Home > Consumer Reviews > Onkyo A-9555S Integrated Digital Stereo Amplifier (Silver)

This is one of the best products I have ever purchased. If you are a crazy audiophile, you will no doubt be able to find some kind of fault with this. If you are a normal person who appreciates gorgeous sound reproduction in a stylish, elegant package, with top-notch build quality, you will be filled with gratitude to have this equipment, at any reasonable price. Of course, the price is ridiculously low, even at list. At the price it is actually selling for, you literally cannot go wrong. Put in the HiFi-Tuning fuse too (see the Stereophile review). It makes it even better. And buy the matched CD player to go with it.

There are already lots of review of this product over the internet, so I will only focus on what is not being mentioned often.

First, this amp requires a fair amount of break-in. Right out of the box, it sounded edgy and unrefined. After a long break-in, it transformed into a very solid amplifier. I always like Onkyo product due to its solid construction and no-frill-but-well-thought-out appearance. This one is no exception.

I do have two operation issues with this amp. First, it should have a balance knob, besides the bass and treble knobs. Second, this amp has only a power button and no standby button. So you can only use your remote to wake up the amp from standby. There are these two buttons on all the Onkyo home theater receivers, and Okyo should put a standby button on this amp also!

Performance wise, it is a very solid amp, which has been appraised by so many people.

This was to possible replace either my Pioneer Elite A91D or my Pioneer Reference A717 integrated amp in some casual listening systems I have. I kind of bought it on a whim without doing any research on it.
First blush casual listening I thought the Onkyo A-9555 had some potential, seemed warm and inviting sounding, but that all changed with more listening time. After doing some critical listening with widely varied sources over time I have to do an about face. First impressions are not what they seem with this amp.

Quick summary: Joni Mitchell, Court and Spark for vocals. Vocals sound nice, but things seem a bit soft. Time to get more demanding on the amp.

Holst The Planets for classical. Again sounds smooth at times, but when there's powerful passages, things go limp, the power of the orchestra actually seems to collapse in on itself. An odd thing to say the least and VERY unacceptable for any listening situation.

Some bass demanding pop stuff, Chumbawamba Tubthumping, NOW we really find the pig with lipstick on showing up. The guts just are not there. This tune can easily make the whole house shake with either Pioneer amp, it isn't happening with this thing. The speakers are willing but the amp is seriously straining.

Some pretty demanding jazz fusion, Love Devotion Surrender W/ John McLaughlin & Santana, the tune Love Supreme, where's the beef? Just does not pin me in my seat like it should. John's guitar loses that immediate in your face quality that I love about this recording.

Rock, Robin Trower, remastered Bridge Of Sighs. Same story, the amp just doesn't have any beef when pushed above casual listening levels, everything seems to collapse in on itself and gets compressed.

The final nail in the coffin, some of my own tapes, these were loose off the cuff jams that actually sound pretty good, there's a lot of quiet passages as well as full tilt rock blues....a Fender Twin with a wailing Gibson Explorer, a Fender bass guitar through a Peavy 2X15" amp, and a small drum kit, very raw, simple, clean uncompressed recordings. Here's where the amp really fell on its face. The Pioneer Elite amps play my stuff and never run out of steam. I always get a bit of a grin listening to my own brand of sonic noise. But with this amp it sounded like someone did too much compression on the recordings and they actually sounded harsher than normal. I literally had to turn the tapes off, I couldn't stand what I was hearing.

To verify I drug out another similar power rated integrated amp I had laying around, a Sansui AUX 911DG, which I always felt was a bit smoother sounding than the Pioneers, but didn't quite have the same amount of beef. It got moth balled due to an occasionally noisy volume pot.

The Sansui sounded easily just as smooth as the Onkyo on the same passages when the Onkyo was actually managing to sound smooth, but the Sansui didn't fall flat on its face when things got demanding like the Onkyo does.

My opinion, I now think the high end is rolled off on this amp giving a first impression of tube like warmth and smoothness. Fact is though the air and extreme top end is sorely lacking on this amp, the edge of breath on vocals, the tail of reverb, cymbals, all lose that top end making them sound more lifeless.

First impression may be one of "oh this amp sounds musical, smooth" BUT....When asked to deliver the goods it's true colors show. Mind you all of these amps I'm comparing it to are "rated" at around 85 -100 watts per channel, close enough to being the same power for all intents. But this class D amp just can't run with a class A/B of similar rating when pushed. It might be fine for quite, low demanding music and background listening, but for any attempt at serious listening it falls far too short.


For $399 it's a nice little amp, list $799, forget it. I'll hang on to my old Pioneers until they smoke out. This one goes into the garage system or on E bay.

UPDATE 06/29/09.

Well after a few months of living with this I stand even FIRMER by my original review. Time has not changed anything and I have now pulled the amp from the system it was in and relegated it to my garage system, which is where it belongs. A FAR CRY from a great amp for sure.

I just got off the line with their product support. They were very rude to me. It seemed they were trying to get me off the phone as quick as possible. Completely unwilling to help or stand by there product. Buy one and hope nothing ever goes wrong with it.

I am returning this item because it does not include a receiver. On the description of product line on the website it is listed as a receiver ("Onkyo Digital 85 Watt Stereo Receiver"). My understanding, based on information on the website, was that it was both an amplifier and a receiver. Since I need a unit that performs both functions, I am returning it.