Rogers High Fidelity 65V-1 Integrated Amplifier

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Integrated amplifiers
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Rogers High Fidelity 65V-1
Rogers High Fidelity 65V-1 Integrated Amplifier

One puzzling design aspect is the insertion of a high-pass filter at the input to intentionally roll-off bass frequencies below 100Hz. Bass response is already off 6dB at 30Hz, and this is clearly audible as a loss of bass weight, not only on organ sustains but also on upright bass. The intent was to provide the user with a rumble filter, but the puzzling thing is that there is no way to bypass the roll-off when rumble isn’t an issue. A positive consequence of the filter is reduced output-transformer saturation due to a heavy bass signal.

The 65V-1’s first task was to drive the Watkins Generation Four loudspeaker, which is capable of exceptional imaging, and pricewise is a good match for the Rogers. As fate would have it, I started my listening tests with the KT88 beam power tube. In hindsight, it became obvious that this was not the best choice. I am not at all suggesting that the Russian Genalex Gold Lion is a bad-sounding tube; it’s just that in this context it didn’t do the 65V-1 any favors. The overall sound took on a distinctly bland character. With the amp lacking a strong sonic personality and being way too polite dynamically, the Gen Four speaker became a mere shadow of itself. From a design standpoint, it’s likely that the 65V-1’s bias resistor is optimized for an EL34. A KT88 needs to draw a bit more bias current—that is, run hotter—to sound its best. It didn’t take me long to substitute the stock Mullard reissue EL34. To say that I was surprised by the resultant transformation would be an understatement. Power tube differences can normally be measured in inches; in this case it was a matter of miles. The Gen Fours took off with convincing microdynamic expressiveness, much better color saturation, and sufficient punch, especially in ultralinear mode, making it sound like it was driven by a much more powerful amp. Watkins recommends a minimum amplifier power of 40Wpc, so in all fairness, the 65V-1 should not be considered an ideal choice for this application.

It was time to make life easier for the Rogers by giving it a chance to drive a much higher-sensitivity speaker load. The OB3 open-baffle DIY speaker (94dB) was rotated into the reference system for that reason, and for the fact that it had shown a preference for low-power tube amplification. It was then that I started falling in love with the Rogers. The crux of it was a lush and expansive midrange that I could get lost in when I closed my eyes. I preferred triode mode to UL. Not a big surprise here. With high-sensitivity speakers, it’s all about the quality of the first watt, and at least with this amp a triode watt sounded sweeter and more relaxed. It takes the amp a while to start singing. A slight veiling of the soundstage and defocusing of image outlines disappeared after about 30 minutes. Image outlines fleshed out to almost palpable presence, and it became possible to access the inner recesses of the soundstage. There was an organic wholeness to the stage that gave the impression of continuous width—a far cry from the discontinuous left, right, and centerfill presentation that some amp/speaker combos insist on. Moving my head from left to right in no way disrupted the illusion of “being there.”

Power response was fairly well extended. As a result, perceived transient speed was quite decent without overly liquid textures. Tube liquidity and richness are good things, but at a certain point can turn sonics into a gooey mess that masks low-level detail. To its credit, the Rogers negotiated the richness/detail tipping point quite well. As mentioned earlier, the significant fly in the ointment was the bass range, which lacked sufficient heft. The amp’s source impedance is 9.5 ohms, which gives it a damping factor of about one into an 8-ohm load, though I don’t think that this is necessarily the reason for the loss of bass line tightness. (The Coincident Dynamo 34SE Mk. II, which sports an almost identical source impedance, does much better in this regard.)

This dichotomy in sonic character was clearly evident on the Charlie Hayden/Jim Hall duet concert album recorded at the 1990 Montreal International Jazz Festival. Hall’s guitar was boldly and vividly etched in space within the confines of a lovely acoustic. On the other hand, Hayden’s doublebass lacked authority and precision. To my mind, the reason to buy the 65V-1 is its midrange, which towers above the competition at this price point. You really would be hard-pressed to find a more cogent and emotion-packed midrange. And that’s what keeps me coming back to this amp. These are basically the same reasons I still own and enjoy a pair of the classic Quad 57 ESLs. On balance, indulge yourself. This is an entertaining amp that deserves a serious audition.

Specs & Pricing

Frequency response:  20Hz–20kHz +/-0.1dB
Power output: 25Wpc at clipping at 10% THD
Inputs: Four RCA
Features: Headphone jack; Bluetooth communication with iPad
Weight: 24 lbs.
Dimensions: 17" x 7.5" x 12"
Price: $4000

ROGERS HIGH FIDELITY
info@rogershighfidelity.com
rogershighfidelity.com

Associated Equipment
Speakers: Watkins Stereo Generation Four, OB3 open baffle (DIY)
Analog source: Kuzma Reference turntable and Stogi Reference 313 VTA tonearm, Clearaudio da Vinci V2 MC
Digital sources: MacBook Pro laptop running Amarra V3.04 software, DiDit 221se DAC, ModWright modified Sony XA-5400ES SACD player
Cables: FMS Nexus-2, Wire World, and Kimber KCAG interconnects, Acoustic Zen Hologram II speaker cable
A/C Power: Monarchy Audio AC-Regenerator, Sound Application power line conditioners

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