New amp to replace my Marantz

[ace2109]

Hi Guys,
Having messed about with the settings on my Marantz SR5300 im still convinced it can be better so i am therefore looking at getting a new amp.

I have been looking at the ONKYO TXSR608. It is giving me an extra 30w per channel as will as TrueHD sound and the ability to switch HDMI which is really handy as my TV only has 1 HDMI input.

Have you guys any recommendations or thoughts?

 

[james.miller]

I wouldnt bet on it giving you an extra 30 watts a channel, when HomeTheatre benched the 608, it only managed 40w/channel which is actually pretty typical of amps in that price range believe it or not. However, i'd bet a good money that the sr5300 is closer to its rated output than the onkyo is. the real question is do you need more ?

my opinion, arrange a demo at your local av shop and have a listen to a few amps. specs can be VERY misleading.

 

[ace2109]

what really annoys me is the TrueHD issue in that it doesnt sound as good as amps with this feature.

 

[lucid]

To be fair on the power specs, Onkyo does make it clear that they measure 160W in to a 6 Ohm load with just a single channel driven @ 1kHz and at 0.1% distortion. The problem is those figures aren't well understood by the average consumer.

If the amp were capable of delivering 7 x 160W total then it would gobble up electricity at the mains socket at a rate of at least 1120W when running at full volume

The Home Theater review does measure the amp at 129W in stereo in to an 8 Ohm load. I presume that's running with a 1kHz test tone. That's still a very respectable result, and about right when you look at Onkyo's own claim of "100 watts minimum continuous power per channel, 8 ohm loads, 2 channels driven from 20 Hz to 20 kHz, with a maximum total harmonic distortion of 0.08% (FTC)." for their North American spec measurement.

In the real world then amp draws a maximum of 620W at the mains socket. As a rough guide assume about 50% efficiency, and then divide the result by 7 channels and you'll get to 44 W/ch max. This tallys pretty closely to the HT mag review.

 

[marv]

is there any benifit in running my speakers in 6ohm over 8, my speakers are rated 6-8 ohms

 

[Bear]

If the amp were capable of delivering 7 x 160W total then it would gobble up electricity at the mains socket at a rate of at least 1120W when running at full volume

In the real world then amp draws a maximum of 620W at the mains socket. As a rough guide assume about 50% efficiency, and then divide the result by 7 channels and you'll get to 44 W/ch max. This tallys pretty closely to the HT mag review.

This is incorrect. The wattage of an amplifier is not related to the power taken from the mains in the way you say. An amplifier is rated in watts in terms of the transistors in DC conditions not AC as there is a transformer in the way. To know the true relationship between AC power and DC power you would need to know the turns ratio etc.of the transformer

 

[wonko]

This is incorrect. The wattage of an amplifier is not related to the power taken from the mains in the way you say. An amplifier is rated in watts in terms of the transistors in DC conditions not AC as there is a transformer in the way. To know the true relationship between AC power and DC power you would need to know the turns ratio etc.of the transformer

Not quite sure what you mean here... Audio amplifiers are normally rated in watts rms using a sine wave input, and if an amp was outputting 50W to the speakers, then the power drawn from the wall would be 50W plus whatever losses were involved (e.g. affected by the class of the amp). Music is far from a sine wave though, having massive transients, so I'd not expect an amp rated at 50W rms for a sine wave to put out 50W of (undistorted) music output.

 

[Jano]

The Marantz is a very very musical amp, I would very strongly recommend trying to get a demo using a few different amps, but also, probably as importantly, using either your speakers or something similar to your speakers.

Pretty sure that I used to have that Marantz amp, and my old man now uses it. From what I've heard of Onkyo's, I would be very surprised if you thought they were an upgrade sonically over your Marantz.

 

[Bear]

Not quite sure what you mean here... Audio amplifiers are normally rated in watts rms using a sine wave input, and if an amp was outputting 50W to the speakers, then the power drawn from the wall would be 50W plus whatever losses were involved (e.g. affected by the class of the amp). Music is far from a sine wave though, having massive transients, so I'd not expect an amp rated at 50W rms for a sine wave to put out 50W of (undistorted) music output.

Sorry I was talking out of my backside. I was confusing power and current stupidly. Serves me right trying to work, eat my lunch and post at the same time. Sorry Lucid aswell

 

[james.miller]

To be fair on the power specs, Onkyo does make it clear that they measure 160W in to a 6 Ohm load with just a single channel driven @ 1kHz and at 0.1% distortion. The problem is those figures aren't well understood by the average consumer.

If the amp were capable of delivering 7 x 160W total then it would gobble up electricity at the mains socket at a rate of at least 1120W when running at full volume

The Home Theater review does measure the amp at 129W in stereo in to an 8 Ohm load. I presume that's running with a 1kHz test tone. That's still a very respectable result, and about right when you look at Onkyo's own claim of "100 watts minimum continuous power per channel, 8 ohm loads, 2 channels driven from 20 Hz to 20 kHz, with a maximum total harmonic distortion of 0.08% (FTC)." for their North American spec measurement.

In the real world then amp draws a maximum of 620W at the mains socket. As a rough guide assume about 50% efficiency, and then divide the result by 7 channels and you'll get to 44 W/ch max. This tallys pretty closely to the HT mag review.

absolutely and I'm not knocking them for that, however rightly or wrongly people do take that as all channels driven and people should be aware not to expect that sort of power output, and the potential differences between brands. onkyo's more expensive models do better in this regard, especially the older 8 and 9 series amps. the 875 meets the quoted output in to all 7 channels driven and almost tripples that in stereo, from what i remember.


edit: http://www.soundandvisionmag.com/te...1988/09/test-bench-onkyo-tx-sr875-av-receiver

DOLBY DIGITAL PERFORMANCE

All data were obtained using various test DVDs with 16-bit dithered signals, which set limits on measured distortion and noise performance. Reference input level is -20 dBFS, and reference output is 1 watt into 8 ohms. Volume setting for reference level was -7.5. All level trims were at zero, except for subwoofer-related tests, and all speakers were set to "large," subwoofer on. All are worst-case figures where applicable.

Output at clipping (1 kHz into 8/4 ohms)
1 channel driven: 201/322 watts (23/25.1 dBW)
5 channels driven (8 ohms): 141 watts (21.5 dBW)
7 channels driven (8 ohms): 128 watts (21.1 dBW)
Distortion at 1 watt (THD+N, 1 kHz)
8/4 ohms: 0.02/0.03%
Noise level (A-weighted): -76.1 dB
Excess noise (with sine tone)
16-bit (EN16): 0.7 dB
Frequency response: 20 Hz to 20 kHz +0, -0.8 dB

MULTICHANNEL PERFORMANCE, ANALOG INPUT

Reference input and output level is 200 mV; volume setting for reference output level was -14.0.

Distortion (THD+N, 1 kHz, 8 ohms): 0.01%
Noise level (A-weighted.): -82.9 dB
Frequency response: <10 Hz to 183 kHz +0, -3 dB

STEREO PERFORMANCE, DIGITAL INPUT

Reference level is -20 dBFS; all level trims at zero. Volume setting for reference level was 6.5.

Output at clipping (1 kHz, both channels driven)
8/4 ohms: 185/320 watts (22.7/25.1 dBW)
Distortion at reference level: 0.02%
Linearity error (at -90 dBFS): 0.2 dB
Noise level (A-weighted): -75.6 dB
with 96-kHz/24-bit signals: -88.8 dB
Excess noise (with/without sine tone)
16-bit (EN16): 0.3/0.3 dB
quasi-20-bit (EN20): 9.6/9.9 dB
Noise modulation: 0.2 dB
Frequency response: <10 Hz to 20 kHz +0, -0.8 dB
with 96-kHz/24-bit signals: <10 Hz to 44.5 kHz +0, -1.7 dB

ok so it meets the 140w/channel claim in to 5 channels and not 7, close enough