Problem with cd walkman and speakers

[someone]

I have a Sony portable CD player that I want to use indoors for playing talking books. I don't want to use batteries indoors if I can help it so I bought an AC adaptor to plug the CD player into the mains. This all works fine, except the portable speakers I had, also mains-powered, were too tall and kept falling over.

Recently I bought a nice little mains-powered Altius portable speaker from a local supermarket and it's only about 8" long, and flat, so it doesn't fall over.

Now the strange problem: when playing a talking book, the sound cuts out frequently for several seconds, always at the same random point on the CD. I have pinpointed some of these cut-out points and tried them again and again. I assumed it was the CD player, so I bought another one (stupid me). The sound still cuts out at the same point of the CD on the new CD player, and the light flickers on the Altius speaker.

I didn't have this problem with the larger speakers, but I have traced it down to this: When I'm using the AC power supply with the CD player, the sound cuts out. But if I have batteries in the CD player, it doesn't. So I put a couple of *dead batteries* in each of the two CD players, and they work fine with the Altius speaker. But with no batteries I get the cut-out problem with the CD.

Should I a) return the Altius speaker, b) put up with using dead batteries in the CD player and hope I don't burn the house down. I can't believe two different CD players can have the same problem, so it's not down to them. I can't figure out where the problem lies.

Any ideas would be appreciated.

someone

[Brian Gaff]

Well before you said about the batteries, I was going to suggest a level sensitivity. Presumably this player is playing mp3cds, but although the cd does stop for periods during playing these, I cannot really see why starting current would knock out the sound if the psu is also running the cd player. Are there two supplies, does the cut out coincidew with the spopping and starting of the cd?

Brian

[Dave W]

I Googled for Altius without success. I wondered if you meant Altus, but they're Sony wireless speakers. So I assume your speaker is a speaker with built-in mains-powered amplifier.

I suspect your Altius speaker has a lower input impedance than the speakers that came with your CD player, e.g. 4 ohms instead of 8. So your CD player takes too much current when a loud sound comes along, starving its internal amplifier. Batteries can provide higher peak current than the mains supply.

Does the Altius speaker have its own volume control? If so, you could try turning this to max and turning down your CD player volume control, so that the player doesn't have to put out so much power.

If the speaker impedance claimed for the Altius is lower than the speaker impedance of the player then you've bought the wrong speaker, but maybe you could get a refund.

Dave W

[someone]

Thank you Brian and Dave for your replies. I know not a lot about electrics/electronics, but here are the details of my setup.

As I mentioned I mainly play talking books, and this player (Sony D-EJ011) is playing files entitled track1.cda, track2.cda and so on to track20.cda depending on the length of the recording. There are usually about 10 CDs for a talking book. There are two power supplies, one to power the CD player and one to power the little speaker(s).

The spec for the CD player is:

DC 4.5V external DC supply, or battery 1.5V x 2.

I purchased an AC power adapter for this CD player, it is as follows:

Input AC 100V-240V - 50/60 Hz Output DC 5V 2A

Although it is Output 5V I was assured that it would work OK with my CD player. And so it has, with the bigger awkward falling-over speakers. But not with this little one.

The spec for the small speaker is:

5V 1A max Output 2 X 2.5W Switching adapter - power plug = Input 100-240V AC, 50/60 Hz 0.3 A max. Output = 5.0 V 500 mA Frequency response: 100Hz=20kHz Battery: 500mA, rechargeable

And it comes with a USB power connection cable which connects to the mains plug with another smaller USB-looking connector.

So, Brian, there are two mains power supplies, one for the CD player and one for the speaker. However this is the same as I had with my larger awkward speakers and they worked fine. The cutout of the sound doesn't coincide with anything at all except that it always happens at particular points in the given CD.

And to Dave W.: the speaker is an Altius CP-0011 "portable speaker with slimline design" bought from Aldi. It has the specs mentioned above. Nowhere do they mention ohms, and I don't know how to calculate them with this setup. I'll try what you say re turning the Altius speaker to a higher volume, and the CD player to low and see what happens. Fortunately, I have two months within which to take the speaker back if it is unsuitable or doesn't work, no questions asked. I am amazed that batteries can provide higher peak current than the mains supply.

Again, thank you for your interest in my problem and I will check out what happens with turning down the CD player volume.

Linda

[NT]

So far we know its speakers, not player

should be plenty for a portable player

So youre running an amp requiring 1A off an adaptor only able to supply half that. No surprise it hits problems.

If the 2 supplies have the same polarity and connectors, evebrything might or might not work if you simply swap them. If not, get a 1A or more 5v supply for the speakers.

new amp presumably has less efficient speakers or more bass response

where sound output power is greatest

wont make the least difference

You should find turning down the speaker volume avoids cutting out.

NT

[John Williamson]

Or where there's a big enough defect on the CD surface to cause the sound to mute.

Does the sound cut out at loud points on all CDs or only on this CD set at particular locations?

As Dave says in his reply, have you checked the speakers at high output on another CD, or with another source, such as a USB based mp3 player?

[Dave W]

True, if it's the speaker at fault. I was thinking it was the player cutting out due to overloading its output. It now looks like the fault is just an inadequate power supply for the speaker, making its light flicker as well.

Dave W

[Dave W]

I found out that your Sony player output is quoted as driving 16 ohm headphones, but I can't find anything about the Aldi speaker input except that it has an internal rechargeable battery which takes 3 hours to charge.

I take it that when the sound returns after cutting out, the speech has not jumped back or forth, i.e. it's exactly as if the volume control had been turned to zero for the cutout period? So there's no question of the CD being upset?

My theory is that there is an inaudible low frequency thump from the player which makes the speaker take too much current from its inadequate power supply, but when you put batteries in the player, somehow the thump is reduced enough not to overload the speaker. It might be worth ensuring that the speaker has been powered up for 3 hours so that its internal battery will smooth over the deficiency of the mains power supply that gives only half an amp instead of the possible one amp peak required.

Another theory is that the player is too near the speaker, which then vibrates the player and upsets the CD. When you put batteries in the player the added weight holds it steady!

Dave W

[someone]

I've now tried everything that I can think of. I can only conclude that the problem is somehow because I am using an external power supply for the CD player, rather than batteries. Strangely, the speakers work fine with my desktop PC for things like BBC news and so on, and also if I play a music or talking book CD on it.

I am admitting defeat, have re-setup my clunky speakers and will take the Altius back to Aldi. There is really nothing wrong with it in general, it's probably my configuration, but I'm not enough of an electronics engineer to be able to go any further.

Thank you all for your suggestions and help, I learned a lot.

Linda