I have quite powerful higher end stereo amplifer that accepts signals from most of the usual input sources. We tried connecting an Ipod output to the stereo at a party to discover we could not get much volume. Not sure if this is resistivity issue or maybe the Ipod needs a pre-amp, but I am guessing there are people here who immediately recognize this problem and know how this is generally solved. If there exists a commercial pre-amp, for instance that would be nice to hear about.
I think there's a French law intended to save the hearing of youngsters that limits the output from the headphone socket to a couple of milliwatts.
A ridiculous law but that's the French for you. As a result some manufacturers ensure that ALL their manufacturing destined for the European market is similarly crippled.
If you can get a firmware upgrade for the world market model it may overcvome this problem.
While the followup was quite amusing, and I enjoyed reading it, I suspect this is not specifically "crippled" for European market since it is purchased in USA from major vendor. Checking some search engines, I see there are some things like "iTube" that look like something intended specifically to deal with this. On the other hand, those things are quite pricy and it is not clear what characteristics I am after. Anyone know any sanely priced solutions that have worked well?
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Maybe you connected it to a high-level input on your stereo?
If they still make stereos with phono inputs and yours has \'em, it
seems that should work.
Failing that, Why not build a little battery powered amp to go
between the Ipod output and the stereo amp?
Is the issue that you can't get things "loud enough" or that you have to turn up the volume control to get the same level of loud out of the stereo?
The former is more serious than the latter. Having to turn up the volume control on the stereo doesn't mean anything but that the level on the iPod is lower than the rest, as long as you can get the same "loudness" out of the stereo it will do no harm. It's merely inconvenient.
"Line level" is usually pretty vague. Even with stereo components, I often find I have to adjust volume for various bits of equipment, a combination of differing line levels and maybe source material. That classical music CD is likely going to sound "quieter" than that Led Zeppelin LP (because classical music tends to have more dynamic range, ie ratio of loudest to weakest passages, and an LP may be forced to compress to some level to keep it within specs).
Merely having to adjust volume between sources is generally just annoying.
But if you find that you have to turn up the volume all the way and it's still not "loud enough" then yes, likely a simple preamp will be needed. I don't know what sort of commercial products are available. It's not going to need much gain, and would be simple to build if you were already into building electronic projects.
My kids had Creative mp3 players that would not produce sufficient sound volume when connected to "aux" inputs directly. I made an adapter cable that loaded each headphone output with a 33 ohm resistor; this gave useable volume. A later Samsung unit did not have the problem.
That's not going to work. Even a "weak" iPod is going to have significantly higher output than a phono cartridge, and I'm sure it's within the realm of overloading that phone stage.
Plus, the phono input would have all kinds of equalization that he won't want, since the iPod doesn't have the required pre-emphasis.
And given how many times people keep asking about how they can connect their turntable to a stereo or sound card without a phono preamp, chances are good that there is no phone input on whatever unit he has.
I have two iPods in the household (an Original and a new Nano), and both of them drive the (Sony) amp to a house shuddering loudness with gain to spare.
You haven't mentioned the output volume setting of your iPod. Have you turned it up?
OK, I just have to ask: How does loading with a 33 ohm resistor
*increase* the volume? Normally we would expect a load to only
*decrease* volume, since it becomes the bottom leg of a voltage divider with the output impedance of the source the top leg.
Or is there some sort of automagical sensing in the output circuit, that increases the level when it sees a low load impedance? Seems possible, and maybe even logical, so the same connector can serve as headphone and line out. But I haven't encountered it before... it this common?
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I was thinking the current-oriented output was unable to drive the relatively high impedance input; the 33 ohm load allowed the output circuit to function, developing enough signal voltage across the resistor to give useable volume.
My stereo has RCA jacks mainly and I used a cable with a microphone jack on the Ipod headphone and the other end had RCA connectors. I am not immune to building a simple battery powered preamp if you know a simple design?
That's a viable explanation, depending on the actual output circuit. I haven't a clue what they use in those things, but certainly if they had something that used the headphones to to supply the current to the output stage, it certainly would provide a terribly weak signal unless there was a suitably low load there.
I thought, though, that they'd generally use something like an op-amp, where there's current to the output device whether or not there's a load. I do note that out of three portable CD players, one portable cassette player and one MP3 player that I have, none require a low impedance DC load to provide suitable output level. Their outputs vary in level, and they all seem to be lower level than my component CD player (though my component DVD player seems to suffer from a lower output level), but not a major difference in level.
If you tuern down the volume control you'll still get significant output noise. The volume control is not some passive attenuator acting directly at the output.
So the output noise will be amplified by the high gain phono input and the signal-to-noise ratio will be atrocious.
You really shouldn't try to give advice about areas of technology you're completely ignorant of. But of course you simply can't resist butting in and trying to look 'smart' can you, you utter f****it.
Well I'm not interested in getting involved in the ad hominem stuff going on here, but on this occasion, Graham "Eeyore" is absolutely and totally right.
There's no way that you could get acceptable sound by plugging a nominally frequency-flat source (e.g. an iPod) into a phono input, no matter how much the source was attenuated. The phono input has a _severely_ tailored frequency response designed specifically and only for turntable playback. Tone controls will only make the mess worse, or at least, will go no way to sorting out the response.
The sound would be VERY bass-heavy, and there'd be almost no treble. For a SMALL range of frequencies, somewhere in the middle of the frequency band, the response would be flat. All of this assumes an ideal RIAA response on the phono input.
You need to wiki "RIAA Equalisation".
The response used in phono inputs - being the opposite of that used when driving the cutting head - has 2 main features:
1) It boosts bass, and lower frequencies are boosted more.
2) It attenuates treble, and higher frequencies are cut more.
The reasons are as follows:
1: To get decent bass playback without boosting bass on playback, the groove excursions would be *enormous* and the stylus could and would never, ever track. So you cut bass on recording and boost it back on playback. That way, groove excursion is kept under control. Lower frequencies need this treatment even more.
2: To mitigate surface noise, it is good to cut treble on playback, so you boost it when cutting. That way, you maintain a good signal from the original music, but severely attenuate high-frequency surface noise. This is a good thing.
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