|Adcom GTP-830 AV Preamplifier/Processor|
|Home Theater Preamplifiers AV Preamps|
|Written by Brian Kahn|
|Thursday, 01 November 2001|
The GTP-830 ($1,200) is the latest home theater processor from Adcom, and their first to offer 7.1 processing. The GTP-830 surprisingly features a RDS (Radio Data Systems) AM/FM tuner in addition to its preamplifier and processor section.
The preamplifier-processor section of the unit has five video inputs (three with S-video), a CD input and a tape loop. There are also three digital inputs, one toslink and two coaxial, which are linked to the first three video inputs. Lastly, there is also a 5.1 input for multi-channel SACD or DVD-Audio. The Adcom comes with a variant of the Theatermaster learning remote and also features a 12v trigger to aid in integrating with the rest of your theater system.
The Adcom is a full-featured processor with both Dolby Digital and DTS capabilities. 24-bit 96kHz digital to analog converters are used throughout as well as true 24-bit signal processing for sources at that level of resolution. The 5.1 input bypasses all digital signal manipulation and is affected only by volume and trim controls.
The GTP-830 features four different surround modes: DTS, Dolby Digital, Dolby Pro-Logic and Hall. The 7.1-channel output capability is available in all surround modes. The output is proprietary and not set up for DTS ES or THX EX. Adcom claims its advanced digital bass management reduces phase shifting and keeps the bass tight and defined. The GTP-830 also features dynamic range control for late-night viewing. Unlike many similar systems, which only offer one level of dynamic reduction, the GTP-830 offers four levels of range control.
The video side of the GTP-830 is unique in its ability to up-convert composite video inputs into S-video output. This feature alone normally takes a separate device priced at around $100. I found this feature particularly useful, as it requires only a single S-video cable to be used for the video output.
The RDS tuner supports both RDS PS and RDS RT formats. The RDS system displays information on the front panel of the tuner. In the RDS PS format, that information is limited to the identification of radio stations. The RDS RT format, also known as Radio Text, allows for additional information to be displayed on the tuner. During my evaluation of this unit, I saw various types of information being transmitted through this system, including programming and promotional content.
I utilized the GTP-830 in my reference theater system. The Adcom fronted my system, which also features the following components: Adcom 5802 and 5503 amplifiers, three McIntosh Laboratories MC602 stereo amplifiers, M&K MX-350 subwoofer, Martin Logan Ascents, Theater and Scenarios, Sony DVP-CX850D DVD player, Pioneer Elite DV-38A DVD-Audio player, Pioneer CLD-704 Laserdisc player, ASC room treatments, Barco BarcoGraphics 808s, Silicon Graphics iScan Pro, Monster Cable power conditioning, video and line level cables and Audioquest speaker cables.
Programming the inputs was pretty easy. There is plenty of real estate on the back of the preamp, but there are some limitations as to which inputs go where, especially for digital. Composite can be transcoded to S-Video if needed, but there are no component video inputs, which is perplexing. Component makes for a noticeably better video connection and it’s the way I’d prefer to hook up sources like my DVD player, my DVD jukebox and my Playstation 2, not to mention an HDTV tuner. In an HDTV-capable system, you are going to need to use a completely different video switching system in conjunction with the Adcom. A good Extron switcher alone can cost nearly as much as the Adcom itself.
Music and Movies
The Adcom had no problems decoding any surround format on a level consistent with this class. The Adcom provided a generally smooth and enveloping soundfield, free of any digital artifacts. The GTP-830’s 5.1 inputs provide a clean signal path with no signal degradation. I’d call it sonically superior to nearly every receiver in this price range that I have heard to date.
I started out with an old favorite of mine, Air Force One (Columbia Tri-Star, the newly released Superbit DVD edition with DTS soundtrack). The GTP-830 provided sound that was clean and detailed enough to realistically place the viewer right in the middle of the action. I did all my critical listening with the dynamic range control off and was satisfied with the GTP-830’s overall punch. The sound never seemed to be restricted at any reasonable volume level, regardless of the amplifier combination used.
On U-571 (Universal), the Adcom remained accurate, painting a convincing sonic picture of an underwater world, disturbed only by the deep blasts of devastating depth charges. It appeared to me that the digital bass management was working well, as the bass was consistently tight and detailed, even compared with the results on my B&K Reference 30.
The Adcom’s surround processing remained fairly neutral and thankfully omitted the commonly found distorted and screeching highs. I found that there was some background noise present in just about every source utilized and in every decoding format (excepting the 5.1 input). This noise was only noticeable in a very few passages and did not intrude on the overall listening experience, especially at higher listening levels.
I was dying to try out the GTP-830’s 5.1 audio input for DVD-Audio. I began with Toy Matinee’s self-titled DVD-Audio (DTS) disc. The full and detailed first track "Last Plane Out" enveloped me with its vocals and string work. The percussion was deep and detailed. I noted that the sound through the 5.1 inputs was smoother and lacked the background noise I noted while listening to surround soundtracks that did not utilize the 5.1 input. I got my freak on with the newly-released DVD-Audio disc, Missy Elliott’s So Addictive (Warner Brothers), which further strengthened my initial listening impressions. The Adcom’s 5.1 input provides a clean and pure signal path with no noticeable degradation.
For $1,200, it is hard to argue against the Adcom GTP-830. I would like to see a few more A/V inputs. In today’s increasingly complex systems, four rear-panel A/V inputs don’t really cut it, especially without at least one HD-capable component video input. I would also like to see S-video and digital inputs for each source, or at digital inputs assignable to sources as needed. In comparison to comparably-priced (say, $2,500, including five channels of amplification) Japanese receivers, the Adcom comes up way short in connection options.
As for the sonic downsides, they are fairly minor. Adcom is experienced in building reasonably-priced high-quality gear, which is evident in the GTP-830. I found the GTP-830 to have a slightly higher amount of background noise and a bit more grain than my B&K Components Reference 30 ($2,800) processor. This sonic shortcoming was not evident when listening through the 5.1 inputs.
Bang for the buck – the Adcom GTP-830 delivers a lot of it. For the majority of simple theater systems, the Adcom will fit the bill. The Adcom’s surround processing is accurate and the interface was very easy to use, with the unit automatically detecting the proper input and mode. The Adcom excelled in its video capabilities with composite to S-video transcoding and clean signal paths. Sonically, the Adcom held its own, never becoming uncomfortable to listen to, even over extended listening sessions. The background noise in this unit, while higher than some, is likely to be masked by other components and in any event will be lost in actual listening sessions.
The Adcom GTP-830 is well suited for those with moderately-sized systems that have reached the transition level between mid-fi and the high end. Adcom, with the GTP-830, makes the same decision I would. It forgoes adding a bunch of (useless) features in exchange for a higher quality product.