Home Cinema Amplifier Test – Onkyo TX-SR605 v Denon 2308

I have recently wanted to upgrade my Sony STR-DB940 Amplifier. The only real choices available to me were the Onkyo TX-SR605 and the Denon 2308. I went for a demo last week, bought the Onkyo and finally installed it yesterday. Heres the story…

The Demo

It wasn’t an ideal demo as each amp was being played by a different make of speakers (B&W for the Onkyo and KEF for the Denon) so I couldn’t do a complete like for like test. I have KEF’s at home so my initial thoughts were that the Denon would swing it – it also looks fantastic in silver.

First thing we watched was Casino Royale on Blu-ray. The Onkyo sounded busy and there wasn’t enough separation between sounds for my liking. But that said it did sound very cinematic and was very impressive, especially at this price point. The same scene on the Denon was much more subtle, the trebles were higher (although this could have been the KEF’s) but it didn’t seem as crisp, or as full.

Next, we put on a disc I had bought – the Lobby Scene from The Matrix. I have always found this a great scene to test with because as well as the gunfire, you have trebles from the empty rounds hitting the floor, the walls exploding and the thumping bass track to process. Inadequate equipment seems to struggle with this bass track, and it is a scene I know very well. Both amps coped very well with it, the Denon was marginally better on the bass track, but the rest of the sounds were better handled by the Onkyo.

Finally we moved onto 2 channel stereo, and it was no real contest, the Denon was far superior. The prime reason for getting this amp though was for surround sound, so this was a secondary importance.

In the store, I didn’t get that much of an improvement in sound – both were marginally better than the Sony STR-DB940. Had it not been for the HDMI connectivity and the HD features, I would have had to think whether it was actually worth upgrading to one of these amps.

Denon 2308

The Denon was refined, high quality, but subtle. The shop said that the Denon was £599 (despite their website saying £499), and there were no black models available. The 2 channel stereo was a big plus point, and I also felt that it would go well with my KEF’s at home.

Denon 2308

Onkyo TX-SR605

The only real shortcoming of the Onkyo, to my ears, was the busy-ness of the sound – I couldn’t fault anything else. I did have the suspicion that my KEF Q15’s would handle the sound better than the store speakers, and the HD features of the 605 would make it a good buy for the future.

Onkyo TX-SR605


Had they been the same price, it would have been a tough choice. They were different, but equally worthy. Both had some great features that the other didn’t (HD decoding on the Onkyo, upscaling on the Denon). What swung it for me was that I felt I was getting a more cinematic sounding amp in the 605. The 2308 was at least £100 more and I couldn’t really see where the extra cost was going. So the Onkyo it was.

Getting it home

The build quality of the 605 was better than I was expecting and probably on a par with the Sony. The binding posts aren’t quite as solid, but I’ll rarely touch them again so it doesn’t matter too much. I dod have some slight reservations about the silver version of the 605, but in black, the Onkyo looks great.

Connecting it up was straightforward, and when I finally got the kids out the way, the speaker set up was straightforward too with the Audyssey 2EQ calibration microphone supplied. This natty device allow the amp to determine the best settings for your room – you simply position it in 3 listening position, and start it off on the amp. Each speaker fires test signals out, and the amp will determine the best settings. My first attempt failed because the ambient noise was too high, the second time it didn’t pick up the sub. I had to change the sub cross over to its highest setting as recommended in the manual, but after that, it was a breeze. I used a tripod to put the microphone on – try and borrow one if you don’t have one – it makes it a whole lot easier.


As expected, the sound was a lot less busy through the KEF’s, and my earlier thoughts about it being only a slight improvement on the DB940 were incorrect. With the same speaker set up, it was a definite improvement, and a worthy upgrade. The lobby scene from The Matrix was handled very well, and I could notice a genuine improvement in most areas. Everything seemed to go together well, there didn’t seem to be any weak spots. Even stereo music sounded better at home than I had expected.

The first full movie (Fantastic Four – not my choice!) was superb – everyone was suitably impressed. And the end of a great day, I was well satisfied with my purchase and would recommend the amp highly.


Overall, the Onkyo 605 is a worthy upgrade from the Sony STR-DB940. In the year 2000, the Sony was judged to be probably the best Home Cinema Amp you could buy for under £1000. I don’t know if the Onkyo quite takes that crown, but it is probably one of the best value for money amps you can buy, and in my opinion, the spiritual successor to the Sony.

The Onkyo 605 has been superceded by the Onkyo TX-SR609.