Okay, I should say I'm somewhat confused. Most of the unexplained advice floating around these forums states that sony daps are great at driving low impedance phones but not so hot with high(er) impedance varieties, where a hiss will be produced. If I have understood the bones/basic principal of electrical impedance, it is akin to resistance in (D/C) electrical circuits (rather, in A/C circuits, resitance is shown to be a component of impedance), in that it is a qualification of an opposition force to your current (and voltage?) in the circuit. To me, then, it would seem to make sense, that higher impedance phones apply to your electrical circuit a greater amount of opposition force to the current and voltage. Logically, then, this would mean that a greater amount of power is needed to drive your current and voltage around the circuit, to overcome the increased impedance along the way. To me then, I can only imagine that, with the sony product, the hiss detected is as a result of the clash/'friction' between the curreent and the impedance forces? Would it be limitations of the sony dap driver to drive (at high enough powers) that means a his is picked up upon, ie at greater powers the current to opposition forces would be more unevenly matched in favour of current and so hiss suppressed or drowned out?

Ok, the reason this confuses me, though, is that advice given for the cowon d2 in helping to cut out hiss, amoungst other beneficaries, is to add a resistor adaptor to your rig, which, as I think I underdstand it, adds more impedance to the circuit. I'm guessin the d2 dap driver is more powerful than the sony one but how, if my above theoretical understanding is correct, does it make sense that adding more impedance to a circuit will reduce hiss? Hence, will adding a resistor adaptor to the sony cut down hiss?

bump!!

I've been really confused about this too. Can someone please answer this question?

Any thoughts, ideas, educated guesses or even complete wild punts would be welcome! Anything.

adding resistor adapter will diminish hiss.
however, it will also degrade the SQ.

Quote:



You couldnt possibly elaborate some more could you?

I would not say that it degrades SQ at all.

If you are using very sensitive iem's straight out of any DAP, you will hear hiss. Adding resistance will cure the hiss problem. The hiss is a constant noise that does not increase in volume. So adding resistance will make sure this noise doesn't get through.

I soldered 50ohm resistors to the signal line on my SF3's, and I don't hear hiss on any of my players anymore.

SQ is actually increased, because details aren't being masked by the hiss. It also depends on how sensitive your phones are, your ohmage may vary.

Great answer faichiu. Lots of help. Makes sense. The PK1 and RE1 and ER4s all have higher impedance to degrade the SQ. The it hurts the SQ thing is absolutely not simply black and white like that.

Usually more impedance is good for SQ. If you don't have enough power then there can be some degradation. Also, with some attenuators/volume controls their is SQ loss. This is due to bad components like the Shure volume control.

I guessing that since the hiss is enough of a problem, the phones you are using are quite easy to drive. If you aren't past two-thirds volume you should still have enough volume head room left for an adapter. Of course, you will take a hit on some battery life using higher volume.

I did have a Sony for a few days before I returned it and I still use a Sony Minidisc player(for the AM radio) so I have had some experience with them plus an 75 Ohm adapter. The 75 Ohm is the max with the Sony output. It should do the trick for hiss. For SQ, it will add some bass with a Sony so you should factor an increase in. Don't know how that suits you. I thought it worked well with PK2's which needed some more bass but not with other phones that became too bottom heavy with the added impedance. It may tighten up the bass but there will be some more so you might EQ-down if need be. Either EQ-down or even the service mode hack from the other thread can tune the Sony for use with an adaptor.

So, make sure you have enough power left volume-wise or it may be underpowered. Use a quality adaptor. I would avoid the plug ones in favor of a cable one due to the added stress on the headphone jack. And factor in the bass boost that most likely will occur and if it will be welcomed or can be remedied. If all seems good then pick one up. It should tighten up the sound and give a bit more detail and extension as well as eliminate the hiss.

I hope you need to understand that PK1's resistant is inside the driver which is the resistant of the magnetic coil. More resistant means more number of coil inside the driver.

Adding resistor adapter is the same as adding resistant to the cable which is totally different approach.

If adding resistor adapter increase SQ, then why would you buy PK1?
Why not just buy PK3 and add a resistor on the cable?




Quote:

Before I lost my PK1, I saw absolutely no reason to add an extra resistor to the PK1. It was insensitive enough to not pick up any hiss anyway.

I found my SE420 + 120 ohm straight out of a 5G iPod bearable, but my Triple.fi + 120 ohm was not very good at all.

Quote:



The pk3 doesn't need it. 32 ohms is high enough that you shouldn't hear hiss.

It seems people are adding way too much resistance. My sf3's need only 50 ohms to reach their peak, and it cures absolutely all hiss.

You think people buy PK1 for bearing the hiss?

Quote:

No, but the OP is interested in hiss specifically, and I was just stating that 32 ohm phones don't need any higher resistance.

Anything under 20 and hiss will become more noticeable, especially in-ears.

My e5c(110ohm) hiss crazy with my U3.
Hiss seems to also related to sensitivity also. Not only impedance.

Quote:

Many thanks for the replies everyone, they are suddenly coming more thick and fast! However, I am still left confused, over the same issue of theoretical to practical connectivity of understanding. Don't get me wrong, I want adding a resistor adaptor to diminish hiss, that would please me and be very welcome indeed! However, why does adding further resitance/impedance to the circuit diminish/mask over/drown out hiss? Maybe I am unsure of source of hiss and how its created? So far I understand it to be associated with the dap driver. Isn't it funny though, if adding resitor adaptors is helpful to SQ and to reduce driver hiss, therefore, that higher impedance phones detect hiss less, that many people falsely go round saying that sony daps are great at driving low impedance phones but crap with higher impedance ones where they return a hiss ie that low ipedance hps= no hiss, higher impednace hps= hiss. Whywould people be thinking and/or observing this? In my personal observations, granted only gpoing on the basis of the supplied phones with the sony dap and my sa6 (50 ohms), that the hiss is significantly more noticeable with the supplied (I assume these are of lower impedance than the sa6). However, I had begun to notice it with my sa6 on quiet tracks or where very little is goin on in a song to mask over it and it was becoming mildly annoying/you were craving for it not to be there. I am prepared to give adding a resistor adaptor a go like- does anyone have any retailers/sites where I could look at offerings? I am from UK. Cheers!