Wavelength Audio Gemini monoblock power amplifier Page 4
I'd heard rumors about AVVT 2A3 mesh plates being microphonic, so I did a bit of informal testing. Tapping the tube gently, or even tapping the amplifier chassis, resulted in a clear bong coming through the speakers. (The response to tapping the amplifier chassis was greater when the amplifiers were not supported by the Aurios.) With the other tubes (2A3 or 45), the same sort of tap produced hardly any sound.
Then, in an even more literal test of microphonics, I got within a few inches of the tube and sang at it, as if it were a microphone. I was going to have my wife listen to the speaker to check if my voice was being amplified, but I didn't have to: when I stopped singing, I could hear the echo of my voice coming from the speaker! The sound-pressure level produced by a person singing a few inches from the tube is undoubtedly much louder than the sound that would normally reach the tube from the system itself, but this level of microphonic response can't be good for unvarnished sonic fidelity. My guess is that at least part of the AVVT mesh plate's exciting sound and big soundstage derives from the tube's microphonics. I know that many tubeophiles are enamored of this tube, but given its high level of microphonics and its selling price of $560/pair, I can't really recommend it.
The NOS Raytheon and the Sovtek 2A3s had a fairly similar sound, a sort of compromise between the transparency and finesse of the 45 and the bigger, more dynamic presentation of the AVVT mesh plate. If anything, I preferred the stock Sovteks, which were a little quieter (with the hum-pot settings optimized), and had a more powerful bass response.
The Gemini meets the Triangle Titus
The Gemini/Avantgarde Uno partnership was a very happy one, and most of my listening was to this combination. But I also wanted to find out how the Gemini would fare driving a speaker of more conventional design. I didn't think there was much point in trying speakers normally paired with high-powered solid-state amplifiers, but some speakers using dynamic drivers are said to be "SET-friendly." The Triangle line of speakers that Sam Tellig wrote about in Vol.23 No.8 falls into this category, so I got hold of the Triangle Titus XS, a small $495/pair two-way with a 91dB/W/m sensitivity. "I wish I had a 2W amp with a 45 output tube to try!" exclaimed Mr. T., and, for once, I was ahead of him in having just such an amp. The Tituses were placed on the matching Boomerang stands, and the Geminis were switched to 4 ohms to match the speaker's nominal impedance.
I agree completely with Sam's favorable assessment of the Titus XS: this is a lovely-sounding little speaker, and a steal at $495/pair. The sound with the 45-equipped Gemini was predictably on a much more limited dynamic scale than that of the Avantgarde Unos, but the maximum comfortable level was not as low as one might think, and the sound really did have the "definition, delicacy, and detail" that Sam raved about. With the 2A3s installed, the dynamic ceiling was higher, and the speakers acquired a bit more authority. People who spend $5000 for an amplifier probably have a speaker budget that exceeds $500, so the Gemini/Titus XS is not a very likely combination. But musically, it was a surprisingly viable one.
I'm a fairly cautious person, so I'd have difficulty recommending an amplifier that uses a tube that hasn't been manufactured for decades, no matter how good the sound. The fact that the Gemini can use the widely available 2A3 as well as the harder-to-come-by 45 is, for me, a major point in its favor. Although the method of changing the amplifier settings to match each tube is somewhat inconvenient, this is more a problem for reviewers than consumers, who are less likely to be switching tubes willy-nilly.
The decision to use the 45 was, in my opinion, justified, in that the Gemini equipped with this tube had a magic that left the 2A3 version second-best. I'm troubled by the fact that the first two sets of 45s became noisy during the review period, but I'm prepared to consider that these were instances of the bad luck that seems to follow products sent for review. Tube problems of this sort are covered by the warranty, and J. Gordon Rankin has an impeccable reputation among audiophiles for his fairness and helpfulness in dealing with consumers.
The Wavelength Audio Gemini is what's sometimes classified as a "boutique product": one handbuilt by its designer, with the micro-tuning of design, attention to detail, and level of craftsmanship that this implies. While not inexpensive, it's actually the lowest-priced amplifier that Wavelength makes. The Gemini's need for high-sensitivity speakers and its inability to exploit those speakers' full dynamic range mean that it's not the amplifier for everyone—but then, I don't know of any amplifier that is. What the Gemini offers, particularly when equipped with 45 tubes, is transparency, detail, harmonic "rightness," and an ability to maximize musical values with a minimum of electronic artifacts. For those who value these characteristics more than sheer loudness, the Gemini may in fact be the ideal amplifier.