McIntosh C1000 Stereophile Review - The Listening Post

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MCINTOSH C1000freedom from overload, noise increasesas the volume is lowered. Lower backgroundnoise can be achieved by placingthe volume control after the gainstage, but at the expense of dynamicrange and the ability to prevent inputoverload. McIntosh’s solution is to usetwo volume controls, one before thegain stage and one after; they claimthat this results in wide dynamic range,freedom from input overload, and animpressively low noise floor of–118dB. The two volume controls arelinked together and controlled by whatMcIntosh calls a Dynamic ControlMultiplexer.There is a separate Mute button;when you mute the C1000, the soundstops suddenly and completely, thoughit ramps up pleasantly when you wantto listen again. I liked that feature.For the C1000, McIntosh’s engineersdeveloped a new, fully shielded,low-noise MM/MC phono preamplifierthat can handle medium-low-output(0.45mV) MC cartridges withoutneeding a step-up transformer.Ultralow noise is claimed, thanks tothe shielding and a dedicated doublefilteredpower supply. Both the tubed(four 12AX7s) and solid-state phonopreamps are specced equally in termsof MM/MC input sensitivity, thoughthe solid-state model’s signal/noiseratio is 88dB to the tubed version’s80dB. Both offer the same loadingfacilities: for MM, 47k ohms, with50–750pF in steps of 50pF; for MC,25, 50,100, 200, 400, or 1000 ohms, inparallel with 100pF.Setup and programmingThe C1000C controller’s Setup mode(push the Setup button) will confoundaudiophiles used to straightforwardplug-and-play preamplifiers. (Thankgoodness I’ve set up and programmedhome-theater receivers.) While youcan operate the C1000 with its factorydefault settings, it makes more sense totake advantage of its flexible configurability.In fact, for certain functions,you’ll have to. Within Setup mode, theListen, Balance, and Record buttonsassume fresh identities that can be confusingif you’re not careful. It’s easy toget lost in the maze of possibilities, andonce you’ve made a change, it’s easy toforget what you did, and damned difficultto figure out how to get back towhere you once were.At one point, I auditioned the latestversion of Merlin’s VSM loudspeakerfor a Follow-Up review. Programmingthe C1000’s processor loop so it wouldpass through the unit’s electronic BAMoutput) of 116dB! The C1000T was not in that class butwas still good, with the same measurement giving 76dB,which improved to 88dB when A-weighted.The C1000P and C1000T could both swing very highoutput voltages. Figs.5 and 6 show how the percentage ofTHD+noise present in the balanced outputs of the ’P and’T, respectively, changed with output voltage into 100kohms and 600 ohms. The solid-state preamp clipped (1%THD+N) at 32.5V into the higher impedance and at 18Vinto the low load, with the maximum unbalanced outputhalf these figures, as expected. The tube preamp clippeda little earlier, at 20V into 100k ohms and 11.3V into 600ohms, but the difference is academic—any power amplifierwill be driven well into overload at these levels.The downward slope below 10V of the traces in figs.5and 6 suggests that actual distortion is buried under thealready low noise at normal signal levels. To examine howthe THD+N percentage changes with frequency, I thereforechose a high output level: 10V for the C1000P (fig.7)and 5V for the C1000T (fig.8). Into high impedances, theTHD+N remains constant with frequency in theFig.7McIntosh C1000P, balanced THD+N (%) vs frequency at 1V into(from bottom to top): 100k and 600 ohms (right channel dashed).Fig.6McIntosh C1000T, balanced distortion (%) vs 1kHz output level into(from bottom to top at 1V): 100k and 600 ohms.Fig.8 McIntosh C1000T, balanced THD+N (%) vs frequency at 1V into(from bottom to top): 100k and 600 ohms (right channel dashed).www.Stereophile.com, August 2006 4
MCINTOSH C1000bass equalizer was a nerve-rackingexperience requiring the combinedbrain power of three not-stupid individuals.The instructions try to beexplicit, but too few examples are provided—andif you don’t get it right, youget no sound.Among the Setup features are inputleveltrim, so that the volume doesn’t“jump” between inputs; a Pass Thrumode for use in a multichannel sound orhome theater system; adjustments forthe fluorescent display and meter brightness;input title reassignment (forinstance, if you have a DVD playerplugged into the Aux input, you canchange that input’s label to read“DVD”). And, of course, in Setup modeyou can change MM capacitance andMC resistive loading. You can even setthe C1000 for mono operation, via theSetup menu or the remote control.Actually, there are two remote controls:a plastic, full-function, A/V receiver typethat can control other McIntosh products,and a hefty model of extruded,anodized aluminum that controls basicfunctionality. The latter is the one you’lluse most of the time, especially whenyou show off your C1000 to friends.Using the C1000When you have both the C1000Psolid-state and C1000T tube preampsconnected, the C1000C will recognizethe fact and double your input-selectionoptions. Scrolling through theseoptions can be tedious, especially whenyou’re not using all of them: CD1,D/A, PH/MM1, PH/MC1, DVD2,Aux2, Tuner2, Srvr2, CDR2, CD2,PH/MM2, PH/MC2, CD3, Srvr3,CDR3, Srvr1, CDR1. Early on I reassignedone input but can’t remembernow what I did. I kept forgetting whatwas where, and often did a lot of huntingto find the input I wanted, but itwas hardly painful. Otherwise, onceeverything’s up and running and programmedto your liking (a big otherwise),using the C1000 is easy.The C1000C switched between thetubed and solid-state preamps seamlessly,the meters on each are activatedonly when that preamp is selected. Asfor which you’ll end up using for eachsource, that will take some experimenting—onepreamp or the other willsurely be more complementary to eachTHE C1000P SOLID-STATE PREAMP DELIVERED ABLOOM USUALLY ASSOCIATED WITH TUBED GEAR,WHILE THE TUBED C1000T PRODUCED THE EVEN-HANDED TONAL BALANCE AND NEUTRALITY ONEUSUALLY ASSOCIATES WITH SOLID-STATE.source. That said, the tubed and solidstatepreamps sounded more alike thannot, which is how it should be.A sonic delicacyWhile the C1000 outputs single-endedsignals, I felt it important also to listenin balanced mode, so I borrowed a pairof mbl 9007 balanced monoblockpower amplifiers (review in theworks). I also auditioned the C1000using my reference Musical FidelitykW single-ended monoblocks.The C1000’s sound remained consistentrun either balanced or singleended.The C1000P solid-state preampdelivered a bloom usually associatedmeasurements, continuedaudioband for both the ’P and ’T, the former offering avery low 0.001% or less compared with the latter’s stilllow0.016%. Into 600 ohms, however, these graphs showthat the actual THD rises at both very low and very highfrequencies, though not to any extent that might evenbegin to be audible.At normal levels, spectral analysis reveals that the harmoniccontent is vanishingly low for both preamps:0.0005% (true sum of the harmonics; fig.9, C1000P;fig.10, C1000T). The increase in THD at low frequenciesand high levels into 600 ohms was due primarily to anincrease in the subjectively innocuous third harmonicFig.9McIntosh C1000P, unbalanced spectrum of 1kHz sinewave,DC–10kHz, at 1V into 8k ohms (linear frequency scale).Fig.10 McIntosh C1000T, unbalanced spectrum of 1kHz sinewave,DC–10kHz, at 1V into 8k ohms (linear frequency scale).www.Stereophile.com, August 2006 5
Page 1 and 2: EQUIPMENT REPORTMichael FremerMcInt
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Page 7 and 8: MCINTOSH C1000Phono preamps: tube v

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