McIntosh C2200 Tube sound, Tone control

Brand new bulb replaced with led lights. Treble & bass control. Phono inputs and multiple pre-out that allows u to connect to a second amplifier or sub-woofer. Balanced and RCA input/outputs.

The C2200 has been designed from scratch, and has virtually every modern feature you can hope for in a modern preamp. The C2200 is rated as having a 93 dB S/N ratio, but McIntosh notes this rating is very conservative, and that production units can measure 110 dB at 2 volts output, close to the 112 db at 2 volts output of its best solid-state unit.
Circuit and Features
The active circuitry uses two 12AX7A and two 12AT7A twin-tri-ode tubes, tubes well known to most experienced audiophiles. The same tube compliment is duplicated for the moving-magnet phono section. It operates these in a conservative manner for long life and high performance. Tube management is enhanced by muting the outputs until delay circuits sense the tubes are stabilized, to prevent noise generated by other components being heard during warm up.
The C2200 is designed to work as well with solid-state amplifiers as with tube amplifiers - indeed to be largely insensitive to amplifier load. It also has a host of modern features lacking in most tube preamps. These include eight source selections for unbalanced inputs while four of the eight also have balanced inputs. Any of 12 standard names can be assigned to a source selection and the panel display can be customized to indicate only available sources. There are three balanced and three unbalanced outputs, one main and two switched from the front panel. There is also a tape recorder loop.
Switching and signal routing use digitally controlled electromagnetic switching devices. The switch contacts are isolated from environmental contamination inside inert gas-filled glass tubes. One, two or three power amps may be run at the same time either balanced or unbalanced and the C2200 will swing enough voltage to drive any combination of McIntosh amps to full power. The C2200 can be controlled from a remote area using an IR eye or McIntosh WK2 keypad. This allows two amps to be used in two zones or one at a time from either area. The C2200 will go into a slave "pass-through mode" if so desired so as to be folded into a multi channel set up. All McIntosh HT controllers will work with the passthrough feature and the C2200 is at unity gain when in pass-through. For you interface freaks, there are component source data ports, and three programmable triggers for controlling other units.
All of the front panel controls "talk" to the microprocessor including the volume control, which is a digital encoder. The C2200 has the ability to have the source names changed to reflect the actual components used by a consumer. Six of the inputs can be renamed to any of the 12 on the handheld IR remote control. This feature, however, is a mixed blessing at best. You cannot transfer key names like phono, CD, and tuner to the balanced inputs.
The volume control uses an output attenuator that controls volume over 214 steps of 0.5 dB each with accuracy within 0.1 dB. The volume versus rotation rate varies as preamplifier gain varies and attenuation changes occur at the zero crossings of the audio signal to prevent audible artifacts during adjustment. The 214 step ladder resistor grids have a dynamic range of 120 dB and are controlled by a digital microprocessor. This microprocessor allows the source levels to be offset +/- 6 dB for level matching, and controls programming of other features through the set up menus.
The C2200 also uses post attenuation: A second set of volume controls tied to the main volume control to reduce the output amplifier gain to unity almost immediately as the volume is reduced. This sharply cuts low-level noise and allows the tubes to operate in what McIntosh says is their operational "sweet spot."
The bass and treble controls are the only analog pots, and their turnover points and rate of adjustment are well chosen to both boost the deep bass and roll off excessive treble energy without deadening the sound. Others include a doubleshielded power transformer; high-quality caps, low-noise 1-per cent metal film resistors; an IR remote control; and a front panel headphone jack.