Very good sound, well built, simple to use, very cheap as used.

None.

Just a little note about the noise coming out of all the 5 channels. I was shocked about it in the beginning, could not believe that an Adcom product would have that hiss. The 560 was simply plugged into the mains in the beginning. Then I plugged it in my Monster Power HTS-2500, and guess what, that hiss disappeared absolutely, it's gone forever.

Similar Products Used:

Sony ES.

Excellent presentation of surround sound.

Some bleedthrough on center channel but not a major problem when you consider what it does do right.

First off, lets put things in perspective. This Adcom processor has three built in high current amps (one for center and two for rear) and when added to your existing two channel stereo it completes a quality Dolby Prologic surround system. This is a great way to keep your high end two channel components and still have quality surround sound. Unlike some cheaper units it uses a analog steering system (highly desirable) rather than the digital steering system found on other run of the mill products which equates to better dynamics and sound quality. If your not hung up on Dolby Digital this is still a good value and you can use the analog outputs of any dvd player to derive surround sound. This unit is not without it's minor problems but they are easily overshadowed by it's impresive presentation.

Similar Products Used:

Too many

good Dolby performance and separation

noise problems; poor engineering quality

Associated equipment for the GSP-560 review: Acurus DIA-100 direct input amplifier, NAD-502, Rotel-855 and Sony XA20ES (ES line) CD players, Adcom ACE-515 power conditioner, Adcom GFT 555 MkII tuner, Vandersteen 2ce speakers (biwired), all interconnects Kimber "PBJ", and speaker cabling is Kimber 4TC (highs) and Kimber 8TC (lows).

Well folks let me first say this is the product that caused my local high end dealer to stop carrying Adcom! He reports that many of the GSP-560's that went out the door came back for amplifier or processor problems. Having said that, mine has skipped a beat other than that all too well documented noise from it’s amplifiers.

I contacted Adcom after I purchased the GSP-560 and explained to the engineer my mass market Sony receiver never made such noises. The nice gentleman form Adcom then said something I was shocked by. He stated "well if the local cable company isn't properly grounding their signal, the unit will produce very bad noise because we have not designed a ground for this problem into the unit". (I again noted my mass market Sony receiver didn't suffer from this design blunder at a fraction of the cost). The Adcom engineer told me to "go to Radio Shack and get a cable grounding system" for which he provided the part numbers. (Sounded as if he had been through this conversation many times before). The "fix" which was actually 2 male to female adapters, eliminated the hum and noise from the GSP-560 but in the process badly degraded my video signal. Not a good compromise. Luckily I moved to a different house shortly thereafter where the cable was properly grounded. End of noise problems right??? (Wrong). In my new home I had designated a home theater area in the basement complete with new theater-type lamps. They use florescent bulbs and guess what…more noise from the GSP-560! My Acurus DIA-100 amplifier makes no noise whatsoever, nor do my source components all of which are filtered by an Adcom ACE-515 power conditioner, but the old GSP-560 hums like hummingbird! This is really inexcusable for a "highend" product to be designed so badly. Yes I also get the humming through my rear channels and center channel. Once the lights are turned off or to the brightest setting with the reastat the humming disappears completely. So for those of you who are having noise problems check to see if the cable is grounded or if room lighting is the source of the noise.

Having pointed out the obvious design flaws, I must admit the GSP-560 is excellent when used for video surround sound. It is not in the same league as my Acurus amplification and when used in the "stereo' mode veils the sound and places a slight "glaze" over the entire soundstage. I do occasionally use it in the "5 channel matrix" setting to play back old monophonic recordings. It's a mixed bag in the long run. Driving my home theater setup it actually sounds very good. Decoding is excellent compared to my earlier Sony, but there are no user friendly features to remember settings after power failure, the remote is useless if even slightly off axis, and the "rear/cntr channel reset" button is directly next to the "balance check" button to set the output levels resulting in several accidental default resets when trying to verify the proper settings.

All in all a very bad showing from Adcom in spite of very good sound quality. I'll rate the GSP-560’s sound quality 4 but reduce my overall rating to 2 due to all of the design and engineering problems noted above. On a brighter note, I have never had these type of problems with other Adcom products, and my dealer states I am lucky my 560 is still working properly after this amount of time. But I'm out of luck if it fails now because all local dealers have stopped carrying Adcom, so fingers crossed it will serve my need until I decide about the next upgrade out of the Adcom line. A big disappointment from such a reputable company…

Similar Products Used:

Sony Dolby reciever

Looks good on paper.

Where to begin?

I installed this unit in a system with B&W matrix speakers and M-L mains for HT use. Although the amplifiers are pretty powerful and the Pro-Logic decoding was quite good (when the unit was functioning), the pros end there. Cons include:

1) Frequent, complete failures of the power amplification. Of the 3 years I owned this unit, it spent about 11 months at Adcom being repaired.

2) Noise and hiss in the amplifiers, which my speakers rendered with great precision.

3) Substantial bleed of the signal to the mains into the surround system, such that when listening to 2-channel music on the mains I would get little bursts of static from the other three channels on the beats. Irritating in the extreme.

4) Poor design of the channel balance system. Every time power was lost, all of the channel level information was lost and the unit had to be rebalanced completely from scratch.

5) Cheap parts and switches--buttons having to be pressed several times before they "take," that sort of thing.

In sum, this is easily the worst piece of audio gear I've ever owned. Absolute garbage. When the amps finally went out for the last time, I insisted on dumping it in the trash can rather than donating it to Goodwill or some other organization--nobody was going to deny me that final bit of joy.

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Yamaha

Good Value For Money

Doesn't retain memory

I have this in my HT set-up and think it is fine for the money i paid. I do get a vey slight hiss from the center speaker but it not noticible and is normally drowned by my Vandersteens anyway.

This was my first SS processor and I am now moving to a digital set-up. My unit has always worked flawlessly and I have had absolutly no problems with it.

I will give it 4 stars especially since you can get them on ebay now for $130-$150. That in my book is a great value.

Similar Products Used:

None

kevin,you must have got a great deal on yours because the GSP-560 LIST PRICE is $600.00, it sells used for about 300.00 dollars. I truely like adcom products. I've owned and still own several adcom products. Including the GSP-560. If you are not into dvd and just want great sound from your vcr for you home theater, this is the one. It is simple without all the buttons to get lost in. It sounds as good as any theater you will go to, in the privacy of your home. It does everything it should do, without straining your brain or your budget. Which isn't that what we want?

Just purchased the GSP560 processor for a price I couldn't overlook. Unfortunatley it is not Dolby Digital, but this is the first addtion to bringmy current system into the home theater world. Has anyone had any dealings
with this processor and could you let me know what you think?

I bought a used 560 2 weeks ago and I am not very happy with it. Thankfully I only paid $150 for it as a temporary solution for my HT. The static noise during low volume scenes, from the central channel, is getting on my nerves. I don't now if the amps are fried in this unit, but I have to turn it 60% up before I get good sound out of it, and that is with very efficient Klipsch speakers. I must say it does sound good with DolbyPro effects on. I would give this thing a 1 star, but because of the price I will give 2. Got what I paid for.

ADCOM GSP-560 - fading center volume
I have had the GSP-560 (paid close to $ 600 list) in my configuration for several years now with a GTP-450 and GFA 545II- driving Klipsh's and a Velodyne sub. Here;s my take:

Overall system - great sound system for home theater and normal stero; excellent fidelity with the GCD-700; and thunder is awesome -
Other Surround modes - less than impressive but ok - have to reset all the levels when you go from prologic to the others
Stero Bypass Mode = too much loss - better to exit the processor loop altogether
On Dolby Prologic mode when it is working is great - I;ve had a nagging problem for three years - the center dialog channel volume just fades out sometimes for no reason - souce input does not matter - back at ADCOM for the third time - Overall I am dispointed in ADCOM service but happy with the sound .

Inexpensive way to add Prologic to a two-channel system (used price on these is about $150)

It's too noisy when listening to stereo sources.
Low tolerance for differing input levels.

Luckily, I got this equipment used at a cheap price. Dolby Prologic from laserdisc sources sounds nice. However, The unit suffers from several boneheaded design flaws:

1) It's too noisy. As others have pointed out, a "buzz" comes through the center and surround speakers when listening to two-channel mode (why are the amps for these channels even on when we're not using them?). Depending on your speakers and listening volume, this can be barely audible or REALLY ANNOYING. This noise is also passed through into the line-level outputs (doh!).

2) It forgets level settings when it loses power. This would be less of a problem if the defaults were sane. Instead, center and surround levels are by default set to be barely audible.

3) Despite having inputs, it's difficult to use as a preamp without overloading it (causing popping noises). Basically, ignore everything except the main input, and run THAT with another preamp. Also, you'd think that something which was meant to turn a two channel system into a home theater would have some sort of video switchingcapability.

I could easily forgive 2 and 3 if 1 wasn't there. Adcom's put out the GSA 700 which appears to address at least some of these flaws. The 700, too, can be picked up cheaply. It's also DD-upgradable. 3 stars because it was cheap. I'd rate it much lower if I paid list.