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DACS Clarity headphone amp

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DACS Clarity headphone amp

Postby ef37a » Sun May 27, 2018 9:39 am

I agree with Hugh, one's instinct is to dive for the biggest knob for wick adjustment but I was very surprised to read in a review of a device north of 1/2 bag that the output chips are the same ones as those in my Behringer HA400? Namely the entirely adequate but hardly audiophile JRC4580.

Also, those jacks on the front! Not in keeping to me with the quality of presentation of the rest of the unit? Chrome bezels on the front surely, or at least a plastic jack with the silver internal barrel. The all plastic jobbys are fine for rear panels but look naff on the front IMHO.

I do take your point Hugh that amplifier drove all your headphones to high and clean levels but 0.5W seems a low rating for high end headphone amps these days? What was the lowest impedance phones you tried please?

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Re: DACS Clarity headphone amp

Postby Hugh Robjohns » Sun May 27, 2018 2:08 pm

32 ohms
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Re: DACS Clarity headphone amp

Postby James Perrett » Sun May 27, 2018 8:04 pm

ef37a wrote:but 0.5W seems a low rating for high end headphone amps these days?

Half a watt through most headphones is certainly enough to deafen most people! One tenth of that is more sensible. I was a little bit surprised to see that a dual op-amp chip is used for the output of a headphone amp until I saw the current output plot - 100mA is an awful lot of current for an op-amp! Most op-amp headphone circuits use a couple of additional transistors to give the current required.
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Re: DACS Clarity headphone amp

Postby ef37a » Mon May 28, 2018 8:58 am

James Perrett wrote:
ef37a wrote:but 0.5W seems a low rating for high end headphone amps these days?

Half a watt through most headphones is certainly enough to deafen most people! One tenth of that is more sensible. I was a little bit surprised to see that a dual op-amp chip is used for the output of a headphone amp until I saw the current output plot - 100mA is an awful lot of current for an op-amp! Most op-amp headphone circuits use a couple of additional transistors to give the current required.

Yes James, 1/2W would be very loud in many headphones but is not a very helpful figure. Half a watt into what resistance* ? I tried to make some sense of impedances and sensitivities from my (latest?) SoS Smart Guide on monitors and cans. The speccs given are mostly a mess. If you get a power level, you get no SPL figure. Get SPL? No mW or volts.

Note, the TI spec for that chip give a minimum load of 100 Ohms in the output I/R graph.

Perhaps I have become "conditioned" to expect OTT performance from expensive headphone amplifiers? The output impedance 'MUST' be close to zero we are told and the current delivery on a par with a small speaker amp! If the Clarity is delivering sound quality as good as the (imho) over-engineered audiophool amps I am very happy for it to use the same chip as my wee Bellringer!

*Most dynamic headphones are 'all' pure resistance.

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