As you know, a display's gamma setting interacts with all its other video settings, including color hue and saturation, so it is crucial to get the gamma curve right if you want the best possible picture. Thus, every DVD player should be able to output the correct gamma level and curve, and an accurate picture in all parameters, without relying on adjustments in your display to compensate for its shortfalls.
      The whole concept of independent audio or video components as building blocks in a serial chain relies on the precept that each building block is accurate at its job, so that other links do not have to be adjusted to compensate for its errors. Otherwise there are no standards, and we wind up chasing our tails every time we change the chain by changing serial links. The same argument applies for selectable plural parallel sources for any link in the serial chain, e.g. plural parallel video signal sources for your display. It makes little sense to have no reference standards among parallel program sources, since that forces you to re-calibrate your display for every program source (DVD player, OTA receiver, D-VHS recorder, a second DVD player you want to compare the first one to, etc.). How many video adjustment preset memories does your display have?
      In sum, the GDV-850 offers reasonable DVD player performance for its modest price, but there are compromises, both audio and video, and competing DVD players at a similar price might perform as well or even slightly better. Meanwhile, if you want to enjoy the euphonic sonic transformation discussed above, the GDV-850's toughest competition in providing this comes from Adcom's own GFA-7807 power amplifier, which gives you the same euphonic transformation, without the compromise of gauze veil obscuration heard from the GDV-850.

GTP-880 Surround Processor

      That is the shortest product review you have ever read, and I have ever written. But we owe you (and we owe Adcom) some explanation of why this product in fact does not merit recommendation.
      The GTP-880 imposes an obscuring veil over the sound of all music and sonic events. But it is much worse in degree than the slight veiling heard from the GDV-850 DVD player. Even more importantly, this veiling, instead of sounding like a benignly soft gauze curtain, sounds downright ugly, so it interposes itself as an ugly sounding accompaniment and overlay to all music and sonic events. Specifically, this veiling embodies some of the worst aspects of IC chip sound. It sounds tonally too lean and bright, and imposes some hard glare upon everything. Most annoying (and fatiguing) of all, it features a sandy, raspy distortion that permeates the sound. Just as an emery board with its fine sand rasps away at your fingernails, so also this sandy distortion rasps away at your ears, even as it veils and obscures much of the genuine information contained on a recording.
      As part of our usual thorough analysis, we tested the GTP-880 in three principal modes, involving three different levels of circuit complexity, to analyze just how bad this problem was and where it might be coming from.
      The GTP-880 sounded its best in the expected mode, the direct analog throughput mode, which involves an absolute minimum of circuitry and therefore represents a processor in its purest, most pristine, highest fidelity mode. In this bypass mode, the only thing that a processor should be inserting into the signal path is a volume control and a simple line stage buffer, so it should sound very good. And the GTP-880 reportedly employs a bi-fet circuit for this simple analog stage, presumably a chip selected for superior sonics. So it was disappointing to find that, already in this mode, the ugly sandy rasp, the excess leanness and brightness, the artificial hardness, and the veiling obscuration were all sonically very evident. These flaws were already present in sufficient amount to severely degrade the superb sonic prowess of our lab reference system (when the GTP-880 was inserted all by itself into our reference system), and to completely undermine the excellent sound and euphonic beauty of Adcom's excellent GFA-7807 power amplifier (when the GTP-880 was added to our reference system that already incorporated the GFA-7807).
      We next tested the GTP-880 in the analog input mode but without doing any signal processing. This engages the A-D converters of the GTP-880, and some additional circuitry, but still does not engage the additional chips that do processing (such as Dolby Pro Logic). The sonic flaws noted above stayed the same in nature, but got significantly worse in degree.
      Finally, we also engaged the chips doing the processing, such as Dolby Pro Logic. The sound of the GTP-880 got even worse. Now the ugly sandy rasp, and the veiling obscuration, and the other artificialities were so bad in degree that they dominated the sound, such that the sound seemed strongly processed, as though it had been through a meat grinder. The sound of our magnificent lab reference system had now been reduced to something very like a home theater in a box system.
      To its credit, the GTP-880 does offer a generous set of features, and once again for Adcom at a modest price of $2400. There's a built in tuner, and the GTP-880 offers a bonus surround mode developed by Adcom that sends pseudo-stereo information to the back surround loudspeakers, to provide an enriched surround ambience from many types of recordings. But bells and whistles are not a substitute for good sound, and that's what the GTP-880 still sorely lacks.
      As we've discussed in pervious reviews, surround processors are very complex devices, which necessitate the use of many IC chips and imply at least some sonic degradations. The trick is to get the IC chips to sound good, and to minimize the degradations going through all that complex circuitry. We know that it can be done, since other, better sounding processors have done it (such as our reference processor, the Arcam AV8). The question is whether it can be done at a price matching the attractive price of this Adcom. It may be a tough job, and we would not want to be in Adcom's shoes, trying to deliver so many features at such an attractive price while maintaining good sound. We would hope that somewhere out there is waiting, for us to review and bring to your attention, a surround processor at or near this attractive price that can indeed give you decent sound. What the world needs is a good 10 cent cigar, and a really good sounding budget A/V processor. Perhaps Arcam can rescue the world of good sound lovers on a budget, by shoehorning some of their AV8's superior performance into a processor in this price range.
      Meanwhile, Adcom may well be able to rescue the sound of this GTP-880. The fact that the sonic signature of its flaws is pretty constant for all its stages, and simply increases as more stages are brought into play, suggests a valuable clue to this sonic detective. Perhaps the root cause of the GTP-880's sonic flaws might merely be in its power supply that feeds all the stages, thereby causing the same flawed sonic signature to appear in all stages (even the supposedly better bi-fet analog output stage), and causing it to be additive as more stages are brought into play. The ground reference circuit concept in the GTP-880 might be similar to that in Adcom's GFA-7807 power amplifier, which yielded mediocre sound until we deliberately enabled the power supply ground to help the audio signal ground, via the ground lug on the power cord. The GTP-880 in its present configuration cannot benefit from this user fix, since it employs only a two prong power cord connection with no ground, but this would be easy for Adcom to change. Perhaps, then, a simple, inexpensive modification to the power supply by Adcom might rescue the GTP-880, and make it a worthy contender at its modest price.

(Adcom reviews written Feb. 2004)

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