Price Paid:  $150.00 from Ebay

Summary:
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.

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

Weaknesses:
None.

Similar Products Used:
Sony ES.

Price Paid:  $500.00 from Magnolia HiFi

Summary:
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.

Strengths:
Excellent presentation of surround sound.

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

Similar Products Used:
Too many

Price Paid:  $175.00 from eBay

Summary:
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.

Strengths:
Good Value For Money

Weaknesses:
Doesn't retain memory

Similar Products Used:
None

Price Paid:  $350.00 from Tweeter

Summary:
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.

Strengths:
Looks good on paper.

Weaknesses:
Where to begin?

Similar Products Used:
Yamaha

Summary:
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…

Strengths:
good Dolby performance and separation

Weaknesses:
noise problems; poor engineering quality

Similar Products Used:
Sony Dolby reciever