Received the very powerful Crown 802D amplifier this week. After the $150 rebate this amplifier is a real value at $400. Please refer to the attached picture as it depicts the internals of the amplifier. The 20 power transistors and 10 individual heat sinks layout is new and nice. I think is superior to the common tunnel sinks. Each channel has a 20 amp switched output relay.
The fans are of excellent quality and do not need to be replaced. For home use installed one 47 ohm 10w power resistor (from Radio Shack) in series with the 12 volt supply to reduce the two fans rpms.
The layout could be better as the input audio signal goes up one side of the power supply board right next to the rectifier block. This physical coupling induces diode switching noise into the audio signal. Worse its tied to the secondaries of the power transformer. As a result the amps signal to noise ratio is poor. As a result you can hear noise even in the tweeter that is just not there in modern amplifiers.
This grey ribbon cable is glued in place and is not practical to modify. So I could only cut the plastic ties and separate the audio cable from the others. This helped somewhat.
The front panel gain pots are of good quality and were set to their maximum for best sound quality.
For conspiracy theorists are Crown and Tapco are deliberately designing in sub-optimized layouts to give buyers a reason to buy their other highly profitable lines? Or are the Chinese designers just inexperienced? I dont know but the evidence is certainly there.
The sound quality is powerful yet at ease, very listenable. In other words that signature XLS sound quality. The TL072 op amps err on the side of warmth and being a bit too homogenous. For my system the solution was to insert an 80 cent A/C ground lifter plug. Now the 802 sound qualities can be described as very powerful, articulate and with wide tonal range. It sounds wonderfully just right.
Contrast this to my modified Tapco 1400 (gain pots and cable near power supply removed, fans replaced) with its 5532 op amps, which errs on the side of being a bit to vivid. (Its all about spectral balance.) But once again inserting the ground lift corrected its anomaly too. It sounds just right too. Next I have to intensely compare them both to finalize which amp is to drive which channels (or subwoofers).
Ensuring that all four amplifiers and 7 speakers are in phase is a time consuming effort. Multi-channel speaker placement is very tough to optimize as the surround channels bass can interfere with the front. I only position the L&R surround to face each other and never toward the front. Your mileage may vary but good luck placing two speakers essentially out of phase with each other and you in the middle.
I drive my system with the new $900 Denon 7100 professional A/V controller. Its the best match I know of for driving any professional balanced input amplifiers.
Denon 7100 Preamp Spec Sheet.pdf 314.373046875k . file
