Sorry, I have not used the MP3 panel yet, it's going to be a part of the new xmitter I'm going to build. I should have the final parts for the xmitter here this week but at the speed I work it will be a few weeks until I get it anywhere near operational. Right now I have a Philo 116X in mid refurb, an RCA clock radio also apart waiting for lytics, 3 other radios where the chassis is done but I'm awaiting decent weather to do the cabinets, and the dial string just broke on my daily driver (Stromberg-Carlson 535-M). As soon as I have any more info I'll be sure to post it.

Larry

I'm still waiting for mine to arrive...
They waited about a month then sent a big email of apology to every one asking for patience.. then several weeks ago they said it was finally on its way...
So far .. nuttin.
lol

Did you order off of Ebay or from the co directly? Just curious as mine arrived in exactly 2 weeks. This is the third MP3 player I've ordered off Ebay and they each arrived in 2 weeks or less.

Larry

Direct from their website.

Ahhh well finally mine showed up today... lol

Post marked in Hong Kong 3.4.12
"airmail" no less .... lol

Mine is the one that they offer for $7.80 free shipping.




http://dx.com/1-5-led-mp3-player-module ... 3-7v-94814

Only an hour or so into playing with it.

Well mine looks a little different on the PC board... with B+ marked in a red header plug and the L & R audio the same way in white headers.
As soon as I powered up with 3VDC it played the SD 2-gig chip with MP-3 songs on it... but it was sort of marginally playing because the two AA batteries were a bit lower so I heard this kind of pulsing clicking going on.
As soon as I went 5v the clicking stopped and it started playing beautifully.

The info on the site specs say 3.7v
It does not play WMA format at all as far as I can tell so far ... even though the specs say it has a wma chipset. Whatever that's supposed to mean.

- Model: KSD-396
- 1.5" LED display
- Built-in MP3/WMA decode chipset
- Supports USB flash drive (up to 4GB) & SD card (up to 8GB)
- FM range: 87.5~108MHz
- Supports MP1 Layer3/MP2 Layer3/MP3 Layer3
- Voltage: 3.7V
- Comes with remote controller (1 x CR2025 included)
- Remote control range: 10m


The FM radio works beautifully.

I don't know how or what to do with the other mini front panel jack though.

The SD card plays automatically.

anyway...
So far so good.

I just want to feed it into my tube-amp and operate the remote from the couch.
Wish it had shuffle though.

EDIT update:
It does play mp3s from the usb flash drive... OR the SD card... either one.

I'm not sure if I'm real happy right now though because I hear an irritating background hiss.
Even if I'm only using headphones... but of course it's just as loud when feeding my tube-amp.

I'm only using batteries (3 AA = 4.5 vdc) so it's not coming from B+

It's there during FM and playing Mp3s.
It only stops if I select aux mode with no input.

What can this be caused by?

Also I normally feed my Tube-amp from my Mp3 player's Headphone jack and that is always totally silent.. even on both my different brand Mp3 players.

But this thing seems to have a line level because it is really loud feeding my Tube-amp (which has no vol adjustment on it)
If I try to feed the FM radio to the tube amp I have to keep the digital vol control down at the very minimum level 1 or 2 and still that's too loud.

I've tried going through the six various equalizer or (tone?) settings... but none of them will completely eliminate the hiss.

It's quite irritating..... like "tape-hiss" and fixed constantly there exp in Aux with no input..

Any ideas of how to eliminate that hiss?

Have any of you heard it on your players?

One thing about the Chinese; they love to cut each others throats in retail. Here's almost the same thing for $3.17, free shipping;
http://www.ebay.com/itm/Car-Kit-MP3-Pla ... 3373f16f60


I might even splurge, myself.

I bought the one you show, the black one, and that's what I paid. It works great. There is one minor issue that I want to deal with and that is that it's designed to plug into a cigarette lighter, not the Power Plug, so it's a little loose in there and if you hit a hard bump it can momentarily loose contact. That causes everything to reset. I think a little tape around it at the right spot should fix that. I can't use the cigarette lighter because it's just above knee level and with the player plugged in there it's just too close to my knee.

Larry

So ...? Does anyone else hear background hiss with their player?

By comparison, if I hook up anything to the Aux input.. that seems perfectly quiet.

It's kind of curious looking at the types of ground connections.
Each channel's audio output has it's own separate + and - contacts ... So I guess it is meant to have each output connect to separate speakers each with their own two wires.
( most stereo speakers share a common ground wire though typically.. no?)

So.. if I feed each of those two individual "plus" & "minus" points to a stereo-headphone jack for each of the two channels the two minuses will need to be connected to the same, common "gnd" point on the jack since the jack only has 3 contacts = a contact for L & R & Gnd.
...but hooking the minuses together at that jack seems to work ok.

So I don't think that combining the two minus leads is causing the hiss .. because I hear the hiss even on only one channel without the two minus leads being commmon-ed.

The aux input ground however isn't the same ... and I cannot connect THAT aux-input gnd to the audio-out chip's signal gnd
because it starts to make very slow clicking sounds or oscillations or something.

The two audio out chips have the number 8002 on them...
That must be the PAM-8002 class-D power amplifier chip:

http://www.poweranalog.com/pdf/PAM8002.pdf

I also have a question about the signal labels on the Aux input pc board contact area.
There are 6 solder holes labeled:
1 = VCC
2 = 5V
3 = Gnd
4 = L-in
5 = R-in
6 = Gnd

I can put some audio from my other mp3-player headphone out jack ... into the L &R input and the last ground.
Then in AUX mode that audio sound clean.

What is the VCC and 5V points for?

I have two of the mounted panel type players. I have not heard any hiss on the first one and the second one has not yet been installed.

Larry

The two negative speaker outputs should not be connected together, because this is a bridge output circuit. One of them can be at the positive supply voltage while the other one is at ground. I suspect that the outputs are protected, but connecting them this way will cause crosstalk between channels.

Yes! .. I'm certain you are right.
As I looked at the circuit I had the same conclusion.

So Earlier today I connected each output individually to separate speakers... (and no common negative)

This works, (as designed and intended) of course... sure fine... [but hiss is still there too.]
The volume is surprisingly quite loud too especially since the whole thing is being driven from only 3 AA batteries.
[ current varies with the varying signal volume from about 60ma-150ma]

The two, now completely isolated, audio channels now, however... still has no effect on improving that background hiss of course, as I'm sure that's some kind of a result maybe of the signal feeding into the output chips probably already having hiss at the previous stage for some reason.

BUT ...It's just not quite as noticeable now, while listening to the speakers from across the room. ...compared to having the headphones connected.... or when feeding my tube-amp input.

But the only reason I got this in the 1st place was to feed into my tube-amp. The value of this thing to me was the remote control.
But it's too (hiss) noisy for that.

Perhaps if I could just find a good MP3 player that has a headphone out jack it might be as beautifully quite as my two other regular potable MP3 players... but I'd just want it to also have a remote control.

That's all I really want.... but I guess it doesn't make sense for manufacturers to design and make a stationary MP3 unit with both head phones and remote control.
The logic of this current design I guess was to bring MP3 into the stationary home unit... and then you'd want a remote control and also to drive speakers to of course.. (not headphones).

But I only believe or think I want/need a headphone output because it's quieter... and clean ....like my other two MP3 players.

So essentially I want clean pure quiet audio output with a remote control ... and of course shuffle too.
Do they make it?
Is it too much to ask for?

This begs the question:
Why is the headphone output from other MP3 players so quiet and clean?
What kind of solid-state amp chip is it that drives the headphones?

After all.. I am feeding my hi-quality hi-fi tube amp with this signal.. right?

If I have to feed my tube-amp from the output of this device that uses this class D bridge amplifier...
am I defeating the purpose of driving my tube amp with a quality input?

Why does it sound so beautiful when I feed the tube-amp from the headphone output circuit vs this kind of Class-D bridge power amp?

Curious minds NEED to know.

Maybe I missed it but I can't tell how you're connecting it to the tube amp. You should be using the line outputs, shown here
http://f.io.ua/img_aa/medium/2031/32/20313297.jpg , and not the power amp.

Hi Flipperhome:
On my unit those points that you are referring to in your photo above are marked as L-input and R-input
and when I change the mode to AUX.. and put a tone in on either of those two points I get that tone out on the header +/- output that I am now using for output.

Notice the whited printed text on the PC board just below that COM2 connector with the arrow pointing upward to that area.
So I'm taking the output from those white plastic headers marked L_O +/- and R_O +/-

I tried power in at the RED BATT +/- connector and also at the com2 connector points marked 5VIN and GND
and it seems to operate exactly the same with the prominent hiss sound in the background.

Those points marked Lin and Rin are actually connected to the points where the MP3 decoder outputs are connected to the power amp inputs. So, you can use them for the line out. Your unit appears to be identical to mine, and that's the place I connected to, to get a line out.

I didn't get any noticeable hiss on my unit, but there is an extremely faint ticking noise in the background which is only audible between tracks when the volume is turned way up.

Thanks Bob:
That's interesting. So The MP3 decoder feeds the 8002 PAs and that is the same point that an Aux input would feed the PAs.
OK ..I see.
Where is the volume control at though?
Can I still control vol if I take output from this point?

I'll try it later ... hope the hiss disappears.

The volume control should still work.

I think the proper place for the aux input is the micro USB connector on the front panel.

Hi again Bob:
Not looking so good.
I do not have any audio at all on the points labeled L-in and R-in.

But if I poke around a little I can pick up a clean signal for each channel where chip U2 (the MP3 decoder?) connects into C20 & C21
(red arrows)
The headphones are connected between the point marked GND and each headphone channel to each cap
This does adjust by the vol control.. but it's tough trying to solder leads to that end of those two tiny SM caps...
I did do it but I'm sure it isn't proper because... it sounds pretty good in my headphones but when I plug it into my tube-amp... the input caps (maybe) in the tube amp must be no good for the signal at this spot or it loads it down too much ....because I hear that slow clicking ....which I can almost get rid of by increasing the vol real high.. but it just doesn't seem right.

Are you SURE your board is EXACTLY the same?

Any other ideas?

You're right. There appears to be a difference in the boards. I notice from your photo, the model number is ZTV-CT02E, and mine is ZTV-CT02B.

What may be simpler, is to connect the positive speaker outputs through a resistive attenuator to your tube amp input. Leave the negative speaker outputs unconnected, and use the regular ground as the common. You'll also have to put a DC blocking capacitor in series with the output, because the positive speaker output will have a DC bias on it.

That should give you more volume control range, and hopefully reduce the amount of hiss.

LIN and RIN are inputs, not outputs so you would not detect any signal there. Curious as to why you're soldering wires directly to the board, did it not come with pigtails?

Larry