[a6equj5]

Hi, this is my first time posting here. I just got a RioRiot portable mp3 player, and I'm not a high end headphone user by any stretch, but I need a little help on getting my sound right.
I might be the oddball here, but I like my bass boomy, deep, and rich. I haven't found any cd or mp3 players since I had my Sony D-11 cd player that produce deep boomy bass. I don't like it so boomy that I can't hear the rest of the song, but I like it to be pumpin.

So, here's my problem, and question. I have a WOW Thing from SRS labs, I've had it for a couple years, it has a bass boost on it, which works good for what I need it for, when I'm at home with an AC outlet. I'm out of luck when I'm travelling though.

I wanted to know if there's a way I could "Radio Shack" together a battery box that could run off of AA, C, D cells or whatever that would run the WOW Thing (It takes 14vAC @200ma according to the specs at www.wowthing.com). My mp3 player has a built in lithium battery, so the only thing I need to power is the WOW Thing.

Thanks in advance.

*EDIT*
Here are the specs from the website

Connectors: 3 stereo mini jacks
1 line input, 1 line output, 1 headphone output
Power jack - 14Vac, @200mA

Electrical Specifications: Frequency Response - 20Hz to 20kHz
Maximum input level - Controls maximum / WOW on - 2Vrms @ 1kHz. THD+N - (-10dBu input, 20Hz to 20kHz) 0.4% (WOW on / controls maximum)

Power Output
Headphones - 400mW / Channel X2 (@ 32 ohms)
*EDIT*

 

[Audio Redneck]

Howdy!

Yes, you can make a simple battery pack to run it. First question is how long do you want to run it between battery changes, and second is how big a pack are you willing to carry?

All your basic batteries (AAA, AA, C, D) are 1.5v, so you'll need 10 to get 15v (most devices easily handle +/- 20% voltage difference as batteries will drop in V as they weaken). The bigger the size, the longer the run time will be. If you are going the rechargeable route, you could get a pair of 9v NiCad's (7.2v each for 14.4v) and that would be the smallest package (and you could us a mint tin as a case for it).

RS sells cages for different numbers of cells and I think 10 souldn't be too hard to find for AA or AAA. They also sell the plug you'll need. Look at the power adaptor and find out if the center of the plug is + or - to determine which wire to connect to center.

I'll try to snap a picture of what you're wanting tonight (my telescope uses the exact pack you need).

 

[a6equj5]

I've discovered a simple battery pack will only work for me if I crack open the amp and solder the batteries to the "wave bridge rectifier" (I have no idea what that is, but that's what someone told me on another board)

I read the specs wrong and assumed it was 14vdc, but in fact it's input is 14vac. If you re-read my original post, I say 14vdc in the post, but the specs I list actually say 14vac... I feel so stupid for overlooking such a small detail.

So, I would either need to solder a battery pack to the internal ac/dc converter (the bridge rectifier thing?) or build some kind of inverter to convert the DC to AC, just so the amp could convert it back into DC... *sigh*

I may try opening it up and doing the modifications one day, but until I have time to open it up, do research on the chips inside, and find out what pins I need to solder to, I'm just going to hold off.

Thanks for the reply, I really appreciate it!

 

[Audio Redneck]

Amazing the difference an "a" makes.

Good luck.

 

[CaptBubba]

DC should go right though a rectifier with no problems.

 

[Joe Bloggs]

So you can just plug your batteries into your AC input...

 

[PRR]

> I say 14vdc in the post, but the specs I list actually say 14vac...

Arg. That can make BIG difference. And I'm kicking myself for not reading every line and getting specs myself. (Actually... you edited the post while I was composing a reply... rather startled me to see a different message by the time I got back to the thread.)

> battery pack will only work for me if I crack open the amp and solder the batteries to the "wave bridge rectifier"

Has this been tried? Or is it guessing?

It is usually "full wave bridge rectifier" or "bridge rectifier". It will be near the power jack, either a black epoxy box with 4 legs or four 2-leg little round epoxy logs. It switches AC into pulsating DC. Most DC devices powered by wall-AC have something like this.

However as CaptBubba says, DC will go through a rectifier. That's how the old AC/DC tube radios worked. Most of the US had 115VAC, but a large part of NYC and a few remote farms had 110VDC well into the 20th century. An AC/DC radio used about 100 volts DC internally. This passed through a rectifier on the way in.

On AC, the rectifier passed only the positive side of the AC swing, and a capacitor held the voltage from one AC cycle to the next. On DC, if plugged right, the rectifier was a small waste of power and the capacitor had little to do, but it worked fine. And if you plugged the radio into the wall backward (this was long before we had plugs with one blade wide than the other), the radio would not work and the rectifier blocked the reverse DC from doing any harm. "Try both ways", one way worked. (A "full wave" rectifier would have worked with the DC either way... most telephones use one to power the touchpad even if the phone company does not know red from green. But full-wave tube rectifiers cost too much for cheap radios, so they were all half-wave.)

Smaller issues: a 14VAC source through a rectifier and filter may make up to 20 volts (the rectifier and cap make a peak detector, and the peak of a sine wave is 1.414 times the RMS). A 20V battery is a heck of a lump. Does it really need 20V internally? I don't know and I shouldn't guess at a distance.

I wonder if the company would discuss powering it from a car cigar lighter. They might see that as a valid use. They might say "Don't!" or they might say "It will work but not at full power", or maybe they know it works fine.

-PRR

 

[a6equj5]

I got the "wave bridge rectifier" from a reply to a post I made on another message board.

I don't really know anything about any of the electronics stuff, I was hoping it would be as easy as wiring up a battery box and fixing up a plug, but apparently it's a lot more complicated than I thought.

I don't know how big a 20V battery is, but I'm guessing I wouldn't be very portable if I had one that would power the unit for any decent amount of time.

What I think I'm going to do is just power the box off of AC power when I'm at home, get a DC/AC inverter like they make for laptops for when I'm near a cigarette lighter, and just deal with the tinny sound with no bass when I have to be absolutely mobile.

I should just pony up and buy a real amp from Headroom that will run off of DC power eh?

I don't know if that will do anything to boost the bass output, but I've always wanted to try one.

I saw somewhere that a set of pro DJ headphones had a built in bass boost function, I guess so they can hear the beat in a noisy club or something. I might look into some DJ suppliers and find out if they make a pair of headphones that would suit my needs.

Thanks for all the replies. I just wish I knew enough about all this stuff to make use of it all.

 

[Joe Bloggs]

As people here have pointed out, a DC power supply would work just fine plugged into the AC input as long as you get the right voltage.

But yeah, a portable headphone amp should be a better solution...

You don't like the bass boost on the discman either huh?