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Sunfire Cinema Grand Review (5-channel Amp)

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 101 59.1%
  • 2. Not terrible (postman panther)

    Votes: 56 32.7%
  • 3. Fine (happy panther)

    Votes: 10 5.8%
  • 4. Great (golfing panther)

    Votes: 4 2.3%

  • Total voters
    171

amirm

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This is a review and detailed measurements of the (vintage?) Sunfire Cinema Grand five channel power amp designed by Bob Carver. It is on kind loan from a member. In 1996 it cost US $2,375. This unit is from 1999 and has had its caps upgraded.

Sunfire Cinema Grand Review Balanced Bob Carver Five Channel Power Amplifier Home Theater.jpg


I can't say I am a fan of this look. The meter shows an obscure measurement of the "power supply joules." The dial never moves so it is useless.

Back panel shows some deviations from norm as well:
Sunfire Cinema Grand Review Back Panel Bob Carver Five Channel Power Amplifier Home Theater.jpg


In addition to normal speaker terminals, the front channels also have "current output." This just means that there is a 1 ohm resistor in series with the output. This causes voltage/power loss that is inversely proportional to the impedance of the speaker. As such, it varies the frequency response of the speaker so can have different tonality.

There is balanced XLR input which is what I used for my testing.

This amplifier is the third iteration of Bob Carver. After leaving Phase Linear, he designed the "Magnetic Field" amplifier under the Carver name. That product varies the AC duty cycle as a way to change the incoming AC voltage and with it, the output DC. This lowers the losses in the output transistors since they don't have to operate for worst case (maximum power). See my review of Carver M-1.5t amplifier. Bob then left and started Sunfire and with it, came this amplifier design. Instead of crudely changing the AC duty cycle, this amplifier has a DC to DC converter which tracks the incoming music. The higher the input level, the more it will increase its output voltage, thereby keeping the output transistors in their optimal voltage level. Result again is very high efficiency compared to normal class AB design. Let's measure it to see how well it works.

BTW, there are two versions of this: one at 200 watts and one at 400 watts. Maybe I am going blind but I could not see any designation of such on the unit.

Carver Cinema Grand Amplifier Measurements
As with the M-15.t, I noticed a lot of noise before I fed the unit a signal so let's look at that:

Sunfire Cinema Grand Measurements Idle Noise Bob Carver Five Channel Power Amplifier Home Thea...png


We see that the dc to dc converter is pass through a lot of AC noise and harmonics. This impacts the performance of the unit:


Sunfire Cinema Grand Measurements Balanced Bob Carver Five Channel Power Amplifier Home Theater.png


While second harmonic distortion dominates at -72 dB, the mains noise is not far behind, causing SINAD (relative sum of noise+distortion) to drop further to just 67 dB. This is ranks pretty close to the bottom of all the amplifiers tested:

best multichannel amplifier review.png


SNR is not good as a result of that noise:

Sunfire Cinema Grand Measurements SNR Bob Carver Five Channel Power Amplifier Home Theater.png


Multitone at 5 watts suffers from both power supply spikes and high intermodulation distortion:
Sunfire Cinema Grand Measurements Multitone Bob Carver Five Channel Power Amplifier Home Theater.png


Crosstalk is surprisingly poor:
Sunfire Cinema Grand Measurements Crosstalk Bob Carver Five Channel Power Amplifier Home Theater.png


There seems to be inductive leakage at frequencies below 5 kHz which I am guessing is bleed through the shared power DC to DC converter.

Oddest thing was the frequency response:

Sunfire Cinema Grand Measurements Frequency Response Bob Carver Five Channel Power Amplifier H...png


There is some verbiage from Bob Carver about "voicing" the amplifier. Perhaps this is intentional but then why is one channel different than the other?

Claim to fame here is high power capability so let's see if it delivers on that:
Sunfire Cinema Grand Measurements Power into 4 ohm Bob Carver Five Channel Power Amplifier Hom...png


It does indeed. At the expense of noise and distortion but still, a 37 pound amplifier of the time, with 5 channels no less, would be in no position to produce such a power.

The new DC to DC converter is regulated so no headroom power:

Sunfire Cinema Grand Measurements Max and Peak Power into 4 ohm Bob Carver Five Channel Power ...png


There is healthy power at 8 ohm as well:

Sunfire Cinema Grand Measurements Power into 8 ohm Bob Carver Five Channel Power Amplifier Hom...png


I had to lower the input level substantially to get the amp to run the frequency dependence as it would pull back severely at higher frequencies:

Sunfire Cinema Grand Measurements Distortion vs Frequency vs Power into 4 ohm Bob Carver Five ...png


The lines are very high in vertical scale indicating high noise and distortion which we already know about. What we had not seen is the difficulty the amp has with high frequencies. This is likely due to the dc to dc converter not being able to track the voltage at higher frequencies. Fortunately music naturally has far lower level at higher frequencies so actual impact is low.

Finally, the amplifier is stable from power on:

Sunfire Cinema Grand Measurements Bob Carver Five Channel Power Amplifier Home Theater.png


Scale is heavily exaggerated with the one channel improving just 1 dB. And the other being stable from start.

Conclusions
Bob seems to have gotten the "high order bit" right in figuring out how to produce a high efficiency, high power amplifier. Alas, much of the talk is about fidelity and in that department, this is a poor showing. Mains noise gets through readily and distortion is quite high even by 1996 standards. From buying used point of view, the cool running environment of this amp means that it ages very well so the risks are lower. Then again that dc to dc converter brings a lot more complexity to the design.

Overall, the Carver Cinema Grand is not something I would recommend. But I can see people purchasing it as a lightweight, multichannel amplifier that delivers a lot of power. To the extent you can purchase it for a lot less than modern class D amps, it would be a decent buy.

P.S. no, I don't have any more carver amps to test. :) Nor did I seek them out. They just happen to become available all around the same time.
 
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amirm

amirm

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Lambda

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500W peak is not to bad.
everything else is.

Maybe an amp with this mush noises is a good test subject to see if this power generators can do a thing.
as you said "you don't listen to mains power" but with this amp you kind of do...
 
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amirm

amirm

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Maybe an amp with this mush noises is a good test subject to see if this power generators can do a thing.
You need a monster and expensive power regenerator to power this kind of amplifier. You are much better off getting a class D amp.
 

retro

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Too bad. One of my dream amps of the time...

Seem to recall these amps always dimmed the lights in the room and often blew fuses in the house AC system when turned on.
 

RndmLstner

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For those that aren't into home theater, or were not yet into it in the late 90's and early 2000s, the Sunfire Grand Cinema line of amps was very popular on various online forums and commonly recommended. The alternative output option of the front l/r (current/voltage) was also a highly touted and discussed feature. And they aren't mutually exclusive outs. You can use both outputs in a bi-amp fashion to achieve "warm chocolately mid-range and highs of a tube amp while maintaining the power for controlling bass offered by solid state amps." In short, the audiophile amp for a home theater enthusiast. I guess. :facepalm:

Evidencing the importance of the meter that only moves to show that it's powered on is the fact that the meter is lit by a dimmable bulb. Lol. The bulb in mine died long ago and it's not easily replaced (if at all). So, yes, as you note...a very important meter.

Thanks Amir for a great week of reviews and for rummaging through my equipment /s. First, the Onkyo TX-RZ50, one of which I have in a box soon to get installed once I find time, gets reviewed with acceptable results for use as a pre-pro. Then this review of an amp I've long wondered how it would review (figured not well given one of the written specs) since I've been running a 400w unit since 2004 or 2005.

I've been meaning to replace the Sunfire amp with Benchmark AHB2's for the front l/r and one of the other fine amps you've reviewed for the remaining channels for some time but just havn't pulled the trigger. This review will be the impetus I needed to finally do so. So, thank you.

Interested in testing the 400w version once it's removed from service? ;) There are various versions over the years although Im not sure the underlying mechanisms were changed (they certainly changed the rear layout as my unit is different than the unit tested). How about an Integra 80.2 pre-pro? Maybe others are also curious to see how older pre-pros compare to newer models.
 
Last edited:
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amirm

amirm

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Seem to recall these amps always dimmed the lights in the room and often blew fuses in the house AC system when turned on.
You can hear the transformer groan when you power the unit on. So definitely a lot of in-rush current.
 

respice finem

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...Maybe others are also curious to see how older pre-pros compare to newer models.
Sure, I for one would be interested to see the measurements of this one:
or this one:
but I'm afraid not many are willing to send them "half way around the world" these days...
 
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DanielT

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Thanks Amir.

Here from a DIY page where there is talk of repairing Sunfire Cinema Grand. :)

 

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wwenze

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this amplifier has a DC to DC converter which tracks the incoming music. The higher the input level, the more it will increase its output voltage, thereby keeping the output transistors in their optimal voltage level. Result again is very high efficiency compared to normal class AB design

Fortunately class D quality has come far enough that people started wondering "instead of using a variable supply voltage to power output transistors why not we just output that variable supply voltage"

Very low noise if not for that mains noise tho.
 

fordiebianco

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Looks like I have to start selling my vintage power amplifiers before this becomes more common knowledge.
 

SIY

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@amirm For the "5W" multitone, what is the reference level (i.e., A in dBRA)? Thanks.
 

respice finem

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Again, 25 YO amp that needs factory repair and adjustment.
Nothing to worry about but avoiding old equipment with complicated design.
I'd like to see how good will perform DSP-driven powered monitors in 25 years...
Many will be "stone dead" by then I guess. As long as "standard components" fail, they remain repairable, but if a chip amp fails, and isn't available any more, "adios amigos". Nothing lasts forever... On the other hand, some early ones like the Klein & Hummel O300D (from the last Millennium) are alive and kicking https://reverb.com/item/735478-klein-hummel-o-300-d-active-studio-monitors-pair-used
 

FeddyLost

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On the other hand, some early ones like the Klein & Hummel O300D (from the last Millennium) are alive and kicking
O300D is not DSP-driven by itself, it's just classic analog monitor with extended connectivity and external digital controller option, so, it shall last as long as some another ATC or Quested actives.
 
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