2. amps-preamps
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UcD vs TriPath Digital amps.


I have been enthusiastic about the CarverPro ZR1600 digital power amp which I have used for several years with Magnepan MG1.6 speakers. Actually I have three ZR1600, each driving a MG1.6 with one channel and a two-driver subwoofer with the other. The ZR1600 uses the Tripath digital control module.

I have just purchased three CI Audio D-200 amps, which use the UcD digital module. The TriPath module does its digital switching at a commanded variable frequency (“spread spectrum”). The modulation pattern is between 200 KHz and 1.5 MHz. The UcD module is self-oscillating (like the ICE module) at (I think) 44KHz.

Let me say at the onset that the ZR1600 is a very fine amplifier, and mates particularly well with the MG1.6. My reasons for replacing it are not primarily on account of its sonic character. I wanted an amp that I could attach directly to the rear of the speakers, thereby avoiding any issue with speaker cables. This is not practical with the ZR1600 because it has a cooling fan, and needs to be in a remote location, like the cellar. Also, as my subwoofer system has evolved its impedance has ended up at 2 ohms. While the ZR1600 is rated for 2 ohm operation, distortion with this load is increased, and I am worried about what happens to the other channel, which shares the power supply. My plan is to drive one subwoofer driver with each channel of a ZR1600, and use a CI Audio D-200 for the Maggie.

All three ZR1600, six channels of 600 watts at 4 ohms, cost me less than $2500. Three D-200, 325 watts each, cost me almost $3500. If cost is important I think that the ZR1600 wins.

Thus far I have simply inserted the D-200 amps in place of one channel of the ZR1600, in the cellar without changing speaker cables, but initial listening is encouraging. Playing a Mozart violin concerto, Pentatone SACD PTC 5186 064 (an excellent disc) the sound is really smooth, sweet, tube-like (?), without loss of the clarity that I liked in the ZR1600. I find that violin is most affected by any sharpness in the midrange. More extensive listening will be interesting, especially when I get around to relocation of the amps at the speakers without speaker wires.

The CI D-200 is well built. It has received enthusiastic reviews by the various gurus, and it seems that this is not hype.
eldartford
eldartford OP
4,262 posts
 
Just to close out my observations about the CI D200 in my system...

Physically attaching the amps to the MG1.6 speakers proved impractical mostly because there would be both a line cord and a signal cable to drag around when moving the speakers. Instead I bought Goertz Biwire cables, which, at a four foot length are about as close to no speaker wire as matters.

I think that I have taken the MG1.6 about as far as possible.
1.. Subwoofers keep frequencies that the MG1.6 can't reproduce out of them.
2.. The passive crossover has been redone with premium capacitors and a heavy duty air coil inductor.
3.. Stands raise the speakers off the floor.
4.. Very short Goertz biwire cables.
5.. Last, but not least, a very nice power amp.

I am not so keen about the ribbon tweeter, so upscale Maggies are not in the cards. Soundlab electrostatics would be nice, but I don't have fifty grand (for three) handy.
drubin
3,282 posts
 
You don't like the Maggie ribbon? Really?
eldartford OP
4,262 posts
 
Drubin...It's not that I dislike the Maggie ribbon. Rather, I like the QR approach just as much. I did listen to both, and I could not hear any reason to pay so much more for the MG3.6. The QR does have the advantage of using the same technology and membrane for all frequencies, which perhaps leads to a better integrated sound (IMHO).
eldartford OP
4,262 posts
 
I continue to enjoy my three CIA D200 amps, and have ordered two more for the surround channels. Nevertheless, it is hard to describe exactly what is so good about them. I am not a professional high end reviewer with fancy subjective words like "transparency".

There is one objective observation that I can pass on. I have a SACD, The Sound of Glory" which is the Mormon Tabernacle Choir along with a full orchestra and a monster organ. (I recommend this disc when your subwoofer needs exercise). When I hooked up my first digital amps, Tripath-based CarverPro ZR1600, the 500-voice choir became more separated from the orchestra and organ, and seemed much clearer. (This is probably "Transparency"). With the CIA D200 I can, at times, actually pick out individual voices from the huge choir.
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