[BeeBop]

I've been impressed with what I have been reading about the Carver ZR series amps. My understanding is that these are digital amps which makes me wonder how would a 2 channel guy like me connect them to the digital out of say a cd player? There do not seem to be any 2 channel pre-amps that have coax or optical inputs. I am not planning to leave the 2 channel world for some time; can anyone offer some advice?

[KevinW]

Carefull... you are stepping into one of the most common misconceptions of 'digital' amplifiers.

A Class D amp is really a digitally controlled 'analog amplifier'.  Consequently, it works better with an analog signal.  The primary reason why is that digital signals from CD players have a much different sampling frequency than Class D amplifiers.  So the signal needs to be re-sampled for a different frequency, which introduces audible errors and distortion.  Technology for this resampling has never been in high demand in the audio marketplace, and is very raw.  In contrast, technology for converting the digital signal to analog is ALWAYS in demand and has become quite refined over the last 20+ years.  If you want to run a digital amp, the best thing to do is feed it a high quality analog signal.

[BeeBop]

Like from an outboard DAC?! Thanks very much for the explanation.

[BrunoB]

Carefull... you are stepping into one of the most common misconceptions of 'digital' amplifiers.

A Class D amp is really a digitally controlled 'analog amplifier'.  Consequently, it works better with an analog signal.  The primary reason why is that digital signals from CD players have a much different sampling frequency than Class D amplifiers.  So the signal needs to be re-sampled for a different frequency, which introduces audible errors and distortion.  Technology for this resampling has never bee ...

Does this apply to the Sony, Panasonic and Sharp receivers as well?
I don't think so. But then,  they might not be class D amps?
Just curious.

Bruno

[KevinW]

I haven't had any direct experience with those receivers, so I don't know what their internal configuration is like.  Assuming that they use a direct-digital connection from source to the class D amplification module, then my criticism would indeed apply.  However, there's no reason why this can't be done, all I'm saying is that it won't be as "hi-fi" compared to analog.... today.  This could all change in a few years, though it is likely only to be the case with SACD and not conventional CD's.

[BrunoB]

This could all change in a few years, though it is likely only to be the case with SACD and not conventional CD's.

Not in a few years. Actually, a few years ago. Sharp did it in 1999 (http://sharp-world.com/corporate/news/031008.html).

A Class D amp is really a digitally controlled 'analog amplifier'. Consequently, it works better with an analog signal. The primary reason why is that digital signals from CD players have a much different sampling frequency than Class D amplifiers. So the signal needs to be re-sampled for a different frequency, which introduces audible errors and distortion.

This resampling is done at a much higher frequency (64 times higher for Sony, 64, 128 or 256 times higher for Sharp, I don't know for Panasonic). I am not an expert at all, but my intuition tells me that such upsampling can be done by a relatively simple mathematical transformation that should not add any distortion& errors on the signal. On the other hand, digital amps like Carver, Solar or Icepower need one extra digital to analog  conversion, which might introduce sound degradation.
Some AC members had the opportunity to compare the two approaches:

http://www.audiocircle.com/index.php?topic=4991&postdays=0&postorder=asc&start=25

My reference amp is an engineering evaluation unit of the ICEpower digital amp technology that is the same as used in the $3000 Danish eAR amp frequently mentioned in this forum. Supposedly the eAR has been tweeked with additional filtering and capacitance in the power supply. To my ears, ICEpower is the best amp I have heard and I've listened to a bunch of them.

In the bass and midrange area the XR25 is very competitive. Dynamics are outstanding, particularly with digital inputs. The treble is a bit on the rough side. I was hoping this would smooth out with break in, but there has been only minor improvement in the week I have had the unit. It's very good for the price, but not world class. This may be something that is fixable, since Tact amps use the same technology but don't seem to have this problem.

I've had a chance to break in the XR25 some more and upgrade cables as Scotty suggested. Everything is improved. Analog input is now hard to differentiate from my ICEpower amp. The direct digital input at both 44khz and 96khz sounds significantly better than analog input. This technology is really something special.

Bruno

[BeeBop]

So Bruno, any advice for me regarding my original question?

[RussKon]

the carver ZR1000 has only analog inputs.....

unless you are willing to get the schematic from carver pro...(it is on the website)... and create a digital input yourself....

no

but on the other hand it is truly an incredible amplifier....i've had mine now for about 2 months and i keep hearing more and more detail from older recordings that i thought i knew very well....

[BeeBop]

Thanks, Russ. What are yo using for a pre-amp and source?

[RussKon]

i'm using my carver ZR1000 as part of my home theatre....

here is my list:

Pioneer Elite VSX-55TXi (as a preamp only)
Carver Professional ZR1000 amplifier - mains
Electrovoice 7100 amplifier - surrounds
Electrovoice 7100 amplifier bridged - center
Klipsch KLF-30's mains
Klipsch RS-3's surrounds
Klipsch KLF-C7 center
Velodyne CT-150 subwoofer
Bang and Olufsun Beogram RX-2 turntable
Sony DVP-NC650V  dvd/sacd changer
Philips CDR770  cd burner
Sony DTC-75ES  dat recorder
Pioneer Elite CT-05D  dual cassette deck
JVC  HR-S7900U svhs deck
Surge-X  SX115RT  power conditioner/surge protector
Middle Atlantic Slim 5-29 rack with oak side panels
Mitsubishi 35" tube tv

[BeeBop]

i'm using my carver ZR1000 as part of my home theatre....

here is my list:

Pioneer Elite VSX-55TXi (as a preamp only)
Carver Professional ZR1000 amplifier - mains
          :
          :
Pioneer Elite CT-05D   ...

Nice setup! How do you control volume? Since the Carver has no remote I'm wondering if the pre can do the job. Sorry if it's a dumb question, but I am a bit of a newbie at this - I've always had receivers before and I'm now looking at separates.

[RussKon]

i use the pre-outs on the pioneer receiver.....

the volume control on the receiver controls the volume on the carver ZR...

make sure that you bypass the carver's volume controls.... it does make the carver sound even better.....(there are defeat controls on the front of the amp)

most receviers that are over $300 have the preouts so you can use them as a preamp...

[BeeBop]

Yes, my Rotel RX1050 has them. Thanks again. I appreciate you taking the time to share your experience.

Bob

[BrunoB]

So Bruno, any advice for me regarding my original question?

If you don't need too much power, I think you might have a better sound (and save some money) by going with the Panasonic SA-XR45 (using the direct digital inputs) than with an analog class D amp such as the Carver.

I don't own a Panasonic. I based my thinking on the Panasonic thread . Dmason owns both.   He could probably give you better advice.

Bruno


PS: do you need to play SACD or DVD-A with direct digital input?

[BeeBop]

Thanks Bruno! I'll check it out.

[Dmason]

I'll second Bruno; If you don't need too much power, and especially if your speakers can be bi amped, try the Panasonic.

Once it has burned in and one does the [essential] tweaking of the PC, this thing, when using digital direct, in my opinion, is a killer, and is not, I have found, out of place with outstanding speakers. If your speakers have bi wire capability, the value of the Panasonic doubles. DOUBLES. If I were starting again, I would get the Panasonic, and blow the rest on the very best speakers I could get, which were of 89db or greater. And then you have plenty of power AND remote control over the volume, without the committment to IC's, pre, XLR, Speakon, etc., which confronts you with the ZR.

The Number One Question with these digital amps, which does not get any discussion in these pages is whether one's speakers are up to the task, in order to get the most out of what this new stuff has to offer. Have a chat with the drivers in your current speakers and then consider the added expense of separates here, when a far less circuitous and expensive route is available to you. I have now heard the Panny with some truly outstanding speakers, and it keeps up, believe me. Sermon Over.

[BeeBop]

Thanks DMason! I have been following your posts and I am a fan.

I have decided to go with a Perpetual Technologies P3-A DAC because it can handle TOS input and does de-jitter as well. The TubeDAC and dAck! would need a front end to do this and with the front end would cost the same.

I've read the Panny posts and it looks really tempting but I've decided to hold off with an upgrade to pre/proc until the whole DVI/HDMI/Firewire thing is worked out, maybe in a couple of years. Then I am indeed going to look at digital amps.

Right now, I am going to try to get the most out of the system I have - ACI Sapphire speakers (looking at upgrade to Panoramas) with the Rotel RX1050 Receiver. I like the Rotel's warm sound, although it is admittedly a little low on punch/headroom.

My budget is not big so after the DAC, I may do the speakers, but that would be it for a while I think.

Once I get the DAC I was thinking of doing an A/B - the DAC against the Burr-Brown DAC inside my Denon 1600. Maybe it's a bit simple-minded?

Thanks again to everybody. People like you make this a great forum.