Another headphone amp question for PRR

I built an amp based on the tori amp posted in late december for my 32 ohm phones - it sounds great. Reading on headwize (which seems to be down now) an article on opamp based amp designs suggested replacing the 50 ohm resistor with another component (which I can't remember) in combination with a resistor to be a more accurate current source which would improve linearity of the amp. Can you suggest what this component may be and do you recommend trying this? I really enjoyed experimenting with this design.

THanks, JEff

> replacing the 50 ohm resistor with another component (which I can't remember) in combination with a resistor to be a more accurate current source which would improve linearity of the amp.

Using a bipolar transistor or a big FET, the resistor-load is fine. You won't "improve linearity" at normal power levels, since with the suggested supply and resistor it will BLOW your ears off before it goes nonlinear. A current source would just go a little more into over-kill before it distorted.

And personally, I don't trust most hi-power current sources not to add their own little nonlinarities. KISS.

you rule!

Jeff

When implementing a stereo design that uses a single chip (5532) are there any tips with laying out the components and traces. With the chip using only 1 set of power rails but the other components being doubled, how much of the power should be seperated, and what can affect the crosstalk of the left right channels.

THanks, Jeff

> what can affect the crosstalk...

Of a headphone amp????

Crosstalk is good in headphone amps. Split-head listening is abnormal, and there are a bunch of schemes to increase headphone crosstalk for more natural sound on loudspeaker-balanced sources.

And your main sources of crosstalk are input-pot wiper wires, input jack-pot grounding, and the common ground on the headphone jack. You'd have to be mighty sloppy around the chip and transistors to have any extra crosstalk there.

I hope Cmoy is OK. I thought he'd settled his web-host hassles. If anybody has his email, PM me. That site is too good to lose.

[quote author="PRR"]I hope Cmoy is OK. I thought he'd settled his web-host hassles. [/quote]

If he's having trouble maybe I could help. I've been meaning to pick up and run with one of the projects over there one day. I would hate to see the site go down. If he needs some forum space, I think we could work something out, especially since we're in similar areas of interest.

Headwize is back up or at least it was yesterday,
Steve