Gain of Commercial Cd Players too high?

[neutralzz 0]

in an experiment conducted at home, i found the gain of commercial CD players a little high for headfi. i had been puzzled on how sounds became less bright and more comfortable to listen to

 

I was adding resistances from 50 ohm to 500ohm to the headphone output of an amp, i.e. in series, and listening to the tonal differences. i found that adding 50 ohm/100ohm had very little difference from not adding resistances at all.

 

at low resistances, the volume knob on the amp only needs to be turned a little bit before it becomes too loud, this means that there is very little gain from the amp, due to the large gain of the cd player output. the sound could be described as "cd playerish"

 

but when resistances were added to an insane high of 500 ohms, and the amp having to be driven to be about 70% vol, it sounds entirely different, and bears more of the amp characteristic.

 

maybe if you find amping your low Z headphones not beneficial, try increasing the amp output resistance. there might be some losses but then again, the amp has to be driven decently hard for it to impart its own characteristic to the sound.

 

 

[Rameish 0]

I think what you mean is the output from the CDP is too high. Russ Andrews offers when is known as attenuated interconnects to prevent input overload on the amp side. There are also 3rd market adapters that offer attenuation like the harrison lab adapters (http://www.headphone.com/products/adaptors-and-accessories/harrison-labs-attenuators-6db.php). There are 2 versions - one for - 6dB and the other for - 12 dB.

 

According to him (russ andrews) if the input sensitivity of your amp is 500mV and the output of your CDP is 2 volt then you do not need any attenuation. If your CDP output is higher (say 3 V) or your input sensitivity is lower (say 350 mv) then you need attenuation BETWEEN your CDP and amp.

[neutralzz 0]

i find that even 2v, for headfi its a big too high, thats why sometimes people dont find the diff between amping and non amping certain headphones of lower resistances. the amp does not provide much gain to the cdp output for a listening volume

 

 

[lekguan 0]

Actually IMHO, adding output resistance itself changes the characteristics of the amp. According to what I've tried with my system, adding 120ohm was quite a change in tonal quality for my DT931 headphones. Almost immediately you can hear that the highs are less, the bass increases, almost like a tonal shift towards the lower frequencies, and 1 thing in particular which kind of disturbed me, which is that the sound becomes very much laidback. More so than without the 120ohm in place. I've tried with 82ohm, yielding similar results, albeit to less effect. My guess is probably that you prefer a rolled-off high frequency, and somehow attribute it to the "cd-player-ish" sound, or perhaps to a similar effect, an extremely laidback sound. Actually a more laidback sound, IMO, sometimes gives you more of a feeling akin to listening to speakers. The issue might be there My guess is that you have confused the change in sound brought about by increasing output resistance as the shifting of the sound from "cd-player-ish" to "amp-ish" (Oh well what a description i'm using LOL)

 

BTW you can try using a CDP with variable line out, and decrease the output, then increase the volume pot level of the amp, and see if the sound is more to your preference that way. My guess, not exactly, as reducing the output, at least for my case in the CD6000ose, does change the sound characteristic a little, ever so slighlty, but is almost negligible when compared to increasing the output resistance of the amp.

 

Anyhow just my 2 cents based on guess-work. Hoping maybe to shed some light, some food for thought perhaps? Oh yes, must not forget, YMMV!

[Mackie 0]

the amp does not provide much gain to the cdp output for a listening volume

 

Most if not all unbalanced output of cdps are specified at 2V. If the gain is too high, don't question the cdp but the amp instead. By definition of gain, it's inherent with the design of amplification stage. An amp with higher gain will benefit transducers that are difficult to drive but wreak a certain degree of havoc with easy loads; small distance travel of volume pot may result in large volume changes. This is also one reason why pro cdps have variable outputs (L/R pots at the back panel) for better impedance matching with mixer/amp etc.

Edited December 13, 2005 by Mackie