Adcom GTP-880 AV Preamplifier 
Home Theater Preamplifiers AV Preamps
Written by Bryan Dailey   
Saturday, 01 May 2004

Value-oriented high end - this is how Adcom has long branded their products and their latest series of home theater separates is no exception. Built to be a perfect match for the recently reviewed Adcom GDV-850 progressive scan DVD-Audio/Video player, Adcom’s new GTP-880 7.1 preamp/tuner is chock full of goodies and very competitively priced at $2,400. Features including multiple 5.1 analog inputs, six assignable digital inputs, “Pure Path” component video switching featuring three inputs and one output via BNC connectors with 100MHz of bandwidth for high-definition sources and Adcom’s proprietary 7.1m2 algorithm, to name just a few. This is a serious piece of AV gear, yet simple enough for almost any user to set up and operate.

The GTP-880 has a fit and finish that is as beautiful as the Adcom GDV-850 DVD player. The two are so similar that they might be mistaken for one large component when stacked on top of each other. The unit weighs 28 pounds and is 17 inches wide, five-and-a-quarter inches tall and 16 inches deep. It is available in matte silver or black finish for easy integration into almost any system cosmetically. For my installation, I placed the GTP-880 under the GDV-850 DVD player and both fit inside my equipment rack quite nicely on a single shelf.

The back of the GTP-880 is loaded with connectors, yet is laid out in a very intuitive manner. One of my biggest complaints with AV preamps and receivers is that sometimes companies are forced to jam connectors so close to each other that installing and removing connectors can be a tedious exercise. Adcom somehow found a way to get just about every connection that you could ever want on the unit, yet it doesn’t feel overly cramped. A detachable power cord makes installing or removing the preamp for maintenance or cleaning much easier.

The Right Connections
I have all of the major video game systems, a TiVo and two VCRs, so I can burn through inputs on an AV preamp pretty quickly, but I was able to get all of these components and the GDV-850 DVD player connected to the GTP-880 with plenty of inputs to spare. I still had room for a dedicated CD player and cassette deck should I wish to add those components to the system down the road. In total, the GTP-800 features three component video inputs, five S-video inputs, five composite video inputs, eight analog stereo inputs, two multi-channel (one db-25) inputs, three TosLink digital inputs and three SPDIF digital inputs. For outputs, the preamp has one component video output, two S-video outs, two composite video outs, two stereo and one multi-channel audio output. Is anyone’s head spinning yet?

I give major kudos to Adcom for including two sets of analog inputs for users who have both DVD-Audio and SACD players. I had previously used a Kenwood receiver that only had a single set of 5.1 analog inputs and although I do not have an SACD player yet, I was going to have to get a combo player or manually swap out six cables every time I wanted to switch between SACD and DVD-Audio. Now with the Adcom, I’ll be able to have the luxury of switching between the two formats with a simple press of a button on the remote or the faceplate of the unit. Just having analog inputs is nice, yet without some type of bass management in your system, multi-channel audio often ends up being a recipe for disaster. Adcom has provided analog bass management in the form of a three-way toggle switch that gives you several options, all of which avoid digital to analog conversion. In the “Bypass” mode, the subwoofer is only fed material that is mixed for the .1 channel. The LPF setting, which stands for “low pass filter,” sends full-range audio to the main speakers and the subwoofer receives all signal below 80Hz. The last setting that I found to be most effective when using the smallish Energy speakers in my room is called HPF, or “high pass filter.” In this mode, all frequencies below 80Hz are sent to the subwoofer, preventing the satellite speakers from being fed material that they are not able to properly reproduce. These fixed crossover points may not be ideal for your system and if they are not quite up to your liking, you may need to tinker with your player if it has any kind of bass management of its own.

To power the system, I ran the analog audio outputs from the GTP-880 to the stout Adcom GFA-7805 amplifier via unbalanced RCA interconnects. The GFA-7805 has balanced XLR inputs, but the GTP-880 does not have balanced outs. It would have been nice to have XLR outs, yet there comes a point where you can’t have everything and still keep the price reasonable. Other than not having balanced outputs and no direct digital video inputs (DVI or HDMI), there aren’t many connections that the GTP-880 is lacking.

In a recent survey of readers who were asked what sound formats where most important for an AV preamp to feature, the overwhelming answer was “all of the above.” With the exception of a THX license, the GTP-880 has just about all of them, including Dolby Digital EX, DTS ES NEO:6 and Dolby ProLogic II decoding. It also has 24-Bit / 192 kHz DSP processing and digital to analog conversion. The GTP-880 is smart enough to auto-detect the source material coming from your DVD player, so you won’t have to fiddle with tons of complex menus.

I began my video evaluation with Quentin Tarantino’s stylish ode to cheesy kung fu movies titled “Kill Bill Volume 1” (Miramax). I chose the DTS soundtrack of the “Kill Bill” DVD and the Adcom combo, paired with my Energy Connoisseur 5.1 speaker system, did not disappoint. The GTP-880 automatically sensed the sound format I had selected via the TosLink cable connection from the DVD player. Just for kicks, I changed the sound format to Dolby Digital for a minute and, like clockwork, the GTP-880 automatically sensed the audio format change. After turning the sound back to the killer DTS mix, I cued up the scene in the Asian restaurant/night club where Uma Thurman’s character the Bride, codename Black Mamba, has gone to destroy Lucy Liu’s character O-Ren Ishii, codename Cottonmouth, one of the members of the Deadly Viper Assassination Squad that had tried to kill her.

When Go-Go, the innocent looking Asian schoolgirl with a cold heart and a mean spiked ball and chain, starts swinging her weapon around the nightclub, the speakers began to light up the room. I don’t recall seeing and hearing a demo scene that makes better use of discrete surround sound. As the ball and chain whirls around the room, the sound effects are crystal clear and, at one point when a wooden table is destroyed during the battle, it is possible to hear what sounds like bowling pins crashing down. The Adcom/Energy combo was so clean that it sounded like I was right there in the foley studio as they were adding the sound effects.

After the Bride destroys Go-Go, the sound of hundreds of motorcycles ridden by O-Ren’s henchmen can be heard in the distance. As they arrive and begin flooding into the room to surround the Bride in classic kung fu style, the action turns from color to black and white, apparently to avoid an NC-17 for violence if the subsequent copious flow of blood were to appear in color. The color to black and white change was a formable test for the component video inputs and outputs on the GTP-880. The contrast was stellar and none of the detail of the scene was lost when moving from color to black and white. The shiny blades of the swords, the spurting blood and the sweat on the brow of the Bride were not washed out.

Watching Disney’s “The Haunted Mansion” starring Eddie Murphy, the latest in their batch of popular rides turned blockbuster movies, I was impressed by the clarity of the sound and picture during the opening THX logo and Disney Home Video logo. Ironically, the THX certification is one of the few badges that this Adcom combo does not sport. However, the Dolby Digital surround soundtrack sounded particularly good. The spooky voice that guides guests through the Haunted Mansion at Disneyland begins the movie and is particularly faithful to the sound that you hear on the ride. The movie is as one might expect, a little on the hokey side, with multi-million-dollar special effects and a plot that seems a little forced, but the Adcom again performed flawlessly.

Queen’s tune “Bohemian Rhapsody” from the DTS Entertainment DVD-Audio release of A Night at the Opera (DTS Entertainment) is the track that I usually use to show my friends and neighbors the power of DVD-Audio. This familiar song gave me a chance to try the three different bass management settings on the Adcom GTP-880. I was using fairly small rear speakers and medium-sized floor-standing fronts, so I found the HPF setting to be the most effective, sparing the small rear speakers from being overloaded with low-frequency material. The rear speakers get a workout on this entire disc, and “Bohemian Rhapsody” is no exception.

Moving from ‘70s classic rock to early ‘80s jazz/R&B, I cued up the album Winelight by saxophonist extraordinaire Grover Washington Jr. on DVD-Audio (Elektra/Rhino). Like the audio on “Kill Bill,” the sound on this DVD really takes advantage of the rear speakers. The huge reserve of power available from the Adcom amp allowed me to push the volume up to obscene levels, higher than I’d ever normally listen to, yet it remained clean and articulate. The signature track on this album is the classic “Just the Two of Us,” a song just about everyone has heard before. In surround, it was familiar and new all at the same time. The analog inputs of the GTP-880 added minimal if any coloration to the sound. The marimbas and percussion elements moved around the room in an interesting but never cheesy manner. The percussive higher tones from the bass strings came through in the main speakers but the real bottom end was properly reserved for the sub. The onscreen image of Grover playing his saxophone was rock solid, thanks to the clean video output of the GTP-880. This disc makes one thing very apparent. Kenny G can’t even carry Grover Washington’s saxophone case to work.

TiVo and Video Games
As important as it was to evaluate some DVDs through the GTP-880, my TiVo is really the item I use most on a day-to-day basis in my home theater. I used “Video Input 1” of the AV preamp via S-Video and a pair of RCA cables for audio to connect the TiVo. It was a breeze to hook up and the preamp automatically sensed the type of video and audio connections that I was sending to it. Unfortunately, I do not have a digital output on my particular TiVo unit in this room. However, the GTP-880 could sense the analog Dolby Pro-Logic output from my TV and all I had to do to get the TiVo working was press “Video 1” on the preamp’s remote control or the receiver’s front panel. The speed, from the time I selected a new input on the GTP-880 to the time that it switched over, was virtually instantaneous. I have seen some AV preamps that have a more noticeable delay when changing inputs, but the GTP-880 is as quick as I could ever ask for.

The sign of a good AV preamp is that it does its job but stays out of your way, so that you almost forget it’s there. To test this, I used my Microsoft X-Box, first by playing some video games with the system plugged directly into the set of RCA jacks on the front of the TV. This meant the sound was in stereo but the picture was as direct as possible. I played some games on the X-Box, including Microsoft’s NFL Fever 2004, a game that always makes me wish it could always be football season. After several games, I then took the same set of analog outputs and brought them into the GTP-880 to see if it was adding any kind of visual distortion. The image of the X-Box had a little more color saturation, but the average person would be hard-pressed to tell the difference between the two images. I found the picture improved even more when running through the AV preamp after I replaced the S-Video cable going from the preamp to the TV with a higher quality one from Accell. The GTP-880 is so good that you can actually see the difference when you upgrade the quality of the cables. When using lower-end AV preamps or receivers in the past, the quality of the cables that were used was not such an important factor.

7.1 Surround
Not many people truly know what 7.1 surround is, but chances are, if you asked average home theater shoppers if they want to have it in their next systems, they would most likely say, “Yes.” At present, there are barely any software titles that are 7.1. However, manufacturers have found a way to split the rear channels and distribute it to an extra pair of speakers that are defined as “right back” and “left back.” My room has an awkward shape that does not lend itself to having rear speakers other than the standard surrounds, nor side channels. However, for this review, I temporarily added a pair of Polk LSI speakers so I could test Adcom’s very own 7.1m2 surround mode. I was a little skeptical, but the algorithm that is done for the rear channels sounded much more natural than I would have expected. Note that you’ll have to have an amplifier like the GFA-7805 that has speaker outputs for all of the speakers when doing 7.1. It was obvious to me that I wasn’t hearing true discrete surround, but the rear soundstage opened up a little on both “Kill Bill” and “The Haunted Mansion” DVDs when running in 7.1 mode. I would have probably kept this set-up if I didn’t need to place one of the speakers on top of a stepladder in the room for the purposes of testing the GTP-880 in 7.1. It’s not the must-have feature that many people think it is, but it’s a nice feature to go along with a preamp already filled with many bells and whistles.

AM/FM Tuner
I do most of my radio listening in the car, so it’s rare that I come home from work, plop down on the couch and listen to some talk radio or “Get the Lead Out” on the classic rock station in LA, but for the sake of being thorough, I gave the tuner on the Adcom a try. With the ability to store 30 FM presets and 10 AM presets and a simple method for locking the presets in, I quickly had all of my favorite stations at my fingertips via the remote control. Using the tuner by hand to get the stations set the first time was a little cumbersome, as the tuner would not scroll through the stations quickly. It would stop automatically at anything that it sensed was a radio station, even if it just sounded like pure static to me. When going from 97.1 to 101.1, the tuner stopped about 15 times, even though I know of only about five other stations in between these two. Once I made it though the FM and AM dial with all of the stations that I regularly listen to, this was no longer an issue. The touchiness of the tuner dial could actually be looked at as a benefit in that you might find stations that you might not have known about, but if your tuner presets were ever lost and you wanted to quickly scroll from 101.1 to 106.7, it’s going to take you a good deal of time.

Sonically, the radio tuner was better than I expected. My living room is sunk down and has a block wall under the drywall that is the backside of my garage so it’s hard for me to get a really solid radio signal in it. After playing with the position of the AM and FM antennas, I was able to get an acceptable signal for both bands and listened to a variety of stations. I know that, in a pinch, if there is a specific radio show or sporting event that I’m dying to hear, I’ll be able to pick it up and enjoy it, thanks to the GTP-880’s tuner.

The Downside
The most glaring omission, an understandable one given the price and age of the GTP-880, is its lack of a direct digital connection via DVI or HDMI. I hear people in the industry saying that if a preamp does not have this type of connection, then the product is obsolete and it’s not worth owning. I disagree with that statement, because as much as we like to believe the whole world is going digital, there are still a great number of people who have already invested in TVs and other displays that do not have the ability to accept a digital input via HDMI or DVI. Add to that the fact that only a few DVD players currently have digital outputs and you are talking about a relatively small number of consumers who are ready for this feature. Sure, the number is going to grow and there will be a time when a preamp without a direct digital signal switching will be obsolete, but that is at least several years down the road.

Looking at the balanced XLR connectors on the back of the Adcom amplifier made me wish that it had balanced outputs like those on the back of the Sunfire Theater Grand III and IV. These are more expensive units, so it’s understandable that they would have more features. However, it feels like a bit of a tease by Adcom to have an amp that has balanced inputs while one of their best AV preamps doesn’t have balanced audio outs. Of course I want full balanced operation for the preamp, but that is likely just too much to ask for in a $2,400 AV preamp that is already loaded with features.

With a price tag of $2,400 the Adcom is priced exceedingly well and competes favorably with products such as the more expensive Anthem AVM20 ($3,199) and Sunfire’s latest Theater Grand IV ($ PRICE?), but if you are making the move up from an all-in-one receiver, the price of purchasing the preamp and a separate 5.1 or 7.1 amplifier may still give you a little sticker shock. You’ll want to have an excellent component DVD player, such as the matching $999 Adcom GTP-850, so you’ll need to budget for that as well. You will also have to make extra room in your rack for two or three separate components, but the added price and small inconvenience of adding an amp to your system will pale in comparison to the performance benefits that you will get.

The list of features that you get in this AV preamp for less than $2,500 is mind-boggling. The clean lines and intuitive layout of the GTP-880 make it easy for the weekend warrior to hook up and your custom installer will be able to make it jump though just about any hoop you need. The amount of inputs and outputs will satisfy the needs of almost every consumer and the ability to run the preamp to a second room makes it that much more valuable.

The remote is simple to use and, as I have found with all of Adcom’s current products, the instruction manual is topnotch. Simple wiring flow diagrams take much of the guesswork out of doing complex installations. Just about every scenario that I could think of is covered in the instruction manual in one way or another. When you are ready to move up from a receiver that is underpowered and has run out of inputs, pick up a nice multi-channel amplifier and audition the Adcom GTP-880 AV Preamp.
Manufacturer Adcom
Model GTP-880 AV Preamplifier
Reviewer Bryan Dailey

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