Preamplifiers

Parasound 2100 Stereo Preamplifier and 2250 Stereo Power Amplifier

ARTICLE INDEX

The Design

As one would hope with high quality electronics, a cursing UPS driver delivered the Parasound pair. I guarantee I will not be on the UPS Christmas list with all the incredibly heavy boxes delivered to my house. While not ridiculously heavy, the Parasound amp and preamp need to be shipped in sleeved heavy duty boxes with built-in plastic lifting handles.

After unpacking, one can see why they are heavy, as both units are housed in heavy gauge pressed steel chassis with a crackle black paintjob. Unlike Emotiva, each component gets its own custom designed enclosure. Both the amp and preamp sport a machined aluminum face, with very clean and unobtrusive cosmetics.

The Model 2100 preamp has a relatively slim enclosure, with simple front panel controls. A rotary encoder is used to switch between sources with relay based switching. A potentiometer does volume control duty, in addition to pots for sub level control, tone controls (defeatable), and balance. A mini-jack input labeled "MP3" is available on the front panel for iPod connectivity, in addition to a mini headphone jack. A vacuum fluorescent display shows the selected source and tone settings. For those like me who want to integrate a high quality two-channel preamp in their home theater setup, a bypass input is available that simply routes a set of inputs through the preamp, allowing use of an SSP for home theater duty.

The rear panel offers a slew of RCA single ended inputs, but no balanced inputs or outputs. A phono stage, based on the well-received Zphono preamp, is included, as well as a defeatable subwoofer crossover. While only a single pair of RCA outputs is provided, the Parasound amps all offer daisy chained RCA outputs for additional connectivity. For custom installation, RS-232 control, as well as 12V trigger inputs and outputs are provided.

The simple remote for the model 2100 gives you all the controls you need, and none that you don't.

Inside the 2100 preamp chassis, all the circuitry is contained on three PCBs. A small but well built power supply board supplies the DC power to the other two boards. Behind the front panel lives the control board, with all the front panel related electronics. This talks to the main audio board located at the rear of the unit via several discretely wired umbilical cords. The amplification is based on TI NE5532 dual op-amps, with relay-based source switching. Compared to the Emotiva RSP-1, the Model 2100 gives up a little in internal features (the Emotiva RSP-1 offers a larger power supply, higher quality op-amps, and balanced inputs and outputs), but it is still clear that the Model 2100 is a very well built component that belies its $600 price tag.

The model 2250 power amplifier is a beefy 250WPC stereo amp capable of delivering 45A peak into each channel. The amp is housed in a matching crackle black painted chassis with a machined aluminum front panel. Given the considerable heft of the amp, the lifting handles mounted on the rear panel were a welcome addition. Dual binding posts are provided, but not for bi-wiring. Two sets of speakers can be connected to the amp, and selected via an A/B selector on the front panel. An extra set of loop RCA jacks on the rear panel allows daisy chaining amplifiers or connecting to an active subwoofer. The amp can be bridged to mono to deliver 600W of power. A ground lift switch is provided to get around ground loop noise problems. Auto turn-on is present, as well as an adjustable level control. This can be set to a reference detent when not needed.

Inside, the amp has a single large power transformer, and two large extruded heat sinks dissipating the waste heat of all the output transistors. The amplifier's circuitry is contained on a single large PCB, independent from the power supply. This is a traditional stereo amplifier topology, as opposed to the dual-mono construction of the Emotiva RPA-1 that has two separate power transformers and two separate circuit boards for the right and left channels.

The Parasounds stuck mainly to my preferred ideals of offering only necessary features without lots of extra bells and whistles. I could have done without the adjustable gain on the Model 2250 (just another pot for the signal to go though), and the inclusion of tone controls and a subwoofer crossover on the Model 2100, but overall the execution of these two products was excellent.