Eh MUETA specs isn't looks so cool as in 2002. IMHO, time works against MUETA, she's looks like the idea came from 90th, when to be fast was equal being expensive, or not to be at all, and such analog calculator by the six opamps+modulator chip, really can help us have more, more and more loop gain. Nowadays we can buy faster/cheaper mosfets (or the some chip solution (e.g. TDA8939 $3.2 | 1KU), which should dominate anyway) to be almost happy with open loop design even, or with simplest UcD (or old kind hysteresis modulator, to avoid UcD patent collision) with 25db loop gain, and MUETA's virtual specs in the dust.. not sure? Ok, we can add integrator with 20-40db else, so THD=.000*% Zoutput=.00*Ohm and better. So, we need 6 opamps+chip still, or too late?🙂
sorry, just couldn't resist! 
Lars Clausen said:
It's added functionality to show technology. JVC has a little bedroom set that does this already.
😉
classd4sure said:
What do you want me to do, miracles?
I'm always doing something, and some days ago a friend gave me an old CDP. He bought a cheap DVD...
Well, there's always something to do and I have been working on this player.
You press the eject key and all the Philips CDM4 mechanics comes to the outside world. 😱
Spooky.
Fun.
You clean the laser without opening the player.
😀
I'll try a class D amp one day.
The problem is... I'm very satisfied with my current amp, so there's no real motivation for that now.
classd4sure said:
Pure digital link just eliminates D/A and some analog devices, resulting in less parts. This ia always a plus since D/A performance is very critical for audiophile equipment. Of course, multi channels provide better possibilities to add additional sound processing technology which will become another mess unless it's done right.
Hey Carlos,
Try a Amp3 they are only about 25 euros and take a couple of hours to get working. You won't be disappointed. Then you can design a PSU for it for the rest of us!!
That was a joke....or was it?
Honestly they are quite brilliant even my gf recons its a lot better than my gainclones are she said there wasnt much difference between my gainclone and the nad350.
Kind regards and thats for all the advice int the past.
Phil
Try a Amp3 they are only about 25 euros and take a couple of hours to get working. You won't be disappointed. Then you can design a PSU for it for the rest of us!!
That was a joke....or was it?
Honestly they are quite brilliant even my gf recons its a lot better than my gainclones are she said there wasnt much difference between my gainclone and the nad350.
Kind regards and thats for all the advice int the past.
Phil
Re: too much info
My suggestion would be to buy and build the AMP3 or AMP6, take the battery out of your car, and hook the amp up to that for power. Break it in and listen to it for a while. If you don't like it you have a nice little protable amp (can even give it away as a gift) and you're only out 32 (AMP3) or 46 (AMP6) euros - that's including shipping! 😀
If you do like it, keep it or step up to something like the UcD180. Having built a few AMP3's I would say that the resulting output noise depends a lot on the quality of the solder joints - especially around the decoupling caps and the biascap pin on the chip.
Optics, maybe not. Digital (the coaxial type), probably. Digital signals have very high noise immunity. You can also do all kinds of DSP and get rid of the A/D conversions (unless of course you have an analog source). You could now use digital filters that don't shift the phase of the signal. You could also use a single smaller amp for each driver (or a single channel for each driver) and not have to worry about speaker crossover design and implementation.
At least that's the setup I've been dreaming about ever since I was introduced to good sounding class D courtesy of the Sonic Impact.
T11 said:
My suggestion would be to buy and build the AMP3 or AMP6, take the battery out of your car, and hook the amp up to that for power. Break it in and listen to it for a while. If you don't like it you have a nice little protable amp (can even give it away as a gift) and you're only out 32 (AMP3) or 46 (AMP6) euros - that's including shipping! 😀
If you do like it, keep it or step up to something like the UcD180. Having built a few AMP3's I would say that the resulting output noise depends a lot on the quality of the solder joints - especially around the decoupling caps and the biascap pin on the chip.
classd4sure said:
Optics, maybe not. Digital (the coaxial type), probably. Digital signals have very high noise immunity. You can also do all kinds of DSP and get rid of the A/D conversions (unless of course you have an analog source). You could now use digital filters that don't shift the phase of the signal. You could also use a single smaller amp for each driver (or a single channel for each driver) and not have to worry about speaker crossover design and implementation.
At least that's the setup I've been dreaming about ever since I was introduced to good sounding class D courtesy of the Sonic Impact.
soongsc said:
That's very nice, but PCM is not directly amplified, it will have to be converted to PWM.
So, there are always conversions.
And there are analog and digital sources.
If you just have one source connected to the system...
I keep a conventional view: good digital source, with good dac and low jitter, and analog amp.
How many conversions here?
No more than above.
Yes, D/A conversion is critical, and I love my PMD100+AD1862 dac.
These are not new chips. In fact both are discontinued.
But they sound oh so good...
Pure digital
We just aren’t there yet. Building a really good D/A converter that only has to deal with line level signals is problematic enough with out asking it to do power gain as well. Then there is the problem of jitter that is virtually eliminated with the self oscillating design. This would be a major issue in a true digital power amp. For right now the best solution is the UcD design with a conventional front end. Eventually we will get there but the systems won’t be anything like what you think. They will have to be very complex to handle all the different functions needed. To name a few; lossless volume control, format conversion, input conversion, speaker correction, crossover functions, multi channel protocol, etc. All this will require a major software investment as well, don’t hold your breath waiting.
My personal feeling is this “digital revolution” is still many years away. When it does come it will be in a system with a powerful computer as the base and will probably be with a Mac.
Roger
soongsc said:
We just aren’t there yet. Building a really good D/A converter that only has to deal with line level signals is problematic enough with out asking it to do power gain as well. Then there is the problem of jitter that is virtually eliminated with the self oscillating design. This would be a major issue in a true digital power amp. For right now the best solution is the UcD design with a conventional front end. Eventually we will get there but the systems won’t be anything like what you think. They will have to be very complex to handle all the different functions needed. To name a few; lossless volume control, format conversion, input conversion, speaker correction, crossover functions, multi channel protocol, etc. All this will require a major software investment as well, don’t hold your breath waiting.
My personal feeling is this “digital revolution” is still many years away. When it does come it will be in a system with a powerful computer as the base and will probably be with a Mac.
Roger
Re: Pure digital
[
I have seen some devices that go to about 20W, they take in the 4 pin serial signals and drive speakers. Manufacturers have put a USB front end to take signals from PCs, but the original design was to let it site inside a player. I had the opportunity to listen to a little USB dongle about 1~2W capability on my own little speakers, the sound was quite good for such a little device driven by a notebook. I wouldn't be surprised to see good performance on the larger devices(well, the have to resize the output coils too).
[
sx881663 said:
I have seen some devices that go to about 20W, they take in the 4 pin serial signals and drive speakers. Manufacturers have put a USB front end to take signals from PCs, but the original design was to let it site inside a player. I had the opportunity to listen to a little USB dongle about 1~2W capability on my own little speakers, the sound was quite good for such a little device driven by a notebook. I wouldn't be surprised to see good performance on the larger devices(well, the have to resize the output coils too).
carlosfm said:
I do beleive PCM to PWM is done in software code conversions. If someone else know better, please educate us. The serial data is first separated into channels, and then converted to PWM. The process really should be lossless until it reaches the driving stage. D/A converters have more quality issues involved. In software, the losses that will be encountered are when there is a change between data formats when you convert floating point to integers. Using D/A converters, it is always necessary to convert to integer before feeding the D/A. I'm not sure with the PCM to PWM conversion.
I realize beauty is in the eye of the beholder.🙂
Re: Re: too much info
Now I'm worried. I have an AMP 2 sitting on my bench, under a manifying glass. and I've bee struggling to get thos beautifult solder joints instead of the droplets that I end up with. Seems like I really need a fine tip solder iron.
BWRX said:
Now I'm worried. I have an AMP 2 sitting on my bench, under a manifying glass. and I've bee struggling to get thos beautifult solder joints instead of the droplets that I end up with. Seems like I really need a fine tip solder iron.
A fine tip isn't a requirement, extra flux is though. I have completed three AMP1-B's using a standard tip and 30w iron. I used a very fine paint brush to dab flux on each pad before I soldered. This was the first time I have ever soldered SMD's and all three amps turned out perfect.
theAnonymous1 said:
I need to try that. For those little cap and res, I try to dip some solder on one pad, push one end into the pad to make the soldered connection, then do the other end. It's the second end that I normally end up with too much solder.
How do you clean off the flux after all work is done?
sorry to go off topic in this thread but just a quick tip for soongc.
if you don't have flux, there is a simple way to solder the SMD parts with flux core solder. hold the part in place with tweezers or needle nose pliers, get a little blob of solder on the iron tip, and tack one side of the part to the pad - it just needs to hold the part in place. clean the tip off, heat the other side of the part and pad and apply just enough solder to get a good joint. go back and redo the other side and you'll have two good solder joints.
but yes, if built properly, these class d amps are absolutely hifi material! 😉
if you don't have flux, there is a simple way to solder the SMD parts with flux core solder. hold the part in place with tweezers or needle nose pliers, get a little blob of solder on the iron tip, and tack one side of the part to the pad - it just needs to hold the part in place. clean the tip off, heat the other side of the part and pad and apply just enough solder to get a good joint. go back and redo the other side and you'll have two good solder joints.
but yes, if built properly, these class d amps are absolutely hifi material! 😉
Hi.
I agree with Chris. I have just completed a hybrid design using a valve pre driving 2 250watt class D power amps. I did an AB comparison with a conventional linear amplifier and the results were quite amazing.
Firstly, the bottom end. The linear amp was good but a little slack in it's control. Mid band was good but HF seemed to roll off.
The class D, On the other hand, was as good at 30Hz as 20 KHz. In other words, consistent. Any "harshness" was removed with the valve pre. The end result?. A good all round performer.
I honestly believe that Class D will actually succeed T and, yes. It does work for HiFi. Very well actually.
Ricky.
www.arcaydis.co.uk
I agree with Chris. I have just completed a hybrid design using a valve pre driving 2 250watt class D power amps. I did an AB comparison with a conventional linear amplifier and the results were quite amazing.
Firstly, the bottom end. The linear amp was good but a little slack in it's control. Mid band was good but HF seemed to roll off.
The class D, On the other hand, was as good at 30Hz as 20 KHz. In other words, consistent. Any "harshness" was removed with the valve pre. The end result?. A good all round performer.
I honestly believe that Class D will actually succeed T and, yes. It does work for HiFi. Very well actually.
Ricky.
www.arcaydis.co.uk
interesting but same
you are all right. that is the problem...
it just seems that everybody is too much time in this "business" of comparing, mixing and truly wanting to achieve that golden throw that would bring everybody to the heavens audio. Do you remember the goal you are aiming to? It is just music. The industry always followed if people knew what they want. You want specs? You will get them! Do you want pure joy and singing music? You will get it... Come on... D class is just one of the paths that "maybe" leads to something better but it is not granted to be the last one in your life. Do you get it!? Pick one D-amp try it, keep it if you like. Do you realy need 15 people to say to you that it measures like nothing before it and that alll world is in hype with it? They do not have your ears, your brains... it just doesn´t matter. Please just listen and then choose. I would say that everything that plays better but is simpler and leave us more out of it (like neverending tweaking of SS and tube amps at home) put us in the domain of pleasure and not into the mental processing circles that developers must go through.
oh i should go to sleep... new is good; it reflects old...old gets new face...
t
you are all right. that is the problem...
it just seems that everybody is too much time in this "business" of comparing, mixing and truly wanting to achieve that golden throw that would bring everybody to the heavens audio. Do you remember the goal you are aiming to? It is just music. The industry always followed if people knew what they want. You want specs? You will get them! Do you want pure joy and singing music? You will get it... Come on... D class is just one of the paths that "maybe" leads to something better but it is not granted to be the last one in your life. Do you get it!? Pick one D-amp try it, keep it if you like. Do you realy need 15 people to say to you that it measures like nothing before it and that alll world is in hype with it? They do not have your ears, your brains... it just doesn´t matter. Please just listen and then choose. I would say that everything that plays better but is simpler and leave us more out of it (like neverending tweaking of SS and tube amps at home) put us in the domain of pleasure and not into the mental processing circles that developers must go through.
oh i should go to sleep... new is good; it reflects old...old gets new face...
t
The main advantage of class-D will always be efficiency, enabling smaller and lighter equipment that runs cooler and wastes less electrical energy. Simple as that. This is enough driving-force for many companies to change to class-D as soon as it is easy enough for them to implement it with appropriate quality.
Regards
Charles
Regards
Charles
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