[robert_cyrus]

Hi, I'm just wondering if anyone has done direct comparisons between home amps and portable amps.
I imagine the home ones will have an advantage in that they have mains rather than batteries. Plus there's no size restriction.
e.g. I paid the same £ for a Little Dot MKV as a Graham Slee Voyager, both £180.
thanks, Robert

 

[FallenAngel]

First and foremost, batteries are pretty much the cleanest power source - no ripple, they stay at the same voltage for a long time, they're just great as a power source.

Voltage swing on amps is directly related to power supply voltage. Having an amp run off a 9V battery will give you about 8V of voltage swing in the perfect case using an AD8397. Running an amp off a regulated supply at +/- 15 will obviously give you higher voltage swing as long as you don't use a really bad opamp.

There is a serious consideration of power supply current draw in portable amps, this is not there with stationary designs so they can usually be biased much deeper into Class-A and in general have higher current abilities.

To compare home amps as a category to portable amps as a category is almost impossible and won't get much more specific than that, perhaps you want to compare specific amps?

Also, what exactly are you comparing? Current output potential, voltage swing, ability to drive inefficient headphones, noise floor? Or is it a completely general question of which sounds better? In the last case, no help there buddy, sorry.

 

[donunus]

ok. lets say meier arietta vs the headamp picos amp. why do i get the feeling the pico is better except for the crossfeed. I find my headfives very dry sounding

 

[DennyL]

What makes me uncomfortable in these discussions where voltage swing crops up is that I've never seen any measurements. I've even thought of getting an oscilloscope card for my PC and trying to look into it. I don't even know that with a home amp the voltage swing ever exceeds 8v anyway. I would think that batteries, which have low internal impedance, would be able to supply all the current a headphone could ever want but I agree that one wouldn't want a battery-driven amp that was deep into class A, maybe having cooling fins

 

[FallenAngel]

Quote:

Originally Posted by DennyL /img/forum/go_quote.gif What makes me uncomfortable in these discussions where voltage swing crops up is that I've never seen any measurements. I've even thought of getting an oscilloscope card for my PC and trying to look into it. I don't even know that with a home amp the voltage swing ever exceeds 8v anyway. I would think that batteries, which have low internal impedance, would be able to supply all the current a headphone could ever want but I agree that one wouldn't want a battery-driven amp that was deep into class A, maybe having cooling fins

Don't trust the opamp datasheet? It specifies distance from the rail voltage that the opamp can swing. AD8397 need a few millivolts, OPA2134 needs about 3V. My PPAv2 with OPA627/OPA637 (which need about 2.5V from each rail) running off a 24V supply swings about 9V in each direction

 

[tfarney]

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif First and foremost, batteries are pretty much the cleanest power source - no ripple, they stay at the same voltage for a long time, they're just great as a power source. Voltage swing on amps is directly related to power supply voltage. Having an amp run off a 9V battery will give you about 8V of voltage swing in the perfect case using an AD8397. Running an amp off a regulated supply at +/- 15 will obviously give you higher voltage swing as long as you don't use a really bad opamp. There is a serious consideration of power supply current draw in portable amps, this is not there with stationary designs so they can usually be biased much deeper into Class-A and in general have higher current abilities. To compare home amps as a category to portable amps as a category is almost impossible and won't get much more specific than that, perhaps you want to compare specific amps? Also, what exactly are you comparing? Current output potential, voltage swing, ability to drive inefficient headphones, noise floor? Or is it a completely general question of which sounds better? In the last case, no help there buddy, sorry.

OK, this is cool, as I've been trying to get an answer to this question. This one is still a bit technical though, so let's try this:

What sonic effects do the differences between battery powered and AC powered have?

How is battery power at driving inefficient phones?

Where does current come in? What sonic effects does it have?

I think I understand that, in general, batteries are quieter, but correct me if I'm wrong.

And by the way, do most regulated supplies run off of +/- 15 volts? So what about the amp I'm considering, which draws 12 volts via firewire from my computer -- no batteries, no internal power supply, almost as much juice, if I understand you, as the regulated power above.

Oh, last but not least - love your avatar. Where did you find her?

Tim

 

[robert_cyrus]

Hi, well I realise the characteristics in terms of voltage etc is going to be different, since we're talking mains vs battery.

But on a strict listening test, how do they compare? I've never had the opportunity, but some of you out there seem to have some very good home and portable set ups.

 

[DennyL]

I was saying that I've never seen waveforms or measurements of the signal that is output to headphones when they are playing at usable levels, so I don't even know what are the voltage peaks we should design for. In nature sound pressure intensity has random distribution that has no maximum, but sources are psuedo-random with a maximum. In random vibration testing I know we often assume that no vibrations are more than 3.5 standard deviations from the mean, but I don't know what is reasonable in music reproduction, or what is used in digital sound technology or vinyl cutting equipment. Don't we need this type of information before we assess the suitability of different designs of amp? Or we could look at the voltage peaks appearing at the source and multiply them by the amp gain. Same thing if the amp is linear. I just looked at the specification of an Arcam CDP, and the output is 2.2v rms referred to 0dB. Perhaps someone can help me to understand this. The zero dB refers the 2.2v rms to what?

 

[Asr]

Quote:

Originally Posted by tfarney /img/forum/go_quote.gif What sonic effects do the differences between battery powered and AC powered have?

In my experience with portable and AC-powered amps so far, I've heard a consistency between them in that the AC-powered amps had greater audible bass depth & extension than the portables.

 

[tfarney]

Quote:

Originally Posted by Asr /img/forum/go_quote.gif In my experience with portable and AC-powered amps so far, I've heard a consistency between them in that the AC-powered amps had greater audible bass depth & extension than the portables.

Would that be due, do you think, to an ability to provide a burst of greater power when needed?

Tim

 

[Asr]

That probably has something to do with it I'd guess. But I'm not knowledgeable on the subject, there are plenty of others here who are though.

 

[boomana]

Other than a Rockhopper mini^3 and a Darkvoice 336i, which I own/owned, I don't have any experience with under $300 amps, so I don't know what differences are present, if any, at this level, but it's been my experience that for headphones that require an amp, there's a pretty significant difference between home and portable, with home amps just plain sounding better across the board (differences depend on which amp and which headphones used).

Think about it. If portables could do the job as well as home amps, Ray, Mikhail, Justin, Tyll, Craig, and others would never make home amps again, since everyone seems to want portable amps to do everything. That's not happening, because portable amps can't do everything (drive certain headphones well), and mostly because good home amps sound better with most full-sized headphones.

 

[jrosenth]

x2 for Boomana.

And I'd like to thank here for the landmark thread on this very subject.

I couldn't agree more.

I do have some experience with under $300 home versus portable amps and in every case I can think of the home amp sounded better than the portable.

If the original poster is asking whether, as a general rule, home amps are better (ie sound better) than portable amps at their price points, then I would say absolutely!

Yes, there are some exceptions, where a tonk of a home amp is beaten by a gem of a portable but on the whole home amps just sound better dollar for dollar.

Go put a Gilmore Lite next to the portable amp or your choice and see if any portable amp can best it (I haven't heard the Pico and Lisa, but I'm highly dubious and the bits I've read indicate they can't best it).

Now take that same Gilmore Lite and put it next to a $200-$300 portable.

Wash, rinse, repeat (personally I dig the sub $200 Original Master or a good old PPA, but to each their own).

By the way, I've found the same thing to hold true for source including DACs (home versus portable).

I think very often new folks who come in asking about an amp are told to go portable.

Instead, the question should be asked whether they need portability or not, and if not, as a general rule they'll get better band for their dollar going for home gear - especially if going used.

One little example. I picked up a used PPA with Glassman and STEPS for about $200. I just can't imagine ever finding a portable amp, even used, at that price that even comes close.

 

[Capunk]

So is there any equivalents for Pico in desktop setup?
Separate DAC & AMP is fine, they doesn't need to be in similar total price ($500).

 

[Capunk]

My DAC = OMZ v4
OMZ sound much better than my iMod Photo, but I never heard Pico DAC/AMP, so that's why I ask here for people opinions