Which integrated amplifier headphone jack style is the best? Resistor vs seperate circuit?

[NewbieAudiophileExpert]

When it comes to integrated amps and their accompanying headphone amplifiers, which style do you think is the best?

Resistor from main speaker output, or when there is a seperate circuit and amplifier powering the headphone jack?

The reason that I ask is that I have a yamaha A-S501 which uses the resistor-style headphone jack and it doesn't sound bad at all...

What's your opinion?

 

[fpitas]

It depends entirely on the resistor value and the headphone impedance.

 

[NewbieAudiophileExpert]

It depends entirely on the resistor value and the headphone impedance.

Go on....

My headphones are the HD 560S from Sennheiser

 

[fpitas]

Go on....

My headphones are the HD 560S from Sennheiser

I don't know their impedance. Nor the resistor value. Basically, the resistor value should be less than 1/10 of the nominal headphone impedance (just a rule of thumb) to prevent the impedance variations being important.

 

[restorer-john]

I don't know their impedance. Nor the resistor value. Basically, the resistor value should be less than 1/10 of the nominal headphone impedance (just a rule of thumb) to prevent the impedance variations being important.

That's never going to happen in an amplifier to HP situation. The goal is to limit the available swing from the power amplifier stage to the headphones and not burn them out. Sensible.

And FR response variations are really only an issue if the headphones have a wild impedance curve themselves.

Yamaha uses 470R 1W resistors in series for the headphone jacks in the A-Sxxx series.

 

[NewbieAudiophileExpert]

That's never going to happen in an amplifier to HP situation. The goal is to limit the available swing from the power amplifier stage to the headphones and not burn them out. Sensible.

And FR response variations are really only an issue if the headphones have a wild impedance curve themselves.

Yamaha uses 470R 1W resistors in series for the headphone jacks in the A-Sxxx series.

View attachment 309775

Is this superior or inferior to having a seperate circuit that amplifies the preamp signal? Pretty sure my Cambridge audio azur has a seperate circuit

 

[restorer-john]

Is this superior or inferior to having a seperate circuit that amplifies the preamp signal? Pretty sure my Cambridge audio azur has a seperate circuit

Generally inferior, but not always.

A dedicated headphone stage can be configured to have a virtually zero output impedance and if excellent in other areas, (noise, available swing, distortion, repsone etc), it should be a better option than direct amplifier output via resistors.

And it depends on the headphones. Most traditional headphones are designed to be driven from a source of around 50-600R. Super low driving impedances actually can result in poorer bass response, expecially with larger diameter, dynamic headphones.

IEMs and low impedance designs will benefit from a dedicated, active HP stage.

If you H/P jack sounds good to you, and you're happy with it- use it. You have full control via remote, you're not wasting money on another box and it cost you nothing.