[tubeytubeamp]

To my knowledge, there are no "fully digital" amplifiers....yet

Vinne,

This sight claims that there are some amplifiers that keep the signal digital throughout the chain.

Dennis


http://www.puredigitalaudio.org/digitalamplifiers/index.shtml

http://www.puredigitalaudio.org/resourcesSections.shtml

http://www.puredigitalaudio.org/glossary/index.shtml#D2D

[Vinnie R.]

To my knowledge, there are no "fully digital" amplifiers....yet

Vinne,

This sight claims that there are some amplifiers that keep the signal digital throughout the chain.

Dennis


http://www.puredigitalaudio.org/digitalamplifiers/index.shtml

http://www.puredigitalaudio.org/resourcesSections.shtml

http://www.puredigitalaudio.org/glossary/index.shtml#D2D

Dennis,

Thanks for the links.  I don't believe that this information is correct.  In the home audio industry, the standard digital output is SPDIF.  You cannot amplify SPDIF and low-pass filter it for speakers.  To my knowledge, all the digital amps that claim to be "fully digital" use a chip that takes in the SPDIF signal, but inside the chip, there is D/A conversion to convert the SPDIF to analog (L and R are separated), and an A/D stage to to process the signal into a PWM type of format, where it can then be amplified and sent out of the chip to a low-pass filter to recover the analog info to be sent to the speakers.

If there really is an amp that is digital all the way through, please let me know about it (datasheets, specs, etc).  I'd love to see it.

Thanks,

Vinnie

[tubeytubeamp]

Vinnie,

Check out this review on the same pure audio website. I agree with you, there is something that cannot be trusted by this sight. Check out the stellar review for this Zenith all in one player.

http://www.puredigitalaudio.org/digitalamplifiers/articles/zenith_DA3520/index.shtml

Thanks
Dennis

[ToddSTS]

I don't believe that this information is correct.  In the home audio industry, the standard digital output is SPDIF.  You cannot amplify SPDIF and low-pass filter it for speakers.  To my knowledge, all the digital amps that claim to be "fully digital" use a chip that takes in the SPDIF signal, but inside the chip, there is D/A conversion to convert the SPDIF to analog (L and R are separated), and an A/D stage to to process the signal into a PWM type of format, where  ...

Equibit?

http://focus.ti.com/lit/ds/slas328/slas328.pdf

SDIN(PCM) in, PWM out to amplifier stage.  This is old and one of the first products to come out of TI after they bought Tocatta (I think).  But it looks like the signal stays digital all the way without a DA/AD conversion.  Unless it happens in the Equibit Modulator.  Which looks like another name for "black box with secret stuff".  

But I could be wrong.

Todd

[dwk]

brj,

The digital receivers that you mention are NOT fully digital from source to speaker.

They take the digital input from you source and do a D/A conversion inside the amp, then then convert it that analong signal to a digital to be amplified (Class D or Class T style), and then the amplified digital signal is filtered to recover the analog signal to be fed to your speakers.  

To my knowledge, there are no "fully digital" amplifiers....yet  

-Vinnie

ToddSTS is correct - the Equibit chipset as used in the Panny receivers (and an earlier variant in the Tact stuff) is basically as close to a 'fully digital amplifier' as is possible with PCM data. The modulator directly maps the input PCM digital signal to an output PWM modulated signal without any conventional D/A stage present. As a necessary consequence, the Equibit units operate completely open-loop with no feedback whatsoever.  (since there is never any analog signal present against which to reference the output)

Of course, many folks will dispute whether the PWM signal is digital, and would argue that the PCM->PWM conversion is a form of  D->A conversion, but IMHO that's splitting hairs.

FWIW, this is why it's a bit tough to compare say the T-Amp with an XR-45, as you'd have to pair the T-Amp up with at least a DAC, which makes a one-to-one comparison meaningless.

[Vinnie R.]

Equibit?

http://focus.ti.com/lit/ds/slas328/slas328.pdf

SDIN(PCM) in, PWM out to amplifier stage.  This is old and one of the first products to come out of TI after they bought Tocatta (I think).  But it looks like the signal stays digital all the way without a DA/AD conversion.  Unless it happens in the Equibit Modulator.  Which looks like another name for "black box with secret stuff".  

But I could be wrong.

Todd

Todd,

This is exactly what I was looking for, thanks!  

I didn't realize that the Panasonic receiver used this chipset, and was incorrect to say that it wasn't digital all the way.  This is about as close as it gets.  

Tripath mentioned to me that they are working on something like this.  We'll see what they come up with  

Regards,

Vinnie

[Vinnie R.]

Hi Vinnie,

I have a question. In your FAQ you said that:

"Unlike most conventional amplifiers, the L/R Negative (-) speaker binding posts of the Clari-T-Amp are not tied to GND or each other. Therefore, make sure that the equipment that you are connecting to them to DOES NOT tie these terminals together."

Would you say that this pretty much rules out wiring this amp for headphones? A headphone jack always ties the two output grounds together. Does this apply to the standard Tripath amp also or does ...

Doggie,

Sorry I overlooked your question...

If the headphone jack ties the two speaker output negative terminals together, you can't use it.  The negative speaker output terminals on tripath equipment are not tied to ground and are independent of each other.  

My guess is that you 'can' use headphones, but you need to change the wiring so that the negative terminals are not connected.  I believe that there was some discussion about using the Sonic Impact with headphones on www.headfi.com...

Regards,

Vinnie

[brj]

I didn't realize that the Panasonic receiver used this chipset, and was incorrect to say that it wasn't digital all the way.  This is about as close as it gets.

Whew!  I'd hate to think I did all that reading for nothing!

Tripath mentioned to me that they are working on something like this.  We'll see what they come up with  

I love having options!

I don't suppose they mentioned any sort of time frame, did they Vinnie?  Like I said, I'd love to see a marriage of your battery based solution with a complete digital path.

Thanks for the info!

[ChuckT]

Sony S-Master amps are also digital all the way.

[smargo]

Chuck T wrote "Sony S-Master amps are also digital all the way."

Why does it matter so much - if this and other amps are digital all the way. I listened to the sony's and they sound awful in comparison. Yes it would be great if the true digital amps were great. But in the hear and now you have the clari t that is audiphile grade and wipes the floor against the current stuff available. (I haven't heard The Zenith DA3520 DVD Receiver) But everything described in that review is exactly what im getting with the clari t.

I mean isn't the amp cheap enough that the point is moot.

smargo

[ChuckT]

I agree, it is the sound that counts.
We merely point out that Equibit and S-master are digital all the way.
However, I have a Sony all-in-one (slightly modded) and I have to disagree with you, it is audiophile grade!

[Tr3vWh0r3]

Which all in one Sony do you have ChuckT? If you dont mind me asking..

[ChuckT]

It is a DAV-S10.
Now back to Clari-T.

The only tripath I've heard is the JVC EX-A1 and it is indeed very good considering the low efficient wooden cone speaker (81dB and 4 Ohm )

I cam imgine how a battery driven tripath with a high efficient might sound like.