Carver Pro ZR1600

I have a carver pm 1200 when i turn up the vol or the gains the fans seem to follow the audio sig level when irecieved amp fans were not operating i cleaned fans now there working any schematic would be appreciated.

I tried 1 of the 1600 amps with my 16 year old Mirage m3 (86db) and it sounded more open, alive, more bass, and played louder than my Classe 400. I immediately sold the Classe and ordered another 1600. Both of the new 1600s cost less than what I got for my used Classe 400, and I can't wait to hear them in mono.
I am going to try and talk my brother into this as his set-up is quite similar.

I was wishing for the Spectron amp, but the price tag for 6 channels is a bit steep. Three stereo Carvers cost about 1/3 of the cost of the 6-channel Spectron, and having the amps in three units is more convenient for me.

The Carver and the Bel Canto (I have heard) use a basic digital amplification control module made by an outfit called TriPath. (You can get complete technical details from their web site. The Carver amp schematic is also available on the Carver Pro website). The TriPath amplifier has some theoretical advantages over the Spectron design, but these don't necessarily translate into audio quality.

I agree with many others who have tried the Carver that it sounds great. The other digital amps may also sound great, but the Carver is the one that you can afford to try.

How does this Carver amp compare to the Spectron Musician amp or the Bel Canto.

I had a friend whos had a nice system that started out with 200 watt monos on each side. He then got another pair of 200 watt monos, sent all 4 amps back to the factory to be "calibrated". The speakers dropped to 3 Ohms and were 91 db sensitive. It wasn't just an increase in volume and power, it was amazing how the speakers bloomed, the soundstage became more holographic and took on an effortless ease with the extra pair of amps. 1200 watts per side @ 3 Ohms into 91 db speakers. For the life of me I can't explain the gains in improvement. Perhaps the amps stayed in class A longer before sitching over to class AB?

sean...I think I will stick with 600X6 for a while (for the fronts). I also have biamped rears (misc amps) to annoy the neighbors.

I find curious the way that speakers, Maggies in particular, respond to very high powered amps. I know that the actual power level is nowhere near the ratings of the amps, but something about them is very helpful...Ed

El: I've got over 1400 wpc rms driving some 86 dB 4 ohm speakers. I don't know how your maggies would respond, but i know that this is how i was finally able to get my speakers to sing. I know that Mike aka Magnetar over on AA was using Classe' M700 mono-blocks ( 700 @ 8, 1400 @ 4 / 3 dB's of dynamic headroom ) to drive his Maggie 3.5's, which were slightly older but more expensive models. From what i can gather based on the path that he took after this, i don't think that he found this to be "dynamic" enough for him. As such, you better order another amp or two : ) Sean
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With arrival of the third ZR 1600 I now have the "final" setup with each ZR 1600 driving a MG1.6 with one channel, and a subwoofer system with the other.

It's true that Maggies just get better and better as you increase the power amp, and they ain't bad even with 60 watts. They say that the Carver ZR1600, unlike many conventional amps, gets better when bridged. Hmmm...1600 watts into four ohms. I better not try it.

lkosova@yahoo.com...Trust the lawyers to screw things up!

sean...The circuit, which includes the OP Amp is linear, even if the open loop performance of the device is "junky".

An analogy might be the output transformer of a tube amp, where, when tested as a component, out of its circuit, its bandwidth and frequency response is "junky". However, put it in a circuit with appropriate feedback (usually derived from extra windings on the transformer) and the resulting performance can be superb.

Certainly there are different levels of OP amp quality, Noise being the parameter of greatest interest. Also, the type of circuit that the device implements affects the degree to which the "junky" characteristics are suppressed by the circuit. For a unity gain buffer amp, (which is what the OP Amps in the Carver ZR1600 mostly are) quality OP Amps would be of minimal value. (Resistors and Capacitors should be the principal concern). When you try to implement a phono preamp, with high gain and heavy RIAA equalization, it's a different story. Even the "best" Op Amps are not so hot in this application, which has given Op Amps their bad reputation.

I guess this is another case of a myth (Op Amps are always evil) that is based on a kernel of truth.

El: You stated that Op-amps "should never be thought of as a linear amp".

If these are your honest thoughts on the subject, why would you buy a unit that uses Op-amps for hi-fi use ? After all, "hi-fi" is all about "high fidelity" i.e. linear replication of a signal. Are you now saying that the amp that you are happy with / raving about is a non-linear device, but you like it anyhow ? Help me to understand where you are coming from with these statements as they seem to be contrary to your previous posts in other threads. Sean
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Eldartford,

Carver pro's hands are tied. They can only sell to the pro market. All this Audiophile stuff took them by suprise. Do to legal reasons they can not market to the home user BUT you can buy a pro amp for your home system if you want to!!!

You will see different products to go with the ZR seris also. I don't think that Carver Pro will be doing the mods themselves, but as you can see,are letting some of the best people in the business do the mods and sell them.

Hope this helps,

Larry

sean...Yes, noise is a significant characteristic of an Op amp. However, the OP Amp circuit topography is such that an IC which is "junky" in other ways, like distortion (thermal or otherewise) gain tolerance, slew rate tolerance (as long as it is above some value) etc, will work just as well as an OP Amp that is perfect in these regards. Op amps can only be evaluated in context of the performance of the overall circuit in which they are used. They should never be thought of as a linear amp.

El: Op amps have the potential for high quality sound, but most Op amps are under-designed mass produced pieces of junk. They work great for many applications, but many of them just aren't suitable for use with "hi-fi". On top of that, when put into a circuit that is an under-designed piece of junk, you end up with one BIG under-designed piece of junk.

If you would like further clarification as to why many Op-amps are "junky", try reading a very informative article written by Ben Duncan as published in Stereophile a few years back. This amassess the results obtained after testing over a dozen different Op-amps from various manufacturers. Some of the same Op-amps from different manufacturers performed VERY differently. We are talking about S/N ratios that varied by as much as 40 - 60 dB's here. Needless to say, a few dB's here and there might be understandable, but not variances as mentioned above.

As a side note, this article also mentions thermal distortions, which most IC's are not very good with. Sean
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Dmason...I hear the term "junk OP Amp" used a lot lately. What does this mean?

With the exception of noise, the open loop electrical characteristics of an OP Amp have almost no effect on how it performs in a circuit, especially for a unity gain buffer application. All that is necessary is high open loop gain and slew rate sufficient to handle the highest frequency of interest. These minimal requirements on the active amplification devices is the reason why the OP Amps circuit is so widely used in all kinds of electronic equipment.

I have it on good advice that Carver Pro has already tapped Stan Warren as a consultant on the matter of a stripped down audiophile version, doing away with all the ancillary circuitry, such as the junk op amps and clip limiters up front, and some more useable audio jewellery on the back, with a view to producing a great amp that does more, for less, and come in 'under the radar.' This movement is currently under way. Stay tuned.

Regarding mods...After studying the schematics, and reading about Mod activity, I "popped the cover" (a simple matter of sixteen screws) and looked inside. From what I saw I don't think much is practical with a few exceptions.

The fan replacement (with a quieter model) is easy.

Bypassing all the preliminary signal processing stuff with a wire to the amp itself is practical. Connection can be made without great difficulty at a coupling capacitor location.

Input and output terminal hardware can be changed, although what's there looks OK to me.

The inputs are on a small separable assembly which occupies a shielded box about 4X3X6 inches. It connects to the mother board with a plug-in cable. There is lots of room for a completely new input/driver/processor circuit: for example a Marchand electronics crossover module would fit with room to spare. Carver plans to sell various modules to replace the standard input circuit, but they have not yet told us what will be offered.

Now the bad news. The components (including IC OP Amps) are all surface mount which I find almost impossible to remove/install. There are many. The chances of swapping out all the OP Amps without destroying some part of the circuit board is near zero IMHO. With perhaps a few exceptions, the existing circuits cannot be upgraded with better components. You would have to go completely around them with a wire or with completely new circuitry.

If audiophiles think that the ZR1600 would be better without various ProSound features, and with some better capacitors here and there, the obvious course of action is to get Carver to build an "Audiophile" version. Carver would do well to hire some of the better known Mod people as consultants to do the design. I suspect that the audiophile version would cost no more to build, as quite a lot of circuitry would be eliminated.

Sean.

All demos of the Carver 1600 unmodded and modded were using Maggie 1.6s.

Sean, the best answers are to be found at the ongoing threads specifically on the Carver Pro ZR Tripath amps and modification discussion, at audiocircle.com.

The short answer to your question is that from what I am seeing, they are pretty much load-invariant. I sat and listened to a ZR1600 cruise through difficult and highly dynamic material on a pair of Maggie 1.6 which were enjoying that particular combination ALOT. Resistive loads don't seem to worry these amps at all, nor do wildly varying moduli. Further, they run merely warm to the touch. I have twice read that some are buying them for their Apogees, which kinda says it all.

sean...Get with the program!! :)

I have a question for you guys that are familiar with these Tri-Path amps. I have heard two of these amps, but not under conditions that i was familiar with or could really pass judgment with. Compared to a modified Adcom amp, i thought that the Tri-Path's were a step forward.

How do these amps do with lower impedances ? From what i've seen, they are higher in distortion at 8 ohms and measurably lacking in terms of the ability to pass current as impedance drops. On top of that, if they are like most other amps, the distortion will climb noticeably as impedance is reduced.

Given that i tend to prefer speakers that have a lower impedance with high quantities of reflected EMF ( multiple drivers, large motor structures, speakers with sharp phase angles like E-stat's ), i have to wonder how suitable they would be for installations using anything but benign dynamic loads ?

In my book, a "good" amp should be able to drive most any load that you throw at it. Obviously, some will do better than others due to build quality and circuit design, but then again, some do miserably with all but a few types of speakers. As such, what i'm asking is "how universal are these amps" and "do you think that the results that you are obtaining in your system will be easy to duplicate in other systems" ? Sean
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Eldartford, ...if ALL of those amps are ZR's, I want to come to your house...I cannot imagine what that is going to be like in a couple of months. It may be of interest to know that Ashly also has Tripath amps, 4 and 6 channel muscle amps which look pretty good as well, and they have an impeccable reputation for quality in all their products. Crest, Crown too have digital switching amps which should be explored. Either way, the pricing for all these brands has been revised downward, the last 12 months, due to market conditions, and decreased overhead associated with production by way of increased efficiency, less heat output, lesser component requirements, etc. Vive le Revolution!

Dmason...The Carver is not my first adventure into the ProSound waters. I have a QSC amp which I bought for its capability with 2 ohm load, driving subwoofers. In the SW application I reasoned that superlow distortion and the like is not critical. But, I have run this amp full range into MG1.6 and Dynaudio speakers, and it sounds embarrasingly good. Checking the specs, I find that at low power level, typical of home audio, distortion spec is 0.06. Not too shabby!

Maybe in the old days ProSound meant a Bogen PA system, with rotten sound for music. Times have changed.

All that being said, I would like to point out once again, that after a year and a half owning the amp, -as one of the original heretics who "dared" wade into the dark pro-audio waters, this is the best amp I have ever heard, owned and heard plenty, and plenty good. It is for this reason that I caution that the amp is so damn good, for those of you contemplating one, please note, the mods are by no means "necessary" for ultimate enjoyment. And yes, it STILL reminds me of an exceptional tube amp, coming dangerously close to SET, "to these ears, on this equipment, in my environment." I know what real instruments sound like, and have the advantage of perfect pitch. The amp 'matures' over a six month period....Passive preamplification and non-oversampling source for the Redbook crowd most strongly advised. Value Value Value.

El: Try using solder as an interconnect rather than a speaker cable. The gauge of the solder used would be more appropriate for line level signals than for the much higher current levels of a speaker connection.

If i remember correctly, i think that Jennifer Crock of JennaLabs did this with several different solders. According to audiophile folk-lore, she preferred Cardas solder to the others that she tried in this manner.

As a side note, take a relatively long yet identical length of various generic and high quality solders and measure the resistance of them using precision test equipment. My business partner kept telling me that "solder is solder", so we did this along with some other tests at the shop using some of my HP test equipment. Needles to say, he was pretty amazed at the differences in conductivity between various solders. Then when i explained to him the differences in metallurgy in various solders, the variances in how different solders dry, bond to the surface and how well they hold up over time, he wanted to verify this. After watching how various eutectic and non-eutectic solders performed in these areas, he was pretty much a "convert" as far as "high tech" solder goes. Sean
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DMason - I listened to the Carver mods at The Eighth Nerve. The mods have been discussed at Audiocircle.

Kana813...Neutric Speakon connectors certainly look like excellent devices, but I do not need to frequently connect and disconnect speakers, so I think that bare wire clamped into the binding posts is probably best. (Least number of contacts, per sean's rule).

Gmood1...Yes those reviews and others like them is what got me all excited. The comment "uncanny ability to unbundle instruments" is exactly what I hear.

Sean...Undoubtedly multiple contacts on a switch or relay is a good idea. Sliprings that we use in the gimbal system of the missile guidance system that I work on have (for each of the many circuits) two brushes each with spherical tips riding in a v groove, so that there are four points of contact. But these are sliding contacts.

The sound of switches (unless the contacts are dirty, and resistance is measurable) is something that I personally don't worry about, but let's not get into that one. As to solder, some day when I have nothing else to do I will use about 20 feet of roll solder as speaker wires and see how it sounds. If 20 feet of solder isn't a total disaster, I will conclude that a few millimeters is OK.

Eldartford- I highly recommend you pick up some Neutrik Speakon NL-4FC cable connectors for you speaker connections. The CarverPro is set up to accept these. They cost about $5@ and are easy to install.

I think waiting to get a handle on the amps before doing any mods is a wise move. Stan Warren is reported to
be looking at these amps. I'd wait until a real pro like Stan comes up with a mod.

Have fun.

There's a lot of talk and review of the Carver Pros on http://www.audioasylum.com here's a link to one review.

http://db.audioasylum.com/cgi/m.pl?forum=amp&n=21654&highlight=carver+pro&r=&session=

El: I don't doubt your observation comparing the ZR1600 to the Adcom. Adcom amps to me have always tended to get muddy, blurred and jumble things up at volume. This also includes the big ones that Nelson Pass designed and Adcom built to their own spec.

As far as your comments about bypassing the switches, you need twice the amount of contacts on a switch in order to reduce audibility of a decent switch. In other words, two contacts in and two contacts out wired in parallel reduce the audibility of a single switch in the signal path. As such, where one is using a single pole double throw ( spdt ) switch, going to a double pole double throw ( dpdt ) would work better. The only thing with this is that you end up with a whole lot more making and breaking of the signal path and solder joints galore. If you have no fear of overdriving the amp, i would suggest using good quality cabling and bypassing all of that. On top of that, don't forget to break the connections feeding into the circuit at the board level. Having circuitry that is still connected at various points but not active will cause differences in signal loading. Sean
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Kool39...A "full review" of the amp is something that I am really not qualified to do. Others have evaluated and reported on this amp, and their reviews are the reason I bought it. I could write some glowing praise using all the usual words (tranparency, punchy bass, etc) but these are all subjective things that you really need to hear for yourself. I therefore condense my comments to the statement that "this amp is something special, particularly in view of its cost, and it is worth you while to try it".

If I had to put my finger on one characteristic that is better than my Adcom 5503 (350 wpc) it is that in an orchestral recording, individual instruments of the orchestra seem to be separately distinguishable. (Subjective as hell!). I am unsure of how much credit should go to the amp's sonics, as opposed to the Magneplanar speakers. It could be that the more powerful amp is simply getting more out of the Maggies. Different speakers could give different results.

Dmason...One mod that I heard described pretty much amounted to bypassing the input signal processing (Level controls, high pass filters, clipping management, amplification configuration, etc) replacing the fan with one that is more quiet, and changing the input and output connectors to a different type.

My thoughts about this are that the fan is a good idea, and the rest of it can wait until I get things sorted out. The input and output terminals are just fine IMHO. I use bare wire clamped into the terminals for output, and converting to RCA plug input is a matter of two gold plated adapter plugs for a grand total of $3.60. At the input there is a 0.47 mfd capacitor in the signal path that might be upgradeable, and running a straight wire around the input circuitry is like chicken soup. However the various features of the circuit are individually bypassable with switches, so we really are talking about the difference between circuit board runs and switch contacts and unbroken copper wire (and that discussion could become long and heated). I don't think that anyone knows enough about the digital power amplification circuitry to justify messing with it. In summary, I think that this amp does not particularly lend itself to useful mods, and I would need to have a detailed description of the mod before I would go for it. The fan change, capacitor, and bypass wire are simple enough to do oneself.

If there is someone out there who can shed more light on the mod details, please chime in.

Tayfiji,

Can you tell us what mods were done to your friends's ZR? I am about to look in to this matter for my own ZR1000

The Carver Pro Amps are being modded by many with excellent results. There have been many threads discussing the Carvers on Audiocircles. I have listened to the 1600 before and after modification by a local modder, and I must confess the difference was dramatic. Bass and treble were extended after modification. Soundstage and clarity also improved.

I hear Phoenix Gold and i automatically think of car audio. They use to put out some killer car amps in late 80's early 90's.
Glad to hear your liking your new amps Eldartford. Are you going to give us a full review sometime? Also some comparisons to your adcoms and other amps you have auditioned? From your comments so far sounds like alot of bang for the buck. Still curious if it will walk all over aragons or if i still wait for the next new amp to come out.

Sean...About the Carver Pro line of products being unrelated to Bob..yes I heard that. For what it's worth, the amps have a "made in USA" label on them, which makes them sound just a little bit better. This Phoenix Gold outfit confuses the hell out of me, it seems like some kind of umbrella company for several brands. I have some interconnects by them which appear to have all the features of other brands except the price.

6X600 wpc @4ohms...$2500. Some other manufacturers have a lot of catching up to do.

Glad you like your amps El. I hope that they do everything that you wanted / expected and even a bit more : )

For sake of clarity, these amps are not made by the Carver Corporation or have anything to do with Bob Carver. I made that mistake myself and someone on Audiocircle clarified it for me. Phoenix Gold purchased the rights to use the name Carver Pro several years ago and are marketing various cables and electronics using that moniker. Sean
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Glad your enjoying the Carvers!
Happy Listening!