Quote:
Originally Posted by Etunes
(Post 788651)
Will you please share with me what speakers are working well for you with his gear? I have 91db efficient speakers but still not experiencing what is being described here. I recently purchased his KT88 SE and want to love it but its struggling with my current setup. Running with KT150's has been best of far.
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IME the Inspire single-ended-pentode amp is more finicky about speaker synergy than a push/pull (PP) tube amp, or solid state.
I use Klipsch RF-7 II (101dB, 8 ohm, 2 way) and RF-7 (102dB, 8 ohm, 2 way) in my basement system where my Inspire “Fire Bottle” SE Stereo Tube Amplifier HO is installed. My Inspire amp doesn't work as well with my Klipsch Palladium P-37F (96dB, 4 ohm, 3 way) in my TV room. The Inspire also doesn’t work well with my Snell Type CV (90dB, 8 ohm, 3 way) in my living room. Surprisingly the Inspire does OK with my JBL L880 (91dB, 8 ohm, 4 way) in my very small office. (I have 5 systems (different rooms), and a total of 26 amps, and I’ve experimented quite a bit with amp/speaker compatibility in my systems.) I think this shows that a few published specs don’t fully characterize how easy a speaker is to drive. (And room size matters.)
I listen mostly to classical music (ranging from chamber music to large scale orchestral) and opera, plus occasionally big band music. I listen at moderate sound level – not extremely loud. My unfinished basement is a large room (22’ x 30’ x 8’) with “live” acoustics (concrete floor and walls). One speaker is 4 feet from a rear wall; the other speaker is in the middle of the room. My listening position is 13 feet from each speaker.
I connect the Inspire directly to an older model Oppo DV-980H SACD/CD player (i.e., no preamp) and use the Oppo’s volume control. I increase the output level of my Oppo by adjusting its “trim levels” for the l/r speakers to their max value (i.e., +10dB vs. 0dB). As pstrisik said, a preamp will increase the gain – however I choose to use the Inspire amp in a “minimalist configuration” without a preamp. (I can use a McIntosh MX110Z tuner/pre-amp in this system if I wish.)
My Inspire amp was originally equipped with KT88, 5U4, 6CG7. I decided on GT6L6 GE, 5AR4, 6DJ8 based on extensive tube rolling, and based on my goal of recreating the natural timbre of orchestral instruments and human voice (i.e., the full range of male and female singers). My bias is that I don’t like bright sound. Of course my selection of tubes is based on Klipsch RF-7, my listening room, and what I remember hearing in my local symphony hall and opera house (which both have excellent acoustics). (For brighter sound the KT88 would be indicated.)
With the Inspire / RF-7 II combination I realize sound that I would describe as “natural”, “full”, and “rich”, with adequate volume, good dynamics, and good bass. With that said, I’ve recently become a convert regarding subwoofers. (I can activate a Klipsch R-115SW in my basement system with the Inspire and RF-7s.) I can set parameters in my Oppo player so that it provides a crossover and off-loads deep bass from the Inspire amp and main speakers, thereby increasing dynamics and bass. Nonetheless, even without a subwoofer, my Inspire “Fire Bottle” SE Stereo Tube Amplifier HO (with the tube compliment I described above) delivers excellent sound quality with my RF-7 II for everything except the lowest pedal notes of a pipe organ. A big subwoofer is also indicated if you want to experience a mighty
whack of the bass drum the way it sounds in the symphony hall.
To put things in perspective, here’s a list of the other amps in my basement system that I can compare to my Inspire “Fire Bottle” SE Stereo Tube Amplifier HO: Scott 272 (PP EL34 integrated amp), Scott 222C (PP 7189 integrated amp), McIntosh MX110Z pre-amp, Fisher KX-200 (PP 7591 integrated amp), Marantz 2325 solid state receiver (125 wpc), Pilot SA-260 (PP EL34 power amp), Scott 210F (PP EL34 mono integrated amp), Fisher TA 500 (PP KT66 mono receiver), and Scott LK150 (PP KT88 power amp). For large scale orchestral music (e.g., a high resolution digital recording of Mahler Symphony No. 2) the Inspire amp doesn’t deliver the dynamics of the McIntosh MX110Z pre-amp paired with the Scott LK150 (PP KT88 delivering 58wpc). Nonetheless the Inspire amp always sounds good, and sounds fabulous with smaller scale music. I would be satisfied to have the Oppo / Inspire / RF-7 II / R-115SW as my only system, and I think this combination represents a great-value hi-fi system (for an average size room). In other words, IMO additional investment would result in dramatically diminishing returns (assuming an average room size and reasonable listening levels).
I hope that you get your system optimized. What speakers are you using? What deficiencies are you hearing when using the Inspire amp? Where do you live? Perhaps you could hear someone else’s Inspire amp paired with different speakers.