[DeadTrying]

What exactly does that mean...

-What should I compare it to (sound quality wise)
-Is it good enough to get the best out of good headphones?
-I'm looking at this http://www.minidisc.org/part_Sharp_I...410+DR420.html
-Anyone reckon the 4-pole thing will be a problem if i decide on a different pair of headphones than the sharps?

Cheers

 

[Canman]

Read this article on digital (Class D) amplifier topology:

http://www.ofsoundmind.com/OSM2/tech...ment/amp5.html


Likely the unit uses a cheap class d opamp that is designed to get maximum battery life rather than good sound quality.

Edit: Link Fixed

 

[kartik]

Quote:

Originally posted by Canman Read this article on digital (Class D) amplifier topology: http://www.ofsoundmind.com/OSM2/tec...pment/amp5.html Likely the unit uses a cheap class d opamp that is designed to get maximum battery life rather than good sound quality.

firstly that link is broken. (now fixed!

)
Secondly, I'm using a class D amp with my SACD source and it sounds absolutely fabulous. Just because it doesn't radiate heat or drink up gobs of power to sound good is no reason to condemn the technology.

 

[kartik]

Returning to the original question; 1-bit amps amplify the signal in the digital domain while resampling the signal into a 1-bit depth with a frequency of 2.822 Mhz. This theoretically makes the sound smoother. Moreover, since amplification of a digital signal takes less power, the overall power consumption and heat generation is dramatically reduced. This technology is not only in use in relatively low-fi products as well as real High-fidelity products from dCS, Sharp and PS-Audio products, notwithstanding the preceding comments. Sharp products also include delta-sigma modulation which certainly does make the sound smoother.

 

[DeadTrying]

Thanks,

So by the sounds of it, 1 bit is an improvement over previous MD amplifiers.

Indeed I've just found an article about it here:
http://www.minidisc.org/classd_amp.html

What about the 4-pole design though? I have read it not only improves efficiency but also sound quality. However, in the process have they made the player incompatible with ordinary 3-pole headphones?

 

[Takashi]

Not sure about efficiency but Sharp claims that the channel separation improves by even separating left and right ground. And you can use 3 pole earphone on 4 pole jack with no problem. (You need adoptor to use 4 pole earphone on 3 pole jack, otherwise you only hear 1 channel)

 

[Canman]

Quote:

Originally posted by kartik What is it exactly that you are smoking?!!!? firstly that link is broken. Secondly, I'm using a class D amp with my SACD source and it sounds absolutely fabulous. Just because it doesn't radiate heat or drink up gobs of power to sound good is no reason to condemn the technology.

whoah, easy there

why are you on the defensive about your amplifier? If you read my post you will see that I did not make any blanket statements about Class D topology.

I don't doubt that your amp sounds good. I do doubt that any portable device using class D amplification sounds good because they are likely to use the plethora of cheap class D ICs which are made specifically for portable devices to conserve battery life. They are not made with sound quality in mind.

I edited the link in the original post. It is a good article explaining class D topology.

 

[Canman]

Quote:

Originally posted by kartik Returning to the original question; 1-bit amps amplify the signal in the digital domain while resampling the signal into a 1-bit depth with a frequency of 2.822 Mhz. This theoretically makes the sound smoother. Moreover, since amplification of a digital signal takes less power, the overall power consumption and heat generation is dramatically reduced. This technology is not only in use in relatively low-fi products as well as real High-fidelity products from dCS, Sharp and PS-Audio products, notwithstanding the preceding comments. Sharp products also include delta-sigma modulation which certainly does make the sound smoother.

A "digital" amplifier does not amplify in the digital domain. It uses a 1-bit PWM signal to control the switching frequency of the output transistors. Since the output transistors are used as switches, they are either outputting at maximum power or none at all. This produces output in the form of a square wave. Since a loudspeaker does not have the ability to respond quickly enough to reproduce a square wave, it ends up producing the average which ends up being the analog audio signal.

Note that Class D topology is not a new idea. According to one article it has been around for at least 50 years. The reason we have seen more use of this topology in recent years is that a) manufacturers have figured out ways to get around problems with load bearing issues and b) chip manufacturers have started to produce cheap Class D op amps for use in portable devices where battery life is an issue, like cell phones, PDA's, and portable audio.

 

[kartik]

Quote:

Originally posted by Canman whoah, easy there why are you on the defensive about your amplifier? If you read my post you will see that I did not make any blanket statements about Class D topology. I don't doubt that your amp sounds good. I do doubt that any portable device using class D amplification sounds good because they are likely to use the plethora of cheap class D ICs which are made specifically for portable devices to conserve battery life. They are not made with sound quality in mind. I edited the link in the original post. It is a good article explaining class D topology.

Sorry for being defensive. I will edit my post to tone it down. It's just that I've seen digital amps being ruthlessly attacked more often than defended. Most of the Sharp Auvi 1-bit stuff seems to contain better than average electronics, so I think that giving the MD player a try might not be a bad thing. Their implementation on a lot of their Mid fi and Hi fi products has been excellent.

 

[kartik]

Canman,
That link is informative although dated. Most of the current error correction and delta sigma modulation available on contemporary one-bit products significantly reduces the noise level that was associated with the 1-bit technology previously. Nonetheless, the bass handling on these systems is absolutely outstanding.

 

[Canman]

Quote:

Originally posted by kartik Canman, That link is informative although dated. Most of the current error correction and delta sigma modulation available on contemporary one-bit products significantly reduces the noise level that was associated with the 1-bit technology previously. Nonetheless, the bass handling on these systems is absolutely outstanding.

Kartik, That is true although the use of 1 bit DAC's for decoding PCM has fallen out of use since multibit converters seem to do a better job. Of course, SACD is a different story since the recording is 1-bit to begin with.

I would really like to give one of these amps a listen someday in my speaker system. I imagine that running the output transistors directly from the SACD datastream would sound really nice.

As for the original question, the 1 bit amplification may or may not be a good thing on the Sharp portable. I have my doubts, but it is impossible to generalize until someone actually listens to it.