Adcom GTP-760


The Adcom GTP-760

Adcom's GTP-760 is a preamp/tuner/processor for home theater that supports Dolby Surround, Dolby Digital (AC-3), and DTS. The 760 can control six video sources (S-video or composite), as well as two audio-only sources. For laserdisc lovers, an RF demodulator is included, so you don't need to spend the money on an external demodulator. There are two switched AC outlets of the back of the 760 - which you can use to power things like CD players or control components like Adcom's ACE-515 power conditioner and get your whole system turned on with the touch of one button. In short, you get a lot of neat features.

Now - how well do these features work? Well, that's the whole point of this review.


The GTP-760 is easy to set up. You plug in your audio and video sources, make a few adjustments in the on-screen menus, and you're ready to go. Perhaps the only weird thing you have to do here is you have to set whether the on-screen display comes up on the s-video output or the composite output. To me, this is annoying - the display should pop up on both.

Aside from some gripes below, the 760's pretty easy to use on a day-to-day basis. The supplied learning remote is backlit and easy to use.

Once the 760 is set up, you'll probably run into one of my major gripes with this unit - the volume control. For some reason, the volume control is delayed. Turn up the sound (knob or remote), and the sound doesn't actually get louder until a second or two later. Why this is so is a mystery to me - other users have reported the same behavior, so it's not something that's wrong with my unit. It's just annoying.

Another usability issue is the 760's seemingly random choice of what input is selected when you power the system on. Most of the time, it comes up with the input that was last selected. That's sensible behavior. Sometimes, though, it'll seem to pick an input at random. For example, sometimes I'll turn the unit off with the DVD input selected. Next time I turn it on, I'll (sometimes) get greeted by a blast of loud static, as the 760 decides I really wanted to listen to the tuner (to which I don't have an antenna connected). I wish the thing would just make up its mind.

A third gripe about the usability of the 760 is that sometimes surround modes don't behave as I'd like them to - and there's no way to change the behavior. For example, if I put a CD in my DVD player, I'd like it to play in two-channel mode. Later, I put in a DVD. The 760 sometimes switches to Dolby Digital (which is what I want), but sometimes I get the 5-channel stereo mode (which basically puts the same thing on all the speakers). Like I said before, I wish the thing would just make up its mind.


The GTP-760 comes with a tuner, though I wish they hadn't bothered. It's a rather poor tuner. It doesn't pull in stations well, and it's very basic. Plus, it doesn't even show you what you're tuning on the on-screen display. My HK Signature 2.0 and my old Adcom GTP-500 from the late 80s have much better tuner sections than the GTP-760.

In short, don't buy the GTP-760 for its tuner.


The GTP-760 can control up to six video sources. Of these six, three of these are associated with the 760's digital inputs. The other three are associated with analog inputs. A Dolby Digital-capable laserdisc player will require two of these inputs (one digital, one analog for lsitening to analog or non-Dolby Digital discs). That leaves you with two digital inputs and two analog inputs. One of the analog inputs you'll use for your VCR, and one digital input you'll use for your DVD player. You're left with one free digital and one free analog input.

One set of audio/video outputs can be routed to another room. This is nice, as you can watch one source in one room and another source in your main room. The only drawback here is that the second source is somewhat difficult to control.

The video inputs can't be reassigned, so if you need more analog inputs with video, you're out of luck and will need to spend the $40-$80 for an automatic switchbox. I have several video game systems and had to go this route. If you have satellite TV, you won't be able to hook up your Playstation without a switchbox. Bummer.

No component inputs or outputs are provided. Given that this unit is a few years old, you can't fault it for that.


I had some troubles with the audio on this unit. You have to turn the volume knob up to a little over halfway to get a usable volume out of the unit for movies. However, when the volume knob is up that far, you might notice an audible hiss through your speakers on quiet passages. Adcom, despite their very nice CD players and amps, seems to have never gotten the hang of making a quiet surround processor.

The unit also hums slightly. It's not that noticable unless you're listening to soft music, but I expect better from a component with the GTP-760's list price. The Adcom manual says that there might be a ground loop problem, but my other preamps hooked up identically are quiet, so it's something in the Adcom that's causing the hum.

The unit also seems to have trouble with mode switching in Dolby Digital / DTS modes. Everytime the surround mode switches, there's an audible thumping sound. It's not loud enough to damage speakers or cause headaches, but it's noticable, particuarly when navigating DVD menus. Again, I might expect this from an el-cheapo receiver, but not from a quality component.

The auto-detection on the unit's digital inputs is slower than I'd like. When you play a CD or track forward, for example, the unit takes a second or so to lock onto the new signal. It's not as slow as my HK Signature 2.0 or some receivers I've looked at, but you might want to hook up the analog outputs of your CD player for some discs and if you like to track forward/back a lot. It also makes using the Playstation 2's digital output troublesome, as sometimes the 760 will lose the lock on the digital signal and you might miss some sound effects. In games where there is constant music or effects playing in the background you won't notice this effect.

Speaking of the digital inputs, there aren't enough of them for me. At the very least, I'd have liked another optical input. I have two components that have only optical digital outputs. Since many components these days provide coaxial digital outputs, this won't be a problem for many users.

The GTP-760 has 5.1 channel in for external audio decoders. Supposedly, this set of inputs isn't processed at all by the 760 except to regulate the volume. There is no video input associated with this set of inputs, and I didn't have anything interesting to hook through them to see how they sounded.

The GTP-760 has another nice feature - dual subwoofer outputs. A second sub output is provided for hooking up a second subwoofer. This is a nice touch. The output level on these outputs is rather low, though. Even hooking up both of them to my NHT Sub Two's two inputs sometimes doesn't automatically turn on the sub when I start listening to music. This isn't the fault of the sub - I've hooked the sub up to several different preamps including a different Adcom and the sub behaved as expected. This is probably related to the overall low output of the GTP-760 (see above).

Despite the audio problems, this unit really does sound good when you're watching a movie. You'll want to look elsewhere if you listen to a lot of music or radio.

Build quality

Adcom's stuff used to be made in the USA - now they seem to have moved production to China. Has this affected the quality of their products? I have GFA-535, GFA-545, and GFA-2535 amplifiers (made in the USA) that still work as if they're brand new. They're built heavy and built to last. My 760 suffers from a bad display backlight that Adcom wants $450 to even take a look at. Given the Ebay price of a 760 these days, it'll stay bad. Most functions (except the brain-dead tuner) display on the on-screen display as well as the front panel. In fact, for movie watching you'll probably like a burned-out display backlight, since there's no way to turn the front panel display off.

Looks like Adcom has some quality control issues they need to work on - or they need to stick to amps and CD players.


I've been rather harsh on the GTP-760. It does have flaws. These units sell on Ebay for about $600. Given that price, I can excuse some of the flaws of this unit - because in many ways it's very nice. The remote is good. The unit has lots of nice features (even if some don't work so well). It's relatively cheap on Ebay. Just make sure you get a fully functional unit, as Adcom wants a lot to repair a broken one!

If you can get one cheap on Ebay ($500 or less), the GTP-760's great for watching your Dolby Digital laserdiscs and for using as a controller in a bedroom system. If you mostly watch DVDs or listen to CDs, though, you can do better.without spending much more money. Heck, you can spend $300 or so more and go with the Outlaw Audio preamp.processor - which should blow the Adcom GTP-760 out of the water.

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This web site was last updated December 19, 2009.