If you think Class D is not HiFi...you are fool

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soongsc said:


I think DVD resolution is about 1/4 pixel count of HDTV.
Lots of things are involved with good video playback, as with audio, may things still cannot be determined by spec values quite yet.
Window XP media Edition? That's what it sounds like it.


I just looked up XP media edition to figure out what you meant by that. I see they make some claims about automating etc.

Could be interesting, if it works OK and the quality is there (hahah).

Whatever is best for the job at the time is what I'll use. It would be interesting to know if anyone went that far with XP though.
 
I use a hacked xbox and XBMC. If you can find a better system your welcome to it but for standard def IMBO after trying out many other ways of delivering media content to the living room you can't do better.
And the codec support is mind blowing, plays stuff all the time that xp just has no idea what to do with. And it is remote controlled out of the box, has great networking support and has an excellent GUI (depending on skin)

Off topic but then you guys started that.

Phil
 
Off topic?

This whole thread has been a general purpose catch all and I am not sure what it is anymore. Aside from that you are right about the codec issue with XP media player. It seems like no matter how many packages I download or how many come directly on demand there is always something that won’t play. I have never understood this need for all the different codecs. To me it is just plain stupid. If they are using it as another layer of copy protection why bother as no one will want it if it can’t be played anyway.
Some of the codecs have a real playback quality issue. You can just compress data so far before it starts to fall apart. Then there is real player and quick time with there own formats and so full of adds and spyware like stuff that they are almost as bad as a virus. Getting them to stop loading and connecting to the internet is a real pain in the a**.
Now load a DVD and try to play it! It will probably require its own player which conveniently will be be on the disk. These players also will have spyware stuff but at least they are easy to dump.
All in all not a good way to recover quality video, just too much b.s. to go through. I don't know how the Xbox can do it , I don't have one but if they can why can't the media player?
Roger
Ps. IMBO?
 
This whole thread has been a general purpose catch all and I am not sure what it is anymore.

Yes you do :) You just said so.

I've been thinking about it as our general off topic thread lol.

Anyway, codecs my man, codecs.

Here's what you're going to do:

Download the only codec pack I bother with it's called "K-lite Codec pack" and believe you me Sir it is substantial!

Let me tell you all about it.... maybe I should start thread :)

It includes everything from codecs to a nice little app called "Gpsot" which is for checking video files to see what video /audio codecs they require, and tells you if it's installed on your machine or not.

But the codec pack is so good you'll likely never need it.

It also includes BSplayer and Media Player 9. Why? Because the ODD time when it wont' work with Media Player 10, it will always work with Media Player 9!

At the start of installing the codec pack, you'll be prompted for what mode you desire. This determines what it installs, if you're into ripping video you'll need the playback/recording install which is likely alot more confusing.

If you're like me and just into watching video, take the "playback" option and only the tools/codecs required for playing it get installed, slipstreams the process nicely and doens't leave you at all guess about compatibility issues between codecs or anything.

What else does it do that impresses the hell out of me?

Sit down Roger.. waaaaait for it....

Quicktime and Realmedia (SPIT):

It installs the codecs for these programs so that they work seemlessly in Media Player or whatever you're using. You never need to install quicktime or realplayer ever again, never have to haunt through too many preferences to try and find the magic checkbox that stops it from calling home everytime you boot....

The most trouble I've ever had with the K-Lite codec back is just what I already said, sometimes you have to open up the video's in media player 9 because it wont' work with 10.

Other than that, it's smoooooooooooth sailing.

I'm with you guys though I'd have my reservations about associating XP or anything MS with such a system. Whatever works best I say.
 
Some good there, and on Real player i agree. I frankly wont have it on any machine i use. Appalling software, thank god the BBC is offering its streams now in other formats.

Quicktime i am sorry but it is a decent and very useful wrapper lets say rather than a codec. I work in a animation production company and have to say we use quicktime for many things. It is in many ways superior to media player and can be used for everthign from sending tiny preview videos over the interent to packaging up final broadcast video very useful (but its Apple so we have to hate it). I think the fact that these days they are trying to force you to install damn itunes with it is annoying. Oh and beware of QT7 for xp, had a million issues with it so far. Leave well alone til they update it.

How can Xbox Medis Centre support more codec than any other media playing O/S or player? Simpe it's open source and has an excellent group developing it with very focuses vision, it is updated near enough daily and has no loyalty to any media format unlike apple or MS.

Honestly i cannot say enough about it, my dear lady can take or leave the amps i have made (though she does like the AMP3) but she absolutely loves XBMC, no better system out there period.
 
Jaka Racman said:
Hi,

well, I do agree that cables are microphonic. I recently changed humbucker on my son's electric guitar and he complained about increased level of hum. So while testing with his Marshall amp at full gain, i have heard just what mzzj described. This might be attributed to high levels of input and source impedance in guitar amps, where minute changes in cable capacitance get amplified. I'd bet that effect would be far less audible in 50Ohm setup.

Another example of microphonic component is LF356 opamp. I once used it in high gain application ( several tens of times, I don't recall exactly how much), and just by bending the PCB I could get 200mV changes in output offset voltage. Opamp was in SO-8 case, so I later redesigned PCB for DIP-8 footprint.

Best regards,

Jaka Racman

Hi Jaka,

I agree with Bruno's paper, hypothesis and conclusion.

If you mean a 50 ohm source I think I agree with you too.

I have seen the phenomena first hand now, 15' feet of 12awg monster cable speaker wire acting as interconnect. I had unplugged the cable from my sound card while the amp was turned on and someone sitting right next to the speaker could hear me moving the wire around and so asked me to keep moving it/tap it... the term micro no longer applies it's a drum machine with that wire hooked up to a ucd180.

By now buddy is having a good laugh thinking I can't solder a cable together, so I told him I'd make the noise vanish by plugging the wire back in, he mentioned the use of foam cups as I'd shown him the thread. I just plugged it back into the source. Can drum on it all I like now, bend it, twist it, hit it, whatever, and can't hear a thing. I don't know what the output impedance of the audio dock is but it must be low enough.

Jaka like with your case I can fully appreciate the problem and the more scientific eyes with which you looked at it, but foam cups and expensive wire supports will never be the answer.

Best Regards,
Chris
 
Jaka like with your case I can fully appreciate the problem and the more scientific eyes with which you looked at it, but foam cups and expensive wire supports will never be the answer.

I was going to point you to the Vertex AQ web site but I see that is currently not avaialble until the end of the month. When it is back up, it is definitely worth a read. Not voodoo, but real solutions based on the most scientific of research! ;)
 
Class D

Lars Clausen said:
Charles: So right, Class D has obvious technical advantages, just like the CD had technical advantages over the LP, and has therefore now largely taken over the position the LP had before. Of course because 99% of music buyers don't care that the CD does not have the same atmosphere and sound stage as the LP.

And much the same can be said about many Class D amplifiers today. The sound is good, but something is missing. At least compared with the best Class A amplifiers around. (Say in the 5-10000 US$ range). Now since this forum is mainly occupied by that last 1% of amplifier buyers / builders who are concerned with the small sonic lack of the Class D amplifier, that is one of the reasons for the (good and healthy) scepticism.

All i'm saying is we are soon crossing the line where there is no reason at all left for using Class A or Class A/B.
Price, size, efficiency is already at level or better with Class D, only some aspects of the sound is worse or on level with Class A. But that is about to change now.

soongsc: You would see that if people were using really good loudspeakers. But with most normal loudspeakers in the 1000$ / box range you can't hear the difference.

I have been reading the threads from members for the last hour now. Class D versus anythin else. I'll tell you.

Class D sounds"crap" if not driven properly. These amps have a low impedance. No higher than 10K. They also require a large input voltage to drive them. The one's I use which, incidentally, are British, ready made and ready to go, produce 250watts into 4 ohms with a 2volt RMS input. I drive this newest technology with the oldest technology. VALVES!. I use an ECC81 as the input stage and, wait for it, a pair of EL84's as cathode followers. This gives me the voltage swing that I need to make the amps sing. Forget batteries. A good switching regulated power supply is all that is needed. These amps need a supply of 48 volts. The mains tx is a twin 35v @ 7A toroidal. Seriously guys, forget the class T. If you're interested in info on these amps, then I will give it to you. In an A/B, these little darlings destroyed class T amps at 10 times the cost. And that's from a dealer in the UK that holds a lot of stock of class T.

Ricky.
 
The one's I use which, incidentally, are British, ready made and ready to go, produce 250watts into 4 ohms with a 2volt RMS input.

If you're interested in info on these amps, then I will give it to you. In an A/B, these little darlings destroyed class T amps at 10 times the cost.

If you are saying that the amps you use cost ten times less than a class-T amp, I think it's fair to say that you have our attention!

More details please! ;)
 
classd4sure said:
I had unplugged the cable from my sound card while the amp was turned on and someone sitting right next to the speaker could hear me moving the wire around and so asked me to keep moving it/tap it... the term micro no longer applies it's a drum machine with that wire hooked up to a ucd180.

Connect a pair of female RCA plugs terminated with resistors to ground (like 10k) to the end of that cable and it will stop acting as an antenna. :D
 
Class D

GeWa said:
I'm also curious at which amps you're reffering to!:eek:

Regards


This combo has been out on dem to a specialist audio dealer in the UK. This man gives you 10 mins if you are lucky. I got 2 and a half hours and was asked to come back when I had made mods. This combo was played using a Copeland CD player and Pro-ac Response 10's. I was told that the sound was special. It destroyed Electrocompaniet, Pathos etc. This product will be available April next year at the High End HiFi show at the Park Inn, Heathrow. If you wanna come, let me know and I'll reserve you tickets.

Ricky.
 
If you don't mind me saying so Ricky, it's all a bit vague ! :xeye:

You said:

In an A/B, these little darlings destroyed class T amps at 10 times the cost.

Which class-T amps did it better? And what did they cost? Asking us to hang on six months for a demo on what you have told us so far is a bit of a tease! :nod:

(Of course if your source wants these marvels reviewed......... ;) )
 
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