Futurama...

[coolvij]

I was pondering the idea of a headroom portable cd player this morning, and how unlikely it would be for it ever to come into my possesion, because of cost.....

Anyway, i was thinking of how ppl were always posting about how they would like 50mw+ amps in the PCDP. I would too, but i had an interesting idea that may or may not have been discussed already - to my knowledge, it hasn't.

Why can't there be a 12mw (roundabout) amp in the player when the machine is running off of batteries - when plugged into a wall wart, it could switch to a 50mw+ amp.

After all, who's gonna use power hungry Sennheisers on the road when you can just get some Etys (4P) or 888s or EX70s or KSC-35s or......etc, etc.

Then, at home, plug it in, and, voila!, you have a source/amp ready to rumble.

And throwing in HDCD/SACD decoding would be nice.

 

[Neruda]

But the problem is that wouldn't make a really good portable CDP. It would be good for longer trips, though...

Actually, it might work in a way. Since Headroom makes those 4D cell battery packs, you could plug one into the player and have the amp power along with the battery life to make it last. hmm...

 

[thomas]

actually, the headphone amp's output only draws a tiny fraction of the batteries.

A pair of AA batteries =2 x 1.5V x 3000mAh = 9000mWh

divided by 100mW headphone amp, and you'll still get 90 hours of battery life. and anyone other than aphered could gp totally deaf after the 90 hours.

Most of the power in a portable goes to powering the electronics, the motors, lasers, etc...

So why don't portables have more power? probably because they've already made the other components very energy efficient, and the only way to get an extra one or two hours of battery life is to reduce the amp output. Anyone, even the dum-basses would prefer the more powerful amp, but saying somthing like "the world's longest battery life" is a better marketing slogan than "15mW + 15mW RMS headphone amp output 32 ohms".

But headphone amp output has nothing to do with soud quality. I'd prefer a 10mW high quality amp than 100mW of garbage. At normal listening level on my super-cmoy, the output is only abut 5mW and it sounds way better than the amp on any portable (its using up 900mW, but that's another story...)


I personally don't see much of a market for high end portables. Sure, they'd be great on long vacations and business travelers, but most people use portables "portably"! When you're outdoors, on the bus, etc, you couldn't possibly hear the advantages of better DACs, newer formats, etc...

BTW, have any of you tried using a discman with optical out into a portable toslink-input DAC? that would be the ideal solution until someone releases a high-end portable cdp.

 

[topher]

Why haven't any of the diy crowd put together a
portable dac/amp? The chips are out there.
cs8412/4 to receive digital audio, cs4396 or
comparable dac chip and ad825 opamps are a recipe
to make a very high-end system. I could put
together the schematic, but I don't have a layout
package. If anyone wants to do the layout and
have some pcb's made, I would be willing to help
with schematic and design.

 

[coolvij]

Right on, neruda. And when u don't need the extra kick, running the unit off, say, 2 AAs or maybe even 2 AAAs would give u a decent PORTABLE cd player......

 

[thomas]

topher... working on my own portable DAC, but battery life is a problem. I don't have the skill/time to make a PCB for it.

I think i've told you this already, i was using cs8412, ad1868, ad823... all of it could probably be powered off a 9V regulated down to single 5v supply...

 

[Eagle_Driver]

I was going to move this thread to the General Discussion forum...

...until I found out that most of the posts refer to portable audio in general!

Therefore, it will remain in this forum.

 

[topher]

I remember thomas. I have been thinking about it.
The more I think, the more I am afraid to make any
kind of dac without a _serious_ groundplane. I
think I am going to go directly from a prototype
to a 4 layer board. You can get 18 sq. inches
for $135 from pcbexpress.

As for power, you have done very well.

cs8412 40ma
ad1868 10ma 18bit 44.1KHz
ad823 5ma

My plan,
ad8427 36ma
cs4397 20ma 24bit 176.4KHz
ad825 7ma

I had planned on a cs8420, but that is 125ma!
That's fine for me, I seldom am away from a wall
socket, but I want to make something others can
use.

How is you project going?

 

[thomas]

i'm planning on building 2 DACs, a home one and a portable one. I'm gonna put in the orders for the parts for the home DAC, as well as an extra crystal reciever for the portable

Once i finish the home DAC, (and about 5 other projects) i'll start the portable DAC. Its not as much of a priority right now because I don't have any good portable headphones, and even if i did, it would still be hard to appriciate the better sound of the DAC.

It may be the end of summer or christmas break before i get the time to finish this DAC.

So those my part choices will probably change, these just looked like the best choices, based mainly on recommendations from others. I haven't heard much about the AD recievers, i'll check them out, i really need to cut down on current draw. Right now, we're only looking at less than 5 hour battery life

BTW, i just went to cirrus/crystal's website, and just noticed their new Class D headphone amp IC... it could be interesting to make a DAC based on it...won't sound as good as our DACs, but a hell of a lot more efficient, and people like appheared would really like the 100mW output!


http://www.cirrus.com/pubs/cs44L10-1.pdf?DocumentID=536

 

[Deuce_Bigalow]

I think the ultimate pcdp would be not too big, but not small enough to compromise the sounds and durability too much. It would have a switchable amp (10mw-20mw-100mw) or something like that, and switchable skip protection. It would have a remote that doesn't add any noise to the sound (for when you use it in a pocket or bag or something). It would be all aluminum and built really strong.

We have to remember that there is compromises in everything. My idea of the best portable cd player is one that is still actually portable (not too big, doesn't skip easily, half decent battery life) and has good sound. I'm pretty happy with my Sony D-E446CK in that way. It has 15mw/ch, it can power almost any headphones I'll be able to afford, sounds good, batteries last long enough for me on nimh battery pack 16 hours on alkaline 9 hours on Nimh. I just charge it up every couple days. I've dropped it lots of times and it holds up good (its 2 years old).

I think the ultimate pcdp is the D-777. Some might say the D-Z555 is the best, but is it really portable? I don't think so. Everybody has their own idea of what their own "best" portable cd player would be like. It depends what you use it for.

 

[timoteus]

Okay, let's drop the PCDP altogether. I propose wireless phones receiving a direct transmission from Tesla's Wardenclyffe or Colorado Springs lab. This, of course, would require a lead-lined helmet to keep your skull from lighting up like a light bulb. The lead helmet in turn would necessitate the use of a neck brace. Doable in the winter, not so good in the summer.

On a more serious note:

Since Rega already makes a great CDP, and now they have entered the headphone amp market-
I would think the next logical step would be for them to make a great PCDP. The market is wide open and they are already a niche player. I for one would buy one. There are pricey CDP and there are relatively cheap PCDP with nothing in between. You can spend more on a good pair of interconnects than you can on a PCDP. That doesn't make too much sense to me. If you disagree, let me know...

------------------------------------------------------------------------------------

dyslexics untie

 

[coolvij]

Well, i think that portable MDs sound REALLY awesome (or maybe i have new toy shock.......). In fact, my R700 beats my cheapy Philips portable quite handily.....

So......if there was a high-end PCDP, for me to be interested there would HAVE to be a switchable amp (run it off the wall wart and you'd have a decent home CDP with a 50mw+ amp, on the run off AAs or something and have 15 hrs. of 20 mw. life.....).

That's what i think. Otherwise, MD will always be just too good.......especially with Type R recording......aaaaahhhhh......i like Type R recording.

Hey, since this is the Futurama thread, why not contemplate the future of MD?

Last generation: Shrink down - the R70, the mid-level model, was VERY small.....its predecessor was not

This generation: MDLP

Next generation: Net MD

Next-to-next generation: Sony releases "their" ATRAC 7, which comes close to Type R performance in portables

Next-to-next-to-next generation: Type R in high-end portables?

Hmm.....that would be great, if MD progressed into basically maxing out its potential for sound quality before it degenerates the way PCDP have today (batterylife, useless features, "sound effects" etc. becoming selling points..).

 

[thomas]

or how 'about introducing the high capacity MD's (650megs) that sony has had lying around for probably 5 years now? That would have made perfect lossless compression possible, but sony's a recording company as well and that would be bad for their record sales.

By now, i think they could put at least 2 gigs onto an md...

 

[coolvij]

I know thomas - they're ripping us off.....the big giant companies are in it for the money.

However, ATRAC is great-sounding - enough for me. The great thing for me is the boot-leg potential. I'll never have to buy a one-hit wonder CD again....but i can always ENJOY the one hit.

 

[Neruda]

Do MD's really hold 650 megs? if they do, why all the compression?

And hey, wasn't it wheatfield that was showing the DAC/headphone amp at the New York show? Our problems are over! Just hook that up to any player with an optical out and you're set!

well, provided you got the money. But I'm sure many of you do, since the DAC/amp is suprisingly cheap.