Amplifier frequency response

[Gaz37]

I've been browsing old Pioneer amps and comparing specs and noticed something a bit odd.
The monster amps such as 717 & 656 have big power outputs but the lower frequency response is 20hz.
On the other hand the A400 has a lower FR of 5hz but only 40wpc
I know the lower response is academic as both are below human hearing (just in one case)
Is there any reason for the lower range models having better range of FR?

 

[Vladimir]

You are probably confusing Power Bandwidth with Declared Power into 20Hz-20kHz.

Pioneer A-717 has Power Bandwidth of 4Hz-80kHz 0.05%, 8 ohms

Pioneer A-656 has Power Bandwidth of 5Hz-80kHz 0.05%, 8 ohms

Pioneer A-400 & A300 can't find a Power Bandwidth specified, just as CD/Tuner/Aux FR of 5Hz-100kHz -+3db

Don't put faith in websites published data, a lot of it is wrong. Download the original manuals on HIFIENGINE.COM.

 

[Gaz37]

My mistake, it was the a616, according to hifi engine

20hz - 20khz

I really wondered why the FR of some amps goes way below both human hearing and most speakers range?

 

[Vladimir]

My mistake, it was the a616, according to hifi engine

20hz - 20khz

I really wondered why the FR of some amps goes way below both human hearing and most speakers range?

Pioneer A-616 has Power Bandwidth of 4Hz-80kHz 0.05%, 8 ohms

 

[Gaz37]

So what is the quoted 20hz - 20khz?

Specifications
Power output: 80 watts per channel into 8Ω (stereo)

Frequency response: 20Hz to 20kHz

Total harmonic distortion: 0.005%

Damping factor: 70

Input sensitivity: 0.2mV (MC), 2.5mV (MM), 150mV (line)

Signal to noise ratio: 74dB (MC), 93dB (MM), 108dB (line)

Output: 150mV (line)

Dimensions: 420 x 435 x 162mm

Weight: 14kg

Finish: black (A-616), silver (A-616S)

Year: 1988

 

[Vladimir]

So what is the quoted 20hz - 20khz?

Specifications Power output: 80 watts per channel into 8Ω (stereo)

Frequency response: 20Hz to 20kHz

Total harmonic distortion: 0.005%

Damping factor: 70

Input sensitivity: 0.2mV (MC), 2.5mV (MM), 150mV (line)

Signal to noise ratio: 74dB (MC), 93dB (MM), 108dB (line)

Output: 150mV (line)

Dimensions: 420 x 435 x 162mm

Weight: 14kg

Finish: black (A-616), silver (A-616S)

Year: 1988

That is the FTC* standard for declared power. 80W RMS at 8ohms, measured at 20Hz-20kHz, both channels driven, with no more than 0.05% THD.

Measured at 1kHz it may produce 100W RMS at 8ohms both channels driven with 0.05% THD. Measure just one channel driven, you get even more power output. Go higher in distortion, you get even more. Measure at 4ohms, even more power. If you really want to fool the kids don't use RMS but PMPO power. Suddenly you have a rubbish boombox doing 1400W on paper. The FTC standard serves so manufacturers don't overhype the specs and fool the customer. Everyone should declare the FTC standard first so the customer has a comparable data for all competing products. Then manufacturer can specify whatever they want, bloated specs, brag about real performance etc.

The power bandwith specification shows us the full capability of the amp, beyond that 20Hz-20kHz FTC standard.

Pioneer A-656 will do 5Hz-80kHz at 8 ohms with no more than 0.05% THD at rated power (80Wpc RMS).

*FTC - Federal Trading Commissions (US), Competition Bureau (Canada), ASA - Advertising Standards Authority (UK)