Sunfire Cinema Grand Review (5-channel Amp)

[goob]

I have the 400 watt version, 5 channel version of this amp, can Amir or anyone else please tell me is this Sunfire a digital amplifier with differential outputs? I have a pair of Rythmik subs with speaker level inputs that i want to hook up to this amp. The subs manual warns never to use digital power amp with differential outputs to speaker level inputs.
I want to see if there is a difference in sound between line in input vs. speaker level input, but am hesitant that I will blow something up if I connect the amp to the speaker level inputs of the subs.
I run an OPPO UDP-205 directly to this amp.


Gary

 

[musicforcities]

I had the 2x300w version. The noise was not audible as far as I could tell. Until components td start to drift and then it gets noisy fast. Before class d this thing was pretty great in terms of efficiency, lack of heat and watts per pound. The AC line better be stiff and clean however because this thing wants all 120v and 10amps. There is not enough noise filtering inside it either and the design means mains noise can make its way through the signal as we see in this test. Much of the wiring, including the speaker outs and star ground are extremely close to the sizable el transformer—-which looks shielded but that shield is just thin sheet metal glued to the top of the transformer and as far as I could tell is not connected to any ground so I’m not sure how much shielding it’s doing.

They will all fail in spectacular fashion due to age and cheap components and a build that allows everything to flex far too much.

I stopped using mine when without any signal, it moved my speaker woofers slowly full excursion once about 15 seconds after turn on, and even more slowly returned them to normal position.

 

[airboyd]

I've got two of the 5 channel Cinema Grand Signature models and a Series II Signature Stereo edition for my home theater.

It IS possible to get the joule meter to move but it takes a pretty good peak to do it.

I've done it driving my B&W Matrix 802 S3s.

Vintage amps for vintage gear...I'm still a fan.

 

[musicforcities]

I've got two of the 5 channel Cinema Grand Signature models and a Series II Signature Stereo edition for my home theater.

It IS possible to get the joule meter to move but it takes a pretty good peak to do it.

I've done it driving my B&W Matrix 802 S3s.

Vintage amps for vintage gear...I'm still a fan.

lol. The joule meter is such a bob carver thing; very idiosyncratic bit of uselessness.

I would have preferred he spent the money on a soft start circuit, a trigger input and a front mounted power switch.

Or just better build quality than pcbs floating in air, craptastic el caps, the most poorly wound output inductors I have ever seen held together with zip ties and suspended sideways on the board only by its solder connections which means they will crack in time (parts express inductors are a hundred times better), point to point wiring that makes no sense in terms of noise, rca jacks that don’t break with any tension, and maybe feet that screw on instead of $0.25 adhesive rubber feet.

If he had used a toroidal transformer, the whole thing could have been built in half the height and a standard 17” width, and I bet the noise level would be reduced. The transistors should be mounted on the sides and front rather than the bottom (which makes zero sense thermally, though it barely gets warm). The super thick front does Nothing thermally nor structurally… why would you not use it as a heat sink for the tracking downconverter. And the pcb laid out so one didn’t need long wires to the speaker jacks that run right past the huge el transformer, which is pretty much unsheilded because the thin sheet metal cover on it is just hot glued to the transformer and thus has no path to ground. There is no excuse for the poor layout as thing thing is large, not a tiny thing like the carver m400.

It’s like a science project prototype inside. Not a production unit. The CARVER m500 is built so much more logically, and I think the whole sunfire could fit in a case about that size.

 

[searay_89]

lol. The joule meter is such a bob carver thing; very idiosyncratic bit of uselessness.

I would have preferred he spent the money on a soft start circuit, a trigger input and a front mounted power switch.

Or just better build quality than pcbs floating in air, craptastic el caps, the most poorly wound output inductors I have ever seen held together with zip ties and suspended sideways on the board only by its solder connections which means they will crack in time (parts express inductors are a hundred times better), point to point wiring that makes no sense in terms of noise, rca jacks that don’t break with any tension, and maybe feet that screw on instead of $0.25 adhesive rubber feet.

If he had used a toroidal transformer, the whole thing could have been built in half the height and a standard 17” width, and I bet the noise level would be reduced. The transistors should be mounted on the sides and front rather than the bottom (which makes zero sense thermally, though it barely gets warm). The super thick front does Nothing thermally nor structurally… why would you not use it as a heat sink for the tracking downconverter. And the pcb laid out so one didn’t need long wires to the speaker jacks that run right past the huge el transformer, which is pretty much unsheilded because the thin sheet metal cover on it is just hot glued to the transformer and thus has no path to ground. There is no excuse for the poor layout as thing thing is large, not a tiny thing like the carver m400.

It’s like a science project prototype inside. Not a production unit. The CARVER m500 is built so much more logically, and I think the whole sunfire could fit in a case about that size.

Agree with most if not all of this. I first thought these had toroids until I looked closer. It's a difficult amp to work on. It basically has NO protections and can easily self-destruct. It will yank hard on your pre-amp/receiver if you try to power it down first. All that said - a unit with good caps is quite capable.

I could be wrong but it seems the m500 was co-designed with a Japanese company. It is quite logical in it's layout. It has nasty transients on power-up/down, but the output relays mostly take care of that.

 

[kjasey]

Another in the long line of amps of which at one time I coveted , later to be shown for its true self.

lol! Ive owned this amp for over 10 years. Its amazing for cinema and two channel audio. Its a workhorse and the sound is warm and engaging when using Current source inputs for your left and and rights. I love what Amir does for audio enthusiast but never base his decisions on sound over measurements. Buy this amp if it becomes available. Easily serviceable as well. I never found an amp or receiver that made a johnny cash recording sound as good, compared with this amp! Ive had many amps and receivers
What Amir calls distortion is actually engineered sound improvements implemented in the sound design. If Amir built an amp in his world, it would be perfect electrical current with no distortions. The end result would be a ear piercing sterile sound.

 

[JayGilb]

If Amir built an amp in his world, it would be perfect electrical current with no distortions. The end result would be a ear piercing sterile sound.

You mean an amp that perfectly amplifies the input signal ? That's exactly what I am looking for, I prefer to modify the signal in the preamp stage and let the amp do what it was designed to do.

 

[simbloke]

What Amir calls distortion is actually engineered sound improvements implemented in the sound design. If Amir built an amp in his world, it would be perfect electrical current with no distortions. The end result would be a ear piercing sterile sound.

This has to be just deliberate trolling right?

 

[SIY]

The end result would be a ear piercing sterile sound.

If so, you have a speaker issue to unravel.

 

[wrf]

@amirm This is an old but fascinating review. I've been digging through it. My intent is to try and duplicate the results here using a professionally restored Sunfire Cinema Grand amplifier. But, I have questions.

On the first set of graphs, idling noise is presented with no inputs.
1. Have the inputs been shorted or are they open?
2. The spectral display uses dBrA for the vertical axis. What was used for the 0dB reference point.

 

[wrf]

Still looking for an answer. What was the 0dB reference point for the right hand chart above.

Thanks.