[Oedipus Rex]

Hi,

I bough Sennheiser HD-650 yesterday, and am really blown away by them even though they are not even burned in yet. But, im currently using Tandberg tca-3002 preamp as my headphone amp, and was wondering if I really need a dedicated headphone amp (Im really liking the sound of the tandberg, but I have read that the 300 Ohm sennheisers need an amp). After googling around, i found the specs for the Tandberg preamp (http://www.kallhovde.com/tandberg/tc...irc-alignm.PDF) and it lists headphone output impedance as 470 Ohms, which sounds a lot. Is this good or bad

(it is a newbie question I know). What is the optimum output impedance for given headphone impedance and how does it show?

Thanks

 

[charley phogg]

Quote:

Originally Posted by Oedipus Rex /img/forum/go_quote.gif Hi, I bough Sennheiser HD-650 yesterday, and am really blown away by them even though they are not even burned in yet. But, im currently using Tandberg tca-3002 preamp as my headphone amp, and was wondering if I really need a dedicated headphone amp (Im really liking the sound of the tandberg, but I have read that the 300 Ohm sennheisers need an amp). After googling around, i found the specs for the Tandberg preamp (http://www.kallhovde.com/tandberg/tc...irc-alignm.PDF) and it lists headphone output impedance as 470 Ohms, which sounds a lot. Is this good or bad (it is a newbie question I know). What is the optimum output impedance for given headphone impedance and how does it show? Thanks

To paraphrase something I once read but I have been unable to find it

, so hopefully someone can chime in and explain.

The "standard" for headphone amp output impedence was 120 Ohms ( I'm not sure if it still is ). I think I recall seeing that basically, as a rule of thumb you want your output impedence to be 1/3 of your headphones for it to have good bass, figuratively,not literally. Which is why Senn's use 300 ohms, because they designed them to the "standard".

But as we all know, not all manufacter's adhere to the "standard" no matter what it is they manufacture.

Is this simply the synergy we all seek? Is finding an amp with 1/3 the output impednece of your headphones a good rule of thumb?

But, Shirley it can't be that easy..... can it?

 

[Oedipus Rex]

Thanks for the reply!

1/3 rule would make my tandberg best suited for 1410 ohm headphones.. those crazy norwegians. It must be some kind of horned helm design that demands such excessive measures.

Seriously though, I could get a Heed canamp at a reasonable prize, but I'm uncertain whether it would really be that much better than a vintage preamp like the 3002.

 

[Bullseye]

The ideal thing to do is search for an amplifier that has an output impedance similar if not lower than the headphones' impedance.

Read this: http://www.head-fi.org/forums/5769458-post9.html

And this: http://www.head-fi.org/forums/f133/q...t-amps-429660/

 

[Donald North]

From my experience, I prefer the sound of the HD650 when driven by 120 ohm output impedance versus 30 ohm.

That Tandberg preamp has a built-in dedicated headphone amp circuit. 470 ohm does seem high. Looking at the schematic in the link you provided, it is set by 470 ohm series resistors. If you're handy with a soldering iron and want to experiment, you can remove and replace them with lower values and see how it sounds differently.

 

[Oedipus Rex]

Quote:

Originally Posted by Donald North /img/forum/go_quote.gif From my experience, I prefer the sound of the HD650 when driven by 120 ohm output impedance versus 30 ohm. That Tandberg preamp has a built-in dedicated headphone amp circuit. 470 ohm does seem high. Looking at the schematic in the link you provided, it is set by 470 ohm series resistors. If you're handy with a soldering iron and want to experiment, you can remove and replace them with lower values and see how it sounds differently.

Thanks! I'm not handy with soldering iron, but have been planning to learn. I think I'll start messing around with something cheaper first, don't want to break my trusty tandberg.

My Sennheiser HD-650s have now maybe 60 hours of burning in behind them and sound great with the tandberg, even with relatively poor source/dac (SB Audigy) Then again, I have not tried the senns with any other amp.