resonance"
CeU, Vagarosa, "Cangote"
A theme common to all of these tracks is fairly articulate, bass-heavy rhythms, with fairly wide soundstages. The artists Si*Se, Tori Amos, Feist, Toy Division, and CeU highlight female vocals. Bossacucanova highlights male vocals. I let the Genalex tubes burn in for about 24 hours before doing any serious listening.
In comparison to the JJ bottles, the more than twice as expensive Genalex tubes offer slightly more inner detail which was clearly evident in vocals, individual instruments such as horns, as well as in bass notes. You can only imagine how exciting this change is from the audiophile perspective. Also, the sounds seem to even further detach, or maybe a good word is "unstick", themselves from the speaker locations - i.e., letting the speakers disappear even more convincingly than before. I believe this also leads to a slightly more 3-dimensional soundstage, in that its depth has increased a little. The soundstage width does not seem to change, as far as I could determine.
The downside is that, in the time domain, the bass performance seems not quite as aligned with the upper frequency spectrum, as in the JJ's. The net effect is that I am not as driven to tap my toes with the Genalex in the system. Also, the bass amplitude comes across as ever so slightly shelved down with the Genalex, as if bass had been turned down by a dB or two.
Keep in mind that these observations are with the TacT calibrated when the JJ tubes were in the preamp and well burned in over several months. To even up the playing field, I re-measured the TacT with the Genalex tubes in the system, and then re-calibrated using the same response curve (see Fig. 2 in my TacT post from January 1). Looking at the measured frequency response between the JJ and Genalex, there is not an appreciable difference; yet, after the re-calibration of the TacT, the sound did change somewhat, with a slightly more open mid-range balance. The frequency extremes didn't seem to change significantly.
How does this all translate into whether I prefer the JJ or the Genalex? It's a coin toss at this point. I prefer the seeming inner detail and soundstage improvements offered by the Genalex, but prefer the bass performance of the JJ's. Since I'm a PRAT kinda guy, then I may end up transitioning back to the less expensive JJ's. But I am first going to let the Genalex burn in a few more weeks before making any final determination.
If you have any stories to share on your own tube rolling experiences, please add your comments!
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